Back contact battery assembly and photovoltaic system

Abstract

The utility model is applicable to the field of photovoltaic technology, and provides a back contact battery assembly and a photovoltaic system, the back contact battery assembly comprises at least one battery string, and the at least one battery string comprises a first battery piece and a second battery piece which are arranged adjacently. The effective light receiving area of the battery assembly can be increased, and the assembly conversion efficiency is improved; the insulating strip is arranged between the bus bar and the first battery piece, the bus bar is used for converging current carriers on the first battery piece through the first extension part and the second extension part, the insulating strip does not need to be holed or discontinuously arranged, the processing and mounting process of the insulating strip is greatly simplified, in addition, the bus bar can be flexibly arranged on the first battery piece, and the cost is reduced. Effective welding position fitting and welding of the first welding strip and the first battery piece are not affected, and the arrangement of the bus bar does not cause insufficient welding of the first welding strip and the first battery piece to affect current collection.

Description

Technical Field

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

[0002] In existing back-contact battery modules, the series busbars between adjacent battery strings are usually placed at the edge of the module, while the parallel busbars between adjacent battery strings are usually placed in the reserved gap area between the two battery strings. This requires a certain amount of space to be reserved at the edge of the battery module to place the series busbars, and a certain amount of space to be reserved between the two parallel battery strings to place the parallel busbars. On the one hand, this reduces the effective light-receiving area of ​​the battery module and affects the module's conversion efficiency; on the other hand, it affects the aesthetics of the module.

[0003] In some products, the busbar is installed in the middle of the back of the battery cell, and an insulating strip is set between the busbar and the battery cell. Although this setting can hide the busbar, it requires the insulating strip to be perforated so that the busbar can contact the same polarity solder strip on the battery cell, while insulating it from the opposite polarity solder strip on the battery cell. This setting requires high precision in the perforation and arrangement of the insulating strip, which is difficult to produce and can easily cause short circuits or poor soldering due to positional misalignment when perforating the insulating strip. Utility Model Content

[0004] This utility model provides a solar cell that aims to solve the problem that the insulating strip needs to be perforated, which requires high precision in both the perforation and the arrangement of the insulating strip, making production difficult and prone to short circuits or poor soldering due to positional misalignment during perforation.

[0005] This utility model is implemented as follows: a back-contact battery assembly includes: at least one battery string, the at least one battery string including a first battery cell and a second battery cell arranged adjacent to each other, the first battery cell being disposed at the end of at least one battery string; a first solder strip disposed on the back surface of the first battery cell; a second solder strip disposed on the back surface of the second battery cell; a busbar disposed on the back surface of the first battery cell; an insulating strip disposed between the busbar and the first battery cell, the insulating strip being used to isolate the first solder strip and the busbar, the insulating strip and the busbar both extending along a second direction, the first direction intersecting the second direction; a first extension portion and a second extension portion disposed opposite to each other on both sides of the busbar in the first direction, the first extension portion extending away from the busbar toward one side and electrically connected to the first solder strip, the second extension portion extending away from the busbar toward the other side and electrically connected to the first solder strip.

[0006] Optionally, the first battery cell and the second battery cell are disposed within the same battery string.

[0007] Optionally, the first battery cell and the second battery cell are respectively disposed in different battery strings.

[0008] Optionally, in the thickness direction of the first battery cell, the first extension portion overlaps with the busbar portion, and / or, the second extension portion overlaps with the busbar portion.

[0009] Optionally, in the thickness direction of the first battery cell, the first extension portion does not overlap with the busbar, and / or, the second extension portion does not overlap with the busbar.

[0010] Optionally, in the first direction, the distance between the busbar and the edge of the second battery cell near the first battery cell is greater than or equal to the projection distance, where the projection distance is the projection length of the first extension portion or the second extension portion on the first battery cell.

[0011] Optionally, the first extension portion includes a first outer extension segment and a first straight segment. The first outer extension segment is connected to one side of the busbar, one end of the first straight segment is connected to the first outer extension segment, and the other end of the first straight segment extends along the first direction. The first straight segment and the solder strip are arranged parallel to each other and are in contact with each other.

[0012] Optionally, the second extension portion includes a second outer extension and a second straight section. The second outer extension is connected to the other side of the busbar. One end of the second straight section is connected to the second outer extension. The other end of the second straight section extends along the first direction. The second straight section and the welding strip are arranged parallel to each other and are in contact with each other.

[0013] Optionally, the back contact battery assembly further includes a third solder strip extending from the first battery cell to the second battery cell along the first direction, the third solder strip connecting the first battery cell and the second battery cell.

[0014] Optionally, on the first solar cell, a plurality of third solder strips and a plurality of first solder strips are alternately arranged at intervals, and on the second solar cell, a plurality of second solder strips and a plurality of third solder strips are alternately arranged at intervals.

[0015] Optionally, the first battery cell and the second battery cell are disposed on the same plane, and the first battery cell and the second battery cell are spaced apart.

[0016] Optionally, the distance between the first battery cell and the second battery cell is greater than or equal to 0 and less than or equal to 3 mm.

[0017] Optionally, in the first direction, the first battery cell and the second battery cell are partially overlapped.

[0018] Optionally, the overlap distance between the first and second solar cells is greater than or equal to 0.1 mm and less than or equal to 1.5 mm.

[0019] Optionally, the insulating strip is an integrally formed strip structure.

[0020] This invention allows the busbar to be concealed on the back surface of the first solar cell, increasing the effective light-receiving area of ​​the battery module, improving the module's conversion efficiency, and avoiding the exposure of the busbar, thus enhancing the overall aesthetics of the battery module. An insulating strip is positioned between the busbar and the first solar cell. The busbar, through its first and second extensions, collects current from the charge carriers on the first solar cell. The insulating strip requires no openings or interrupted arrangement, greatly simplifying its processing and installation. Furthermore, the busbar can be flexibly arranged on the first solar cell without affecting the effective welding position of the first solder strip and the first solar cell. The busbar design prevents insufficient welding between the first solder strip and the first solar cell, thus ensuring proper current collection.

[0021] Secondly, this utility model provides a photovoltaic system, including the aforementioned back-contact battery module. The technical effects of this photovoltaic system are the same as those of the aforementioned back-contact battery module, and will not be repeated here. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the back contact battery assembly provided by the new practical application.

[0023] Figure 2 yes Figure 1 A magnified schematic diagram of the structure at point A;

[0024] Figure 3 This is a structural cross-sectional view of the back contact battery assembly provided in practical applications.

[0025] Explanation of reference numerals in the attached figures:

[0026] 100. Battery string; 101. First battery cell; 102. Second battery cell; 200. First solder strip; 300. Second solder strip; 400. Busbar; 500. Insulating strip; 600. First extension portion; 601. First outer extension segment; 602. First straight segment; 700. Second extension portion; 701. Second outer extension segment; 702. Second straight segment; 800. Third solder strip. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to 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 utility model, and should not be construed as limiting this utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this utility model and are not intended to limit this utility model.

[0028] In the description of this utility model, 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. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.

[0029] 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 utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] In this invention, unless otherwise explicitly 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 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 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.

[0032] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. 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 the invention. 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, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0033] like Figure 1As shown in the embodiment of this utility model, a back-contact battery assembly includes at least one battery string 100. The at least one battery string 100 includes a first battery cell 101 and a second battery cell 102 arranged adjacent to each other. The first battery cell 101 is disposed at the end of the at least one battery string 100. In one embodiment, the first battery cell 101 and the second battery cell 102 are disposed within the same battery string 100. In this case, the first battery cell and the second battery cell can be connected in series. The busbar 400 can then be used for series connection between adjacent battery strings 100 in the second direction. Further, the battery string 100 may include two battery cells connected in series, three battery cells connected in series, or other numbers of battery cells. The specific number of battery cells to be connected in series can be determined according to the actual usage. This utility model does not impose any limitations on this. For ease of explanation, in this embodiment, the end where the first battery cell 101 is located is referred to as the tail end of the battery string 100. That is, in the first direction, the first battery cell 101 is the last battery cell of the battery string 100, and the second battery cell 102 is the penultimate battery cell of the battery string 100. It is easy to understand that the end where the first battery cell 101 is located can also be referred to as the head end of the battery string 100, in which case the second battery cell 102 is the second positive battery cell of the battery string 100. This will not be elaborated further here. In addition, the grid lines on the battery cells are not shown in the accompanying drawings. The grid lines on the battery cells can be arranged according to the actual situation. For example, it can be a battery cell with a main grid or a battery cell without a main grid.

[0034] In another embodiment, the first battery cell and the second battery cell are respectively disposed in different battery strings 100. In this case, the first battery cell 101 and the second battery cell 102 can be connected in parallel. The first battery cell 101 and the second battery cell 102 are respectively located at the ends of different battery strings. The busbar 400 can be used for parallel connection between adjacent battery strings 100 in the first direction. In this case, the busbar is equivalent to the intermediate busbar in the battery assembly.

[0035] like Figure 3As shown, in some embodiments, a first solder strip 200 is disposed on the backlight surface of the first battery cell 101, a second solder strip 300 is disposed on the backlight surface of the second battery cell 102, a busbar 400 is disposed on the backlight surface of the first battery cell 101, and an insulating strip 500 is disposed between the busbar 400 and the first battery cell 101. The insulating strip 500 is used to isolate the first solder strip 200 and the busbar 400. Both the insulating strip 500 and the busbar 400 extend along a second direction, and the first direction and the second direction are intersected. Firstly, in this embodiment of the present invention, the busbar 400 is disposed on the first battery cell 101, and the busbar 400 and the first battery cell 101 are separated by an insulating strip 500. On the one hand, the edge of the back contact battery assembly no longer needs to reserve space for placing the busbar, and the battery assembly can reserve more space to install the battery cell, so that the effective light-receiving area of ​​the battery assembly is larger and the conversion efficiency of the assembly is higher. On the other hand, when viewed from the light-receiving surface (or "front") of the battery cell, the insulating strip 500 can block the busbar 400, preventing the busbar 400 from being exposed, and the overall aesthetics of the battery assembly are better.

[0036] In this embodiment of the utility model, the first direction is the horizontal direction, which is also the width direction of the battery cell 100, and the second direction is the vertical direction, which is also the length direction of the battery cell 100. The first direction and the second direction are perpendicular to each other.

[0037] In one possible embodiment, the insulating strip 500 does not require holes. The insulating strip 500 is a single, integrally formed strip structure that isolates all the first weld strips 200 from the busbar 400, thus simplifying the processing and installation of the insulating strip 500. During assembly, the insulating strip 500 can simply be placed on the first battery cell 101, effectively reducing production precision requirements and manufacturing difficulty. This also avoids short circuits caused by positional misalignment when holes are made in the insulating strip, increasing product yield.

[0038] As another possible embodiment, a portion of the first solder strip on the first battery cell is electrically connected to the busbar through a first extension and a second extension, and a portion of the first solder strip is electrically connected to the busbar by punching holes in the insulating strip. This solution is also within the scope of protection of the claims of this utility model.

[0039] In one embodiment, in the first direction, the distance of the busbar relative to the edge of the second cell near the first cell is greater than or equal to the projected distance, which is the projected length of the first or second extension portion on the first cell, thereby reserving sufficient space for the arrangement of the first or second extension portion. Preferably, the busbar 400 is disposed in the central region of the first cell 101. Specifically, the central region can be the middle part of the first cell away from the edge, and the area of ​​the central region is at least 2 / 3 of the surface area of ​​the first cell. Compared to the method of disposing the busbar at the edge of the first cell, this structural arrangement can effectively reduce the risk of microcracks at the edge of the first cell during lamination and improve the yield of the battery module.

[0040] like Figure 2 As shown, a first extension portion 600 and a second extension portion 700 are disposed opposite to each other on both sides of the busbar 400 in a first direction. The materials of the first extension portion 600 and the second extension portion 700 can be the same as those of the busbar 400, such as tin-plated copper busbar 400, conductive copper foil or aluminum-based copper strip. This facilitates the integral processing of the first extension portion 600, the second extension portion 700 and the busbar 400, resulting in greater structural strength and reducing defects such as edge burrs. The first extension portion 600 extends away from the busbar 400 and towards one side, and is electrically connected to the first solder strip 200. The second extension portion 700 extends away from the busbar 400 and towards the other side, and is electrically connected to the first solder strip 200. The busbar 400 is electrically connected to the first solder strip 200 through the first extension portion 600 and the second extension portion 700. For example, the first extension portion 600 and the second extension portion 700 are symmetrically arranged on both sides of the busbar 400. The width of the first extension portion can be the same as the width of the first solder strip, or it can be different from the width of the first solder strip. The width of the second extension portion can be the same as the width of the first solder strip, or it can be different from the width of the first solder strip. It can be set according to requirements. The busbar 400 is electrically connected to the first extension portion 600 and the second extension portion 700 and the first solder strip 200 respectively. This ensures a more stable electrical connection between the busbar 400 and the first solder strip 200, improves the carrier transmission efficiency, and reduces carrier transmission loss.

[0041] Furthermore, the first extension portion 600 and the second extension portion 700 are electrically connected to the same first solder strip 200. This reduces the transmission resistance between the busbar 400 and the first solder strip 200, reduces the current carrying capacity loss, and by increasing the connection point between the busbar 400 and the first solder strip 200 (i.e., the first extension portion 600 and the second extension portion 700 are both connected to the same solder strip 200), the connection stability between the busbar and the first solar cell can be enhanced, reducing the risk of the busbar detaching or being damaged due to external forces. Even if one of the first extension portion 600 and the second extension portion 700 has a poor solder joint or detachment from the first solder strip 200, the other of the first extension portion 600 and the second extension portion 700 can still ensure the electrical connection between the busbar 400 and the first solder strip 200, resulting in a high module fault tolerance rate.

[0042] In one embodiment, in the thickness direction of the first battery cell 101, the first extension portion 600 does not overlap with the busbar 400, and / or the second extension portion 700 does not overlap with the busbar 400. This effectively reduces the stacking height between the busbar and the first or second extension portion, thereby reducing the risk of microcracks in the battery cell during the lamination process. For example, the first extension portion 600, the second extension portion 700, and the busbar 400 can be integrally stamped from sheet metal. In another embodiment, in the thickness direction of the first battery cell 101, the first extension portion 700 partially overlaps with the busbar 400, and / or the second extension portion 600 partially overlaps with the busbar 400. This allows the busbar 400, the first extension portion 600, and the second extension portion 700 to be processed independently, and then welded together, effectively reducing the processing and assembly difficulty of the busbar, the first extension portion, and the second extension portion. Preferably, the first extension portion 600, the second extension portion 700 and the busbar 400 are integrally stamped, eliminating redundant processes such as welding during the splicing process, reducing labor costs, and avoiding phenomena such as incomplete welding and burrs caused by manual welding during the welding process.

[0043] For example, the insulating strip 500 can be an insulating adhesive, or a non-conductive tape or insulating film, 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 strip 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.

[0044] It should be noted that the thickness of the insulating strip 500 cannot be too thick or too thin. If the insulating strip 500 is too thin, it is inconvenient to apply, easily deformed by pulling, and may break over long-term insulation. If it is too thick, it will increase the height difference, generate greater stress during lamination, easily cause fragmentation, and increase the risk of poor soldering. Based on this, in this embodiment of the utility model, the thickness of the insulating strip 500 can be set between 0.05 mm and 0.8 mm. In this way, the insulating strip 500 is neither too thin nor too thick. For example, the thickness of the insulating strip 500 can be 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm.

[0045] The width of the insulating strip 500 is greater than or equal to the width of the busbar 400. If the width of the insulating strip 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 dissimilar electrode area or the dissimilar solder strip 300.

[0046] Understandably, multiple first extension portions 600 and multiple second extension portions 700 are arranged one-to-one on both sides of the busbar. The multiple first extension portions 600 are spaced apart in the second direction, the multiple second extension portions 700 are spaced apart in the second direction, and multiple first solder strips 200 are spaced apart on the first battery cell 101. The multiple first solder strips 200 have different polarities, and the multiple first extension portions 600 and multiple second extension portions 700 are all connected to the first solder strip of the same polarity to realize the collection of charge carriers of the first battery cell.

[0047] Furthermore, there are multiple first solder ribbons 200, which are spaced apart along the second direction on the backlight surface of the first battery cell 101. There are also multiple second solder ribbons 300, which are spaced apart along the second direction on the backlight surface of the second battery cell 102. The multiple first solder ribbons 200 and the multiple second solder ribbons 300 are arranged in a one-to-one correspondence.

[0048] The back-contact battery assembly also includes a third solder ribbon 800, which extends from the first battery cell 101 to the second battery cell 102 along a first direction, connecting the first battery cell 101 and the second battery cell 102. Specifically, a portion of the third solder ribbon 800 is disposed on the first battery cell 101, and another portion of the third solder ribbon 800 is disposed on the second battery cell 102. Exemplarily, the third solder ribbon 800 can be used to achieve a series connection between the first battery cell 101 and the second battery cell 102. Understandably, the first solder ribbon 200 and the third solder ribbon 800 are disposed on a portion of the first battery cell without overlapping, and the second solder ribbon 300 and another portion of the third solder ribbon 800 on the second battery cell 102 are disposed without overlapping. Further, the portion of the third solder ribbon 800 on the first battery cell 101 is isolated by an insulating strip 500 and a busbar 400. In this embodiment of the present invention, multiple third solder ribbons 800 and multiple first solder ribbons 200 are alternately arranged on the first battery cell 101, and multiple second solder ribbons 300 and multiple third solder ribbons 800 are alternately arranged on the second battery cell 102. The alternating arrangement of multiple solder ribbons on the battery cell can form more current transmission paths, thereby improving the current transmission capability of the battery module and achieving a uniform distribution of current on the battery cell.

[0049] like Figure 3 As shown, in some embodiments, the first extension portion 600 includes a first outer extension 601 and a first straight section 602. The first outer extension 601 is connected to one side of the busbar 400, one end of the first straight section 602 is connected to the first outer extension 601, and the other end of the first straight section 602 extends along a first direction. The first straight section 602 and the first solder strip 200 are arranged parallel to each other and are in close contact. In particular, the first straight section 602 and the first solder strip 200 are arranged in parallel and fit together, allowing the first straight section 602 to have close surface-to-surface contact with the first solder strip 200, reducing quality problems such as incomplete soldering and over-soldering during the welding process, and improving the stability and reliability of the welding. The first extension segment 601 is used to connect the busbar 400 and the first straight segment 602. Since there is a height difference between the busbar 400 and the first straight segment 602 in the thickness direction of the battery cell 100, the first extension segment 601 can be a bent structure to achieve the connection between the busbar 400 and the first straight segment 602 at different height positions. The specific bending form of the first extension segment 601 is not limited in this utility model.

[0050] In some embodiments, the second extension portion 700 includes a second outer extension 701 and a second straight section 702. The second outer extension 701 is connected to the other side of the busbar 400. One end of the second straight section 702 is connected to the second outer extension 701, and the other end of the second straight section 702 extends along a first direction. The second straight section 702 and the first solder strip 200 are arranged parallel to each other and are in close contact. In particular, the second straight section 702 is arranged in parallel with the first solder strip 200, and the second straight section 702 can make close contact with the surface of the first solder strip 200, reducing quality problems such as incomplete soldering and over-soldering during the welding process, and improving the stability and reliability of the welding. The second extension segment 701 is used to connect the busbar 400 and the second straight segment 702. Since there is a height difference between the busbar 400 and the second straight segment 702 in the thickness direction of the battery cell 100, the second extension segment 701 can be a bent structure to achieve the connection between the busbar 400 and the second straight segment 702 at different height positions. The specific bending form of the second extension segment 701 is not limited in this utility model.

[0051] Understandably, in other embodiments, the busbar 400 may also be electrically connected to the first solder strip 200 through one of the first extension portion 600 and the second extension portion 700. The connection structure between the busbar 400 and the first extension portion 600 or the second extension portion 700 is the same as described above and will not be repeated here.

[0052] In some embodiments, the first battery cell 101 and the second battery cell 102 are disposed on the same plane, and the first battery cell 101 and the second battery cell 102 are spaced apart. This provides a buffer space between the battery cells, preventing them from contacting each other and being damaged when the battery assembly is subjected to external forces.

[0053] Specifically, the spacing between the first battery cell 101 and the second battery cell 102 is greater than or equal to 0 and less than or equal to 3 mm. In this embodiment, the spacing between the first battery cell 101 and the second battery cell 102 can be any value between 0 mm, 1 mm, 2 mm, 3 mm, or 0-3 mm, and is not limited here. Within this range, while reducing the risk of battery cell merging, it also prevents the overall length of the battery string 100 from becoming too long, thus improving the stability of the connection between adjacent battery cells.

[0054] In some embodiments, in a first direction, the first battery cell 101 and the second battery cell 102 are partially overlapped. The contact areas between these overlaps are not electrically connected; that is, no conductive adhesive or other bonding agent is needed between the overlapping areas. The battery cells are simply overlapped. Thus, there is no gap between the first battery cell 101 and the second battery cell 102, which better conceals the series solder ribbons. There is no need to provide a shielding insulating layer between the battery cells to hide the series solder ribbons, thereby reducing the use of shielding insulating layers, lowering production costs, and simplifying rework. Furthermore, the overlapping arrangement of the battery cells allows for a smaller size of the battery string 100, resulting in a smaller footprint. In other words, with a fixed size for the battery string 100, more battery cells can be placed, increasing the power of the battery string 100 and reducing the cost per watt. Preferably, the partial overlap distance between the first battery cell 101 and the second battery cell 102 is greater than or equal to 0.1 mm and less than or equal to 1.5 mm. For example, the overlap width can be 0.1 mm, 0.2 mm, 0.4 mm, 0.5 mm, 1 mm or 1.5 mm, and this utility model does not limit it.

[0055] A photovoltaic (PV) system includes the back-contact battery module as described above. It is understood that the PV power generation system includes at least one back-contact battery module as described above, and that the back-contact battery modules can be electrically connected in parallel or in series, depending on actual needs. In this embodiment, the PV system can be applied in PV 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 for power generation, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the PV system are not limited to these; that is, the PV system can be applied in all fields that require solar energy for power generation. Taking a PV power generation system grid as an example, the PV system may include a PV array, a combiner box, and an inverter. The PV array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple PV arrays. The PV array is connected to the combiner box, which can collect the current generated by the PV array. The collected current flows through the inverter and is converted into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0056] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0057] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A back contact cell assembly, characterized by, The back contact battery assembly comprises: at least one battery string, at least one of the battery strings comprising a first battery sheet and a second battery sheet arranged adjacently, the first battery sheet being arranged at an end of the at least one battery string; a first solder strip arranged on a back surface of the first battery sheet; a second solder strip arranged on a back surface of the second battery sheet; a busbar arranged on the back surface of the first battery sheet; an insulating strip arranged between the busbar and the first battery sheet, the insulating strip being used to insulate the first solder strip and the busbar, the insulating strip and the busbar being arranged in a second direction, a first direction being arranged transversely to the second direction; a first extension portion and a second extension portion being arranged on opposite sides of the busbar in the first direction, the first extension portion extending away from the busbar towards one side and being electrically connected to the first solder strip, the second extension portion extending away from the busbar towards the other side and being electrically connected to the first solder strip.

2. The back contact solar cell assembly of claim 1, wherein, The first battery sheet and the second battery sheet are arranged in the same battery string.

3. The back contact solar cell assembly of claim 1, wherein, The first battery sheet and the second battery sheet are arranged in different battery strings respectively.

4. The back contact solar cell assembly of claim 1, wherein, In a thickness direction of the first battery sheet, the first extension portion overlaps the busbar, and / or the second extension portion overlaps the busbar.

5. The back contact solar cell assembly of claim 1, wherein, In the thickness direction of the first battery sheet, the first extension portion does not overlap the busbar, and / or the second extension portion does not overlap the busbar.

6. The back contact solar cell assembly of claim 1, wherein, In the first direction, the busbar is closer to an edge of the first battery sheet relative to the second battery sheet by a distance greater than or equal to a projection distance, the projection distance being a projection length of the first extension portion or the second extension portion on the first battery sheet.

7. The back contact solar cell assembly of claim 1 wherein, The first extension portion comprises a first extension segment and a first flat segment, the first extension segment being connected to one side of the busbar, one end of the first flat segment being connected to the first extension segment, the other end of the first flat segment extending along the first direction, the first flat segment being arranged parallel to and abutting the first solder strip.

8. The back contact solar cell assembly of claim 1 wherein, The second extension portion comprises a second extension segment and a second flat segment, the second extension segment being connected to the other side of the busbar, one end of the second flat segment being connected to the second extension segment, the other end of the second flat segment extending along the first direction, the second flat segment being arranged parallel to and abutting the first solder strip.

9. The back contact solar cell assembly of claim 1 wherein, The back contact battery assembly further comprises a third solder strip, the third solder strip extending from the first battery sheet to the second battery sheet in the first direction, the third solder strip connecting the first battery sheet and the second battery sheet.

10. The back contact solar cell assembly of claim 9, wherein the back contact solar cell assembly is a back contact solar cell module. On the first battery sheet, a plurality of the third solder strips and a plurality of the first solder strips are arranged alternately and at intervals, on the second battery sheet, a plurality of the second solder strips and a plurality of the third solder strips are arranged alternately and at intervals.

11. The back contact solar cell assembly of claim 1 wherein, The first battery sheet and the second battery sheet are arranged on the same plane, and the first battery sheet and the second battery sheet are arranged at intervals.

12. The back contact solar cell assembly of claim 11, wherein, The interval distance between the first cell piece and the second cell piece is greater than or equal to 0 and less than or equal to 3 mm.

13. The back contact solar cell assembly of claim 1 wherein, In the first direction, the first cell piece and the second cell piece are arranged partially overlapped.

14. The back contact solar cell assembly of claim 13, wherein, The partially overlapped distance between the first cell piece and the second cell piece is greater than or equal to 0.1 mm and less than or equal to 1.5 mm.

15. The back contact solar cell assembly of claim 1 wherein, The insulation strip is an integrally formed strip structure.

16. A photovoltaic system characterized by, A back contact cell assembly comprising any of the features of claims 1-15.

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