Battery modules and photovoltaic systems

Abstract

This application relates to the field of photovoltaic technology and provides a battery module and photovoltaic system, including a battery string. The battery string includes at least a first battery cell and a second battery cell arranged sequentially along a first direction. The first battery cell and the second battery cell partially overlap to form a first overlapping region. The width of the first overlapping region in the first direction is a first distance. Adjacent nth battery cells and n+1th battery cells have a second overlapping region. The maximum width of multiple second overlapping regions in the first direction is a second distance. The first distance is greater than the second distance, where n≥2 and n is a positive integer. In this application, the first distance is set to be greater than the second distance to specifically optimize the problem of excessive offset of battery cells in the edge region of the battery string. By making a small-scale modification to the structure of the battery module, the yield of the battery module and the photoelectric conversion efficiency are improved.

Description

Technical Field

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

[0002] In related technologies, solar cells are stacked and connected into strings by solder ribbons. These strings are then laminated into modules after being arranged in series and parallel. This allows for more solar cells to be placed within a limited area, improving space utilization and module power generation. However, during the lamination process, the flow of the molten adhesive film can cause cell misalignment, leading to adjacent cells separating. This is especially true for cells located at the module's edges, where the pressure is higher during lamination. With the addition of busbars, the increased stress concentration due to the larger number of layers intensifies the compression of the adhesive film, resulting in greater cell misalignment / rotation. Excessive misalignment can cause noticeable light leakage at the edge of the cell string, leading to decreased photoelectric conversion efficiency and poor appearance of the module. Utility Model Content

[0003] This application provides a battery module designed to address the issue that cell misalignment is more pronounced in the edge region of the module. When the misalignment is too large, significant light leakage occurs in the edge region of the cell string, resulting in decreased photoelectric conversion efficiency and poor appearance of the battery module.

[0004] In a first aspect, this application provides a battery assembly, including a battery string, the battery string including at least a first battery cell and a second battery cell arranged sequentially along a first direction, the first battery cell being disposed at the end of the battery string; the first battery cell and the second battery cell partially overlap to form a first overlapping region, the width of the first overlapping region in the first direction being a first distance; further including an nth battery cell and an (n+1)th battery cell arranged sequentially overlapping along the first direction, adjacent nth battery cells and (n+1)th battery cells having a second overlapping region, the maximum width of the plurality of second overlapping regions in the first direction being a second distance, the first distance being greater than the second distance, wherein n≥2, and n is a positive integer.

[0005] Optionally, a plurality of the second overlapping regions are equidistantly arranged in the first direction.

[0006] Optionally, the plurality of second overlapping regions are not equidistant from each other in the first direction.

[0007] Optionally, a portion of the second overlapping region has a width in the first direction that is greater than the width of another portion of the second overlapping region in the first direction.

[0008] Optionally, the battery assembly includes a busbar assembly disposed at the edge of the second battery cell near the first battery cell.

[0009] Optionally, the busbar assembly includes an insulating strip and a busbar sequentially stacked on the second battery cell. Both the insulating strip and the busbar extend along a second direction, and the insulating strip is a single strip structure.

[0010] Optionally, the battery assembly includes a busbar assembly disposed on the first battery cell.

[0011] Optionally, the busbar assembly includes an insulating strip and a busbar sequentially stacked on the first battery cell, both the insulating strip and the busbar extending along a second direction, and the insulating strip having an exposed area.

[0012] Optionally, in the first direction, the width of the insulating strip is greater than the width of the busbar.

[0013] Optionally, the first distance ranges from 0.3 to 3.5 mm.

[0014] Optionally, the second distance ranges from 0.1 to 3 mm.

[0015] Optionally, the area ratio of the first overlapping region to the second overlapping region is 1 to 35.

[0016] Optionally, the first overlapping area accounts for 0.2% to 3.8% of the area of ​​the first or second battery cell.

[0017] Optionally, the second overlapping region accounts for 0.1% to 3.2% of the area of ​​the nth or (n+1)th solar cell.

[0018] Optionally, the battery assembly further includes a first solder strip disposed on the first battery cell and a second solder strip disposed on the second battery cell. Both the first solder strip and the second solder strip extend along the first direction. The first solder strip is electrically connected to the busbar, and the second solder strip is insulated from the busbar.

[0019] Optionally, the 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, and the insulating strip isolating the third solder strip from the busbar.

[0020] Optionally, the battery assembly includes at least two sets of battery strings arranged along the second direction, wherein the insulating strip extends from one of the two sets of battery strings to the other of the two sets of battery strings along the second direction.

[0021] This application forms a first overlapping region by partially overlapping the first and second battery cells. The width of the first overlapping region in the first direction is a first distance, thereby preventing the first and second battery cells from misaligning and separating during the lamination process. Adjacent nth and n+1th battery cells have a second overlapping region, where n≥2 and n is a positive integer. The maximum width of multiple second overlapping regions in the first direction is a second distance, thereby preventing the nth and n+1th battery cells from misaligning and shifting during the lamination process. Furthermore, in this application, the first distance is set to be greater than the second distance, specifically optimizing the problem of excessive offset of battery cells in the edge region of the battery string. By making a small-scale modification to the structure of the battery module, the yield of the battery module and the photoelectric conversion efficiency are improved.

[0022] Secondly, this application provides a photovoltaic system including the battery module described in the first aspect. The technical effects of this application are the same as those of the battery module described above, and will not be repeated here. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of the first type of battery assembly provided in the current application;

[0024] Figure 2 This is a structural schematic diagram of the second type of battery assembly provided in the current application;

[0025] Figure 3 This is a structural schematic diagram of the third type of battery assembly provided in the current application;

[0026] Figure 4 This is a structural schematic diagram of the fourth type of battery assembly provided in the current application;

[0027] Figure 5 This is a partial structural diagram of the fourth type of battery module provided in the current application;

[0028] Figure 6 This is a structural schematic diagram of the fifth type of battery assembly provided in the current application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 100. Battery string; 101. First battery cell; 102. Second battery cell; 103. First overlapping area; 104. Second overlapping area; 105. First solder strip; 106. Second solder strip; 107. Third solder strip; 200. Busbar assembly; 201. Insulating strip; 202. Busbar; 203. Exposed area; 204. Insulating block. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] like Figures 1-5 As shown in the embodiments of this application, a battery assembly includes a battery string 100, which includes at least a first battery cell 101 and a second battery cell 102 arranged sequentially along a first direction. It is understood that the battery string 100 may include two battery cells connected in series, three battery cells connected in series, or a greater number of battery cells. The specific number of battery cells to be connected in series can be determined according to the actual usage, and this application does not impose any limitations on this. Furthermore, the grid lines on the battery cells are not shown in the figures. The grid lines on the battery cells can be arranged according to the actual situation; for example, they can be battery cells with main grids or battery cells without main grids.

[0038] Understandably, solar cells can be made of semiconductor materials, such as P-type / N-type silicon wafers, which form a PN junction after phosphorus diffusion. When the semiconductor structure absorbs sunlight, it generates electron-hole pairs. These pairs are separated by the built-in electric field of the PN junction within the semiconductor; electrons flow into the N-region, and holes flow into the P-region, thus forming a photogenerated electric field. Typically, a solar cell has a sheet-like structure. The side that absorbs light energy and converts it into electrical energy is called the light-absorbing side or front side, and the other side is called the back side. A solar cell with electrodes of both polarities on the back side is a back-contact cell, and a solar cell with electrodes of both polarities on the front and back sides respectively is a bifacial cell. In this embodiment, when the solar cell is installed normally, the side facing upwards is called the front side, and the side opposite the front side is called the back side. Preferably, each solar cell includes a positive electrode region and a negative electrode region on the back side of the cell. Each of the positive and negative electrode regions has solder ribbons connected to a fine grid, allowing the current in the fine grid to be conducted through the solder ribbons.

[0039] Each solar cell is essentially rectangular, but this can be a square or another type of rectangle, and can have standard corners, cut corners, or rounded corners, depending on actual production needs. The specific design is not limited here. The number of positive and negative electrode regions is determined by the actual size of the solar cell, and the width and distance between the positive and negative grid lines, and is not specifically limited here. The grid lines can be screen-printed onto the back of the solar cell, and the solder ribbons can be laminated into the positive and negative electrode regions to form an electrical connection with the grid lines, thus guiding the current.

[0040] Furthermore, the first battery cell 101 is located at the end of the battery string 100. 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.

[0041] The battery assembly includes at least two sets of battery strings 100 arranged along a second direction. It should be noted that when the first battery cell 101 is located at the head end of the battery string 100, the bus bar 202 can be used for series connection between adjacent battery strings 100 in the first direction. At this time, the bus bar 202 is equivalent to the end bus bar in the battery assembly. When the first battery cell 101 is located at the tail end of the battery string 100, the bus bar 202 can be used for parallel connection between adjacent battery strings 100 in the first direction. At this time, the bus bar 202 is equivalent to the middle bus bar in the battery assembly.

[0042] The first battery cell 101 and the second battery cell 102 are partially overlapped to form a first overlapping region 103. The width of the first overlapping region 103 in the first direction is a first distance. The battery assembly includes an nth battery cell and an (n+1)th battery cell arranged in a sequentially overlapping manner along the first direction. Adjacent nth and (n+1)th battery cells have a second overlapping region 104, where n ≥ 2 and n is a positive integer. The maximum width of the plurality of second overlapping regions 104 in the first direction is a second distance. That is, in the battery string 100, the overlapping region closest to the end of the battery string 100 is defined as the first overlapping region 103, and the overlapping regions between the remaining battery cells in the battery string 100 are defined as the second overlapping regions 104. For example, if the battery string 100 is composed of 5 battery cells connected in series, then the overlapping region between the first and second cells is the first overlapping region 103, while the subsequent overlapping regions (such as between the second and third cells, between the third and fourth cells, and between the fourth and fifth cells) are the second overlapping regions 104. The multiple second overlapping regions can be equal or unequal, and the maximum width of the multiple second overlapping regions 104 is less than the width of the first overlapping region 103. The first overlapping region 103 is located at the beginning of the battery string 100, and its design differs from that of the second overlapping regions 104. That is, the first distance is greater than the second distance. The first overlapping region 103 adopts a wider stacking structure design (such as trapezoidal overlap) compared to the second overlapping region 104 to enhance the anti-peeling ability of the battery cells at the end of the battery string 100, avoid battery cell misalignment and separation after lamination, resulting in poor appearance of the battery assembly, and enhance stacking stability. In other embodiments, the first overlapping region 103 can also be set at the end of the battery string 100. That is, the overlapping area formed by the penultimate battery cell and the penultimate battery cell of the battery string 100 is designed as the first overlapping region 103. In this way, the first overlapping region 103 is set at both the beginning and end of the battery string 100, further improving the anti-peeling ability of both ends of the battery string 100.

[0043] In some embodiments, the overlapping area between every two battery cells located between the head and tail ends of the battery string 100 is a second overlapping area 104. The width of the first overlapping area 103 is greater than the width of the second overlapping area 104. For example, if the battery string 100 is composed of five battery cells connected in series, the overlapping area between the first and second cells is the first overlapping area 103 at the head end, the overlapping area between the fourth and fifth cells is the first overlapping area 103 at the tail end, and subsequent overlapping areas (such as between the second and third cells, and between the third and fourth cells) are the second overlapping areas 104. In this case, the width of the multiple second overlapping areas 104 gradually narrows along the direction close to the first overlapping area 103 and away from the first overlapping area 103. For example, the first second overlapping area 104 is formed between the second and third cells, and the second second overlapping area 104 is formed between the third and fourth cells. The maximum width of the first second overlapping area 104 in the first direction is greater than the maximum width of the second second overlapping area 104 in the first direction. In other embodiments, the maximum width of the first second overlapping region 104 in the first direction may also be equal to the maximum width of the second second overlapping region 104 in the first direction. In this case, the maximum widths of the first second overlapping region 104 and the second second overlapping region 104 in the first direction are both less than the widths of the first overlapping region 103 at the head end and the tail end in the first direction.

[0044] In some embodiments, if the battery string 100 is composed of multiple battery cells connected in series, the overlapping area between the first and second cells is the first overlapping area 103, and subsequent overlapping areas (such as between the second and third cells, between the third and fourth cells, between the fourth and fifth cells, between the fifth and sixth cells, etc.) are the second overlapping areas 104 (in this case, the first overlapping area 103 can also be formed at the tail end of the battery string 100). When multiple second overlapping areas 104 are included, the overlapping area near the first and second cells is the first overlapping area 103, and the multiple second overlapping areas 104 sequentially along the first direction can be the first second overlapping area 104, the second second overlapping area 104, the third second overlapping area 104, the fourth second overlapping area 104, the fifth second overlapping area 104, etc. When the width of the first overlapping region 103 in the first direction is a first distance, the first distance ranges from 0.3 to 3.5 mm, and the width of the plurality of second overlapping regions 104 in the first direction is a second distance, the second distance ranges from 0.1 to 3 mm, for example, when the first distance is set to 2.5 mm, the width of the first second overlapping region 104 in the first direction can be set to 1.5 mm, the second overlapping region 104 can be set to 1.4 mm, the third overlapping region can be set to 1.3 mm, and the remaining second overlapping regions 104 can all be set to 1.3 mm. In some embodiments, the width of the plurality of second overlapping regions 104 in the first direction can also be set to 1.5 mm, 1.4 mm, etc., or can be set to any value from 0.1 to 3 mm. This application does not limit this.

[0045] In some embodiments, exemplarily, the solar cells are back-contact solar cells, and in a first direction, the first solar cell 101 and the second solar cell 102 are partially overlapped. The contact area between the overlaps is not electrically connected; that is, no conductive adhesive or other bonding agent is needed between the first overlapping areas 103. The solar cells are simply overlapped. Thus, there is no gap between the first solar cell 101 and the second solar cell 102, which better conceals the series solder ribbons. There is no need to provide a shielding insulating layer between the solar 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 solar cells allows for a smaller size of the solar cell string 100, resulting in a smaller footprint. In other words, with a fixed size for the solar cell string 100, more solar cells can be placed, increasing the power output of the solar cell string 100 and reducing the cost per watt. Preferably, the partial overlap distance between the first solar cell 101 and the second solar cell 102 is greater than or equal to 0.3 mm and less than or equal to 3.5 mm. For example, the width of the first overlapping area 103 can be any value between 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 3.5 mm, or 0.3 mm to 3.5 mm, and this application does not impose any limitation on it.

[0046] Understandably, the nth and (n+1)th battery cells have a second overlapping region 104 between adjacent nth and (n+1)th battery cells, where n ≥ 2 and n is a positive integer. No conductive adhesive or other bonding agent is needed between the second overlapping regions 104; the nth and (n+1)th battery cells simply overlap. This allows for better concealment of the series solder strips, reducing the size of the battery string 100 and thus reducing its space requirements. With a fixed size, more battery cells can be placed in the battery string 100, increasing its power output. Preferably, the width of the second overlapping region 104 is any value between 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or 0.1 mm to 3 mm; this application does not impose any limitation on this value.

[0047] Furthermore, multiple second overlapping regions 104 are equidistantly arranged in the first direction. That is, each of the multiple second overlapping regions 104 has an equal width, and the uniformly distributed second overlapping regions 104 form a periodic support structure, enhancing the bending and torsion resistance of the battery string 100. The equidistant second overlapping regions 104 allow the current to flow uniformly in the longitudinal direction (first direction) of the battery string 100, reducing current congestion or hot spot effects caused by local resistance differences. In addition, the width design of the equidistant second overlapping regions 104 simplifies the programming of automated equipment and improves production efficiency. Moreover, the equidistant arrangement of the second overlapping regions 104 can improve the visual consistency of the battery string 100, meeting the aesthetic requirements of specific application scenarios (such as building-integrated photovoltaics).

[0048] In some embodiments, a plurality of second overlapping regions 104 are unequally spaced in a first direction. That is, the width of the plurality of second overlapping regions 104 can be such that some overlapping regions are unequally spaced while the remaining overlapping regions are unequally spaced, or all overlapping regions are unequally spaced. Preferably, in the embodiments of this application, the width of some of the second overlapping regions 104 in the first direction is greater than the width of another portion of the second overlapping regions 104 in the first direction. This allows for flexible design of the width of the second overlapping regions 104, using narrower overlaps in low-stress, low-risk areas (such as uniform sections inside the battery string 100) and wider overlaps in critical areas (such as near component edges or connection points) to ensure stacking stability.

[0049] In some embodiments, exemplarily, the solar cell can also be a bifacial solar cell. In the cell string 100, one side of the solar cell is placed below an adjacent solar cell, such that the electrode on the front of one solar cell overlaps with the electrode on the back of another solar cell. A conductive connection is formed between the two electrodes using a conductive material. The conductive material between the solar cell electrodes includes conductive adhesive, solder ribbon, or solder paste, etc. An appropriate preparation method should be selected based on the characteristics of the conductive material. For conductive adhesive materials, dispensing or screen printing methods can be used for preparation. The stacked design structure of the bifacial solar cell is the same as the stacked structure of the back-contact solar cell described above, and will not be repeated here.

[0050] like Figure 1 and Figure 3As shown, in some embodiments, the battery assembly includes a busbar assembly 200, which is disposed on the edge of the second battery cell 102 near the first battery cell 101. Further, the busbar assembly 200 includes an insulating strip 201 and a busbar 202 sequentially stacked on the second battery cell 102. Both the insulating strip 201 and the busbar 202 extend along a second direction, and the insulating strip 201 is a single strip structure. First, in this embodiment, the busbar 202 is disposed on the second battery cell 102, and the busbar 202 and the second battery cell 102 are separated by an insulating strip 201. On the one hand, the edge of the back contact battery assembly does not need to reserve space for placing the busbar 202, 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 battery cell 102 can block the busbar 202, preventing the busbar 202 from being exposed, and the overall aesthetics of the battery assembly are better.

[0051] In this embodiment, the busbar 202 is disposed on the backlight surface of the second battery cell 102. The solder ribbon on the first battery cell 101 can fully adhere to and weld with the effective welding position of the first battery cell 101, avoiding insufficient welding between the solder ribbon and the first battery cell 101 due to the installation of the busbar 202, which would affect the current collection. At the same time, after the solder ribbon on the first battery cell 101 is welded to the first battery cell 101, it can be directly connected to the busbar 202 without the need to open the insulating strip 201. During assembly, the insulating strip 201 only needs to be placed on the second battery cell 102 as a whole, which effectively reduces the production precision requirements and production difficulty, and can avoid short circuits caused by positional displacement when the insulating strip 201 is opened, thereby increasing the product yield.

[0052] like Figure 2 and Figure 4As shown, in some embodiments, the battery assembly includes a busbar assembly 200, which is disposed on the first battery cell 101. Exemplarily, the busbar assembly 200 can be disposed in the middle region or the edge region of the first battery cell 101; this application does not limit this. Further, the busbar assembly 200 includes an insulating strip 201 and a busbar 202 sequentially stacked on the first battery cell 101. Both the insulating strip 201 and the busbar 202 extend along a second direction, and the insulating strip 201 forms an exposed area 203. Further, the busbar 202 and the exposed area 203 of the insulating strip 201 are electrically connected to exposed solder strips. Thus, with the back of the solar cell facing upwards as a reference, the busbar 202 is located on the top layer of the solder strip, or in other words, the solder strip is located on the side of the busbar 202 facing the solar cell. This ensures that even with the insulating strip 201, the solder strip can be completely attached to the electrode area, guaranteeing that the solder strip connects to a sufficient number of fine grids. This fully utilizes each fine grid on the solar cell, better collecting current and improving the current collection efficiency. Understandably, this structure of the back-contact solar module effectively improves current collection while concealing the busbar 202.

[0053] In particular, the structure described above in this application is more applicable to gridless solar cells. As can be understood, a gridless solar cell refers to a cell with fine grids but no main grids. Solder ribbons are directly placed in the electrode area of ​​what would normally be a main grid, and the current from the fine grids is directly conducted through the electrical connection between the solder ribbons and the fine grids. Thus, the more portion of the solder ribbon is attached to the solar cell, the more fine grids it can connect to, thereby conducting more current. Conversely, the less portion of the solder ribbon is attached to the solar cell, the less portion can connect to the fine grids, and thus the less current is conducted. In this embodiment, by setting specific positions of the solder strip, insulating strip 201, and busbar 202, and by setting a specific structure for the insulating strip 201, that is, by setting the insulating strip 201 on the side of the solder strip away from the battery cell, the insulating strip 201 forms an exposed area 203, the exposed area 203 exposes the solder strip in the positive electrode region or the solder strip in the negative electrode region on the first battery cell 101, and the busbar 202 is set on the side of the insulating strip 201 away from the first battery cell 101, the insulating strip 201 insulates the busbar 202 from one of the positive electrode region and the negative electrode region, and the busbar 202 is electrically connected to the exposed solder strip corresponding to the exposed area 203. Specifically, with the back of the battery cell facing upwards as a reference, the busbar 202 is located on the top layer of the solder strip, or in other words, the solder strip is located on the side of the busbar 202 facing the first battery cell 101. In this way, even with the insulating strip 201, the solder strip can be completely attached to the electrode area, which means that the solder strip can be connected to a sufficient number of fine grids, making full use of each fine grid on the battery cell, better collecting current, and improving the current collection effect.

[0054] like Figure 5 As shown, the insulating strip 201 may further be provided with through holes forming exposed areas 203, that is, through holes extending along the thickness direction of the insulating strip 201 to form exposed areas 203. The insulating strip 201 covers the solder strips in the positive electrode region and the solder strips in the negative electrode region. Because the insulating strip 201 has through holes, one of the solder strips in the positive electrode region and the solder strip in the negative electrode region can be exposed, allowing the busbar 202 to connect with the solder strip at the through holes. The insulating strip 201 can prevent the busbar 202 from short-circuiting the battery cell. Furthermore, due to the presence of through holes, the insulating strip 201 does not obstruct the conductive connection between the busbar 202 and the solder strip, and it also facilitates the complete adhesion of the solder strip to the battery cell, allowing the solder strip to connect with more fine grids.

[0055] In some embodiments, to avoid hindering the complete adhesion of the solder ribbon to the cell, please refer to... Figure 6 The insulating strip 201 includes a plurality of spaced insulating blocks 204, which cover the solder ribbon in the positive electrode region or the solder ribbon in the negative electrode region, and the gaps between adjacent insulating blocks 204 form exposed areas 203. Thus, the insulating blocks 204 only cover the solder ribbons that need insulation, while the solder ribbons welded to the busbar 202 can be completely adhered to the corresponding electrode regions of the solar cell due to the presence of the exposed areas 203, allowing the solder ribbons to connect to more fine grids.

[0056] In some embodiments, the area ratio of the first overlapping region 103 to the second overlapping region 104 is 1 to 35. For example, the area ratio of the first overlapping region 103 to the second overlapping region 104 can be 1, 5, 15, 20, 25, 30, 35 or any value between 1 and 35, and this application does not impose any limitation.

[0057] In some embodiments, the first overlapping region 103 accounts for 0.2% to 3.8% of the area of ​​the first battery cell 101 or the second battery cell 102. For example, the percentage of the area of ​​the first overlapping region 103 to the area of ​​the first battery cell 101 or the second battery cell 102 can be any value between 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.8%, or 0.2% to 3.8%, and this application does not impose any limitation thereon.

[0058] In some embodiments, the second overlapping region 104 accounts for 0.1% to 3.2% of the area of ​​the nth or (n+1)th battery cell. Exemplarily, the area percentage of the second overlapping region 104 in the nth or (n+1)th battery cell can be any value between 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.2%, or 0.1% to 3.2%, and this application does not impose any limitation thereon.

[0059] In some embodiments, the battery assembly further includes a first solder strip 105 disposed on the first battery cell 101 and a second solder strip 106 disposed on the second battery cell 102. The first solder strip 105 and the second solder strip 106 both extend along a first direction. The first solder strip 105 is electrically connected to the busbar 202, and the insulating strip 201 isolates the second solder strip 106 from the busbar 202. In some embodiments, a first solder ribbon 105 is disposed on the backlight surface of a first battery cell 101, a second solder ribbon 106 is disposed on the backlight surface of a second battery cell 102, a busbar 202 is disposed on the backlight surface of either the first or second battery cell 101, and an insulating strip 201 is disposed between the busbar 202 and either the first or second battery cell 101. The second solder ribbon 106 and the busbar 202 are insulated from each other. Specifically, the insulation between the second solder ribbon 106 and the busbar 202 can be achieved by the insulating strip 201 separating the second solder ribbon 106 from the busbar 202 (e.g.,...). Figure 3 (As shown), or the second welding strip 106 and the busbar 202 can be spaced apart in the first direction to achieve insulation (e.g. Figure 4 (As shown). Both the insulating strip 201 and the busbar 202 extend along the second direction, and the first direction and the second direction are intersected. First, in this embodiment, the busbar 202 is disposed on the first battery cell 101 or the second battery cell 102, and the busbar 202 is separated from the first battery cell 101 or the second battery cell 102 by the insulating strip 201. On the one hand, the edge of the back contact battery assembly does not need to reserve space for placing the busbar 202, and the battery assembly can reserve more space to install the battery cells, 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 battery cell 102 can block the busbar 202, preventing the busbar 202 from being exposed, and the overall aesthetics of the battery assembly are better.

[0060] In this embodiment of the application, the first direction is the horizontal direction, which is also the length direction of the battery cell, the second direction is the vertical direction, which is also the width direction of the battery cell, and the first direction and the second direction are perpendicular to each other.

[0061] For example, the thickness of the busbar 202 can be between 0.06 mm and 0.3 mm, and the width can be between 4 mm and 20 mm. The material of the busbar 202 can be tin-plated copper busbar 202, conductive copper foil, or aluminum-based copper strip.

[0062] For example, the insulating strip 201 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 201 may contain materials such as ethylene-vinyl acetate copolymer, resin material, polyimide or polypropylene or polyethylene, polyethylene-polyvinyl acetate copolymer, etc., and may also contain an acrylic adhesive layer.

[0063] It should be noted that the thickness of the insulating strip 201 cannot be too thick or too thin. If the insulating strip 201 is too thin, it is inconvenient to handle during placement, easily deformed by pulling, and may also pose a risk of breakage during long-term insulation. If it is too thick, it will increase the height difference, generate greater stress during the lamination process, easily cause fragmentation, and increase the risk of poor soldering. Based on this, in the embodiments of this application, the thickness of the insulating strip 201 can be set between 0.05 mm and 0.8 mm. In this way, the insulating strip 201 is neither too thin nor too thick. For example, the thickness of the insulating strip 201 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.

[0064] The width of the insulating strip 201 is greater than or equal to the width of the busbar 202. If the width of the insulating strip 201 is too narrow, the busbar 202 will be exposed, posing a risk of short circuit due to contact between the busbar 202 and the dissimilar electrode area or dissimilar solder strip.

[0065] Furthermore, there are multiple first solder ribbons 105, which are spaced apart along the second direction on the backlight surface of the first solar cell 101. There are multiple second solder ribbons 106, which are spaced apart along the second direction on the backlight surface of the second solar cell 102. The multiple first solder ribbons 105 and the multiple second solder ribbons 106 are arranged in a one-to-one correspondence.

[0066] In some embodiments, the battery assembly further includes a third solder ribbon 107 extending 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. An insulating strip 201 isolates the third solder ribbon 107 from the busbar 202. Specifically, a portion of the third solder ribbon 107 is disposed on the first battery cell 101, and another portion of the third solder ribbon 107 is disposed on the second battery cell 102. Exemplarily, the third solder ribbon 107 can be used to achieve a series connection between the first battery cell 101 and the second battery cell 102. Understandably, the portions of the first solder ribbon 105 and the third solder ribbon 107 disposed on the first battery cell 101 do not overlap, and the remaining portions of the second solder ribbon 106 and the third solder ribbon 107 disposed on the second battery cell 102 do not overlap. Along the length of the busbar 202, portions of the first solder ribbon 105 and the third solder ribbon 107 disposed on the first battery cell 101 are spaced apart, and the remaining portions of the second solder ribbon 106 and the third solder ribbon 107 disposed on the second battery cell 102 are spaced apart, thus achieving a series connection of the battery assembly. Further, the portion of the third solder ribbon 107 located on the first battery cell 101 or the second battery cell 102 is isolated by the insulating strip 201 and the busbar 202. In this embodiment, there are multiple third solder ribbons 107, with at least one first solder ribbon 105 and one second solder ribbon 106 disposed between two adjacent third solder ribbons 107 to achieve a uniform current distribution on the first battery cell 101 and the second battery cell 102.

[0067] Understandably, the nth and n+1th solar cells can be connected in series by soldering ribbons to form a series connection between multiple solar cells.

[0068] In some embodiments, the first solder strip 105, the second solder strip 106, and the third solder strip 107 are all flat solder strips, or the first solder strip 105, the second solder strip 106, and the third solder strip 107 are round wire solder strips. The first solder strip 105, the second solder strip 106, and the third solder strip 107 are partially configured as flattened structures. The flattened structures are set in the projection area of ​​the busbar 202 or the insulating strip 201 on the corresponding solar cell to reduce the stacking height of the busbar assembly 200 on the solar cell, which helps to reduce the risk of microcracks in the solar cell assembly and the degree of solar cell misalignment.

[0069] The battery assembly includes at least two sets of battery strings 100 arranged along a second direction. An insulating strip 201 extends from one of the two sets of battery strings 100 to the other along the second direction. This allows the insulating strip 201 to be installed in one continuous operation between at least two adjacent sets of battery strings 100, simplifying the assembly steps of the battery assembly and improving its production efficiency. Understandably, a back-contact battery assembly includes multiple sets of battery strings 100, and the insulating strip 201 can be installed along multiple sets of battery strings 100 in one continuous operation. For example, a back-contact battery assembly may include three sets of battery strings 100, and the insulating strip 201 can extend from the first set of battery strings 100 to the third set of battery strings 100.

[0070] In some embodiments, adjacent battery strings 100 may partially overlap in the extending direction of the busbar 202 (such as the second direction). This allows for better concealment of the busbar 202. Of course, in other embodiments, if adjacent battery strings 100 are spaced apart in the extending direction of the busbar 202, an insulating strip 201 can be provided in the spaced area to cover the busbar 202 in the spaced area.

[0071] In some embodiments, a photovoltaic system includes the battery modules as described. 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 network 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.

[0072] 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.

[0073] 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 battery assembly, comprising: The device includes a battery string, which includes at least a first battery cell and a second battery cell arranged sequentially along a first direction, with the first battery cell located at the end of the battery string. The first battery cell and the second battery cell partially overlap to form a first overlapping region, the width of which in the first direction is a first distance. The device also includes an nth battery cell and an (n+1)th battery cell arranged sequentially overlapping along the first direction, with adjacent nth and (n+1)th battery cells having a second overlapping region. The maximum width of the plurality of second overlapping regions in the first direction is a second distance, and the first distance is greater than the second distance, where n ≥ 2 and n is a positive integer.

2. The battery assembly of claim 1, wherein, Multiple second overlapping regions are equidistantly arranged in the first direction.

3. The battery assembly of claim 1, wherein, Multiple second overlapping regions are unequally spaced in the first direction.

4. The battery assembly of claim 1, wherein, The width of one portion of the second overlapping region in the first direction is greater than the width of the other portion of the second overlapping region in the first direction.

5. The battery assembly of claim 1, wherein, The battery assembly includes a busbar assembly disposed at the edge of the second battery cell near the first battery cell.

6. The battery assembly as claimed in claim 5, characterized in that, The current-combining assembly includes an insulating strip and a current-combining strip stacked sequentially on the second battery cell. Both the insulating strip and the current-combining strip extend along a second direction, and the insulating strip is a single strip structure.

7. The battery assembly as claimed in claim 1, characterized in that, The battery assembly includes a busbar assembly disposed on the first battery cell.

8. The battery assembly as claimed in claim 7, characterized in that, The current-carrying assembly includes an insulating strip and a current-carrying strip stacked sequentially on the first battery cell. Both the insulating strip and the current-carrying strip extend along a second direction, and the insulating strip has an exposed area.

9. The battery assembly as claimed in claim 6 or 8, characterized in that, In the first direction, the width of the insulating strip is greater than the width of the busbar.

10. The battery assembly as claimed in claim 1, characterized in that, The first distance ranges from 0.3 to 3.5 mm.

11. The battery assembly as claimed in claim 1, characterized in that, The second distance ranges from 0.1 to 3 mm.

12. The battery assembly as claimed in claim 1, characterized in that, The area ratio of the first overlapping region to the second overlapping region is 1 to 35.

13. The battery assembly as claimed in claim 1, characterized in that, The first overlapping area accounts for 0.2% to 3.8% of the area of ​​the first or second battery cell.

14. The battery assembly as claimed in claim 1, characterized in that, The second overlapping region accounts for 0.1% to 3.2% of the area of ​​the nth or (n+1)th battery cell.

15. The battery assembly as claimed in claim 6 or 8, characterized in that, The battery assembly further includes a first solder strip disposed on the first battery cell and a second solder strip disposed on the second battery cell. Both the first solder strip and the second solder strip extend along the first direction. The first solder strip is electrically connected to the busbar, and the second solder strip is insulated from the busbar.

16. The battery assembly as claimed in claim 6 or 8, characterized in that, The 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 connects the first battery cell and the second battery cell, and the insulating strip isolates the third solder strip from the busbar.

17. The battery assembly as claimed in claim 6 or 8, characterized in that, The battery assembly includes at least two sets of battery strings arranged along the second direction, wherein the insulating strip extends from one of the two sets of battery strings to the other of the two sets of battery strings along the second direction.

18. A photovoltaic system, characterized in that, Includes the battery assembly as described in any one of claims 1 to 17.

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