Bus bar, module and system

Abstract

The present disclosure relates to the technical field of solar cells, and provides a bus bar for a battery module, a module and a system. A first end of a body part of the intermediate bus bar is connected to a first lead part bent towards a first side with respect to the body part, a second lead part being bent with respect to the first lead part to be stacked on the side of the first lead part facing away from the body part. One side of the second lead part further has an extension part.

Description

Busbars, components and systems

[0001] Cross-references to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202520158099.1, filed on January 22, 2025, entitled "Intermediate Busbar for Battery Module, Battery Module and Photovoltaic System", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of solar cell technology, and more particularly to an intermediate busbar for a cell module, a cell module, and a photovoltaic system. Background Technology

[0004] Solar cells, also known as photovoltaic cells, are devices that directly convert light energy into direct current using the photovoltaic effect. In related technologies, multiple solar cells are connected in series, laminated, and encapsulated to form a solar module. A solar module consists of multiple cell strings, and a central busbar is typically located in the middle of the module. This busbar is used to weld the solder strips of the cell strings on either side to connect the two strings in parallel. The central busbar connects to a junction box.

[0005] In related technologies, as shown in Figure 1, to draw the current from a parallel battery string, the end of the intermediate busbar 310 is bent to form a lead-out portion 311 for insertion into the junction box 300 on the backplate. However, in this technical solution, the lead-out portion 311 is formed by bending one end of the intermediate busbar 300. Located at the edge of the intermediate busbar 310, the lead-out portion 311 is prone to overlap with adjacent lines (e.g., opposite polarity solder strips on adjacent battery strings) due to insufficient distance, causing a short circuit. Furthermore, during manufacturing, since the lead-out portion 310 is formed by bending the end of the intermediate busbar 310, it needs to be pressed down onto the backplate during lamination to facilitate lamination. During this pressing process, the bent portion of the intermediate busbar 310 is prone to warping, easily leading to incomplete soldering between the solder strips at the edge and the intermediate busbar, resulting in poor welding reliability.

[0006] Public content

[0007] This disclosure provides an intermediate busbar for a battery module, a battery module, and a photovoltaic system.

[0008] This disclosure is implemented as follows: the intermediate busbar in the embodiments of this disclosure includes:

[0009] The body portion has a first side and a second side opposite to each other in the thickness direction, and a first end and a second end opposite to each other in the length direction;

[0010] The first lead portion is connected to the first end and is bent toward the first side relative to the body portion;

[0011] The second lead portion connects to the end of the first lead portion and is bent relative to the first lead portion to stack on the side of the first lead portion away from the body portion. The second lead portion and the first lead portion together form a lead structure, which is used to connect to the junction box of the battery assembly; and

[0012] An extension connected to the end of the second lead portion is bent relative to the second lead portion toward the side away from the main body portion and is parallel to the main body portion.

[0013] In some embodiments, the surface of the body portion facing the first side is flush with the surface of the extension portion facing the first side, and the surface of the body portion facing the second side is flush with the surface of the extension portion facing the second side; or

[0014] The height difference between the surface of the main body facing the first side and the surface of the extension facing one side is less than 3.5 mm, and the height difference between the surface of the main body facing the second side and the surface of the extension facing the second side is less than 3.5 mm.

[0015] In some embodiments, the shape of the first lead portion is the same as the shape of the second lead portion.

[0016] In some embodiments, the first lead portion and the second lead portion completely overlap. In some embodiments, the length of the extension portion is 0.5mm-2mm.

[0017] In some embodiments, the width of the first lead portion and the second lead portion is smaller than the width of the body portion.

[0018] In some embodiments, the width of the body portion is 10mm-15mm, and the width of the first lead portion and the second lead portion is less than 12mm.

[0019] In some embodiments, the width of the first lead portion and the second lead portion is less than 10 mm.

[0020] In some embodiments, the lengths of the first lead portion and the second lead portion are 15mm-35mm.

[0021] In some embodiments, the lengths of the first lead portion and the second lead portion are 20mm-25mm.

[0022] In some embodiments, the first lead portion and the second lead portion have the same structure and are stacked and overlapped. The first lead portion includes a first part and a second part. The first part is connected to the body portion, and the second part is connected to the first part. The width of the first part is the same as the width of the body portion, and the width of the second part is less than the width of the first part and the width of the body portion. The second part is used to connect to the junction box of the battery assembly.

[0023] In some embodiments, the width of the second portion is less than 10 mm; or

[0024] The length of the second part is 12mm-23mm; or

[0025] The width of the second part is less than 10mm, and the length of the second part is 12mm-23mm.

[0026] This disclosure also provides a battery assembly, the battery assembly comprising:

[0027] A parallel battery string unit includes a first battery string and a second battery string arranged along a first direction, and both the first battery string and the second battery string include a number of battery cells connected in series along the first direction.

[0028] The intermediate busbar of any of the above, wherein the intermediate busbar is used to connect the first battery string and the second battery string in parallel; and

[0029] Junction box, the lead wire structure is inserted into the junction box and electrically connected to the junction box.

[0030] This disclosure also provides a photovoltaic system, which includes the aforementioned battery components.

[0031] In the intermediate busbar, battery module, and photovoltaic system of this disclosure embodiment, a first end of the body portion of the intermediate busbar is connected to a first lead portion bent toward a first side relative to the body portion. A second lead portion is connected to the end of the first lead portion and bent relative to the first lead portion to stack on the side of the first lead portion away from the body portion. The second lead portion and the first lead portion together constitute a lead structure. Simultaneously, one side of the second lead portion also has an extension portion. Thus, on the one hand, the arrangement of the first lead portion, the second lead portion, and the extension portion ensures that the lead structure formed by the first lead portion and the second lead portion is not located at the outermost edge of the intermediate busbar, thereby reducing the risk of short circuits caused by the lead structure overlapping with adjacent lines (e.g., opposite polarity solder strips). On the other hand, through this special structural design, due to the presence of the extension, the relative bending positions of the first lead portion and the body portion, as well as the relative bending distance between the second lead portion and the extension portion and the edge of the intermediate busbar, are at a certain distance. Even if the lead structure needs to be passed through the through hole on the back plate and bent and pressed onto the back plate during the lamination process, the force generated by bending the lead structure can be offset by the body portion and the extension portion due to the presence of the extension portion, preventing the edge end of the intermediate busbar from lifting up, thereby ensuring the welding reliability of the solder strip at the edge position and the intermediate busbar.

[0032] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0033] Figure 1 is a schematic diagram of the connection structure between the junction box and the intermediate busbar in a battery assembly in the related technology;

[0034] Figure 2 is a schematic diagram of the photovoltaic system provided in an embodiment of this disclosure;

[0035] Figure 3 is a plan view of the battery assembly provided in an embodiment of this disclosure;

[0036] Figure 4 is an enlarged schematic diagram of the battery assembly in Figure 3 at point IV;

[0037] Figure 5 is a front view of the intermediate busbar provided in an embodiment of this disclosure;

[0038] Figure 6 is a top view of the intermediate busbar provided in an embodiment of this disclosure;

[0039] Figure 7 is a left view of the intermediate busbar provided in an embodiment of this disclosure;

[0040] Figure 8 is another left view of the intermediate busbar provided in an embodiment of this disclosure.

[0041] Explanation of key component symbols: Photovoltaic system 1000, battery module 100, parallel battery string unit 10, first battery string 11, second battery string 12, battery cell 101, intermediate busbar 20, body 21, first end 211, second end 212, first lead 22, first part 221, second part 222, second lead 23, extension 24, junction box 30, first edge busbar 40, second edge busbar 50. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this disclosure 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 disclosure, and should not be construed as limiting this disclosure. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this disclosure and are not intended to limit this disclosure.

[0043] In the description of this disclosure, it should be understood that the terms “length”, “width”, “upper”, “lower”, “lateral”, “longitudinal”, 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 disclosure 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 disclosure.

[0044] 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 disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" 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 disclosure according to the specific circumstances.

[0046] In this disclosure, 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 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.

[0047] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. 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 disclosure. 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 disclosure, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0048] Please refer to Figures 2 and 3. The photovoltaic system 1000 in this embodiment may include the battery module 100 in this embodiment. The battery module 100 in this embodiment may include a plurality of battery cells 101. The battery cells 101 may be back-contact solar cells, Topcon solar cells, etc., and there are no specific limitations here.

[0049] In the embodiments of this disclosure, multiple battery cells 101 in the battery assembly 100 can be connected in series to form multiple battery strings. These battery strings can be combined in series and parallel to achieve current collection and output. For example, the connection between the individual battery cells 101 can be achieved by welding solder strips, and the series and parallel connections between the battery strings can be achieved through the intermediate busbar 20, the first edge busbar 40, and the second edge busbar 50 described below. The battery strings can form an array of battery cells 101, which are then encapsulated together by a front panel, a front adhesive film, a rear adhesive film, and a back panel to form the battery assembly 100.

[0050] Referring to Figure 3, the battery assembly 100 includes a plurality of battery strings, each battery string including a plurality of battery cells 101 connected in series along a first direction. As shown in Figure 3, the battery assembly 100 may include a plurality of parallel battery string units 10, each parallel battery string unit 10 including a first battery string 11 and a second battery string 12 arranged along the first direction, each of the first battery string 11 and the second battery string 12 including a plurality of battery cells 101 connected in series along the first direction. In some embodiments, the first battery string 11 and the second battery string 12 may be symmetrical about the centerline of the battery assembly 100 in the first direction.

[0051] As shown in Figures 3 and 4, the battery assembly 100 also includes an intermediate busbar 20 and a junction box 30 as described in this embodiment. The intermediate busbar 20 is used to connect the first battery string 11 and the second battery string 12 in parallel. That is, both the first battery string 11 and the second battery string 12 are connected to the intermediate busbar 20, and the polarities of the first battery string 11 and the second battery string 12 are the same. The junction box 30 is disposed on the back panel of the battery assembly 100, and a bypass diode is provided inside the junction box 30.

[0052] As shown in Figure 3, the battery assembly 100 may have multiple parallel battery string units 10, which are arranged along a second direction. The first direction may be the longitudinal direction of the battery assembly 100, and the second direction may be the transverse direction of the battery assembly 100. In the multiple parallel battery string units 10, adjacent first battery strings 11 are connected in series in pairs through a first edge busbar 40, and adjacent second battery strings 12 are connected in series in pairs through a second edge busbar 50.

[0053] Specifically, as shown in Figure 3, which illustrates a case where there are 6 parallel battery string units 10, as shown in Figures 3 and 4, there are 3 first edge busbars 40, 3 second edge busbars 50, 4 intermediate busbars 20, and 3 junction boxes 30. A junction box 30 is provided between each pair of adjacent intermediate busbars 20. In each pair of adjacent intermediate busbars 20, one intermediate busbar 20 is connected to the positive terminal of the junction box 30, and the other is connected to the negative terminal of the junction box 30. As shown in Figure 4, in the example shown in Figure 4, among the four intermediate busbars 20, the two intermediate busbars 20 located on both sides of the second direction are short busbars, and the two intermediate busbars 20 located in the middle are long busbars. The short busbars are connected to the positive or negative terminal of a junction box 30 at only one end, while the long busbars are connected to the positive terminal of a junction box 30 at one end and to the negative terminal of another junction box 30 at the other end.

[0054] Referring to Figure 5, the intermediate busbar 20 in this embodiment may include a body portion 21, a first lead portion 22, a second lead portion 23, and an extension portion 24. The body portion 21 has opposing first and second sides in the thickness direction, and the body portion 21 has opposing first end 211 and second end 212 in the length direction.

[0055] The first lead portion 22 is connected to the first end 211 and bent toward the first side relative to the body portion 21. The second lead portion 23 is connected to the end of the first lead portion 22 and bent toward the first lead portion 22 to stack on the side of the first lead portion 22 away from the body portion 21. The second lead portion 23 and the first lead portion 22 together constitute a lead structure. The extension portion 24 is connected to the end of the second lead portion 23 and bent toward the side of the second lead portion 23 away from the body portion 21 and parallel to the body portion 21. It should be noted that, in the embodiments of this disclosure, "parallel" means that the two are completely parallel or that the angle between them is approximately parallel within the range of manufacturing error. The second lead portion 23 being stacked on the side of the first lead portion 22 away from the body portion 21 can be understood as the first lead portion 22 having a third side and a fourth side in the length direction of the body portion 21, the body portion 21 being located on the third side of the first lead portion 22, and the second lead portion 23 being located on the fourth side of the first lead portion 22. Furthermore, based on the above understanding, the extension 24 is also located on the fourth side of the first lead portion 22.

[0056] The lead structure is used to connect to the junction box 30 of the battery assembly 100. Specifically, the lead structure composed of the first lead part 22 and the second lead part 23 passes through the back plate of the battery assembly 100 and is inserted into the junction box 30 to connect to the positive or negative terminal of the junction box 30.

[0057] In the parallel battery string unit 10, both the first battery string 11 and the second battery string 12 are connected to the body portion 21 at least to achieve parallel connection. Specifically, both the first battery string 11 and the second battery string 12 have a plurality of solder strips, and both can be soldered to the body portion 21 via the solder strips. It is understood that in some embodiments, the solder strips located at the edge positions of the first battery string 11 and the second battery string 12 can also be soldered to the extension portion 24, and no specific limitation is made here.

[0058] In the intermediate busbar 20, battery module 100, and photovoltaic system 1000 of this disclosure embodiment, a first end 211 of the body portion 21 of the intermediate busbar 20 is connected to a first lead portion 22 bent toward a first side relative to the body portion 21. A second lead portion 23 is connected to the end of the first lead portion 22 and bent relative to the first lead portion 22 to stack on the side of the first lead portion 22 away from the body portion 21. The second lead portion 23 and the first lead portion 22 together constitute a lead structure. Simultaneously, one side of the second lead portion 23 also has an extension portion 24. Thus, by providing the first lead portion 22, the second lead portion 23, and the extension portion 24, the lead structure formed by the first lead portion 22 and the second lead portion 23 is not located at the outermost edge of the intermediate busbar 20, thereby reducing the risk of short circuits caused by the lead structure overlapping with adjacent lines (e.g., opposite polarity solder strips). On the other hand, through this special structural design, due to the presence of the extension 24, the relative bending positions of the first lead portion 22 and the body portion 21, as well as the relative bending distances of the second lead portion 23 and the extension 24 from the edge of the intermediate busbar 20, are at a certain distance. Even if the lead structure needs to be passed through the through hole on the back plate and bent and pressed onto the back plate during the lamination process, the force generated by bending the lead structure can be offset by the body portion 21 and the extension 24 due to the presence of the extension 24, preventing the edge end of the intermediate busbar 20 from lifting up, thereby ensuring the welding reliability of the solder strip at the edge position to the intermediate busbar 20.

[0059] Specifically, the intermediate busbar 20 is made of metal, such as aluminum, copper, or tin, and is not limited thereto. In some embodiments, the intermediate busbar 20 can be a single integral structure, formed by bending and stacking a continuous, flat metal strip multiple times. For example, the metal strip can be bent once to obtain the body portion 21 and the first bent portion, then the first bent portion can be bent a second time to obtain the first lead portion 22 and the second bent portion, and finally the second bent portion can be bent a third time to obtain the second lead portion 23 and the extension portion 24. Subsequently, the first lead portion 22 and the second lead portion 23 can be pressed and stacked together using processes such as compression to form a lead structure. It is understood that in this disclosure, the first lead portion 22 and the second lead portion 23 are merely stacked together and not fixedly welded; under the action of external force, the first lead portion 22 and the second lead portion 23 can be separated.

[0060] In embodiments of this disclosure, the first lead portion 22 and the second lead portion 23 may be disposed perpendicular to the body portion 21.

[0061] Please refer to Figure 4. As shown above, in the intermediate busbar 20 of the battery assembly 100, the short busbar is connected to only one polarity of one of the junction boxes 30. Therefore, in the short busbar, the first lead portion 22, the second lead portion 23, and the extension portion 24 can be only located at the first end 211 of the body portion 21.

[0062] As shown in Figure 4, in the intermediate busbar 20 of the battery assembly 100, the long busbar needs to be connected to ports of different polarities in the two junction boxes 30. Therefore, in the long busbar, the second end 212 of the body portion 21 may also have a first lead portion 22, a second lead portion 23, and an extension portion 24, and the structure of the first end 211 is symmetrical to the structure of the second end 212. That is to say, in the embodiments of this disclosure, the intermediate busbar 20 may have the first lead portion 22, the second lead portion 23, and the extension portion 24 only at the first end 211 of the body portion 21, or it may have the first lead portion 22, the second lead portion 23, and the extension portion 24 at both the first end 211 and the second end 212.

[0063] Please refer to Figure 5. In some embodiments, the surface of the body portion 21 facing the first side is flush with the surface of the extension portion 24 facing the first side, and the surface of the body portion 21 facing the second side is flush with the surface of the extension portion 24 facing the second side.

[0064] In this way, the two surfaces of the main body 21 and the extension 24 are flush in the thickness direction, which can ensure that the part of the intermediate busbar 20 that is welded to the welding strip is on the same plane, ensuring the consistency and reliability of the welding between the welding strip and the intermediate busbar 20, and avoiding the occurrence of incomplete welding of some welding strips.

[0065] Of course, in other embodiments, the height difference between the surface of the main body 21 facing the first side and the surface of the extension 24 facing the first side is less than 3.5 mm. For example, the height difference between the two can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, etc. The height difference between the surface of the main body 21 facing the second side and the surface of the extension 24 facing the second side is less than 3.5 mm. For example, the height difference between the two can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, etc.

[0066] Thus, although the surfaces of the main body 21 and the extension 24 are not flush, their height difference is less than 3.5 mm. The height difference between the two is small enough to effectively ensure the reliability of the welding.

[0067] Please refer to Figures 5-7. In some embodiments, the shape of the first lead portion 22 is the same as the shape of the second lead portion 23. This makes manufacturing simpler and more convenient.

[0068] In some embodiments, the first lead portion 22 and the second lead portion 23 completely overlap. This ensures that the shape of the lead structure remains consistent and overlaps at all locations, simplifying the lead structure and improving the stability of the connection with the junction box 30. It is understood that "completely overlap" means that the first lead portion 22 and the second lead portion 23 are mirror-symmetrical in the direction perpendicular to the surface of the body portion 21 facing the first side.

[0069] Please refer to Figure 5. In some embodiments, the length L1 of the extension 24 is 0.5mm-2mm. By setting the length L1 of the extension 24 within this reasonable range, it is possible to avoid the extension 24 from being too long and causing short circuits due to overlap with adjacent lines, and also to avoid the extension 24 from being too short and causing the solder strips at the edge to fail to form a stable contact with the extension 24.

[0070] Specifically, in such an embodiment, the length L1 of the extension 24 can be, for example, any value between 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or 0.5mm-2mm, and is not limited here.

[0071] Please refer to Figures 6 and 7. In some embodiments, the width D1 of the first lead portion 22 and the second lead portion 23 is smaller than the width D2 of the body portion 21, that is, D1 < D2.

[0072] Thus, by setting the width of the first lead portion 22 and the second lead portion 23 to be relatively small, it is easier for the lead structure to be inserted into the connection terminal of the junction box 30.

[0073] Furthermore, in some embodiments, the width D2 of the body portion 21 may be 10mm-15mm, and the width D1 of the first lead portion 22 and the second lead portion 23 may be less than 12mm.

[0074] Thus, by setting the width of the body portion 21 within the range of 10mm-15mm, the welding stability between the solder strip and the body portion 21 can be ensured while controlling bus transmission loss and cost. Setting the width of the first lead portion 22 and the second lead portion 23 to less than 12mm facilitates the insertion of the lead structure into the connection terminals of the junction box 30.

[0075] In some embodiments, the width D1 of the first lead portion 22 and the second lead portion 23 is less than 10 mm.

[0076] In this way, the difficulty of inserting the first lead portion 22 and the second lead portion 23 into the connection terminal of the junction box 30 can be avoided due to the excessive width of the first lead portion 22 and the second lead portion 23. That is, this makes it easier for the lead structure formed by the first lead portion 22 and the second lead portion 23 to be inserted into the connection terminal of the junction box 30.

[0077] In some embodiments, the length L2 of the first lead portion 22 and the second lead portion 23 is 15mm-35mm. In some embodiments, the length L2 of the first lead portion 22 and the second lead portion 23 is 20mm-25mm.

[0078] In this way, the length of the first lead part 22 and the second lead part 23 can be avoided, which would result in the length of the part of the lead structure inserted into the junction box 30 being too short, leading to poor connection stability between it and the connection terminal of the junction box 30.

[0079] Specifically, in such embodiments, the length L2 of the first lead portion 22 and the second lead portion 23 can be, for example, any value between 15mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 35mm, or 15mm-35mm. In some embodiments, the length L2 of the first lead portion 22 and the second lead portion 23 is any value between 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, or 20mm-25mm.

[0080] Referring to Figures 5 and 8, in some embodiments, the first lead portion 22 and the second lead portion 23 have the same structure and are stacked and overlapped. The first lead portion 22 includes a first part 221 and a second part 222. The first part 221 is connected to the body part 21, and the second part 222 is connected to the first part 221. The width D3 of the first part 221 is the same as the width D2 of the body part 21, that is, D3 = D2. The width D4 of the second part 222 is smaller than the width D3 of the first part 221 and the width D2 of the body part 21, that is, D4 < D3 = D2. The second part 222 is used to connect to the junction box 30 of the battery assembly 100. The above-mentioned "same structure and stacked and overlapped" can also be understood as the first lead portion 22 and the second lead portion 23 being mirror-symmetrical in the direction perpendicular to the surface of the body part 21 facing the first side.

[0081] Thus, by setting the width of the main body 21 and the first part 221 to be wider and the width of the second part 222 to be narrower, the connection between the narrower second part 222 and the connection terminal of the junction box 30 can facilitate the insertion of the second part 222 into the junction box 30, while also saving material costs. On the other hand, setting the width of the first part 221 to be wider can reduce transmission loss.

[0082] In some embodiments, the width D4 of the second portion 222 is less than 10 mm. In some embodiments, the width D4 of the second portion 222 is less than 9.6 mm. This ensures that the second portion 222 can be easily and smoothly inserted into the junction box 30, avoiding the difficulty of insertion into the junction box 30 due to the second portion 222 being too wide.

[0083] In some embodiments, the length L3 of the second portion 222 is 12mm-23mm. This avoids the second portion 222 being too short, which would result in an insufficient length extending from the back panel and thus an insufficient length for insertion into the junction box 30, leading to unstable connections. It also avoids the second portion 222 being too long, which would increase costs.

[0084] Specifically, in such embodiments, the overall length of the first lead portion 22 and the second lead portion 23 can be 15mm-35mm. In some embodiments, the overall length of the first lead portion 22 and the second lead portion 23 is 20mm-25mm. In some embodiments, the length of the second portion 222 is 12mm-23mm, and the length of the second portion 222 can be, for example, any value between 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm or 12mm-23mm.

[0085] 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 this disclosure. 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.

[0086] Furthermore, the above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. An intermediate busbar for a battery assembly, comprising: The body portion has opposing first and second sides in the thickness direction, and opposing first and second ends in the length direction; A first lead portion is connected to the first end and bent toward the first side relative to the body portion; A second lead portion, which connects to the end of the first lead portion and is bent relative to the first lead portion to stack on the side of the first lead portion away from the body portion, the second lead portion and the first lead portion together form a lead structure for connection to the junction box of the battery assembly; and An extension connected to the end of the second lead portion, the extension portion being bent relative to the second lead portion toward the side opposite to the body portion and parallel to the body portion.

2. The intermediate busbar for a battery assembly according to claim 1, wherein, The surface of the main body facing the first side is flush with the surface of the extension facing the first side, and the surface of the main body facing the second side is flush with the surface of the extension facing the second side; or The height difference between the surface of the main body facing the first side and the surface of the extension facing the first side is less than 3.5 mm, and the height difference between the surface of the main body facing the second side and the surface of the extension facing the second side is less than 3.5 mm.

3. The intermediate busbar for a battery assembly according to claim 1, wherein, The shape of the first lead portion is the same as the shape of the second lead portion.

4. The intermediate busbar for a battery assembly according to claim 1, wherein, The first lead portion and the second lead portion completely overlap.

5. The intermediate busbar for a battery assembly according to claim 1, wherein, The length of the extension is 0.5mm-2mm.

6. The intermediate busbar for a battery assembly according to claim 1, wherein, The widths of the first lead portion and the second lead portion are smaller than the width of the body portion.

7. The intermediate busbar for a battery assembly according to claim 6, wherein, The width of the main body is 10mm-15mm, and the widths of the first lead portion and the second lead portion are less than 12mm.

8. The intermediate busbar for a battery assembly according to claim 7, wherein, The widths of the first lead portion and the second lead portion are less than 10 mm.

9. The intermediate busbar for a battery assembly according to claim 1, wherein, The lengths of the first lead portion and the second lead portion are 15mm-35mm.

10. The intermediate busbar for a battery assembly according to claim 9, wherein, The lengths of the first lead portion and the second lead portion are 20mm-25mm.

11. The intermediate busbar for a battery assembly according to claim 1, wherein, The first lead portion and the second lead portion have the same structure and are stacked and overlap. The first lead portion includes a first part and a second part. The first part is connected to the body portion, and the second part is connected to the first part. The width of the first part is the same as the width of the body portion, and the width of the second part is less than the width of the first part and the width of the body portion. The second part is used to connect to the junction box of the battery assembly.

12. The intermediate busbar for a battery assembly according to claim 11, wherein, The width of the second part is less than 10mm; or The length of the second part is 12mm-23mm; or The width of the second part is less than 10mm, and the length of the second part is 12mm-23mm.

13. A battery assembly, comprising: A parallel battery string unit, the parallel battery string unit includes a first battery string and a second battery string arranged along a first direction, and both the first battery string and the second battery string include a plurality of battery cells connected in series along the first direction; The intermediate busbar according to any one of claims 1-12, wherein the intermediate busbar is used to connect the first battery string and the second battery string in parallel; and A junction box, wherein the lead wire structure is inserted into the junction box and electrically connected to the junction box.

14. A photovoltaic system comprising the battery module of claim 13.

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