Aluminum busbar structure and battery pack
The mesh structure formed by the interlacing of conductive wires solves the problems of easy deformation and stress concentration in traditional aluminum busbar structures during thermal expansion, improves the flexibility and welding reliability of aluminum busbars, and ensures the stability and safety of battery packs.
Patent Information
- Application Number
- CN202521000023.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2026-06-19
- Estimated Expiration
- 2035-05-20
Smart Images
Figure CN224384462U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery energy storage technology, and in particular to an aluminum busbar structure and a battery pack. Background Technology
[0002] Aluminum busbars are conductive components in battery packs used to connect the terminals of individual cells. Their function is to achieve electrical connection between batteries. In high-current applications such as power battery packs, aluminum busbars need to have good conductivity, mechanical strength, and thermal stress absorption capabilities to ensure long-term stability and safety. Traditional aluminum busbars are usually formed from a single piece of aluminum through stamping or machining, and their structural design directly affects the battery pack's resistance to deformation and welding reliability.
[0003] In existing technologies, to mitigate the deformation of aluminum busbars caused by thermal expansion during charging and discharging, a stamped arched structure is commonly used as a buffer design for the connection. The locally arched shape of this structure provides a certain amount of extension space, absorbing thermal stress through geometric deformation.
[0004] However, such arched structures still have significant drawbacks in practical applications: First, the ductility of stamped arched aluminum bars is limited by the material hardness and processing technology, and they are prone to losing their buffering capacity due to plastic deformation saturation after multiple thermal cycles; Second, the cross-sectional dimensions and shape of the arched area are fixed, making it difficult to adapt to stress changes in different directions, resulting in insufficient absorption of transverse thermal stress, which may still cause cracks at the welded parts or even the entire aluminum bar to tear; In addition, the stamping process can easily create sharp edges, further aggravating the risk of welding heat accumulation and cracking. Utility Model Content
[0005] One objective of this application is to provide an aluminum busbar structure that addresses the technical problem of insufficient performance of arched aluminum busbars in the prior art.
[0006] To achieve the above objectives, this application provides an aluminum busbar structure, which includes two welded portions and connecting portions respectively connected thereto. The welded portions are configured to be electrically connected to the terminals of a single cell. The connecting portions include multiple conductive wires, with at least some of the conductive wires having their ends connected to the two welded portions respectively.
[0007] According to one embodiment of this application, the conductive wire includes a first guide wire extending along a first direction and a second guide wire extending along a second direction, the first direction intersecting the second direction, the two ends of the first guide wire being connected to the welding part respectively, the two ends of the second guide wire being connected to the welding part respectively, each first guide wire being electrically connected to multiple second guide wires, and each second guide wire being electrically connected to multiple first guide wires.
[0008] According to one embodiment of this application, each conductive wire has an elliptical cross-section perpendicular to its extension direction, the major axis of the ellipse is located in the plane formed by the first direction and the second direction, and the minor axis of the ellipse is perpendicular to the first direction and the second direction.
[0009] According to one embodiment of this application, the first guidewire and the second guidewire are wavy and interwoven to form a mesh structure.
[0010] According to one embodiment of this application, a cross-section of the aluminum strip structure is made on any plane perpendicular to the line connecting the two welded parts. The cross-sectional area of the outer contour of the connecting part is S1, and the cross-sectional area of the welded part is S2, where S1 = S2.
[0011] According to one embodiment of this application, the conductive wire includes a third conductive wire and a fourth conductive wire. The two ends of each third conductive wire are electrically connected to two welding parts, and each fourth conductive wire is electrically connected to multiple third conductive wires.
[0012] According to one embodiment of this application, a cross-section of the aluminum busbar structure is made on any plane perpendicular to the line connecting the two welded parts. The cross-sectional area of the welded part is S2, and the sum of the cross-sectional areas of each fourth guide wire is S3, where S2 = S3.
[0013] According to one embodiment of this application, the aluminum busbar structure further includes a coating layer that covers the surface of the connecting portion.
[0014] According to one embodiment of this application, the natural length of the connecting part in its current-carrying direction is L1, and the distance between the two welded parts is L2, where L1 > L2.
[0015] To achieve the above objectives, this application also provides a battery pack, which includes the aluminum busbar structure described in any of the above claims and a plurality of individual cells, wherein adjacent individual cells are electrically connected through the aluminum busbar structure.
[0016] The beneficial effects of this application are as follows:
[0017] The aluminum busbar structure of this application includes two welded portions and connecting portions connected to them respectively. The welded portions are configured to be electrically connected to the terminals of individual cells. The connecting portions include multiple conductive wires, with at least some of the conductive wires connected to the two welded portions at both ends. By connecting the welded portions with conductive wires, the flexibility and thermal stress absorption capacity of the aluminum busbar are significantly improved.
[0018] In existing technologies, arch bridge structures have rigid and continuous characteristics due to integral stamping. The deformation of adjacent areas restrains each other, resulting in stress concentration in a specific direction and limited extension space.
[0019] In contrast, the conductive wire network of this application breaks the structural continuity through discretization design. On the one hand, the gaps between the conductive wires provide physical space for free expansion and contraction in three dimensions, making the deformation direction of the aluminum busbar more flexible. On the other hand, each conductive wire can undergo independent elastic deformation along its extension direction when subjected to heat or mechanical load. Since the conductive wires are weakly coupled and connected through non-integrated weaving or interlacing, their deformation path exhibits multi-directional dispersion characteristics, avoiding the accumulation of plastic deformation caused by local stress concentration, and greatly enhancing the adaptability to complex expansion conditions. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the overall structure of the aluminum busbar structure provided in the embodiments of this application;
[0022] Figure 2 This is a top view of the aluminum busbar structure provided in the embodiments of this application;
[0023] Figure 3 It is along Figure 1 Schematic diagram of the cross section of line AA in the middle;
[0024] Figure 4 This is a top view of an aluminum busbar structure provided in another embodiment of this application;
[0025] Figure 5 This is a side view of an aluminum busbar structure provided in another embodiment of this application.
[0026] Explanation of icon numbers:
[0027] 10. Welding part; 20. Connecting part; 21. Conductive wire; 22. First guide wire; 23. Second guide wire; 24. Third guide wire; 25. Fourth guide wire. Detailed Implementation
[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0029] Aluminum busbars are conductive components in battery packs that connect the battery terminals, providing electrical connections between individual cells. To ensure output stability and safety, aluminum busbars must possess good conductivity, mechanical strength, and thermal stress absorption capabilities. Traditional aluminum busbars are formed by stamping or machining, and their structural design affects the battery pack's resistance to deformation and welding reliability. To mitigate deformation caused by thermal expansion of the aluminum busbar, a common structure is a stamped arched structure used as a buffer design for the connection, providing extension space to absorb the stress generated by the expansion of individual cells.
[0030] However, the arched structure formed by stamping has many defects, such as: its ductility is limited by the material composition and processing technology, and its buffering capacity will deteriorate significantly after multiple thermal cycles; its cross-sectional size and shape are fixed, making it difficult to adapt to stress changes in different directions; the stamping process is prone to producing sharp edges, which exacerbates the risk of welding heat accumulation and cracking.
[0031] To address the aforementioned technical problems, this application provides an aluminum busbar structure. Please refer to... Figure 1 and Figure 2 As shown, Figure 1 This is a schematic diagram of the overall structure of the aluminum busbar structure provided in the embodiments of this application; Figure 2 This is a top view of the aluminum busbar structure provided in the embodiments of this application. The aluminum busbar structure provided in this application includes two welded portions 10 and connecting portions 20 respectively connected thereto. The welded portions 10 are configured to be electrically connected to the terminals of a single cell. The connecting portions 20 include multiple conductive wires 21, and at least some of the conductive wires 21 are connected to the two welded portions 10 at both ends respectively.
[0032] In this embodiment, the connecting part 20 includes multiple conductive wires 21. The electrical connection between the two welding parts 10 is undertaken by the conductive wires 21, effectively solving the problem of deformation restriction caused by the integral sheet molding of traditional aluminum busbars. Since the conductive wires 21 are not integrally connected, each conductive wire 21 deforms independently under the action of thermal expansion or mechanical stress, and the displacement constraint between adjacent conductive wires 21 is significantly reduced. This changes the stress distribution from concentrated to multi-path dispersed, reducing the internal stress of the connecting part 20 itself caused by uneven deformation, avoiding the accumulation of local plastic deformation, and fully releasing the ductility of the connecting part 20 material.
[0033] In addition, the gaps formed between the conductive wires 21 provide physical space for the connection part 20 to freely expand and contract in three dimensions. The aluminum busbar structure is more adaptable to lateral deformation and can maintain the integrity of the aluminum busbar structure under complex working conditions.
[0034] It should be understood that the fact that each conductive wire 21 can deform independently, relative to the existing whole plate arched connection part 20, means that each conductive wire 21 in this application has different stress conditions and deformation conditions. On this basis, there may also be force between each conductive wire 21, which does not mean that there is no constraint relationship between each conductive wire 21.
[0035] In existing stamping processes, the deformation of different parts within the sheet metal is mutually constrained, resulting in strain being concentrated in a predetermined direction and limited in its extent. This can easily lead to cracking of the welded section 10 or tearing of the aluminum busbar. Compared to existing technologies, the weak coupling connection between the conductive wires 21 in this application allows each conductive wire 21 to respond independently to thermal expansion. Its multi-directional dispersed deformation characteristics not only reduce the risk of stress concentration but also improve overall flexibility by flexibly adjusting the deformation path, thus ensuring the stability of the battery pack.
[0036] In one embodiment of this application, the conductive wire 21 includes a first guide wire 22 extending along a first direction and a second guide wire 23 extending along a second direction. The first direction and the second direction intersect. The two ends of the first guide wire 22 are respectively connected to the welding part 10, and the two ends of the second guide wire 23 are respectively connected to the welding part 10. Each first guide wire 22 is electrically connected to multiple second guide wires 23, and each second guide wire 23 is electrically connected to multiple first guide wires 22.
[0037] In this embodiment, the first guide wire 22 and the second guide wire 23 extend along the first direction and the second direction respectively and intersect. The first guide wire 22 and the second guide wire 23 are each connected to the welding part 10, realizing a robust composite current-carrying network. Specifically, on the one hand, since both ends of each conductive wire 21 are directly electrically connected to the welding part 10, all the first guide wires 22 and the second guide wires 23 form independent current-carrying paths, so that the current-carrying capacity of the entire cross-section of the connecting part 20 is fully activated, and the aluminum busbar can bear a larger current and work stably. On the other hand, the first guide wire 22 and the second guide wire 23 form a composite conductive mesh structure through multiple points of conduction. When any single conductive wire 21 is broken, the adjacent conductive wires 21 will divert the current that the broken conductive wire 21 should carry, and redistribute the current at subsequent intersection nodes, so that the remaining part of the broken conductive wire 21 can still play the role of current carrying, thereby significantly reducing the impact of local breakage on the entire connecting part 20 and improving the fault tolerance and long-term reliability of the aluminum busbar.
[0038] It should be noted that this embodiment only limits the first guide wire 22 and the second guide wire 23 to form an electrically connected network, and does not limit the specific physical connection method between them. For example, the first guide wire 22 and the second guide wire 23 can be wavy and interwoven; alternatively, the axes of all the first guide wires 22 can be coplanar with a first plane, and all the second guide wires 23 can be coplanar with a second plane, with the first plane parallel to the second plane. In the latter case, the first guide wire 22 and the second guide wire 23 can optionally be welded together, or clamps can be provided on both sides of the first guide wire 22 and the second guide wire 23 to press them together and make them conductive.
[0039] Please refer to the above as well. Figure 3 As shown, Figure 3 It is along Figure 1 A cross-sectional view of line AA in the middle.
[0040] Furthermore, each conductive wire 21 has an elliptical cross-section perpendicular to its extension direction, with the major axis of the ellipse located in the plane formed by the first and second directions, and the minor axis of the ellipse perpendicular to the first and second directions.
[0041] By designing the cross-section of the conductive wire 21 as an ellipse, this embodiment achieves directional optimization of the mechanical properties of the connection part 20 while maintaining a constant conductive cross-sectional area. The major axis of the ellipse extends along the first and second planes, while the minor axis is perpendicular to these planes. This results in the conductive wire 21 having significantly lower bending stiffness in the minor axis direction, i.e., perpendicular to the aluminum busbar plane, compared to the major axis direction. This anisotropic design makes it easier for the conductive wire 21 to elastically bend around any axis within the aluminum busbar plane. While ensuring the structural stability of the conductive wire 21 in the planar direction and its overall current-carrying capacity, it allows the connection part 20 to deform more flexibly, making it particularly suitable for actual working conditions where the aluminum busbar needs to twist or undulate around a planar axis.
[0042] Optionally, the first guidewire 22 and the second guidewire 23 are woven in a wave-like pattern to form a mesh structure.
[0043] In this embodiment, the first guide wire 22 and the second guide wire 23 are interwoven in a wave-like pattern to form a mesh structure, which improves the morphological stability of the connection part 20.
[0044] Specifically, the wave-like weaving creates periodic undulations in the conductive wires 21 along their extension direction. At each intersection, the crest of the first guide wire 22 interlocks with the trough of the second guide wire 23, or vice versa, forming an interlocking structure in the plane. This effectively suppresses relative slippage between the conductive wires 21 and enhances their resistance to shear deformation. Simultaneously, the spatial interlocking network formed by the interlaced weaving allows external forces to be dispersed across multiple conductive wires 21 through the geometric deformation of the wave-like surface, reducing the risk of a single conductive wire 21 breaking due to stress concentration. The mesh structure of this embodiment not only imparts near-isotropic tensile and compressive strength to the connecting portion 20 but also retains elastic deformation space through the wave-like allowance. This allows the mesh structure to release internal stress through micro-area deformation when subjected to cyclic loads, thereby improving fatigue resistance and ensuring the long-term morphological stability of the connecting portion 20 under complex working conditions.
[0045] Furthermore, on any plane perpendicular to the line connecting the two welded parts 10, a cross-section of the aluminum strip structure is drawn, with the cross-sectional area of the outer contour of the connecting part 20 being S1 and the cross-sectional area of the welded part 10 being S2, where S1 = S2.
[0046] It should be noted that the cross-sectional area of the fluid carrier should be understood as the area of the plane figure obtained by intersecting the fluid carrier with a virtual plane perpendicular to the direction of flow. The outer contour of the connection 20 should be defined as follows: the area of the connection 20 is the area of the outer contour cross-sectional area in the corresponding direction, which is the sum of the cross-sectional areas of all conductive wires 21 within its range and the area of the gaps between the conductive wires 21.
[0047] According to Joule's law of heating, the heat generated in a conductor under current-carrying conditions is Q = I²Rt, where I is the load current, R is the resistance, and t is the current-carrying time. In this embodiment, under the constraint of the same outer contour cross-sectional area (S1 = S2), the sum of the actual conductive cross-sectional areas of the conductive wires 21 inside the connection part 20 is significantly smaller than S2 of the solid metal of the welding part 10 due to the existence of braiding gaps. Therefore, the resistance of the connection part 20 is greater than that of the welding part 10, and the heat generated in the connection part 20 is greater than that in the welding part 10. When the aluminum busbar is working normally, the area of the connection part 20 of the aluminum busbar has a higher temperature. When the aluminum busbar is overloaded, the local thermal melting point preferentially forms in the connection part 20. By sacrificing the connection part 20, the overall circuit of the aluminum busbar is broken, avoiding damage to the electrode structure caused by the high-temperature melting of the welding part 10, and ensuring that the melting point is far away from the core components of the battery. After an overload occurs, only the aluminum busbar structure needs to be replaced to restore the function of the battery pack, and the replacement cost of parts is low.
[0048] It should be understood that, depending on the working environment, the gaps between the conductive wires 21 may be filled with air or insulating oil. The thermal conductivity of these materials is lower than that of the aluminum busbar itself. Therefore, the high thermal resistance area formed by the gap filler between the conductive wires 21 will further restrict the heat from being conducted to the welded part 10 and the outside world, preventing the welded part 10 from overheating and accelerating the melting of the connection part 20 under overload conditions.
[0049] Please refer to the above as well. Figure 4 As shown, Figure 4 This is a top view of an aluminum busbar structure provided in another embodiment of this application.
[0050] In one embodiment of this application, the conductive wire 21 includes a third conductive wire 24 and a fourth conductive wire 25. The two ends of each third conductive wire 24 are electrically connected to two welding parts 10 respectively, and each fourth conductive wire 25 is electrically connected to multiple third conductive wires 24.
[0051] The third guide wire 24 extends along the connecting line of the welding part 10, forming an axial main current-carrying channel to ensure efficient current transmission along a preset path. The fourth guide wire 25 is regularly arranged perpendicular to the connecting line direction, which not only forms a spatial constraint on the third guide wire 24 through multi-point contact to suppress the displacement of the conductive wire 21 caused by electromagnetic vibration, but also establishes parallel conductive branches between adjacent third guide wires 24 through lateral overlap, reducing local current density differences and reducing the risk of overheating. The orthogonal grid structure of this embodiment gives the connecting part 20 a regular geometric shape while taking into account the electrothermal performance and mechanical reliability of the connecting part 20.
[0052] For example, the extension direction of each fourth guide wire 25 is set at an angle to the line connecting the two welding parts 10, and the two are preferably perpendicular.
[0053] Furthermore, on any plane perpendicular to the line connecting the two welded parts 10, a cross-section of the aluminum busbar structure is drawn. The cross-sectional area of the welded part 10 is S2, and the sum of the cross-sectional areas of each fourth guide wire 25 is S3, where S2 = S3.
[0054] Because the cross-sectional area of the welded part 10 is the same as the sum of the cross-sectional areas of each of the fourth guide wires 25, under normal current-carrying conditions, the connecting part 20 and the welded part 10 have the same current-carrying capacity. When the aluminum busbar is overloaded, due to the high thermal resistance area between the conductive wires 21, the connecting part 20 will still melt preferentially over the welded part 10, thus protecting the battery cell terminal.
[0055] In one embodiment of this application, the aluminum busbar structure further includes a coating layer that covers the surface of the connecting portion 20.
[0056] Depending on the actual material of the coating, the coating can have different effects. For example, if an insulating coating material is selected, the coating can suppress heat dissipation from the surface of the connection 20 while improving its oxidation resistance. It can also further enhance heat accumulation under overload through local thermal resistance, ensuring priority of melting and enhancing the long-term stability of the structure. Alternatively, if a metal coating is selected, it can isolate the conductive wire 21 from the environment while also enhancing the parallel connection between the conductive wires 21, further enhancing the robustness of the connection 20.
[0057] Please refer to the above as well. Figure 5 As shown, Figure 5 This is a side view of an aluminum busbar structure provided in another embodiment of this application.
[0058] In one embodiment of this application, the natural length of the connecting portion 20 in its current-carrying direction is L1, and the distance between the two welded portions 10 is L2, where L1 > L2.
[0059] In this embodiment, the natural length of the connecting part 20 in its current-carrying direction is greater than the distance between the two welded parts 10. When the single cell connected to the aluminum busbar structure expands and the two welded parts 10 are pulled apart by external force, the connecting part 20 absorbs the deformation by naturally straightening due to its redundant length, adaptively releases mechanical stress, and avoids the risk of structural damage or breakage caused by stretching.
[0060] To address the aforementioned technical problems, this application also provides a battery pack, which includes the aluminum busbar structure described in any of the above claims and a plurality of individual cells, wherein adjacent individual cells are electrically connected through the aluminum busbar structure.
[0061] The battery pack of this embodiment includes the aforementioned aluminum busbar structure, and therefore, the battery pack also possesses the technical effects of the aforementioned aluminum busbar structure.
[0062] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.
[0063] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.
[0064] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.
[0065] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the design concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.
Claims
1. An aluminum fin structure, characterized by, include: Two welded portions, which are configured to be electrically connected to the terminals of a single cell; The connecting part includes multiple conductive wires, at least some of the conductive wires having their ends connected to two of the welding parts respectively.
2. The aluminum array structure of claim 1, wherein, The conductive wire includes a first guide wire extending along a first direction and a second guide wire extending along a second direction, the first direction intersecting the second direction. The two ends of the first guide wire are respectively connected to the welding part, and the two ends of the second guide wire are respectively connected to the welding part. Each first guide wire is electrically connected to multiple second guide wires, and each second guide wire is electrically connected to multiple first guide wires.
3. The aluminum slug structure of claim 2, wherein, Each of the conductive wires has an elliptical cross-section perpendicular to its extension direction, the major axis of the ellipse being located in the plane formed by the first direction and the second direction, and the minor axis of the ellipse being perpendicular to the first direction and the second direction.
4. The aluminum array structure of claim 2, wherein, The first and second guidewires are interwoven to form a mesh structure.
5. The aluminum array structure of claim 4, wherein, On any plane perpendicular to the line connecting the two welded parts, draw a cross-section of the aluminum strip structure. The cross-sectional area of the outer contour of the connecting part is S1, and the cross-sectional area of the welded part is S2, where S1 = S2.
6. The aluminum array structure of claim 1, wherein, The conductive wire includes a third conductor and a fourth conductor. The two ends of each third conductor are electrically connected to the two welding parts respectively, and each fourth conductor is electrically connected to multiple third conductors.
7. The aluminum array structure of claim 6, wherein, Make a cross-section of the aluminum busbar structure on any plane perpendicular to the line connecting the two welded parts. The cross-sectional area of the welded part is S2, and the sum of the cross-sectional areas of each of the fourth guide wires is S3, where S2 = S3.
8. The aluminum fin structure according to any one of claims 1 to 7, characterized by, The aluminum busbar structure also includes a coating layer that covers the surface of the connecting portion.
9. The aluminum fin structure according to any one of claims 1 to 7, characterized by, The natural length of the connecting part in its current-carrying direction is L1, and the distance between the two welded parts is L2, where L1 > L2.
10. A battery pack, characterized by, include: The aluminum busbar structure as described in claims 1-9; Multiple individual cells are electrically connected to each other via the aluminum busbar structure.