Conductive structure, cover plate assembly, and battery cell

Abstract

This invention provides a conductive structure, cover plate assembly, and battery cell that can improve the high cost problem associated with composite poles. [Solution] The conductive structure comprises a first metal column and a second metal layer 2. The first metal column has opposing first ends 11 and second ends 12, with a first stepped portion 11a formed at the first end. The second metal layer is bonded to the surface of the first metal column, covering the first end and extending to the second end. The second metal layer has a second stepped portion 26 that matches the first stepped portion, and the second stepped portion is used for welding to a current collector. In this conductive structure, the bonding area between the second metal layer and the first metal column is the same, and the welding strength between the conductive structure and the current collector is the same. Cost reduction can be achieved by making the diameter of the conductive structure smaller and the thickness of the second metal layer thinner.

Description

Technical Field

[0001] This application claims priority based on a Chinese application with application number 202422195837.8 filed on September 6, 2024, and incorporates by reference all the descriptions contained in that application. This application relates to the technical field of batteries, specifically to a conductive structure, a cover plate assembly, and a battery cell.

Background Art

[0002] The pole is an important component that connects the inside and outside of a cell (also called a battery cell). Usually, one end of the pole is connected to a circuit outside the cell, for example, connected to the bus bar of a module through a terminal pressing block, and the other end of the pole is connected to the internal circuit of the cell, for example, connected to the tab of an electrode assembly through a current collecting member. Currently, most poles are made of a single metal material. For example, the material of the positive pole is aluminum, and the material of the negative pole is copper. However, a pole made of a single metal material is likely to cause problems such as difficulty in welding. Taking the negative pole being a pure copper pole as an example, when laser welding a pure copper pole and a terminal pressing block, in order to reduce costs and the weight of the cell, the material of the terminal pressing block is generally aluminum. However, since the melting points of aluminum and copper are different, problems are likely to occur in laser welding, resulting in cracking.

[0003] To reduce the difficulty of welding, composite poles have been developed in related technologies. These composite poles consist of two metal layers, one above the other, made of different materials, which are joined by friction welding or punching. Taking a negative pole as an example, the composite pole includes an aluminum layer and a copper layer. On the one hand, the ends of the copper layer in the composite pole are provided with a stepped portion for welding together with the current collector. To ensure the effectiveness of the welding, the surface area of ​​the stepped portion must not be too small, so the thickness of the copper layer must not be too thin. On the other hand, in order to ensure the bonding strength between the aluminum layer and the copper layer, the diameter of the composite pole must not be too small. These two factors make it difficult to reduce the cost of composite poles. [Overview of the Initiative]

[0004] Embodiments of the present invention provide a conductive structure, a cover plate assembly, and a battery cell that can improve the problem of the high cost of composite poles.

[0005] In a first embodiment, an embodiment of the present application provides a conductive structure comprising a first metal column and a second metal layer, The first metal column has opposing first and second ends, and a first stepped portion is formed at the first end. A conductive structure characterized in that the second metal layer is bonded to the surface of the first metal column, covers the first end and extends to the second end, and the second metal layer has a second stepped portion that matches the first stepped portion, and the second stepped portion is used for welding to a current collector member.

[0006] In one embodiment, the second stepped portion has a connected first stepped portion surface and a second stepped portion surface, the width of the first stepped portion surface in the radial direction of the first metal column is 0.5 mm or more, and the height of the second stepped portion surface in the axial direction of the first metal column is 0.4 mm or more.

[0007] In one embodiment, the first metal column has a boss portion that protrudes radially, the radial dimension of the boss portion is larger than the radial dimension of the first stepped portion, and the second metal layer extends to the boss portion.

[0008] In one embodiment, the end of the second metal layer extends to the side of the boss portion that is close to the first end and is fitted into the boss portion.

[0009] In one embodiment, the end of the second metal layer extends to the side away from the first end of the boss portion.

[0010] In one embodiment, the conductive structure comprises an integrally provided pole column and a terminal pressing block, and the boss portion is the terminal pressing block.

[0011] In one embodiment, the first stepped portion is a counterbore located at the edge of the end face of the first end, the second metal layer further includes a first segment and a second segment, the first segment corresponding to the end face of the first end, the second segment corresponding to the side surface of the first metal column, and the second stepped portion is connected between the first segment and the second segment.

[0012] In one embodiment, a portion of the end face of the first end is recessed to form a recess, and the first segment includes a first subsegment, a second subsegment, and a third subsegment that are connected in sequence, the first subsegment being located outside the recess, the second subsegment being located on the side wall of the recess, and the third subsegment being located on the bottom wall of the recess.

[0013] In one embodiment, the vertical distance between the outer surface of the first subsegment and the outer surface of the third subsegment is 2.5 mm or less, and / or the average thickness of the first subsegment is 0.5 mm or more, and / or the average thickness of the second subsegment is 0.5 mm or more.

[0014] In one embodiment, the second subsegment extends inclined from the first subsegment to the third subsegment, and the inclination angle of the second subsegment is 15° or more and 60° or less.

[0015] In one embodiment, the bonding interface between the second metal layer and the first metal column is an interlocking interface, and / or the diameter of the conductive structure is 10 mm or less.

[0016] In one embodiment, the average thickness of the second metal layer is 3 mm or less.

[0017] In one embodiment, the end of the second metal layer is fitted into the first metal column.

[0018] In a second embodiment, an embodiment of the present application provides a cover plate assembly, which is a cover plate assembly, Cover plate and The aforementioned conductive structure is provided through the cover plate, The system includes a current collector located on one side of the cover plate and welded to the second stepped portion.

[0019] In one embodiment, the cover plate is The cover plate body and A first insulating member is provided between the conductive structure and the cover plate body, The cover plate body and the current collector member are provided together, and the second insulating member is provided between them. The cover plate assembly further comprises a sealing member provided between the cover plate and the conductive structure.

[0020] In a third embodiment, an embodiment of the present application provides a battery cell, the battery cell is, A housing having an enclosure, An electrode assembly provided within the aforementioned housing cavity and having a tab, Comprising the aforementioned cover plate assembly, the cover plate assembly is connected to the housing and seals the opening of the accommodation cavity, and the current collecting member is connected to the tab.

Advantages of the Invention

[0021] In this conductive structure, while realizing that the bonding area between the second metal layer and the first metal pillar is the same and the welding strength between the conductive structure and the current collecting member is the same, the diameter of the conductive structure is made smaller and the thickness of the second metal layer is made thinner, so that cost reduction can be realized.

Brief Description of the Drawings

[0022] To more clearly explain the technical solutions in the embodiments of the present application, the attached drawings used in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can obtain other drawings based on these drawings without creative labor.

[0023] [Figure 1] It is a cross-sectional structure diagram of the conductive structure according to the embodiment of the present application. [Figure 2] It is an enlarged view of the D part in FIG. 1. [[ID=2) [Figure 3] It is a three-dimensional view of another conductive structure according to the embodiment of the present application at a certain viewing angle. [Figure 4] It is a three-dimensional view of another conductive structure according to the embodiment of the present application at another viewing angle. [Figure 5] It is a cross-sectional structure diagram of another conductive structure according to the embodiment of the present application. [Figure 6] It is an enlarged view of the G part in FIG. 5. [[ID=) [Figure 7] It is an exploded structure diagram of the cover plate assembly according to the embodiment of the present application. [Figure 8] It is a cross-sectional structure diagram of the battery cell according to the embodiment of the present application.

Modes for Carrying Out the Invention

[0024] The technical proposal according to embodiments of the present application will be described below clearly and completely with reference to the accompanying drawings of embodiments of the present application. Clearly, the embodiments described are only a selection of embodiments of the present application, not all embodiments. All other embodiments that can be obtained by those skilled in the art without creative work based on embodiments of the present application are included in the scope of protection of the present application.

[0025] It should be understood that the specific embodiments described herein are used solely for the purpose of illustrating and interpreting this application and are not intended to limit it. In this application, unless otherwise stated, directional terms such as “up” and “down” generally refer to the top and bottom in the actual use or operating state of the device, specifically the drawing direction in the drawings, while “inside” and “outside” refer to the contour of the device.

[0026] The terms “first” and “second” are used solely for descriptive purposes and should not be understood as indicating or implying relative importance, or implicitly specifying the number of technical features. Therefore, features limited by “first” or “second” may explicitly or implicitly include one or more of the aforementioned features. In the description herein, unless otherwise specified, “multiple” means two or more.

[0027] In this description, the terms “attachment,” “connection,” and “connection” should be understood broadly unless otherwise explicitly stated or limited. For example, a fixed connection may be a detachable or integral connection. A mechanical connection may be an electrical connection or a communication connection. A direct connection may be an indirect connection via an intermediate medium, or an internal connection or interaction relationship between two elements. A person skilled in the art will understand the specific meaning of the aforementioned terms in this description according to the specific context.

[0028] Furthermore, since the terms “includes,” “equipment,” and other variations thereof are intended in this specification to cover non-exclusive inclusion, it should be noted that a process, method, article, or apparatus that includes a set of elements not only includes those elements but also includes other elements not expressly listed, or elements specific to the process, method, article, or user. Unless otherwise restricted, an element limited by the phrase “includes one…” does not exclude the presence of other identical elements in a process, method, article, or user apparatus that include that element.

[0029] In the description of embodiments of this Application, words such as “exemplary” or “for example” are used to indicate examples, descriptions, or descriptions. Any embodiment or design described as “exemplary” or “for example” in the embodiments of this Application should not be construed as being preferable or advantageous to other embodiments or designs. The use of words such as “exemplary” or “for example” is intended to clearly present relative concepts.

[0030] To facilitate understanding of the solution of this application, spline curves and arrows used by symbols in the drawings are described here. Components indicated by spline curves without arrows are substantial components, that is, components with a physical structure. Components indicated by spline curves with arrows are virtual components, that is, components without a physical structure.

[0031] Embodiments of the present invention provide a conductive structure, a cover plate assembly, and a battery cell.

[0032] In a first embodiment, an embodiment of the present invention provides a conductive structure for connecting the internal circuit of a battery cell to the external circuit of the battery cell (simply referred to as the external circuit), thereby enabling communication between the battery cell and the external circuit, allowing the external circuit to supply power to the battery cell (i.e., charging the battery cell), or allowing the battery cell to supply power to the external circuit (i.e., discharging the battery cell). Specifically, the conductive structure can be used to be attached to the cover plate of a battery cell.

[0033] Specifically, refer to Figures 1 to 8. The conductive structure 10 comprises a first metal column 1 and a second metal layer 2, the second metal layer 2 being bonded to the surface of the first metal column 1. Specifically, the first metal column 1 has opposing ends, a first end 11 and a second end 12, respectively, and the second metal layer 2 covers the first end 11 and extends to the second end 12.

[0034] The conductive structure 10 comprises a first metal column 1 and a second metal layer 2. The first metal column 1 has a columnar structure and its material contains a first metal, while the second metal layer 2 has a layered structure and its material contains a second metal. Here, the second metal and the first metal are different metals.

[0035] The bonding of the second metal layer 2 to the surface of the first metal column 1 means that the second metal layer 2 is located on the outer surface of the first metal column 1, and that the second metal layer 2 is bonded to the first metal column 1. Here, bonding means that the second metal layer 2 and the first metal column 1 do not separate simply due to the action of gravity. For example, the second metal layer 2 is physically bonded to the first metal column 1. As an example, the second metal layer 2 and the first metal column 1 may be bonded by cold heading.

[0036] To make it clear, the second metal layer 2 covers the surface of the first end 11 and extends from the surface of the first end 11 to the second end 12. Specifically, the extension of the second metal layer 2 from the first end 11 to the second end 12 means that the end 20 of the second metal layer 2 extends to the second end 12, and the end 20 of the second metal layer 2 may extend to the second end 12, or it may extend to a position between the first end 11 and the second end 12. Selectively, the end 20 of the second metal layer 2 extends to the second end 12, but the second metal layer 2 does not completely cover the second end 12, that is, at least a portion of the second end 12 is exposed to the outside of the second metal layer 2. Here, the end 20 of the second metal layer 2 refers to the edge portion of the second metal layer 2.

[0037] By extending the second metal layer 2 from the first end 11 to the second end 12 of the first metal column 1, compared to a configuration where the second metal layer 2 is provided only on one end face of the first metal column 1, the bonding area between the second metal layer 2 and the first metal column 1 can be effectively increased for the same diameter, ensuring the overcurrent capability of the conductive structure 10 and reducing the risk of the second metal layer 2 falling off. In other words, for the same bonding area, the above solution allows for a smaller diameter of the conductive structure 10, thereby reducing the cost of the conductive structure 10.

[0038] When the conductive structure 10 is applied to a battery cell 1000, the first end 11 of the first metal column 1 is directed towards the inside of the battery cell 1000, and the second end 12 is directed towards the outside of the battery cell 1000. The second metal layer 2 covers the first end 11 of the first metal column 1 and extends from the first end 11 to the second end 12. In this way, the second metal layer 2 acts as a protective layer, isolating the first end 11 of the first metal column 1 from the electrolyte inside the battery cell 1000 and reducing the risk of the first end 11 being corroded by the electrolyte.

[0039] Here, a first stepped portion 11a is further formed on the first end 11 of the first metal column 1. The second metal layer 2 covers the surface of the first end 11, and a second stepped portion 26 is formed on the second metal layer 2 that matches the first stepped portion 11a. The second stepped portion 26 is used for welding to the current collector member 120. When welding the conductive structure 10 and the current collector member 120, the current collector member 120 is sleeved in the conductive structure 10, the current collector member 120 and the second stepped portion 26 are aligned, and the current collector member 120 can be welded to the second stepped portion 26 by laser welding. The larger the surface area of ​​the second stepped portion 26, the larger the weldable surface area between the second stepped portion 26 and the current collector member 120, and the larger the weld surface area, the higher the reliability of the welding.

[0040] The conductive structure 10 also has a stepped portion at one end, and it is predicted that this stepped portion is formed by stacking the second stepped portion 26 on the first stepped portion 11a, and that the first metal column 1 and the second metal layer 2 are formed by synchronous recessing. The advantage of this arrangement is that it changes the strong correlation between the area of ​​the second stepped portion 26 and the thickness of the second metal layer 2, so that even if the thickness of the second metal layer 2 is very small, a sufficiently large second stepped portion 26 can be formed, and the welding effect between the second stepped portion 26 and the current collector member 120 is ensured.

[0041] Furthermore, this method effectively reduces the risk of the second metal layer 2 rupturing, and the second stepped portion 26 can effectively block the transmission of the laser during laser welding.

[0042] In other words, compared to a method in which the second metal layer 2 is provided only on the end face of one end of the first metal column 1, the conductive structure 10 according to the present invention achieves the same bonding area between the second metal layer 2 and the first metal column 1, as well as the same welding strength between the conductive structure 10 and the current collector member 120, while reducing the diameter of the conductive structure 10 and making the thickness of the second metal layer 2 thinner, thereby achieving cost reduction.

[0043] In some embodiments, the average thickness D1 of the second metal layer 2 is 3 mm or less. By making the second metal layer 2 thinner, the production cost of the conductive structure 10 can be effectively reduced. For example, the average thickness D1 of the second metal layer 2 is 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.5 mm, 2.8 mm, or 3.0 mm. Selectively, the average thickness D1 of the second metal layer 2 is 1.8 mm or less.

[0044] In some embodiments, the diameter R of the conductive structure 10 is 10 mm or less. By reducing the size of the conductive structure 10, the production cost of the conductive structure 10 can be effectively reduced. For example, the diameter R of the conductive structure 10 is 7 mm, 8 mm, 9 mm, or 10 mm.

[0045] In some embodiments, the bonding interface between the second metal layer 2 and the first metal column 1 is an interlocking interface. Here, an interlocking interface refers to a microscopic interlocking of the surface of the second metal layer 2 and the surface of the first metal column 1. Selectively, the conductive structure 10 is a cold-formed product. For example, the first metal column 1 is an aluminum column, the second metal layer 2 is a copper layer, and the conductive structure 10 is obtained by forming a copper-aluminum composite plate by cold forming. Because the metal is ductile, during cold forming, the pressure causes the first metal in the first metal column 1 and the second metal in the second metal layer 2 to deform and penetrate each other, thereby forming the bonding interface between the first metal column 1 and the second metal layer 2 into a microscopically uneven, wavy surface. This increases the bonding area between the first metal column 1 and the second metal layer 2, improving the bonding strength.

[0046] In some embodiments, referring to Figures 1, 2, and 6, the second stepped portion 26 has a connected first stepped portion surface 261 and a second stepped portion surface 262. Specifically, the second stepped portion 26 is L-shaped, the first stepped portion surface 261 is a surface extending along a first direction of the second stepped portion 26, and the second stepped portion surface 262 is a surface extending along a second direction of the second stepped portion 26. Here, the first and second directions intersect. Selectively, the first direction is perpendicular to the second direction. For example, the first direction is the radial direction of the first metal column 1, and the second direction is the axial direction of the first metal column 1. The width W31 of the first stepped portion surface 261 in the radial direction of the first metal column 1 is ≥ 0.5 mm. For example, the width W31 of the first stepped surface 261 is 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm. The height H31 of the second stepped surface 262 in the axial direction of the first metal column 1 is ≥ 0.4 mm. For example, the height H31 of the second stepped surface 262 is 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm. By increasing the width of the first stepped surface 261 and the height of the second stepped surface 262, a sufficient contact surface can be secured when the second stepped portion 26 is aligned with the current collector member 120, thereby improving the welding effect and current tolerance.

[0047] In some embodiments, referring to Figures 1 and 5, a boss portion 13 projecting radially is formed on the first metal column 1, the radial dimension of the boss portion 13 is greater than the radial dimension of the first stepped portion 11a, and the second metal layer 2 extends over the boss portion 13. Specifically, a portion of the first metal column 1 projects outward along approximately the radial direction of the first metal column 1 to form the boss portion 13. For example, the deviation of the angle between the boss portion 13 and the radial direction of the first metal column 1 is within ±15°. A boss portion 13 is formed on the first metal column 1, and the radial dimension of the boss portion 13 is larger than the radial dimension of the first stepped portion 11a. When the conductive structure 10 is applied to a battery cell 1000, the boss portion 13 can be fitted together with other parts (e.g., a cover plate 110) as a stopper structure, and the second metal layer 2 extends to the boss portion 13, allowing the second metal layer 2 to be sandwiched between the boss portion 13 and the part that is fitted together with the boss portion 13. Furthermore, the increased bonding surface between the second metal layer 2 and the first metal column 1 reduces the risk of the second metal layer 2 detaching from the first metal column 1. For example, the boss portion 13 may be formed on the second end 12, or the boss portion 13 may be located between the second end 12 and the first end 11.

[0048] In some embodiments, referring to Figure 1, the end 20 of the second metal layer 2 is fitted into the first metal column 1. For example, the end 20 of the second metal layer 2 extends to the side closer to the first end 11 of the boss portion 13 and is fitted into the boss portion 13. Since the connection between the end 20 of the second metal layer 2 and the first metal column 1 is usually prone to weak points, fitting the end 20 of the second metal layer 2 into the first metal column 1 increases the bonding area between the end 20 of the second metal layer 2 and the first metal column 1, thereby improving the bonding strength. In addition, since the end 20 of the second metal layer 2 is hidden inside the first metal column 1, the end 20 of the second metal layer 2 is less likely to be caught by external forces, and the risk of the second metal layer 2 peeling off is also reduced. Of course, in some embodiments, the end of the second metal layer 2 may be fitted into a portion of the first metal column 1 located on the side away from the first end 11 of the boss portion 13.

[0049] In some embodiments, referring to Figure 5, the end 20 of the second metal layer extends to the side away from the first end 11 of the boss portion 13. Since the end 20 of the second metal layer 2 extends from the first end 11 to the second end 12 of the first metal column 1, extending the end 20 of the second metal layer 2 to the side away from the first end 11 of the boss portion 13 allows the second metal layer 2 to cover most of the surface of the boss portion 13, and even the entire surface, further increasing the bonding area between the second metal layer 2 and the first metal column 1, improving the current tolerance of the conductive structure 10, improving the bonding strength between the second metal layer 2 and the first metal column 1, and reducing the risk of the second metal layer 2 detaching from the first metal column 1.

[0050] In some embodiments, referring to Figure 5, the conductive structure 10 is a pole post 101. In a battery cell 1000, the pole post 101, as a conductive member for connecting to the electrode assembly 1200, is typically located partly inside the battery cell 1000 and partly outside the battery cell 1000. Exemplarily, the pole post 101 is connected to a tab 1210 in the electrode assembly 1200. The pole post 101 may be directly connected to the tab 1210 or may be connected to the tab 1210 by another member (e.g., a current collector member 120). Selectively, the pole post 101 includes a negative pole post.

[0051] In some embodiments, referring to Figure 1, the conductive structure 10 is an integrated pole post-terminal pressing block structure, that is, the conductive structure 10 is an integrally provided pole post 101 and terminal pressing block 102, where the boss portion 13 is the terminal pressing block 102. By integrally providing the pole post 101 and the terminal pressing block 102, the assembly process of the pole post 101 and the terminal pressing block 102 can be omitted, and the production cost of the battery cell 1000 can be reduced. Furthermore, since the second metal layer 2 extends to the boss portion 13, that is, since the second metal layer 2 extends to the terminal pressing block 102, there is no need to increase the volume of the pole post 101, and by simply doubling the terminal pressing blocks 102, the bonding area of ​​the second metal layer 2 can be greatly increased, reducing the risk of the second metal layer 2 falling off, further improving the current tolerance capacity of the conductive structure 10 without adding volume or weight. The terminal pressing block 102 described above is also a component of the battery cell 1000, and is typically located outside the battery cell 1000. That is, when the pole-terminal pressing block integrated structure is attached to the battery cell 1000, for example to the cover plate 110 of the battery cell 1000, the boss portion 13 is located outside the battery cell 1000. The terminal pressing block 102 is also used to electrically connect to external structures; for example, the terminal pressing block 102 is connected to the busbar of the module.

[0052] In some embodiments, referring to Figures 1 to 6, the first stepped portion 11a is a counterbore located at the edge of the end face of the first end 11. Specifically, the counterbore is formed by sinking along the direction in which the edge of the end face of the first end 11 approaches the second end 12. The second metal layer 2 further includes a first segment 21 and a second segment 22, where the first segment 21 corresponds to the end face of the first end 11, the second segment 22 corresponds to the side surface of the first metal column 1, and the second stepped portion 26 is connected between the first segment 21 and the second segment 22. In other words, the second metal layer 2 includes the first segment 21, the second stepped portion 26, and the second segment 22 connected in sequence. The first segment 21, the second stepped portion 26, and the second segment 22 constitute a continuous film layer that covers the outer surface of the first end 11, effectively protecting the first end 11 and reducing corrosion of the first end 11 by the electrolyte.

[0053] In some embodiments, referring to Figures 3 to 6, the second metal layer 2 further includes a third segment 23. The third segment 23 corresponds to the surface of the boss portion 13 on the side closer to the first end 11, and the second segment 22 connects the first segment 21 and the third segment 23.

[0054] In some embodiments, referring to Figures 3 to 6, the second metal layer 2 further includes a fourth segment 24. The fourth segment 24 corresponds to the side surface of the boss portion 13 and is connected to the third segment 23.

[0055] In some embodiments, referring to Figures 3 to 6, the second metal layer 2 further includes a fifth segment 25. The fifth segment 25 corresponds to the surface of the boss portion 13 away from the first end 11. The fourth segment 24 connects the fifth segment 25 and the third segment 23.

[0056] In some embodiments, referring to Figure 6, the fourth segment 24 and the fifth segment 25 are formed such that the folded layer 251 covers the tip of the boss portion 13. Along the axial direction of the first metal column 1, the distance between the outer surface of the third segment 23 and the outer surface of the folded layer 251 is K1, the thickness of the folded layer 251 is K2, and f = K2 / K1, where f is between 0.3 and 1.

[0057] In some embodiments, referring to Figures 3 to 6, a portion of the end face of the first end 11 is recessed to form a recess 11b. Here, recess means recessing into the interior of the first metal column 1. The first segment 21 includes a first subsegment 211, a second subsegment 212, and a third subsegment 213 connected in sequence, with the first subsegment 211 located outside the recess 11b, the second subsegment 212 located on the side wall of the recess 11b, and the third subsegment 213 located on the bottom wall of the recess 11b. In other words, the second metal layer 2 also forms the second subsegment 212 and the third subsegment 213 that are in close contact with the inner wall surface of the recess 11b in accordance with the surface deformation of the first end 11. By providing the recess 11b on the end face of the first end 11 and making the second metal layer 2 in close contact with the inner wall surface of the recess 11b, the bonding area between the second metal layer 2 and the first metal column 1 is increased, improving the bonding strength. Furthermore, when the bonding interface between the first metal column 1 and the second metal layer 2 is formed into a wavy surface with microscopic irregularities, providing a recess 11b promotes the flow of the first metal within the first end 11 to the first stepped portion 11a, compensating for the microscopically irregular wavy surface and making the surface of the second stepped portion 26 relatively flat. This reduces the decrease in welding consistency caused by the presence of large peaks and valleys on the surface of the second stepped portion 26 when the second stepped portion 26 is welded to the current collector member 120.

[0058] In some embodiments, referring to Figure 6, the average thickness d2 of the second segment 22 is ≥ 0.5 mm. The second step portion 26 is welded to the current collector member 120 as a welded portion. As the portion directly connected to the second step portion 26, the second segment 22 needs to be ensured to have sufficient mechanical strength to prevent fracture and corrosion of the first metal column 1 by the electrolyte. Generally, the greater the average thickness of the second segment 22, the greater the mechanical strength of the second segment 22. Here, the thickness of the second segment 22 is the dimension of the second segment 22 along the radial direction of the first metal column 1. For example, the average thickness d2 of the second segment 22 is 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, or 2.5 mm.

[0059] In some embodiments, referring to Figure 6, the average thickness d11 of the first subsegment 211 is ≥ 0.5 mm. The second stepped portion 26 is welded to the current collector member 120 as a welded portion. As the portion directly connected to the second stepped portion 26, the first subsegment 211 needs to be ensured to have sufficient mechanical strength to prevent fracture and corrosion of the first metal column 1 by the electrolyte. Generally, the greater the average thickness of the first subsegment 211, the greater the mechanical strength of the first subsegment 211. Here, the thickness of the first subsegment 211 is the dimension of the first subsegment 211 along the axial direction of the first metal column 1. For example, the average thickness d11 of the first subsegment 211 is 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, or 2.5 mm.

[0060] In some embodiments, referring to Figure 5, the vertical distance H2 between the outer surface of the first subsegment 211 and the outer surface of the third subsegment 213 is ≤ 2.5 mm. For example, H2 is 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, or 2.5 mm. By having the vertical distance H2 between the outer surface of the first subsegment 211 and the outer surface of the third subsegment 213 within the above range, it is possible to ensure excellent bonding strength between the first metal column 1 and the second metal layer 2, and that the manufacturing difficulty of the conductive structure 10 is low.

[0061] In some embodiments, referring to Figure 5, the second subsegment 212 extends inclined from the first subsegment 211 to the third subsegment 213, and the inclination angle σ of the second subsegment 212 satisfies the following condition 15° ≤ σ ≤ 60°. Here, the inclination angle σ refers to the inclination angle of the second subsegment 212 with respect to the plane on which it extends along the radial direction of the first metal column 1. For example, the inclination angle σ is 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, or 60°. By controlling the inclination angle σ of the second subsegment 212, the second subsegment 212 smoothly transitions from the first subsegment 211 to the third subsegment 213, and the fracture phenomenon of the second metal layer 2 due to stress concentration at the connection points between the second subsegment 212 and the first subsegment 211 and between the second subsegment 212 and the third subsegment 213 can be mitigated.

[0062] In a second aspect, embodiments of the present invention further provide a cover plate assembly 100, which, together with the housing 1100 of the battery cell 1000, forms a sealed cavity, which houses the electrode assembly 1200 of the battery cell 1000.

[0063] Specifically, referring to Figure 7, the cover plate assembly 100 comprises a cover plate 110 and the aforementioned conductive structure 10 connected to the cover plate 110. Specifically, the conductive structure 10 is inserted through the cover plate 110.

[0064] In detail, along the thickness direction of the cover plate 110, the cover plate 110 has a first surface and a second surface facing away from each other. When the cover plate assembly 100 is attached to the housing 1100 of the battery cell 1000, the first surface is the surface away from the housing 1100, and the second surface is the surface closer to the housing 1100. Along the thickness direction of the cover plate 110, mounting holes are provided through the cover plate 110, and the conductive structure 10 is provided through the cover plate 110 via the mounting holes.

[0065] Specifically, the cover plate assembly 100 further comprises a current collector member 120. The current collector member 120 is a conductive member for connecting to the tab 1210 of the electrode assembly 1200 in the battery cell 1000. The current collector member 120 is located on one side of the cover plate 110, specifically, on the second surface of the cover plate 110. The current collector member 120 is welded to the conductive structure 10, specifically, to the second step portion 26 in the second metal layer 2. Selectively, the material of the current collector member 120 is the same as the material of the second metal layer 2, i.e., the material of the current collector member 120 is the second metal, thus reducing the difficulty of welding the current collector member 120 to the second step portion 26 and improving the reliability of the welding.

[0066] In some embodiments, the current collector 120 includes at least one of a current collector disc and a connecting piece.

[0067] In some embodiments, the current collector 120 comprises a current collector body and a connecting piece connected to the current collector body. Here, the current collector body is for connecting to the tab 1210 of the electrode assembly 1200, and the connecting piece is welded to the second stepped portion 26.

[0068] In some embodiments, the cover plate 110 comprises a cover plate body 111, a first insulating member 112, and a second insulating member 113. Here, the first insulating member 112 and the second insulating member 113 are each positioned on the opposite side of the cover plate body 111. More specifically, the first insulating member 112 is provided between the conductive structure 10 (e.g., a boss portion 13) and the cover plate body 111, and the second insulating member 113 is provided between the cover plate body 111 and the current collector 120. The cover plate 110 is provided with mounting holes 114 that penetrate the cover plate body 111, the first insulating member 112, and the second insulating member 113. For example, the cover plate body 111 is an untreated aluminum plate, and both the first insulating member 112 and the second insulating member 113 are plastic members.

[0069] In some embodiments, the cover plate assembly 100 further comprises a sealing member 130. The sealing member 130 is provided between the cover plate 110 and the conductive structure 10 and prevents electrolyte leakage from the gap between the conductive structure 10 and the mounting hole. For example, the sealing member 130 is located between the cover plate body 111 and the second insulating member 113.

[0070] In some embodiments, the assembly process for the cover plate assembly 100 includes aligning the holes and stacking the second insulating member 113, the sealing member 130, the cover plate body 111, and the first insulating member 112 sequentially from bottom to top; passing the conductive structure 10 through the mounting holes 114 from top to bottom and bringing the larger end (e.g., boss portion 13) of the conductive structure 10 into contact with the first insulating member 112; attaching the current collector member 120 to the side of the second insulating member 113 away from the sealing member 130; and laser welding the current collector member 120 to the second stepped portion 26 of the conductive structure 10.

[0071] In some embodiments, the cover plate assembly 100 further comprises an explosion-proof valve 140, which is provided on the cover plate 110.

[0072] In some embodiments, the cover plate 110 is further provided with an injection hole 115 and a sealing structure (not shown) for sealing the injection hole.

[0073] In a third aspect, embodiments of the present invention further provide a battery cell 1000, also known as a cell, which is a basic unit that realizes the interconversion of chemical energy and electrical energy.

[0074] Specifically, referring to Figure 8, the battery cell 1000 comprises a housing 1100, an electrode assembly 1200, and the aforementioned cover plate assembly 100. Specifically, the housing 1100 has a housing cavity 1110. The electrode assembly 1200 is located inside the housing cavity 1110, and the cover plate assembly 100 is connected to the housing 1100 and seals the housing cavity 1110. The electrode assembly 1200 includes a tab 1210, to which the conductive structure 10 is connected.

[0075] Specifically, the electrode assembly 1200 further comprises an electrode sheet and a separator. Tab 1210 is connected to the electrode sheet, which includes a positive electrode sheet and a negative electrode sheet, and the separator is located between the positive electrode sheet and the negative electrode sheet. To understand this, tab 1210 further includes a positive electrode tab and a negative electrode tab, where the positive electrode tab is connected to the positive electrode sheet and the negative electrode tab is connected to the negative electrode sheet.

[0076] Furthermore, the battery cell 1000 is further equipped with an electrolyte, which is located within the housing cavity 1110, and the electrode assembly 1200 is immersed in the electrolyte.

[0077] Embodiments of the present application have been described in detail above. While this specification uses specific examples to illustrate the principles and embodiments of the present application, the above descriptions of embodiments are intended solely as reference for understanding the methods and core ideas of the present application. Furthermore, while those skilled in the art may modify the embodiments and scope of application according to the ideas of the present application, in summary, the contents of this specification should not be understood as limitations on the present application. [Explanation of Symbols]

[0078] 10 Conductive structure 101 Pole Pillar 102 Terminal pressing block 1 1st metal pillar 11 1st end 11a First step section 11b recess 12 2nd end 13 Boss Section 2 Second metal layer 20 End 21. Segment 1 211 First Subsegment 212 Second Segment 213 Third Subsegment 22. Segment 2 23 Third Segment 24. Segment 4 25. Fifth Segment 251 Folding Layer 26 Second step section 261 Surface of the first stepped section 262 Surface of the second stepped section 100 Cover Plate Assembly 110 Cover Plate 111 Cover plate body 112 First insulator 113 Second insulator 114 mounting holes 115 Liquid injection hole 120 Flow collection member 130 Sealing member 140 Explosion-proof valve 1000 battery cells 1100 cabinets 1110 Capacity Cavity 1200 Electrode Assembly 1210 tabs.

Claims

1. A conductive structure comprising a first metal column and a second metal layer, The first metal column has opposing first and second ends, and a first stepped portion is formed at the first end. A conductive structure characterized in that the second metal layer is bonded to the surface of the first metal column, covers the first end and extends to the second end, and the second metal layer has a second stepped portion that matches the first stepped portion, and the second stepped portion is used for welding to a current collector member.

2. The conductive structure according to claim 1, characterized in that the second stepped portion has a connected first stepped portion surface and a second stepped portion surface, the width of the first stepped portion surface in the radial direction of the first metal column is 0.5 mm or more, and the height of the second stepped portion surface in the axial direction of the first metal column is 0.4 mm or more.

3. The conductive structure according to claim 1, characterized in that the first metal column has a boss portion that protrudes radially, the radial dimension of the boss portion is larger than the radial dimension of the first stepped portion, and the second metal layer extends to the boss portion.

4. The conductive structure according to claim 3, characterized in that the end of the second metal layer extends to the side close to the first end of the boss portion and is fitted into the boss portion.

5. The conductive structure according to claim 3, characterized in that the end of the second metal layer extends to the side away from the first end of the boss portion.

6. The conductive structure according to claim 3, wherein the conductive structure comprises an integrally provided pole post and terminal pressing block, and the boss portion is the terminal pressing block.

7. The conductive structure according to claim 1, wherein the first stepped portion is a counterbore located at the edge of the end face of the first end, the second metal layer further includes a first segment and a second segment, the first segment corresponding to the end face of the first end, the second segment corresponding to the side surface of the first metal column, and the second stepped portion is connected between the first segment and the second segment.

8. The conductive structure according to claim 7, characterized in that a portion of the end face of the first end is recessed to form a recess, the first segment includes a first subsegment, a second subsegment, and a third subsegment connected in sequence, the first subsegment being located outside the recess, the second subsegment being located on the side wall of the recess, and the third subsegment being located on the bottom wall of the recess.

9. The conductive structure according to claim 8, characterized in that the vertical distance between the outer surface of the first subsegment and the outer surface of the third subsegment is 2.5 mm or less, and / or the average thickness of the first subsegment is 0.5 mm or more, and / or the average thickness of the second subsegment is 0.5 mm or more.

10. The conductive structure according to claim 8, characterized in that the second subsegment extends inclined from the first subsegment to the third subsegment, and the inclination angle of the second subsegment is 15° or more and 60° or less.

11. The conductive structure according to any one of claims 1 to 10, characterized in that the bonding interface between the second metal layer and the first metal column is an interlocking interface, and / or the diameter of the conductive structure is 10 mm or less, and / or the average thickness of the second metal layer is 3 mm or less.

12. The conductive structure according to claim 1, characterized in that the end of the second metal layer is fitted into the first metal column.

13. A cover plate assembly, Cover plate and A conductive structure according to any one of claims 1 to 10 is provided through the cover plate, A cover plate assembly characterized by comprising a current collector member located on one side of the cover plate and welded to the second stepped portion.

14. The aforementioned cover plate is The cover plate body and A first insulating member is provided between the conductive structure and the cover plate body, The cover plate body and the current collector member are provided together, and the second insulating member is provided between them. The cover plate assembly according to claim 13, further comprising a sealing member provided between the cover plate and the conductive structure.

15. It is a battery cell, A housing having an enclosure, An electrode assembly provided within the aforementioned housing cavity and having a tab, A battery cell comprising a cover plate assembly according to claim 13, wherein the cover plate assembly is connected to the housing and seals the opening of the housing cavity, and the current collector is connected to the tab.

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