Post, top cover assembly, post assembly, battery cell, battery module and battery pack

Abstract

The present application provides a post, comprising a first metal member and a second metal member which are stacked in a first direction. The first metal member is provided with a first protruding part protruding in the first direction; the second metal member is provided with a first recessed part, the first protruding part fitting into the first recessed part; the maximum thickness of the first metal member at the first protruding part in the first direction is H1, and the corresponding thickness of the second metal member at the maximum thickness of the first metal member in the first direction is H2, satisfying: 0.25≤H1 / H2≤1.55, wherein the first metal member and the second metal member are made of different materials.

Description

Terminal posts, top cover assembly, terminal post assembly, battery cells, battery modules and battery packs

[0001] This application claims priority to Chinese patent applications filed on March 19, 2025, with application numbers 202520491591.0, 202520491597.8, 202520491586.X and 202510331109.1, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to a terminal post, a top cover assembly, a terminal post assembly, a battery cell, a battery module, and a battery pack. Background Technology

[0003] In the field of new energy vehicles, batteries typically use aluminum and copper as the positive and negative electrode materials, respectively. If the negative electrode post is made of pure copper, it will result in higher costs. Furthermore, when a pure copper negative electrode post is welded to an aluminum terminal, the difference in melting points between the two materials can easily lead to welding failure and subsequent cracking of the weld structure.

[0004] In related technologies, in order to reduce the cost of the negative electrode post and improve the welding stability between the negative electrode post and the terminal, a layered electrode post with an upper part of aluminum and a lower part of copper is usually used. Invention Overview

[0005] However, welding between the aluminum and copper layers is difficult, and intermediate compounds can easily form between copper and aluminum, leading to an increase in resistance and thus affecting the electrical performance of the battery cell.

[0006] This application provides an electrode post, including a first metal member and a second metal member stacked along a first direction. The first metal member has a first protrusion protruding along the first direction, and the second metal member has a first recess, with the first protrusion fitting into the first recess. The first metal member has a maximum thickness H1 at the first protrusion in the first direction, and the second metal member has a corresponding thickness H2 at the maximum thickness of the first metal member in the first direction, satisfying: 0.25 ≤ H1 / H2 ≤ 1.55. The first and second metal members are made of different materials. By stacking the first and second metal members of different materials, the connection stability between the electrode post and the inside and outside of the battery cell can be ensured, while the cost of the electrode post can be reduced through material selection. The fitting of the first protrusion on the first metal member and the first recess on the second metal member increases the bonding area between the first and second metal members, ensuring the structural stability of the electrode post. Furthermore, by making the maximum thickness of the first metal part at the first protrusion H1 and the thickness of the second metal part at the corresponding maximum thickness of the first metal part H2, satisfying the relationship 0.25≤H1 / H2≤1.55, the resistance of the electrode post can be reduced, and the first metal layer and the second metal layer can produce a good mutual penetration effect at the bonding interface, thus ensuring the structural stability of the electrode post.

[0007] This application also provides a top cover assembly including the aforementioned pole. The top cover assembly, by including the aforementioned pole, ensures structural stability.

[0008] This application also provides a battery cell, including a housing, a core package, and the aforementioned top cover assembly. The core package is disposed within the housing, and the top cover assembly is fastened to the open end of the housing. The battery cell provided in this application has good structural stability.

[0009] This application also provides an electrode assembly, including an outer connecting piece and the electrode as described above. The electrode includes a first metal member and a second metal member stacked along a first direction. The outer connecting piece is stacked along the first direction on the side of the second metal member away from the first metal member, and the outer connecting piece is welded to the second metal member to form a first weld portion. The first weld portion penetrates the outer connecting piece along the first direction and is partially located within the second metal member, where 0 < C1 - H1 ≤ 0.5H2, where C1 represents the effective penetration depth of the first weld portion in the first direction, H1 represents the thickness of the outer connecting piece in the first direction, and H2 represents the minimum thickness of the second metal member at the corresponding first weld portion in the first direction. For an electrode composed of a first metal member and a second metal member, by having the first weld portion penetrate the outer connecting piece along the first direction and be partially located within the second metal member, the outer connecting piece and the second metal member can be welded into a whole, thereby realizing the connection between the outer connecting piece and the electrode. By satisfying the formula 0<C1-H1≤0.5H2, it is possible to ensure the welding of the external connecting piece and the electrode post while reducing the impact of heat during the welding process on the composite interface of the first and second metal parts in the electrode post, reducing the risk of composite interface damage, ensuring welding stability, and improving the electrical performance of the electrode post assembly after welding.

[0010] This application also provides a battery module including multiple battery cells, which are connected by the aforementioned terminal assembly, thereby ensuring welding stability while improving the electrical performance between the battery cells.

[0011] This application also provides a battery pack, including the battery module described above, which can ensure stability and improve electrical performance. Attached Figure Description

[0012] Figure 1 is a schematic diagram of the cross-sectional structure of a pole provided in an embodiment of this application;

[0013] Figure 2 is a schematic diagram of the cross-sectional structure of a pole provided in an embodiment of this application;

[0014] Figure 3 is a schematic diagram of the cross-sectional structure of a pole provided in an embodiment of this application;

[0015] Figure 4 is a schematic diagram of another cross-sectional structure of the pole provided in an embodiment of this application;

[0016] Figure 5 is a cross-sectional schematic diagram of a first structure of a pole provided in an embodiment of this application;

[0017] Figure 6 is an enlarged view of point A in Figure 5;

[0018] Figure 7 is a partial cross-sectional schematic diagram of a second structure of a pole post provided in an embodiment of this application;

[0019] Figure 8 is a partial cross-sectional schematic diagram of a third structure of a pole provided in an embodiment of this application;

[0020] Figure 9 is a partial cross-sectional schematic diagram of a fourth structure of a pole provided in an embodiment of this application;

[0021] Figure 10 is a partial cross-sectional schematic diagram of a fourth structure of a pole provided in an embodiment of this application;

[0022] Figure 11 is a partial cross-sectional schematic diagram of a fifth structure of a pole provided in an embodiment of this application;

[0023] Figure 12 is a partial cross-sectional schematic diagram of a fourth structure of a pole provided in an embodiment of this application.

[0024] Figure 13 is a schematic diagram of the structure of the first metal layer and the second metal layer provided in the embodiments of this application;

[0025] Figure 14 is a schematic diagram of the flow region in the pole provided by an embodiment of this application;

[0026] Figure 15 is a schematic diagram of the top cover assembly provided in an embodiment of this application.

[0027] Figure 16 is a partial structural schematic diagram of the pole assembly provided in an embodiment of this application;

[0028] Figure 17 is an enlarged view of point B in Figure 16;

[0029] Figure 18 is an enlarged view of point C in Figure 16;

[0030] Figure 19 is a top view of the pole assembly provided in an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 100. Pole post; 1. First metal component; 11. First protrusion; 111. First protrusion section; 12. Reverse wrapping structure; 13. Second recess; 14. Protrusion; 15. First flow region; 16. Second flow region; 17. Third flow region; 2. Second metal component; 21. First recess; 22. Second protrusion; 23. First step structure; 24. Second step structure; 3. First metal layer; 4. Second metal layer;

[0033] 100a, Metal part; 110, Third recess; 110a, Notch;

[0034] 200. Cover plate; 210. Insulating component; 211. First insulating component; 212. Second insulating component; 220. Sealing ring; 230. Terminal clamping block;

[0035] 300, pole assembly; 310, outer connecting piece; 311, first welding part; 312, welding trajectory; 320, inner connecting piece; 321, second welding part. Embodiments of the present invention

[0036] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances. Furthermore, the terms "first" and "second" are used for descriptive distinction and have no special meaning.

[0037] Firstly, as shown in Figure 1, an embodiment of this application provides an electrode post 100, which includes a first metal member 1 and a second metal member 2 stacked along a first direction Y. The first metal member 1 has a first protrusion 11 protruding along the first direction Y, and the second metal member 2 has a first recess 21, with the first protrusion 11 fitting into the first recess 21. The maximum thickness of the first metal member 1 at the first protrusion 11 along the first direction Y is H1, and the corresponding thickness of the second metal member 2 at the maximum thickness of the first metal member 1 along the first direction Y is H2, satisfying: 0.4 ≤ H1 / H2 ≤ 1.55. The first metal member 1 and the second metal member 2 are made of different materials. By stacking the first metal member 1 and the second metal member 2 with different materials, the connection stability between the electrode post 100 and the inside and outside of the battery cell can be ensured, and the cost of the electrode post 100 can be reduced through material selection. The first protrusion 11 on the first metal part 1 and the first recess 21 on the second metal part 2 fit together, which can increase the bonding area between the first metal part 1 and the second metal part 2 and ensure the structural stability of the pole post 100. In addition, by satisfying the relationship 0.25≤H1 / H2≤1.55, the resistance of the pole post 100 can be reduced, and the first metal layer 3 and the second metal layer 4 can produce a good mutual penetration effect at the bonding interface, thus ensuring the structural stability of the pole post 100.

[0038] When the maximum thickness of the first metal part 1 at the first protrusion 11 is H1 and the thickness of the second metal part 2 at the corresponding maximum thickness of the first metal part 1 is H2, and the condition 0.25 ≤ H1 / H2 ≤ 1.55 is met, mutual penetration will occur at the interface between the first metal layer 3 and the second metal layer 4, and the penetration effect is good, resulting in a tight bond between the first metal layer 3 and the second metal layer 4 and improving structural stability. Furthermore, within the above range, the first metal part 1 has good pressure-bearing capacity, and the thickness of the second metal part 2 ensures that it has a large penetration depth and that its internal structure is not damaged when welded to other components, thereby ensuring good welding strength.

[0039] It is understandable that the first protrusion 11 forms a raised surface on the side near the second metal part 2, and the distance between the highest point of the raised surface and the bottom of the first metal part 1 is H1. The distance from the top surface of the second metal part 2 to the highest point of the raised surface is H2.

[0040] In some embodiments, 0.4 ≤ H1 / H2 ≤ 1.55. By satisfying 0.4 ≤ H1 / H2 ≤ 1.55, the interpenetration effect between the first metal part 1 and the second metal part 2 can be improved, thereby enhancing the bonding force between the first metal part 1 and the second metal part 2. Simultaneously, increasing the thickness ratio of the second metal part 2 improves the stability when the second metal part 2 is welded to external components.

[0041] In some embodiments, 0.5 ≤ H1 / H2 ≤ 1.0. By satisfying 0.5 ≤ H1 / H2 ≤ 1.0, the interpenetration effect between the first metal part 1 and the second metal part 2 can be improved, thereby enhancing the bonding force between the first metal part 1 and the second metal part 2. Simultaneously, increasing the thickness ratio of the second metal part 2 improves the stability when the second metal part 2 is welded to external components.

[0042] In some embodiments, as shown in Figures 2-4, a reverse-enclosing structure 12 is provided on the periphery of the first metal part 1, and a second recess 13 is formed between the reverse-enclosing structure 12 and the first protrusion 11. A second protrusion 22 is provided on the periphery of the second metal part 2, and the second protrusion 22 is fitted into the second recess 13 and is engaged with the first metal part 1 by the reverse-enclosing structure 12 and the first protrusion 11.

[0043] By cooperating with the anti-wrapping structure 12 and the first protrusion 11 in the first metal part 1, a second protrusion 22 can be formed to wrap around the second metal part 2, thereby improving the connection stability of the first metal part 1 and the second metal part 2. That is, the first metal part 1 and the second metal part 2 are connected by mutual interlocking to form an interlocking structure. At the same time, the first metal part 1 and the second metal part 2 are mutually permeable to improve the connection stability.

[0044] In some embodiments, as shown in Figures 2 and 4, the second metal member 2 has a maximum width of W1 in the second direction X, and the first protrusion 11 has a thickness of H3 in the first direction Y. The region in the first protrusion 11 where H3 / H1 ≥ 0.6 forms a first protrusion interval 111, and the first protrusion interval 111 has a maximum width of W2 in the second direction X, satisfying: 0 < W2 / W1 ≤ 0.7. The second direction X and the first direction Y are perpendicular to each other.

[0045] In the application of the pole post 100, it is usually necessary to weld the pole post 100 to other components. During the welding process, a molten pool is formed on the first metal part 1 and the second metal part 2 of the pole post 100. To ensure the welding effect, the first metal part 1 and the second metal part 2 at the welding point need to have a certain thickness. After research, the area in the first protrusion 11 where H3 / H1≥0.6 forms the first protrusion interval 111, which can better ensure the welding quality when welding in the first protrusion interval 111. By making the maximum width W1 of the second metal part 2 in the first direction Y and the maximum width W2 of the first protrusion interval 111 in the second direction X satisfy 0<W2 / W1≤0.7, sufficient space can be reserved for the inverted structure 12, ensuring the size of the inverted structure 12, improving the stability of the interlocking structure between the first metal part 1 and the second metal part 2, and providing sufficient weldable area for the first metal part 1 and the second metal part 2.

[0046] In one embodiment, as shown in Figure 2, the pole post 100 is a cylindrical structure, and both the first metal part 1 and the second metal part 2 are cylindrical. The maximum width W1 of the second metal part 2 in the second direction X is the diameter of the second metal part 2. The first protrusion 11 is a cylindrical boss. The thickness H3 of a portion of the first protrusion 11 along the first direction Y satisfies H3 / H1≥0.6, forming a first protrusion interval 111. The thickness of the first metal part 1 within the first protrusion interval 111 is relatively large, which can meet the welding requirements. The maximum width of the first protrusion interval 111 along the second direction X is W2. By making 0<W2 / W1≤0.7, on the one hand, the contact area between the first metal part 1 and the second metal part 2 can be increased, providing sufficient weldable area for the first metal part 1. On the other hand, sufficient space is reserved for the anti-wrapping structure 12 set on the periphery of the first metal part 1, ensuring the size of the anti-wrapping structure 12, so that when the first metal part 1 and the second metal part 2 form an interlocking structure, they can have good structural stability.

[0047] In another embodiment, as shown in Figure 4, the pole post 100 is also a cylindrical structure, and both the first metal part 1 and the second metal part 2 are cylindrical. The maximum width W1 of the second metal part 2 in the second direction X is the diameter of the second metal part 2. The first protrusion 11 is an arc-shaped protrusion structure without forming a boss structure. The thickness H3 and H1 of a portion of the first protrusion 11 along the first direction Y satisfy H3 / H1≥0.6, forming a first protrusion interval 111. The thickness of the first metal part 1 within the first protrusion interval 111 is relatively large, which can meet the welding requirements. The maximum width of the first protrusion interval 111 along the second direction X is W2. By making 0<W2 / W1≤0.7, on the one hand, the contact area of ​​the first metal part 1 and the second metal part 2 can be increased, providing sufficient weldable area for the first metal part 1. On the other hand, sufficient space is reserved for the anti-wrapping structure 12 set on the periphery of the first metal part 1, ensuring the size of the anti-wrapping structure 12, so that when the first metal part 1 and the second metal part 2 form an interlocking structure, they can have good structural stability.

[0048] In some embodiments, as shown in Figures 2-4, the reverse-wrapping structure 12 has an arc-shaped protrusion that protrudes along the second direction X, and the second metal part 2 forms an arc-shaped recess corresponding to the arc-shaped protrusion.

[0049] By making the reverse-encasing structure 12 have an arc-shaped protrusion that protrudes along the second direction X, and the second metal part 2 forms an arc-shaped depression at the arc-shaped protrusion, the reverse-encasing structure 12 can compress the second metal part 2 at the arc-shaped depression, so that the arc-shaped protrusion and the arc-shaped depression form a barb structure, forming a stable interlocking relationship. Furthermore, the first metal part 1 and the second metal part 2 are mutually squeezed and penetrated at the arc-shaped protrusion and the arc-shaped depression, reducing the risk of interface detachment and improving the axial tensile resistance of the pole post 100.

[0050] In some embodiments, as shown in Figures 3 and 4, the maximum protrusion width of the arcuate protrusion in the second direction X is W3, satisfying 0 < W3 / W1 ≤ 0.3.

[0051] By satisfying 0 < W3 / W1 ≤ 0.3, the reverse wrapping structure 12 can cooperate with the first protrusion 11 and the second metal part 2 to form a stable locking structure, ensuring the bonding stability of the first metal part 1 and the second metal part 2, while reducing the manufacturing difficulty of the reverse wrapping structure 12 and ensuring the strength of the reverse wrapping structure 12.

[0052] In some embodiments, as shown in Figures 1 and 4, a protrusion 14 protruding from the outer periphery of the first metal member 1 is provided on the periphery of the first metal member 1. The protrusion 14 is adapted to connect with the connecting piece inside the battery cell and helps to snap the terminal 100 onto the cover plate 200.

[0053] The protrusion 14 protrudes from the outer periphery of the first metal part 1 to form a flange boss. On the one hand, it can increase the contact area between the first metal part 1 and the internal connecting piece in the battery cell. On the other hand, the flange boss can fix the first metal part 1 to the cover plate 200 of the battery cell.

[0054] In some embodiments, as shown in FIG3, the maximum thickness of the first metal member 1 at the reverse-wrapping structure 12 along the first direction Y is greater than the thickness of the protrusion along the first direction Y. By ensuring that the maximum thickness of the first metal member 1 at the reverse-wrapping structure 12 along the first direction Y is greater than the thickness of the protrusion along the first direction Y, the volume of the reverse-wrapping structure 12 can be guaranteed, giving the reverse-wrapping structure 12 good structural strength, ensuring the connection stability of the first metal member 1 and the second metal member 2, and improving the tensile strength of the pole post 100.

[0055] In some embodiments, as shown in FIG3, the thickness of the protrusion 14 along the first direction Y is H4, and the maximum thickness of the first metal part 1 at the reverse wrapping structure 12 along the first direction Y is H5, satisfying that 0 < H5 - H4 ≤ 0.1 mm.

[0056] That is, the first metal part 1 at the reverse wrapping structure 12 protrudes less than 0.1mm relative to the first metal part 1 at the first step structure 23. On the one hand, this ensures the structural strength of the reverse wrapping structure 12 and the connection stability of the first metal part 1 and the second metal part 2. On the other hand, it reduces the phenomenon that the reverse wrapping structure 12 is easily damaged due to excessive protrusion distance.

[0057] In some embodiments, as shown in FIG3, the second metal member 2 is provided with a first step structure 23 and a second step structure 24. The second step structure 24 is disposed at the end of the second metal member 2 away from the first metal member 1, and the first step structure 23 is disposed between the protrusion 14 and the second step structure 24.

[0058] The second step structure 24 is located at the end of the second metal part 2 and can be used to cooperate with the external connecting piece to form a battery module. The first step structure 23 is disposed between the protrusion 14 and the second step structure 24 and can be used to cooperate with the terminal clamping block 230 to fix the terminal post 100.

[0059] In some embodiments, the first metal part 1 is made of copper, and the second metal part 2 is made of aluminum. Copper has good conductivity but is expensive, while aluminum has poor conductivity but is cheaper. When the electrode post 100 is a negative electrode post 100, the negative electrode connecting piece inside the cell is usually made of copper. By making the first metal part 1 copper, the first metal part 1 and the negative electrode connecting piece inside the cell are made of the same material, improving welding stability and ensuring good conductivity. The external connecting piece used to connect adjacent cells is usually made of aluminum. By making the second metal part 2 aluminum, the welding stability between the electrode post 100 and the external connecting piece is ensured, and the overall cost of the electrode post 100 can be reduced by making part of the electrode post 100 made of aluminum. In addition, through the structure of the electrode post 100 provided in this application embodiment, the first metal part 1 made of copper and the second metal part 2 made of aluminum can form a good bond, ensuring connection stability while allowing them to permeate each other, reducing the resistance of the electrode post 100.

[0060] Please refer to Figures 5 and 6. Figure 5 is a cross-sectional schematic diagram of the first structure of the pole provided in another embodiment of this application, and Figure 6 is an enlarged schematic diagram of point A in Figure 5.

[0061] The pole provided in this application includes at least two connected metal parts 100a, and a third recess 110 is provided at the outer wall of at least one metal part 100a and / or at the boundary position of the outer wall of adjacent metal parts 100a.

[0062] It is understandable that when the terminal post is used in a battery, both ends of the terminal post 100 can be connected to other parts of the battery structure or external structures. For example, one end of the terminal post 100 can be connected to the battery terminal block by welding and used to connect to an external connecting piece, while the other end can be connected to an electrode connecting piece, thereby enabling the battery to supply power. Specifically, by setting the terminal post 100 in the form of multiple metal parts 100a, the connection requirements of different scenarios can be met. For example, metal parts 100a of different materials can be used to connect to other structures of different materials, thereby ensuring electrical performance and reducing production costs while ensuring stable connection (e.g., welding) between the terminal post 100 and other structures, and reducing resistance.

[0063] Multiple metal parts 100a are connected together. Adjacent metal parts 100a can be connected in a close-fitting manner, such as forming a curved surface contact between two metal parts 100a. Stress and heat may be generated at the contact connection points of adjacent metal parts 100a, especially at the outer wall edges. Therefore, in this embodiment, a third recess 110 is formed at the outer wall of the metal part 100a or at the boundary of the connection between adjacent metal parts 100a. This third recess 110 can release the stress and heat generated by the electrode posts during battery operation, thereby improving battery stability, reducing the probability of battery malfunction and damage, and ensuring long-term stable battery operation. In some embodiments of this application, the boundary position specifically includes the location of the boundary line between the outer walls of two adjacent metal parts 100a. Specifically, referring to Figures 5-12, the indicator line M indicates this boundary line.

[0064] In some embodiments of this application, the pole post 100 includes two metal parts 100a, such as the first metal part 1 and the second metal part 2 in Figures 6-12. In this case, a third recess 110 is formed on the side wall of one of the two metal parts 100a. Specifically, referring to Figures 5 and 6, in this embodiment, the third recess 110 at the pole post body 100 is specifically located at the end of the outer wall of the metal part 100a in the upper part of the figure near the dividing position, so as to better achieve the release of stress and heat.

[0065] In other embodiments of this application, depending on actual needs, there can be multiple third recesses 110. For example, at least one third recess 110 may be provided on the outer wall of each metal part 100a, or a third recess 110 may be provided at the boundary between the outer wall of the metal part 100a and the outer wall of the adjacent metal part 100a, so as to release stress and heat.

[0066] Figure 9 is a cross-sectional schematic diagram of the electrode post provided in another embodiment of this application. In this embodiment, the third recess 110 is located at the boundary position of the outer wall of the adjacent metal parts 100a, that is, the electrode post as shown in Figure 9. The third recess 110 is located at the boundary line M, which divides the third recess 110 into upper and lower parts. Specifically, when manufacturing the electrode post 100, notches 110a are respectively opened on the outer wall of the two adjacent metal parts 100a near the boundary position. At this time, based on the stacking arrangement of the two metal parts 100a, the adjacent notches 110a surround to form the third recess 110. Thus, the two notches 110a formed on the metal parts 100a can be spliced ​​to form a third recess 110. At this time, the third recess 110 is located at the point where the stress is relatively concentrated on the electrode post 100, which can achieve a better effect of releasing stress and heat. In this way, when applied to the battery, the failure and defect rate of the battery is reduced, and the stability of the battery power supply is improved.

[0067] In some embodiments of this application, the third recess 110 is arranged around the outer periphery of the metal part 100a. For example, for the pole shown in FIG7, the third recess 110 is arranged around the second metal part 2 above the dividing line M. In this way, by arranging the third recess 110 around the metal part 100a, the stress and heat of the pole can be uniformly released. At this time, the third recess 110 of the pole is an overall annular structure.

[0068] Based on the overall dimensions of the metal part 100a, the inner wall surface area of ​​the third recess 110 can be set to achieve sufficient stress and heat release. In a specific embodiment of this application, the inner wall surface area of ​​the third recess 110 is less than or equal to 500 mm². 2 For example, it can be set to less than 500mm. 2 This ensures that the overall structure of the electrode post remains intact and the electrical performance remains stable, while effectively improving stress and heat release.

[0069] The structural schematic diagrams of the pole shown in Figures 5-12 of this application are all cross-sectional structural schematic diagrams of the pole. It can be understood that the overall structure of the pole can be set according to the actual situation. For example, the pole 100 is composed of square or cylindrical metal parts 100a, and the final pole as a whole can be square or cylindrical.

[0070] Furthermore, this application does not impose specific limitations on the structure of the third recess 110. For example, in one specific embodiment, for a cylindrical metal part 100a, the third recess 110 is provided around the outer periphery of the metal part 100a. In this case, the third recess 110 is specifically annular. In other alternative embodiments, the third recess 110 can also be a concave point, groove, etc. of various shapes. For example, if the third recess 110 is a concave point, multiple concave points are distributed at equal intervals on the outer periphery of the metal part 100a, which can also achieve uniform release of pole stress and heat to a certain extent.

[0071] In some embodiments of this application, the third recess 110 is provided at intervals between the outer wall of the metal part 100a and the boundary position.

[0072] Referring to Figures 7 and 8, which are cross-sectional schematic diagrams of the pole provided in two embodiments, the pole 100 includes two connected metal parts 100a, namely a first metal part 1 and a second metal part 2. The first metal part 1 is made of copper, and the second metal part 2 is made of aluminum, as an example. In the embodiment shown in Figure 7, the third recess 110 is specifically located on the outer wall of the aluminum second metal part 2, and is spaced apart from the boundary position. In the embodiment shown in Figure 8, the third recess 110 is specifically located on the outer wall of the copper first metal part 1, and is spaced apart from the boundary position. On the one hand, the third recess 110 is close to the boundary position on the outer wall of the metal part 100a to improve the effect of stress and heat release on the pole. On the other hand, the third recess 110 is located on the outer wall of the metal part 100a and is a certain distance from the edge of the metal part 100a, making the metal part 100a easier to process and improving the yield rate during pole manufacturing.

[0073] In some embodiments of this application, the distance between the end of the third recess 110 of the pole near the dividing position and the dividing position is less than or equal to 1.5 mm, thereby ensuring that a better stress and heat release effect can be obtained.

[0074] Referring to the poles shown in Figures 7 and 8, the distance between the end of the third recess 110 near the boundary position and the boundary position is the distance between the edge of the third recess 110 and the boundary line M. In some cases, the outer wall of the metal part 100a is not a straight plane, or the outer wall of the metal part 100a with the third recess 110 is not parallel to the outer wall of other adjacent metal parts 100a. For example, in Figure 7, the outer wall of the first metal part 1 and the outer wall of the second metal part 2 are not on the same vertical plane. For example, in Figure 8, the cross-section of the outer wall of the first metal part 1 has a certain curvature. In this case, the above-mentioned distance is the normal distance between the end of the third recess 110 near the boundary position and the boundary line M, as indicated by the distance d1 in the pole shown in Figure 7 and the distance d2 in the pole shown in Figure 8.

[0075] In some embodiments of this application, the outer walls of adjacent metal parts 100a are misaligned.

[0076] Specifically, referring to the poles shown in Figures 10 and 11, the pole 100 includes a first metal part 1 and a second metal part 2, wherein the second metal part 2 is disposed above the first metal part 1. From this cross-sectional schematic diagram, the outer walls of the first metal part 1 and the second metal part 2 are on different surfaces. For example, in a square pole with a straight outer wall, the surfaces of the first metal part 1 and the second metal part 2 on the same side are not on the same vertical plane. For a cylindrical pole with a curved outer wall, the outer walls of the first metal part 1 and the second metal part 2 are not on the same curved surface. As shown in Figure 10, the outer wall of the first metal part 1 protrudes outward relative to the outer wall of the second metal part 2, thus forming a staggered arrangement of the two outer walls. And as shown in Figure 11, the outer wall of the second metal part 2 protrudes outward relative to the outer wall of the first metal part 1, thus forming a staggered arrangement of the two outer walls. Therefore, by setting the outer walls of adjacent metal parts 100a in a staggered manner, the overall manufacturing of the pole is facilitated.

[0077] In some embodiments of this application, the normal distance N between the outer walls of adjacent metal parts 100a is less than or equal to 5 mm.

[0078] Referring to the poles shown in Figures 10 and 11, the aforementioned normal distance is the distance N shown in the figures. For the cylindrical first metal part 1 and the second metal part 2, this distance N can also be regarded as the difference between the radii of the first metal part 1 and the second metal part 2.

[0079] In some embodiments of this application, the opening spacing of the cross-section of the third recess 110 is less than or equal to 3 mm, and / or the depth of the third recess 110 is less than or equal to 3 mm.

[0080] Referring to FIG12, in this embodiment, the cross-section of the third recess 110 is arc-shaped, and the opening spacing of its cross-section is the distance between the two edges of the opening, i.e., the spacing F1 marked in FIG12. The depth of the third recess 110 is the vertical distance from the bottom of the third recess 110 to the outer wall surface of the metal part 100a, i.e., the distance E1 shown in FIG12. By ensuring the opening spacing of the cross-section of the third recess 110 or the depth of the third recess 110, it is ensured that the third recess 110 can better realize the release of pole stress and heat.

[0081] In some embodiments of this application, at least one metal part 100a is made of a material different from that of an adjacent metal part 100a.

[0082] Specifically, the plurality of metal parts 100a includes a first metal part 1 and a second metal part 2 that are interconnected along the axial direction of the metal parts, wherein the material of the first metal part 1 is different from the material of the second metal part 2.

[0083] In some applications, to reduce costs, other battery components connected to the terminal post are made of different materials. Based on this, referring to Figures 6-12, in some embodiments of this application, the terminal post 100 includes two metal parts 100a, namely a first metal part 1 and a second metal part 2 stacked vertically, connected to each other along the axial direction of the metal parts of the terminal post 100. The first metal part 1 and the second metal part 2 are made of different materials, which reduces costs while facilitating welding with other battery structures using the same material, thus reducing welding difficulty and improving the battery's electrical performance. For example, when the electrode connecting piece is made of copper and the battery terminal is made of aluminum, the second metal part 2 can be made of aluminum for welding to the battery terminal and connecting to the external connecting piece, while the first metal part 1 can be made of copper for welding to the copper electrode connecting piece. In this case, welding with the same material ensures that the two materials have the same melting point, thereby reducing welding difficulty, lowering the resistance value, and better preventing structural cracking. This ensures electrical performance while reducing the overall manufacturing cost of the terminal post and battery.

[0084] In some embodiments of this application, the materials used to prepare two adjacent metal parts 100a are copper and aluminum, respectively.

[0085] Specifically, in this embodiment, the electrode post 100 is formed based on a copper-aluminum composite plate and a cold heading process, thereby obtaining multiple metal parts 100a constituting the electrode post 100. For example, the second metal part 2 of the multiple metal parts 100a is composed of the aluminum part in the copper-aluminum composite plate, and the first metal part 1 in the electrode post 100 is composed of the aluminum part in the copper-aluminum composite plate, thereby ensuring a stable connection between the two parts, thereby improving the resistance to push, tension and torsion of the electrode post, and ensuring the electrical performance of the composite electrode post.

[0086] The terminals in the above embodiments include, but are not limited to, the negative terminal for a battery.

[0087] Secondly, embodiments of this application provide a method for preparing an electrode post 100, which is used to prepare the electrode post 100 as described above, comprising:

[0088] A first metal layer 3 and a second metal layer 4 are provided;

[0089] The first metal layer 3 and the second metal layer 4 are stacked along the first direction Y, as shown in Figure 5, to form a composite structure.

[0090] The composite structure is cold-forged to form a pole post 100 including a first metal part 1 and a second metal part 2; wherein, a first protrusion 11 is formed in the first metal part 1, a first recess 21 is formed in the second metal part 2, and the first protrusion 11 is fitted into the first recess 21.

[0091] The first metal part 1 has a maximum thickness of H1 at the first protrusion 11 in the first direction Y, and the second metal part 2 has a corresponding thickness of H2 at the maximum thickness of the first metal part 1 in the first direction Y, satisfying: 0.4≤H1 / H2≤1.55. The first metal part 1 and the second metal part 2 are made of different materials.

[0092] That is, the pole post 100 provided in this application embodiment is obtained by cold forging the first metal layer 3 and the second metal layer 4 that are stacked together, so that the first metal part 1 and the second metal part 2 are combined into a whole and meet the relevant requirements.

[0093] In some embodiments, as shown in FIG13, the thickness of the first metal layer 3 in the first direction Y is H6, 0mm < H6 ≤ 5mm, and the maximum width of the first metal layer 3 in the second direction X is W4, 3mm < W4 ≤ 50mm.

[0094] The first metal layer 3 is the raw material of the first metal part 1 and is formed by cold heading. By ensuring that the initial thickness of the first metal layer 3 in the first direction Y satisfies 0mm < H6 ≤ 5mm and the maximum width of the first metal layer 3 in the second direction X satisfies 3mm < W4 ≤ 50mm, the parameters of the first metal part 1 after cold heading can be guaranteed.

[0095] In some embodiments, as shown in FIG13, the thickness of the second metal layer 4 in the first direction Y is H7, 0mm < H7 ≤ 10mm, and the maximum width of the second metal layer 4 in the second direction X is W5, 3mm < W5 ≤ 50mm.

[0096] Similar to the first metal layer 3, by ensuring that the initial thickness of the second metal layer 4 in the first direction Y satisfies 0mm < H7 ≤ 10mm, and the maximum width of the second metal layer 4 in the second direction X satisfies 3mm < W4 ≤ 50mm, the parameters of the second metal part 2 after cold heading can be guaranteed, and the proportional requirements between the first metal part 1 and the second metal part 2 can be guaranteed.

[0097] As shown in Figure 14, by cold-forging the first metal layer 3 and the second metal layer 4 to form the pole post 100 as shown in Figures 1-3, multiple flow regions can be formed on the second metal part 2. The first flow region 15 is formed by extrusion through the reverse-wrapping structure 12, which improves the connection strength between the first metal part 1 and the second metal part 2 and enhances its resistance to axial tension. The second flow region 16 is formed by extrusion through the first protrusion 11. Compared to the traditional planar joint, this results in a larger thickness of the first metal part 1, allowing the first metal part 1 and the second metal part 2 to maintain good interpenetration, improving stability, and ensuring welding space between the first metal part 1 and the internal connecting piece.

[0098] Furthermore, through the interaction of the first flow region 15 and the second flow region 16, a third flow region 17 can be formed in the second metal part, thereby improving the structural strength of the pole post 100.

[0099] Thirdly, embodiments of this application also provide a top cover assembly, as shown in FIG15, including the pole post 100 as described above.

[0100] The top cover assembly provided in this application embodiment has all the beneficial effects of the pole post 100 as described above, which will not be repeated here.

[0101] In some embodiments, the top cover assembly further includes a cover plate 200. The cover plate 200 is provided with a through hole, through which the electrode post 100 passes. By passing the electrode post 100 through the cover plate 200, one end of the electrode post 100 can be connected to the interior and the other end can be connected to the exterior, thereby supplying power to the outside.

[0102] In some embodiments, the top cover assembly further includes an insulating element 210 and a sealing ring 220. The sealing ring 220 is sleeved on the pole post 100, and the pole post 100 is in sealed contact with the cover plate 200 through the sealing ring 220, while the pole post 100 is kept insulated from the cover plate 200 through the insulating element 210. The insulating element 210 and the sealing ring 220 enable a sealed connection between the pole post 100 and the cover plate 200 and maintain an insulating effect.

[0103] In some embodiments, the top cover assembly further includes a terminal clamping block 230, through which the pole post 100 is pressed onto the cover plate 200. By pressing the pole post 100 onto the cover plate 200 with the terminal clamping block 230, the pole post 100 is fixed, thereby improving the connection stability between the pole post 100 and the cover plate 200.

[0104] Fourthly, embodiments of this application also provide a battery cell, including a housing, a core package, and a top cover assembly as described above, wherein the core package is disposed within the housing, and the top cover assembly is fastened to the opening end of the housing.

[0105] The battery cell provided in this application embodiment has all the beneficial effects of the terminal 100 as described above, which will not be repeated here.

[0106] The embodiments of this application are further illustrated below with reference to specific examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. Experimental methods in the following embodiments that do not specify specific conditions are generally performed according to the conditions recommended by the manufacturer.

[0107] Example 1

[0108] In this embodiment, the structure of the pole post 100 is shown in the figure. The first metal part 1 is made of copper, and the second metal part 2 is made of aluminum. The first metal part 1 has a first protrusion 11 and a reverse-wrapping structure 12, and a second recess 13 is formed between the reverse-wrapping structure 12 and the first protrusion 11. The second metal part 2 has a first recess 21 that fits into and connects with the first protrusion 11, and a second protrusion 22 that is engaged between the reverse-wrapping structure and the first protrusion 11. The pole post 100 is obtained by cold forging the first metal layer 3 and the second metal layer 4.

[0109] Wherein, the first metal part 1 has a maximum thickness of H1 at the first protrusion 11 in the first direction Y, and the second metal part 2 has a corresponding thickness of H2 at the maximum thickness of the first metal part 1 in the first direction Y. H1=2.1mm, H2=4.2mm.

[0110] The above-mentioned pole post 100 is assembled into a top cover assembly according to the structure shown in the figure.

[0111] Example 2

[0112] The difference between this embodiment and Embodiment 1 is that H1 = 2.3 mm and H2 = 4.0 mm.

[0113] Example 3

[0114] The difference between this embodiment and Embodiment 1 is that H1 = 2.8 mm and H2 = 3.5 mm.

[0115] Example 4

[0116] The difference between this embodiment and Embodiment 1 is that H1 = 3.1 mm and H2 = 3.2 mm.

[0117] Example 5

[0118] The difference between this embodiment and Embodiment 1 is that H1=3.5mm and H2=2.8mm.

[0119] Example 6

[0120] The difference between this embodiment and Embodiment 1 is that H1=3.8mm and H2=2.5mm.

[0121] Example 7

[0122] The difference between this embodiment and Embodiment 1 is that H1 = 1.8 mm and H2 = 4.5 mm.

[0123] Comparative Example 1

[0124] The difference between this comparative example and Example 1 is that H1 = 4.0 mm and H2 = 2.3 mm.

[0125] The resistance of the pole, the pull-out force of the joint layer of the first metal part and the second metal part and the bearing pressure of the flange surface in Examples 1-7 and Comparative Example 1 were tested, and the Z-axis thrust of the top cover assembly in Examples 1-7 and Comparative Example 1 was also tested. The resistance testing methods are as follows: The internal resistance between the exposed end of the electrode and the plate in Examples 1-7 and Comparative Example 1 is measured using an internal resistance tester, and the data is recorded. The pull-out force testing method for the bonding layer of the first and second metal parts is as follows: The electrode is fixed with a fixture and placed on a universal testing machine. The material portions at both ends of the electrode are clamped, a pull-out force is applied to the electrode, and the pull-out force is continuously increased. The state of the electrode is observed until the composite interface fails, and the data is recorded. The flange bearing pressure testing method is as follows: The electrode is fixed with a fixture and placed on a universal testing machine. Pressure is applied to the flange surface of the electrode, the state of the electrode is observed, and the data is recorded. The Z-axis thrust resistance testing method for the top cover assembly is as follows: The top cover is fixed with a tooling fixture and placed on a universal testing machine. Continuously increasing pressure is applied to the welded part of the top cover electrode, the state of the top cover is observed, and the data is recorded until the welded part fails. The results are shown in Table 1.

[0126] Table 1. Comparison of test results in different embodiments and comparative examples.

[0127]

[0128] As shown in Table 1, compared to Comparative Example 1, the poles in Examples 1-7 of this application can withstand greater pull-out forces, the resulting top cover has greater Z-axis thrust resistance, and the resistance and flange bearing capacity of the poles are also maintained at a high level, resulting in superior overall performance. Test results of the pole and top cover assemblies in Examples 1-7 and Comparative Example 1 show that by controlling the ratio within the range of 0.4-1.55, better overall performance of the pole and top cover assemblies can be ensured, achieving a balance between low resistance, high pull-out force, high bearing capacity, and high Z-axis thrust resistance.

[0129] In comparison, the overall performance of the pole post and top cover assembly in Embodiments 1-4 of this application is better than that in Embodiments 5-7, indicating that when H1 / H2 is in the range of 0.5-1.0, the relevant performance of the pole post and top cover assembly can be improved.

[0130] Fifthly, as shown in Figures 16 and 17, embodiments of this application provide an electrode assembly including an outer connecting piece 310 and the electrode 100 described above. The electrode 100 includes a first metal member 1 and a second metal member 2 stacked along a first direction Y. The outer connecting piece 310 is stacked along the first direction Y on the side of the second metal member 2 away from the first metal member 1, and the outer connecting piece 310 is welded to the second metal member 2 to form a first weld portion 311. The first weld portion 311 penetrates the outer connecting piece 310 along the first direction Y and is partially located within the second metal member 2, where 0 < C1 - H8 ≤ 0.5H9, where C1 represents the effective penetration depth of the first weld portion 311 in the first direction Y, H8 represents the thickness of the outer connecting piece 310 in the first direction Y, and H9 represents the minimum thickness of the second metal member 2 in the first direction Y corresponding to the first weld portion 311. For the pole post 100 composed of the first metal part 1 and the second metal part 2, the first welding part 311 penetrates the outer connecting piece 310 along the first direction Y and is partially located within the second metal part 2, thereby welding the outer connecting piece 310 and the second metal part 2 into a whole, thus realizing the connection between the outer connecting piece 310 and the pole post 100. By satisfying the formula 0 < C1 - H8 ≤ 0.5H9, while ensuring the welding of the outer connecting piece 310 and the pole post 100, the influence of heat during the welding process on the composite interface of the first metal part 1 and the second metal part 2 in the pole post 100 can be reduced, the risk of composite interface damage can be reduced, the welding stability can be ensured, and the electrical performance of the pole post assembly after welding can be improved.

[0131] For example, C1-H8 can be equal to 0.1H9, 0.2H9, 0.3H9, 0.4H9 or 0.5H9.

[0132] As shown in Figure 15, the pole post 100 includes a first metal member 1 and a second metal member 2 stacked along a first direction Y. The first metal member 1 has a first protrusion protruding along the first direction Y, and the second metal member 2 has a first recess, with the first protrusion fitting into the first recess. Furthermore, a reverse-wrapping structure is provided on the periphery of the first metal member 1, forming a second recess between the reverse-wrapping structure and the first protrusion. The second metal member 2 has a second protrusion on its periphery, which fits into the second recess and is engaged with the first metal member 1 by the reverse-wrapping structure and the first protrusion.

[0133] That is, the first metal part 1 and the second metal part 2 are interlocked through a reverse wrapping structure, ensuring the overall structural stability. Compared with the integrated pole post 100, the pole post 100 provided in this embodiment includes the first metal part 1 and the second metal part 2 stacked together, which makes the welding process more complicated. If the effective penetration depth during the welding process is too large, it is easy to cause the composite interface to be damaged, thereby affecting the relevant performance of the pole post assembly.

[0134] It is understandable that the external connecting piece 310 is a connecting piece located outside the battery cell. When multiple battery cells are assembled into a battery module, the terminals 100 of the multiple battery cells need to be connected in series or in parallel through the external connecting piece 310.

[0135] In some embodiments, 0.4 H2 < C1-H8 ≤ 0.5 H9. By satisfying 0.4 H9 < C1-H8 ≤ 0.5 H9, the first weld portion 311 can penetrate more into the second metal part 2, thereby improving the welding stability between the outer connecting piece 310 and the pole post 100, and also reducing the risk of damage to the composite interface caused by excessive effective penetration of the first weld portion 311.

[0136] In some embodiments, 0.3mm ≤ C1 ≤ 5mm. By ensuring that the effective penetration depth of the first weld 311 is within the range of 0.3mm to 5mm, the welding strength between the outer connecting piece 310 and the pole post 100 can be guaranteed, ensuring connection stability while reducing the increase in welding defects caused by excessive effective penetration depth.

[0137] For example, C1 can be 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm.

[0138] In some embodiments, as shown in FIG17, the effective weld width of the first weld portion 311 in the second direction is C2, 0.3mm≤C2≤10mm. The second direction is perpendicular to the first direction Y. By satisfying 0.3mm≤C2≤10mm, a weld surface of suitable width can be formed between the outer connecting piece 310 and the pole post 100, ensuring the weld quality between them and reducing the occurrence of weld defects. Exemplarily, the effective weld width C2 of the first weld portion 311 in the second direction can be 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm.

[0139] In some embodiments, as shown in FIG19, the first welding portion 311 forms a welding trajectory 312 on the surface of the outer connecting piece 310 away from the pole post 100. The welding trajectory 312 includes a spiral, circular, or annular shape. In the actual welding process, a suitable welding trajectory 312 form can be selected according to actual needs to ensure welding stability and the flow area after welding.

[0140] To increase the flow area, a sawtooth or wavy welding trajectory 312 can also be used.

[0141] It should be noted that when those skilled in the art weld the outer connecting piece 310 and the electrode post 100 to form the first welded part 311, they can set a suitable welding trajectory according to the actual situation and needs of the battery cell. For example, a spiral welding trajectory can reduce the pauses and restarts during the welding process through a continuous welding path, thereby improving welding efficiency. The continuous and smooth welding path helps reduce welding defects and ensures the welding area, thus improving welding strength. A circular welding trajectory allows the welded outer connecting piece 310 and electrode post 100 to fuse together, forming a circular welding surface that can withstand greater tensile and compressive forces. Furthermore, the circular welding trajectory can reduce stress concentration. A circular welding trajectory is suitable for welding circular workpieces. For example, for a cylindrical electrode post, using a circular welding trajectory allows for uniform and stable welding of the outer connecting piece 310 and the electrode post 100, thereby ensuring post-weld stability.

[0142] In some embodiments, the orthographic projection of the pole post 100 in the first direction Y covers the orthographic projection of the welding trajectory 312 in the first direction Y. That is, the orthographic projection of the welding trajectory 312 in the first direction Y falls within the range of the orthographic projection of the pole post 100 in the first direction Y, ensuring the welding quality of the outer connecting piece 310 and the pole post 100 and reducing the impact of heat generated during the welding process on the peripheral components of the pole post 100. For example, to keep the pole post 100 insulated from other components in the top cover, an insulating element is typically provided around the periphery of the pole post 100. By controlling the range of the welding trajectory 312, the impact on the insulating element can be reduced.

[0143] In some embodiments, the area of ​​the solder mark formed by the first solder portion 311 on the surface of the outer connecting piece 310 away from the pole post 100 is S = 20 mm. 2 ≤S≤1000mm 2 By ensuring the solder area is within the aforementioned range, sufficient welding surface can be formed between the external connector 310 and the terminal 100, guaranteeing welding quality. Furthermore, when the solder area is within the aforementioned range, the current-carrying area between the terminal 100 and the external connector 310 can also be guaranteed, improving electrical performance.

[0144] For example, the area S of the solder mark can be 20 mm. 2 50 mm 2 100 mm 2 150 mm 2 200 mm 2 250 mm 2 300 mm 2 350 mm 2 400 mm 2 450 mm 2 500 mm 2 550 mm 2 600 mm 2 650 mm 2 700 mm 2 750 mm 2 800 mm 2 850 mm 2 900 mm 2 950 mm 2 or 1000 mm 2 .

[0145] In some embodiments, as shown in Figures 16 and 18, the pole assembly further includes an inner connecting piece 320. The inner connecting piece 320 is stacked along a first direction Y on the side of the first metal member 1 away from the second metal member 2, and the inner connecting piece 320 is welded to the first metal member 1 to form a second weld portion 321. The second weld portion 321 extends through the inner connecting piece 320 along the first direction Y and is partially located within the first metal member 1, where 0 < C2 - H. 10 ≤0.5H 11 Where C2 represents the effective penetration depth of the second weld 321 in the first direction Y, and H 10 H represents the thickness of the inner connecting piece 320 in the first direction Y. 11 This indicates the minimum thickness of the first metal part 1 at the second welded part 321 in the first direction Y.

[0146] Similar to the outer connecting piece 310, the inner connecting piece 320 is welded to the first metal part 1 via the second welding part 321, satisfying the formula 0 < C2 - H. 10 ≤0.5H 11 This can ensure the welding of the inner connecting piece 320 and the pole piece 100, while reducing the impact of welding heat on the composite interface between the first metal part 1 and the second metal part 2, reducing the risk of composite interface damage, ensuring welding stability, and improving the electrical performance of the pole piece assembly after welding.

[0147] In addition, in order to ensure the welding stability of the inner connecting piece 320 and the first metal part 1 and reduce welding defects, the second welding part 321 is provided in the area of ​​the first metal part 1 with the first protrusion, thereby improving the effective penetration of the second welding part 321 to a certain extent and reducing the influence of welding heat on the composite interface between the first metal part 1 and the second metal part 2, and reducing the phenomenon of the composite interface being damaged.

[0148] Understandably, the inner connecting piece 320 is a connecting piece located inside the battery cell, typically used to connect the terminal 100 to the tab.

[0149] In some embodiments, the effective weld width of the second weld portion 321 in the second direction X is 0.3 mm to 10 mm.

[0150] Similar to the first weld portion 311, the effective weld width of the second weld portion 321 in the second direction X is set within the range of 0.3mm-10mm. This allows for the formation of a weld surface of suitable width between the inner connecting piece 320 and the pole post 100, ensuring the weld quality between the two and reducing the occurrence of weld defects. For example, the effective weld width of the second weld portion 321 in the second direction X can be 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, or 10mm.

[0151] In some embodiments, the outer connecting piece 310 and the second metal part 2 are made of the same material. For example, both the outer connecting piece 310 and the second metal part 2 are made of aluminum. By making the outer connecting piece 310 and the second metal part 2 of the same material, the welding quality of the outer connecting piece 310 and the second metal part 2 can be guaranteed.

[0152] In some embodiments, the inner connecting piece 320 is made of the same material as the first metal part 1. For example, both the inner connecting piece 320 and the second metal part 2 are made of copper. By making the inner connecting piece 320 and the second metal part 2 the same material, the welding quality of the inner connecting piece 320 and the second metal part 2 can be guaranteed.

[0153] Sixthly, embodiments of this application provide a battery module including multiple battery cells. The multiple battery cells are connected via the aforementioned terminal assembly.

[0154] The battery module provided in this application embodiment has all the beneficial effects of the terminal assembly as described above, which will not be repeated here.

[0155] In a seventh aspect, embodiments of this application provide a battery pack including the battery module as described above.

[0156] The battery pack provided in this application embodiment has all the beneficial effects of the terminal assembly described above, which will not be repeated here.

[0157] The effective penetration depth of the first weld portion 311 and the second weld portion 321 can be controlled by controlling the power during the welding process. For example, when laser welding is used, the effective penetration depth is controlled by changing the power of the laser.

[0158] The embodiments of this application are further illustrated below with reference to specific examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. Experimental methods in the following embodiments that do not specify specific conditions are generally performed according to the conditions recommended by the manufacturer.

[0159] Example 8

[0160] The outer connecting piece 310 is welded to the pole post 100 by laser welding to form a pole post assembly. Laser welding is used, and during the welding process, the laser power is set to 1200W, ensuring that the effective penetration depth C1 of the first welded portion 311 in the first direction Y, the thickness H8 of the outer connecting piece 310 in the first direction Y, and the minimum thickness H9 of the first metal part 1 at the first welded portion 311 in the first direction Y satisfy C1-H8=0.1H9.

[0161] Example 9

[0162] The difference between this embodiment and Embodiment 1 is that the power of the laser is 1500W and C1-H8=0.21H9.

[0163] Example 10

[0164] The difference between this embodiment and Embodiment 1 is that the power of the laser is 1800W and C1-H8=0.29H9.

[0165] Example 11

[0166] The difference between this embodiment and Embodiment 1 is that the power of the laser is 2100W and C1-H8=0.37H9.

[0167] Example 12

[0168] The difference between this embodiment and Embodiment 1 is that the power of the laser is 2400W and C1-H8=0.45H9.

[0169] Example 13

[0170] The difference between this embodiment and Embodiment 1 is that the power of the laser is 2700W and C1-H8=0.52H9.

[0171] Comparative Example 2

[0172] The difference between this comparative example and Example 8 is that the power of the laser is 3700W and C1-H1=0.58H2.

[0173] By testing the composite interfaces of the electrode assembly in Examples 8-13 and Comparative Example 2, it was found that the composite interfaces between the first metal part 1 and the second metal part 2 in Examples 8-13 were not damaged, while the composite interfaces between the first metal part 1 and the second metal part 2 in Comparative Example 2 showed signs of damage. This indicates that by ensuring that the effective penetration depth C1 of the first weld portion 311 in the first direction Y, the thickness H1 of the outer connecting piece 310 in the first direction Y, and the minimum thickness H2 of the first metal part 1 at the first weld portion 311 in the first direction Y satisfy 0 < C1 - H1 ≤ 0.5H2, the risk of damage to the interface between the outer connecting piece 310 and the second metal part 2 in the electrode 100 caused by welding heat can be reduced while ensuring welding stability. This improves the electrical performance of the electrode assembly after welding.

Claims

1. A pole post, comprising a first metal member and a second metal member stacked along a first direction; The first metal part is provided with a first protrusion that protrudes along the first direction, and the second metal part is provided with a first recess, wherein the first protrusion is fitted into the first recess. The first metal part has a maximum thickness of H1 at the first protrusion in the first direction, and the second metal part has a corresponding thickness of H2 at the maximum thickness of the first metal part in the first direction, satisfying: 0.25≤H1 / H2≤1.55; in, The first metal part and the second metal part are made of different materials.

2. The pole post according to claim 1, wherein, 0.4≤H1 / H2≤1.

55.

3. The pole post according to claim 2, wherein, 0.5≤H1 / H2≤1.

0.

4. The pole post according to any one of claims 1-3, wherein, The first metal part has a reverse wrapping structure on its periphery, and a second recess is formed between the reverse wrapping structure and the first protrusion. The second metal part has a second protrusion on its periphery; The second protrusion is fitted into the second recess and is engaged with the first metal part by the reverse wrapping structure and the first protrusion.

5. The pole post according to claim 4, wherein, The second metal part has a maximum width of W1 in the second direction, the first protrusion has a thickness of H3 in the first direction, the area in the first protrusion where H3 / H1≥0.6 forms a first protrusion interval, and the first protrusion interval has a maximum width of W2 in the second direction, satisfying: 0<W2 / W1≤0.7; The second direction and the first direction are perpendicular to each other.

6. The pole post according to claim 4 or 5, wherein, The reverse-wrapping structure has an arc-shaped protrusion that bulges along the second direction, and the second metal part forms an arc-shaped recess corresponding to the arc-shaped protrusion.

7. The pole post according to any one of claims 4-6, wherein, The maximum width of the arc-shaped protrusion in the second direction is W3, which satisfies 0 < W3 / W1 ≤ 0.

3.

8. The pole post according to any one of claims 4-7, wherein, The first metal part has a protrusion on its periphery that protrudes beyond the outer periphery of the first metal part.

9. The pole post according to claim 8, wherein, The maximum thickness of the first metal part in the reverse-wrapping structure along the first direction is greater than the thickness of the protrusion along the first direction.

10. The pole post according to claim 8 or 9, wherein, The thickness of the protrusion along the first direction is H4, and the maximum thickness of the first metal part at the reverse wrapping structure along the first direction is H5, satisfying that 0 < H5 - H4 ≤ 0.1 mm.

11. The pole post according to any one of claims 8-10, wherein, The second metal part is provided with a first step structure and a second step structure; The second step structure is disposed at the end of the second metal part away from the first metal part, and the first step structure is disposed between the protrusion and the second step structure.

12. The pole post according to any one of claims 1-11, wherein, The first metal part is made of copper, and the second metal part is made of aluminum.

13. The pole post according to any one of claims 1-12, wherein, The pole post includes at least two connected metal parts, and a third recess is provided at the outer wall of at least one of the metal parts and / or at the boundary position of the outer wall of the adjacent metal parts.

14. The pole post according to claim 13, wherein, The third recess is provided at an interval from the dividing position on the outer wall of the metal part.

15. The pole post according to claim 14, wherein, The distance between the end of the third recess near the dividing position and the dividing position is less than or equal to 1.5 mm.

16. The pole post according to any one of claims 13-15, wherein, The adjacent metal parts have notches on their outer walls near the dividing position, and the adjacent notches together form the third recess.

17. The pole post according to any one of claims 13-16, wherein, The outer walls of adjacent metal parts are staggered.

18. The pole post according to claim 17, wherein, The normal distance X between the outer walls of adjacent metal parts is less than or equal to 5 mm.

19. The pole post according to any one of claims 13-18, wherein, The opening spacing of the cross section of the third recess is less than or equal to 3 mm, and / or the depth of the third recess is less than or equal to 3 mm.

20. The pole post according to any one of claims 13-19, wherein, The third recess is provided around the outer periphery of the metal part.

21. The pole post according to claim 20, wherein, The inner wall surface area of ​​the third recess is less than or equal to 500 mm². 2 .

22. A top cover assembly comprising a pole as described in any one of claims 1-21.

23. A battery cell comprising a housing, a core package, and a top cover assembly as claimed in claim 22, wherein the core package is disposed within the housing, and the top cover assembly is engaged with an opening end of the housing.

24. A terminal assembly, comprising an outer connecting piece and a terminal as described in any one of claims 1-21; The pole includes a first metal component and a second metal component stacked along a first direction; The outer connecting piece is stacked along the first direction on the side of the second metal part away from the first metal part, and the outer connecting piece is welded to the second metal part to form a first welded part; The first welded portion penetrates the outer connecting piece along the first direction and is partially located within the second metal part, where 0 < C1 - H1 ≤ 0.5H2. C1 represents the effective penetration depth of the first weld in the first direction, H1 represents the thickness of the outer connecting piece in the first direction, and H2 represents the minimum thickness of the second metal part at the corresponding first weld in the first direction.

25. The pole assembly according to claim 24, wherein, 0.4H2<C1-H1≤0.5H2.

26. The pole assembly according to claim 25, wherein, 0.3mm≤C1≤5mm.

27. The pole assembly according to claim 26, wherein, The effective weld width of the first welded part in the second direction is C2, 0.3mm≤C2≤10mm; wherein the second direction is perpendicular to the first direction.

28. The pole assembly according to claim 26 or 27, wherein, The first welding part forms a welding trajectory on the surface of the outer connecting piece away from the pole post; The welding trajectory includes spiral, circular, or annular shapes.

29. The pole assembly according to any one of claims 26-28, wherein, The orthographic projection of the pole post in the first direction covers the orthographic projection of the welding trajectory in the first direction.

30. The pole assembly according to claim 29, wherein, The area of ​​the solder mark formed by the first welding part on the surface of the outer connecting piece away from the pole post is S, 20 mm. 2 ≤S≤1000mm 2 .

31. The pole assembly according to claim 30, wherein, The pole assembly also includes an internal connecting piece; The inner connecting piece is stacked along the first direction on the side of the first metal part away from the second metal part, and the inner connecting piece is welded to the first metal part to form a second welded part; The second welded portion penetrates the inner connecting piece along the first direction and is partially located within the first metal part, where 0 < C2 - H3 ≤ 0.5H4, where C2 represents the effective penetration depth of the second welded portion in the first direction, H3 represents the thickness of the inner connecting piece in the first direction, and H4 represents the minimum thickness of the first metal part at the corresponding second welded portion in the first direction.

32. The pole assembly according to claim 31, wherein, The external connecting piece and the second metal part are made of the same material; And / or, the inner connecting piece is made of the same material as the first metal part.

33. A battery module comprising multiple battery cells; The plurality of said cells are connected by the terminal assembly according to any one of claims 24-32.

34. A battery pack comprising the battery module as described in claim 33.

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