Pole, cover plate assembly and battery monomer

Abstract

The utility model provides a pole, a cover plate assembly and a battery monomer. The pole column comprises a first metal column and a second metal layer; the first metal column comprises a first section and a second section which are connected with each other; the second metal layer comprises a cylinder and a flange, the cylinder wraps the first section, the flange is connected with the end face, close to the second section, of the cylinder, and the flange extends in the radial direction of the pole and is embedded into the end face, facing the first section, of the second section; wherein in the axial direction of the pole, the flanging has a thickness size Hb, and the thickness size Hb of at least part of the flanging is increased along with approaching to the axis of the pole. According to the scheme, the welding thickness of the edge of the second section can be guaranteed, and more materials can be arranged at the end, close to the axis, of the turned-over edge, so that the depth of the part, close to the axis, of the second metal layer embedded into the first metal column is increased. Therefore, the reliability of combination between the first metal column and the second metal layer can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to an electrode post, cover plate assembly, and battery cell. Background Technology

[0002] The terminal is an important component that connects the inside and outside of a battery cell. One end of the terminal is connected to the external circuitry of the battery cell, for example, the terminal is connected to the module tab, and the other end is connected to the internal circuitry of the battery cell, for example, the terminal is connected to the tab in the electrode assembly via a current collector.

[0003] To reduce the cost and weight of individual battery cells, aluminum is used for current transmission in the external circuitry. However, within the battery cell, the negative electrode current collector and the negative electrode sheet share the same current-carrying material: copper. Therefore, to improve the conductivity of the terminals and control the weight and cost of the battery cell, a copper-aluminum composite terminal is used to connect the negative electrode current collector and the external circuitry. The copper portion of the copper-aluminum composite terminal connects to the negative electrode current collector, while the aluminum portion connects to the external circuitry.

[0004] Because copper and aluminum have different melting points and different fluidity, the bonding reliability between the copper and aluminum materials in the electrode is poor, making it easy for them to separate. Utility Model Content

[0005] Embodiments of this application provide an electrode post, a cover plate assembly, and a battery cell, which can improve the reliability of the bonding between the copper and aluminum materials of the electrode post.

[0006] In a first aspect, embodiments of this application provide an electrode post, which includes a first metal post and a second metal layer; the first metal post includes a first segment and a second segment connected together, the outer diameter of the first segment being smaller than the outer diameter of the second segment; the second metal layer includes a cylindrical body and a flange, the cylindrical body covering the first segment, the flange being connected to the end face of the cylindrical body near the second segment, the flange extending radially along the electrode post and embedded in the end of the second segment facing the first segment; wherein, in the axial direction of the electrode post, the flange has a thickness dimension Hb, and the thickness dimension Hb of at least a portion of the flange increases with the axis of the electrode post.

[0007] In one embodiment, in the longitudinal section of the flange of the pole post, along the axial direction close to the pole post, the interface formed by the flange and the second segment includes a first line segment, a second line segment, and a third line segment connected in sequence; wherein, the curvature of the second line segment is less than the curvature of the first line segment and the curvature of the third line segment.

[0008] In one embodiment, the curvature of the third line segment is greater than the curvature of the first line segment.

[0009] In one embodiment, the curvature of the first line segment is 2 × 10⁻⁶. -4mm -1 ~8×10 -4 mm -1 The curvature of the third line segment is 7 × 10⁻⁶. -3 mm -1 ~1.2×10 -2 mm -1 .

[0010] In one embodiment, the curvature of the second line segment is less than or equal to 1 × 10⁻⁶. -4 mm -1 .

[0011] In one embodiment, in the longitudinal section, along the axial direction of the pole post, the interface formed between the surface of the second metal layer near the axis of the pole post and the outer peripheral surface of the first metal pole post includes a fourth segment and a fifth segment, the two ends of the fourth segment being connected to the third segment and the fifth segment respectively; wherein, the curvature of the fourth segment is less than the curvature of the third segment and the curvature of the fifth segment.

[0012] In one embodiment, the curvature of the first line segment is less than the curvature of the fifth line segment.

[0013] In one embodiment, the curvature of the first line segment is 3 × 10⁻⁶. -4 mm -1 ~9.5×10 -4 mm -1 The curvature of the third line segment is 5 × 10⁻⁶. -4 mm -1 ~2×10 -3 mm -1 The curvature of the fifth line segment is 7 × 10⁻⁶. -4 mm -1 ~3×10 -3 mm -1 .

[0014] In one embodiment, the curvature of the fourth line segment is less than or equal to 1 × 10⁻⁶. -4 mm -1 .

[0015] In one embodiment, in the longitudinal section of the pole post, the first metal post has multiple forging streamlines, and the contact area between the first metal post and the second metal layer forms a bonding interface; the first metal post has a bonding region close to the second metal layer, and multiple forging streamlines in the bonding region extend along the bonding interface; the bonding region includes a tight region, and the spacing between the multiple forging streamlines in the tight region is smaller than the spacing between the multiple forging streamlines in the remaining areas of the bonding region; wherein, the tight region includes a first dense region, a second dense region and a third dense region, and along the thickness direction of the second metal layer, the first dense region and the second dense region are respectively disposed opposite to the third line segment and the fifth line segment; the third dense region is located at the axis of the first metal post and is disposed away from the bottom wall of the cylinder.

[0016] In one embodiment, the two endpoints of the second line segment are point U and point V, respectively; the straight line UV and the radial direction of the pole form an angle W on the side away from the flange, satisfying: 0 < W ≤ 20°.

[0017] In one embodiment, the outer diameter of the second segment is Rb1, and the maximum radius of the flange is Rb2, satisfying: 65%Rb1≤Rb2≤93%Rb1.

[0018] In one embodiment, there are multiple flanges, which are arranged sequentially along the circumference of the pole post, and at least two flanges are arranged opposite each other along the radial direction of the pole post.

[0019] In one embodiment, in the axial section of the pole post, the length of the interface formed by the contact between the first metal post and the second metal layer is Lb, and the outer diameter of the cylinder is φb0, satisfying: 1φb0≤Lb≤5φb0.

[0020] In one embodiment, φb0 ≤ 4 mm, and 3.6φb0 ≤ Lb ≤ 5φb0; 4 mm < φb0 < 8 mm, and 3φb0 ≤ Lb ≤ 3.6φb0; φb0 ≥ 8 mm, and 1φb0 ≤ Lb ≤ 3φb0.

[0021] In one embodiment, there are two flanges, and the second metal layer further includes two transition portions. The two transition portions are connected to the end face of the cylinder near the second section. The two transition portions and the two flanges are staggered along the circumference of the pole post. The two ends of the flanges along the circumference of the pole post are respectively connected to the two transition portions. The transition portions are embedded in the end face of the second section facing the first section, and the interface between part of the transition portion and the second section is located on the circumference of the second section.

[0022] In one embodiment, the second segment has a rectangular cross-section, with two flanges spaced apart along the long side of the rectangle and extending along the wide side of the rectangle. Two transition portions are spaced apart along the narrow side of the rectangle and extend along the long side of the rectangle.

[0023] In one embodiment, the end face of the transition portion away from the axis of the pole post is coplanar with the side wall where the long side of the second segment is located.

[0024] In one embodiment, the contact area between the first metal post and the second metal layer forms a bonding interface; the post includes a metal hybrid layer that extends along the bonding interface and covers the bonding interface; the metal hybrid layer includes a first metal material and a second metal material that are mixed together; wherein the thickness dimension of the metal hybrid layer is Dc, and the thickness of the metal hybrid layer is uniform.

[0025] In one embodiment, the thickness dimension Dc satisfies: 1μm≤Dc≤8μm.

[0026] In one embodiment, the metal mixing layer includes a first mixing portion and a second mixing portion. The first mixing portion is formed by mixing the material of the bottom wall of the cylinder with the material of the end face of the first section away from the second section. The second mixing portion is formed by mixing the material of the inner circumferential surface of the cylinder near the flange with the material of the outer circumferential surface of the first section near the second section. The thickness of the first mixing portion is greater than the thickness of the second mixing portion.

[0027] In one embodiment, the metal hybrid layer is a metallurgical layer, or the metal hybrid layer is an alloy layer in which a first metal material and a second metal material are interlocked.

[0028] In one embodiment, the flange extends circumferentially in a ring shape along the first segment.

[0029] In one embodiment, the diameter of the end of the first segment closer to the second segment is smaller than the diameter of the end of the first segment farther from the second segment.

[0030] In one embodiment, the end face of the second segment facing the first segment is provided with a fitting groove, and the flange fits into the fitting groove; there is a gap a between the flange and the fitting groove.

[0031] In one embodiment, the gap a is located between the end of the flange away from the pole post axis and the groove wall of the fitting groove.

[0032] In one embodiment, the second segment has a thickness dimension Da in the axial direction of the pole post; wherein the dimension of the gap a in the radial direction of the pole post is La, satisfying: 0 < La ≤ 10% Da; and / or, the dimension of the gap a in the axial direction of the pole post is Ha3, satisfying: 0 < Ha3 ≤ 40% Da.

[0033] In one embodiment, a mating groove is provided at the end of the cylinder away from the second section.

[0034] In one embodiment, the first segment has a mating bottom wall that is away from the second segment, and the bottom wall of the cylinder protrudes toward the mating bottom wall to be embedded within the mating bottom wall.

[0035] In one embodiment, the first segment has a mating bottom wall that is away from the second segment, and the periphery of the mating bottom wall protrudes toward the periphery of the bottom wall of the cylinder to be embedded in the bottom wall of the cylinder.

[0036] In one embodiment, the diameter of the end of the cylinder furthest from the second section is smaller than the diameter of the end of the cylinder closest to the second section.

[0037] In one embodiment, the outer circumferential surface of the cylinder is a conical surface, or a stepped groove b is provided at the end of the outer circumferential surface of the cylinder away from the second section, and the stepped groove b extends in a ring shape along the circumference of the cylinder.

[0038] In one embodiment, the pole post further includes a base plate; the base plate is connected to the end of the cylinder away from the second section.

[0039] In one embodiment, a base plate is fitted onto the cylinder and riveted to the cylinder; wherein, a pre-punched hole is provided at the end of the cylinder away from the second section, and the diameter of the pre-punched hole gradually increases along the direction away from the second section.

[0040] In one embodiment, a stepped groove b is provided at one end of the cylinder away from the second section. The stepped groove b extends in a ring around the circumference of the cylinder, and the bottom plate is fitted in the stepped groove b.

[0041] In one embodiment, the base plate is welded to the cylinder.

[0042] In one embodiment, the second section is configured to be located outside the battery cell, and the end of the cylinder away from the second section is configured to be connected to the current collector, so that the electrode post is clamped to the cover plate of the battery cell by the current collector and the second section.

[0043] Secondly, embodiments of this application provide a cover plate assembly, which includes a cover plate and the aforementioned pole post, with the pole post passing through the cover plate.

[0044] In one embodiment, the cover plate assembly further includes a first insulating member and a second insulating member; the first insulating member is disposed on one side of the cover plate; the second insulating member is disposed on the other side of the cover plate; wherein the second segment and the flange are located on the side of the first insulating member opposite to the cover plate.

[0045] In one embodiment, the cover plate assembly further includes a seal disposed between the flange and the cover plate; or, the seal is located between the base plate and the cover plate, with the base plate connected to the end of the cylinder away from the second section.

[0046] In one embodiment, the surface of the first insulating member facing the second segment is provided with an exhaust groove, the two ends of which extend to the inner and outer peripheral surfaces of the first insulating member, respectively.

[0047] In one embodiment, the second segment has a first surface close to the first segment, the first surface including a first region located on the outer periphery of the flange; the surface of the flange facing away from the second segment is the second region; wherein there is a height difference between the first region and the second region, and both the first region and the second region are pressed against the first insulating member.

[0048] In one embodiment, along the axial direction of the pole post, the first region protrudes outward along the axial direction of the pole post to form a height difference, and the thickness dimension of the first region protruding relative to the second region is Ha1. The second segment has a thickness dimension Da in the axial direction of the pole post, satisfying 0 < Ha1 ≤ 15% Da.

[0049] In one embodiment, 2%Da ≤ Ha1 ≤ 15%Da.

[0050] In one embodiment, along the axial direction of the pole post, the second region protrudes outward along the axial direction of the pole post to form a height difference, and the thickness dimension of the second region protruding relative to the first region is Ha2. The second segment has a thickness dimension Da in the axial direction of the pole post, satisfying 0 < Ha2 ≤ 15% Da.

[0051] In one embodiment, 2%Da ≤ Ha2 ≤ 15%Da.

[0052] In one embodiment, the first region protrudes outward along the axial direction of the pole post to form a first protrusion, the first protrusion extending in a ring shape along the circumference of the pole post; or, the second region protrudes outward along the axial direction of the pole post to form a second protrusion, the second protrusion extending in a ring shape along the circumference of the pole post.

[0053] Thirdly, embodiments of this application provide a battery cell including a housing, an electrode assembly, and the aforementioned cover assembly; the housing has a receiving cavity; the electrode assembly is disposed in the receiving cavity, and the electrode assembly includes tabs; the cover is connected to the housing and closes the opening of the receiving cavity, and the electrode post is connected to the tabs.

[0054] The beneficial effects of the embodiments of this application are as follows:

[0055] In the embodiments of this application, by increasing the thickness Hb of at least a portion of the flange along the axis closer to the pole post, on the one hand, it is beneficial to increase the thickness of the edge of the second segment to ensure the welding thickness of the edge of the second segment. This allows the edge of the second segment to have more material to impede the heat transfer during welding with other components, effectively preventing the second segment from being welded through. On the other hand, the thickness Hb of the flange edge can be reduced by overburdening, allowing the material at the edge of the flange to flow towards the axis of the pole post. This results in more material at the end of the flange closer to the axis, which helps to increase the embedment depth of the second metal layer into the first metal pole near the axis. Thus, the reliability of the bond between the first metal pole and the second metal layer can be improved. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a schematic diagram of the structure of the first type of pole provided in the embodiments of this application;

[0058] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0059] Figure 3 This is provided by the embodiments of this application. Figure 1 An enlarged view of another structure at point A;

[0060] Figure 4 This is a schematic diagram of the forging flow line of the first metal column provided in an embodiment of this application;

[0061] Figure 5 This is a schematic diagram of the structure of the second type of pole provided in the embodiments of this application;

[0062] Figure 6 This is a schematic diagram of the structure of the second metal layer provided in an embodiment of this application;

[0063] Figure 7 This is a schematic diagram of the structure of another second metal layer provided in an embodiment of this application;

[0064] Figure 8 yes Figure 1 Enlarged view of point B in the middle;

[0065] Figure 9 yes Figure 1 An enlarged view of another structure at point B;

[0066] Figure 10 This is a schematic diagram of the structure of the third type of pole provided in the embodiments of this application;

[0067] Figure 11 This is a schematic diagram of the structure of the fourth type of pole provided in the embodiments of this application;

[0068] Figure 12 This is a structural schematic diagram of the first cover plate assembly provided in the embodiments of this application;

[0069] Figure 13 This is a schematic diagram of the structure of a second cover plate assembly provided in an embodiment of this application;

[0070] Figure 14 This is a schematic diagram of the structure of a third cover plate assembly provided in an embodiment of this application;

[0071] Figure 15 This is a structural schematic diagram of the fourth cover plate assembly provided in the embodiments of this application;

[0072] Figure 16 This is a structural schematic diagram of the fifth cover plate assembly provided in the embodiments of this application;

[0073] Figure 17 This is a schematic diagram of the structure of the first insulating member provided in an embodiment of this application;

[0074] Figure 18 This is a schematic diagram of the structure of a battery cell provided in an embodiment of this application.

[0075] Explanation of reference numerals in the attached figures:

[0076] 101-Pole post; 1013-First surface; 1015-First region; 1016-Second region; 1017-First protrusion; 1018-Second protrusion; 1019-Base plate;

[0077] 1-First metal pillar; 14-First segment; 141-Matching bottom wall; 15-Second segment; 16-Matching groove; 161-First line segment; 162-Second line segment; 163-Third line segment; 164-Fourth line segment; 165-Fifth line segment; 166-Sixth line segment; 17-Joint interface; 18-Forging flow line; 19-Joint area; 191-Tight zone; 1911-First dense zone; 1912-Second dense zone; 1913-Third dense zone; 192-Metal mixing layer; 1921-First mixing section; 1922-Second mixing section;

[0078] 2-Second metal layer; 27-Cylinder body; 271-Matching groove; 272-Step groove b; 273-Pre-punched hole; 28-Flanged edge; 281-Transition section; 29-Gap a;

[0079] 100 - Cover plate assembly; 110 - Cover plate; 112 - First insulator; 1121 - Exhaust channel; 113 - Second insulator; 120 - Current collector; 121 - Protrusion; 130 - Sealing element;

[0080] 1000 - Battery cell; 1100 - Casing. Detailed Implementation

[0081] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0082] Furthermore, it should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operation, specifically the directions shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0083] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection 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 according to the specific circumstances.

[0084] The terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a product that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such a product.

[0085] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0086] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a first type of pole post 101 provided in an embodiment of this application. An embodiment of this application provides a pole post 101. The pole post 101 includes a first metal post 1 and a second metal layer 2. The first metal post 1 includes a first segment 14 and a second segment 15 connected together. The outer diameter of the first segment 14 is smaller than the outer diameter of the second segment 15. The second metal layer 2 includes a cylindrical body 27 and a flange 28. The cylindrical body 27 covers the first segment 14. The flange 28 is connected to the end face of the cylindrical body 27 near the second segment 15. The flange 28 extends radially along the pole post 101 and is embedded in the end of the second segment 15 facing the first segment 14. The flange 28 has a thickness dimension Hb in the axial direction of the pole post 101. The thickness dimension Hb of at least a portion of the flange 28 increases as it approaches the axis of the pole post 101.

[0087] It can be understood that the flange 28 may include an end with a gradually changing thickness dimension Hb and a portion with a uniform height and consistent thickness dimension Hb. Alternatively, the thickness dimension Hb of the entire flange 28 may be gradually changing.

[0088] It is understood that the first segment 14 and the second segment 15 are axially connected. Optionally, the first segment 14 and the second segment 15 are coaxially arranged.

[0089] It is understandable that the diameter of the second segment 15 is larger than the diameter of the first segment 14, so that the flange 28 can be embedded in the end face of the second segment 15 facing the first segment 14.

[0090] It can be understood that the first metal pillar 1 has a columnar structure, and its material includes a first metal. The second metal layer 2 has a layered structure, and its material includes a second metal. Here, the second metal and the first metal are different metals.

[0091] Optionally, the conductivity of the second metal is greater than that of the first metal, that is, the conductivity of the second metal is better than that of the first metal.

[0092] Optionally, the first metal has greater liquidity than the second metal.

[0093] Optionally, the hardness of the second metal is greater than that of the first metal.

[0094] It is understood that when the electrode post 101 is applied to a battery cell, the first segment 14 and the flange 28 can be located on the outside of the battery cell to serve as the output electrode of the battery cell. In this case, the material of the second metal layer 2 is the same as the material of the negative electrode current collector. The material of the first metal post 1 can be aluminum. The first segment 14 and the flange 28 can also be located inside the battery cell to prevent the electrode post 101 from detaching from the cover plate 110 of the battery cell when the internal high voltage is applied. In this case, the material of the first metal post 1 is the same as the material of the negative electrode current collector, and the material of the second metal layer 2 can be aluminum.

[0095] In this embodiment, by increasing the thickness Hb of at least a portion of the flange 28 closer to the axis of the pole post 101, on the one hand, the thickness of the edge of the second segment 15 can be increased to ensure the welding thickness of the edge of the second segment 15. This allows the edge of the second segment 15 to have more material to impede the heat transfer during welding with other components, effectively preventing the second segment 15 from being welded through. On the other hand, the thickness Hb of the edge of the flange 28 can be reduced by overburdening, allowing the material at the edge of the flange 28 to flow towards the axis of the pole post 101. This results in more material at the end of the flange 28 closer to the axis, which helps to increase the depth of the second metal layer 2 embedded in the first metal pole 1 near the axis. Thus, the reliability of the bond between the first metal pole 1 and the second metal layer 2 can be improved.

[0096] In addition, by causing the material at the edge of the flange 28 to flow toward the axis of the pole post 101, so that the end of the flange 28 near the axis has more material, it also helps to increase the depth of the second metal layer 2 intruding into the first metal post 1 radially. This allows the side of the flange 28 near the axis to engage with the first metal post 1 along the axis of the pole post 101 to prevent the first section 14 from coming out of the cylinder 27.

[0097] In one embodiment, the thickness Hb of the flange 28 gradually increases along the direction close to the axis of the pole post 101. In the longitudinal section of the pole post 101 through the flange 28, along the direction close to the axis of the pole post 101, the interface 17 formed by the flange 28 and the second segment 15 includes a first segment 161, a second segment 162, and a third segment 163 connected in sequence. The curvature of the second segment 162 is less than the curvature of the first segment 161 and the curvature of the third segment 163. And the end of the third segment 163 away from the second segment 162 extends between the outer peripheral surface of the first segment 14 and the inner wall of the cylinder 27.

[0098] It is understandable that the first line segment 161, the second line segment 162, and the third line segment 163 are connected smoothly in sequence.

[0099] Specifically, the concave sides of the first segment 161 and the third segment 163 are opposite to the second segment 15.

[0100] In this embodiment, the above-described configuration allows for several advantages: firstly, it enables a smoother connection between the side of the flange 28 facing away from the second segment 15 and the surface of the flange 28 embedded in the second segment 15; secondly, it allows for a smoother increase in thickness Hb through the second segment 162; and thirdly, it allows for a smoother transition of the surface of the flange 28 embedded in the second segment 15 to the inner wall of the cylinder 27 through the third segment 163. This improves the stress concentration at the mating point between the flange 28 and the first metal pillar 1, thereby improving the stress state of the pole pillar 101 and enhancing the reliability of the bond between the first metal pillar 1 and the second metal layer 2.

[0101] In one embodiment, the curvature of the third line segment 163 is greater than that of the first line segment 161. This arrangement results in a larger radius at the end of the flange 28 furthest from the axis of the pole post 101, and a smaller radius at the end of the flange 28 closest to the axis of the pole post 101. This reduces the bulge at the end of the flange 28 furthest from the axis of the pole post 101, thus reducing the amount of material at that end and allowing more material to flow towards the axis of the pole post 101. Simultaneously, it allows for more material at the end of the flange 28 closest to the pole post 101, facilitating a greater insertion depth of the second metal layer 2 into the first metal pole post 1. This, in turn, improves the reliability of the bonding.

[0102] In one embodiment, the curvature of the first line segment 161 is 2 × 10⁻⁶. -4 mm -1 ~8×10 -4 mm -1 The curvature of the third line segment 163 is 7 × 10⁻⁶. -3 mm -1 ~1.2×10 -2 mm-1 .

[0103] It is understandable that the curvature of the first line segment 161 is, but is not limited to, 2 × 10⁻⁶. -4 mm -1 3×10 -4 mm -1 4×10 - 4 mm -1 5×10 -4 mm -1 6×10 -4 mm -1 7×10 -4 mm -1 8×10 -4 mm -1 .

[0104] The curvature of the third line segment 163 is, but is not limited to, 7 × 10. -3 mm -1 8×10 -3 mm -1 9×10 -3 mm -1 1×10 - 2 mm -1 1.2×10 -2 mm -1 .

[0105] In this embodiment, the above-mentioned limitations allow the first line segment 161 to connect the surface of the flange 28 away from the second segment 15 to the surface of the flange 28 that fits into the second segment 15 in a relatively smooth manner, and also allow the third line segment 163 to connect the surface of the flange 28 that fits into the second segment 15 to the inner surface of the cylinder 27 in a relatively smooth manner.

[0106] In one embodiment, the curvature of the second line segment 162 is less than or equal to 1 × 10⁻⁶. -4 mm -1 In this way, the material in the part of the flange 28 forming the second segment 162 can be reduced, so that the material in this part can flow to the third segment 163, so that the end of the flange 28 near the axis has more material, thereby increasing the depth of the second metal layer 2 embedded in the first metal pillar 1 near the axis.

[0107] It can be understood that when the curvature of the second line segment 162 is 0, the second line segment 162 is a straight line. When the curvature of the second line segment 162 is less than 0, the center of the second line segment 162 and the center of the first line segment 161 are located on opposite sides of the joint surface between the flange 28 and the second segment 15, respectively. Specifically, the center of the second line segment 162 is located on the side of the joint surface between the flange 28 and the second segment 15 away from the first segment 14, while the centers of the first line segment 161 and the third line segment 163 are located on the side of the joint surface between the flange 28 and the second segment 15 closer to the first segment 14.

[0108] Based on the structure of the joint surface between the flange 28 and the second segment 15 provided in the above embodiments, the embodiments of this application further describe the structure of the joint surface between the flange 28 and the second segment 15 as follows.

[0109] Please see Figure 3 , Figure 3 This is provided by the embodiments of this application. Figure 1 An enlarged view of another structure at point A. In one embodiment, in the longitudinal section of the pole post 101 through the flange 28, along the axial direction of the pole post 101, the bonding interface 17 formed between the surface of the second metal layer 2 near the axis of the pole post 101 and the outer peripheral surface of the first metal pole 1 includes a fourth segment 164 and a fifth segment 165. The two ends of the fourth segment 164 are connected to the third segment 163 and the fifth segment 165, respectively. The curvature of the fourth segment 164 is less than the curvature of the third segment 163 and the curvature of the fifth segment 165.

[0110] It is understood that the bonding interface 17 formed between the surface of the second metal layer 2 near the axis of the pole post 101 and the first metal post 1 also includes a sixth line segment 166, one end of which is connected to the fifth line segment 165, and the other end extends toward the bottom wall of the cylinder 27.

[0111] It is understandable that the bottom wall of the cylinder 27 is the part where the second metal layer 2 covers the first section 14 and is away from the second section 15.

[0112] In this embodiment, the material at the fourth segment 164 of the flange 28 can be reduced by the above-described arrangement, allowing the material originally located at the fourth segment 164 to flow towards at least the fifth segment 165 based on the piercing pressure. This facilitates the fifth segment 165 protruding radially towards the axis of the pole post 101, thereby increasing the embedment depth of the second metal layer 2 near the axis into the first metal post 1. This allows the side of the flange 28 near the axis to engage with the first metal post 1 along the axis of the pole post 101, preventing the first segment 14 from detaching from the cylinder 27.

[0113] In one embodiment, the curvature of the first line segment 161 is less than the curvature of the fifth line segment 165. This arrangement allows for a larger radius at the end of the flange 28 furthest from the axis of the pole post 101, while the radius at the end of the flange 28 closest to the axis of the pole post 101 is smaller. This reduces the bulge at the end of the flange 28 furthest from the axis of the pole post 101, thus reducing the amount of material at that end and allowing more material to flow towards the axis of the pole post 101. Simultaneously, it allows for more material at the end of the flange 28 closest to the pole post 101, facilitating a greater insertion depth of the second metal layer 2 into the first metal pole post 1. This, in turn, improves the reliability of the bonding.

[0114] In one embodiment, the curvature of the first line segment 161 is 3 × 10⁻⁶. -4 mm -1 ~9.5×10 -4 mm -1 The curvature of the third line segment 163 is 5 × 10⁻⁶. -4 mm -1 ~2×10 -3 mm -1 The curvature of the fifth line segment 165 is 7 × 10⁻⁶. -4 mm -1 ~3×10 -3 mm -1 .

[0115] It is understandable that the curvature of the first line segment 161 includes, but is not limited to, 3 × 10⁻⁶. -4 mm -1 4×10 -4 mm -1 5×10 -4 mm -1 6×10 -4 mm -1 7×10 -4 mm -1 8×10 -4 mm -1 9×10 -4 mm -1 9.5×10 -4 mm -1 .

[0116] It is understandable that the curvature of the third line segment 163 includes, but is not limited to, 5 × 10. -4 mm -1 6×10 -4 mm -1 7×10 -4 mm -1 8×10 -4 mm -1 9×10 -4mm -1 1×10 -3 mm -1 2×10 -3 mm -1 .

[0117] It is understandable that the curvature of the fifth line segment 165 is not limited to 7×10. -4 mm -1 8×10 -4 mm -1 9×10 -4 mm -1 1×10 -3 mm -1 2×10 -3 mm -1 3×10 -3 mm -1 .

[0118] In this embodiment, the above-mentioned limitations allow the first line segment 161 to connect the surface of the flange 28 away from the second segment 15 to the surface of the flange 28 that fits into the second segment 15 in a relatively smooth manner, and also allow the third line segment 163 and the fifth line segment 165 to connect the surface of the flange 28 that fits into the second segment 15 to the inner surface of the cylinder 27 in a relatively smooth manner.

[0119] In one embodiment, the curvature of the fourth line segment 164 is less than or equal to 1 × 10⁻⁶. -4 mm -1 Thus, the curvature relative to the fourth line segment 164 is greater than 1×10. -4 mm -1 In terms of structure, this arrangement can reduce the material in the part of the flange 28 forming the fourth segment 164, so that the material in this part can flow to the fifth segment 165, so that the end of the flange 28 near the axis has more material, thereby increasing the depth of the second metal layer 2 embedded in the first metal pillar 1 near the axis.

[0120] It can be understood that when the curvature of the fourth line segment 164 is 0, the fourth line segment 164 is a straight line. When the curvature of the fourth line segment 164 is less than 0, the center of the fourth line segment 164 and the center of the third line segment 163 are located on opposite sides of the joint surface between the flange 28 and the second segment 15, respectively. Specifically, the center of the fourth line segment 164 is located on the side of the joint surface between the flange 28 and the second segment 15 away from the connection between the flange 28 and the cylinder 27, while the centers of the third line segment 163 and the fifth line segment 165 are located on the side of the joint surface between the flange 28 and the second segment 15 closer to the connection between the flange 28 and the cylinder 27.

[0121] Please see Figure 4 , Figure 4This is a schematic diagram of the forging flow lines 18 of the first metal pillar 1 provided in an embodiment of this application. In one embodiment, in the longitudinal section of the pole pillar 101, the first metal pillar 1 has a plurality of forging flow lines 18. The contact portion between the first metal pillar 1 and the second metal layer 2 forms a bonding interface 17; the first metal pillar 1 has a bonding region 19 close to the second metal layer 2, and the plurality of forging flow lines 18 within the bonding region 19 extend along the bonding interface 17. The bonding region 19 includes a tight region 191, and the spacing between the multiple forging flow lines 18 located in the tight region 191 is smaller than the spacing between the multiple forging flow lines 18 located in the other regions of the bonding region 19. The tight region 191 includes a first dense region 1911, a second dense region 1912 and a third dense region 1913. Along the thickness direction of the second metal layer 2, the first dense region 1911 and the second dense region 1912 are respectively arranged opposite to the third line segment 163 and the fifth line segment 165. The third dense region 1913 is located at the axis of the first metal column 1 and is located away from the bottom wall of the cylinder 27.

[0122] It is understood that the metal grains of the first metal material located in the compact region 191 are refined and arranged more closely, so that the first metal material located in the compact region 191 has an enhanced ability to hinder dislocation movement, thereby improving the strength and hardness of the first metal pillar 1 and improving the structural reliability of the pole pillar 101.

[0123] In addition, the first dense region 1911 and the second dense region 1912 are respectively positioned opposite to the third line segment 163 and the fifth line segment 165. In this way, the first dense region 1911 and the second dense region 1912 can clamp the flange 28, thereby improving the reliability of the connection between the first metal pillar 1 and the second metal layer 2.

[0124] Please see Figure 2 or Figure 3 In one embodiment, the two endpoints of the second line segment 162 are points U and V, respectively; the straight line UV and the radial direction of the pole post 101 form an angle W on the side away from the flange 28, satisfying: 0 < W ≤ 20°. This allows control over the steepness of the joint surface between the first metal post 1 and the second metal layer 2 located at points U and V. Consequently, the joint surface between the first metal post 1 and the second metal layer 2 located at points U and V is relatively gentle, thus, given a fixed maximum thickness of the flange 28, allowing the first metal post 1 and the second metal layer 2 to have a larger joint surface in the axial direction, thereby improving the reliability of the joint between the first metal post 1 and the second metal layer 2.

[0125] Please see Figure 1 In one embodiment, the outer diameter of the second segment 15 is Rb1, and the maximum radius of the flange 28 is Rb2, satisfying: 65%Rb1≤Rb2≤93%Rb1.

[0126] It is understood that the maximum radius Rb2 of the flange 28 includes, but is not limited to, 65%Rb1, 66%Rb1, 68%Rb1, 69%Rb1, 70%Rb1, 76%Rb1, 81%Rb1, 85%Rb1, 90%Rb1, and 93%Rb1.

[0127] In this embodiment, the above-mentioned limitations ensure, on the one hand, the radial dimension of the flange 28 and the second segment 15 is sufficient to ensure a reliable connection between them, thereby facilitating the reliability of the connection between the first metal pillar 1 and the second metal layer 2; on the other hand, the large radial dimension of the flange 28 is prevented from affecting the thickness of the second segment 15, thus ensuring the smooth welding of the second segment 15 with other components and preventing the second segment 15 from being welded through, which would affect the reliability of the connection between the second segment 15 and the flange 28.

[0128] Please see Figure 5 and Figure 6 , Figure 5 This is a schematic diagram of the structure of the second type of pole post 101 provided in the embodiments of this application. Figure 6 This is a schematic diagram of the structure of the second metal layer 2 provided in an embodiment of this application. In one embodiment, there are multiple flanges 28. The multiple flanges 28 are arranged sequentially along the circumference of the pole post 101. At least two flanges 28 are arranged opposite each other along the radial direction of the pole post 101. In this way, the reliability of the connection between the first metal pole 1 and the second metal layer 2 can be improved, and the structural symmetry of the pole post 101 can be improved, so as to improve the stress state of the pole post 101.

[0129] In one embodiment, in the axial cross-section of the pole post 101, the length of the bonding interface 17 formed by the contact between the first metal post 1 and the second metal layer 2 is Lb, and the outer diameter of the cylinder 27 is φb0, satisfying: 1φb0≤Lb≤5φb0. This allows for a larger pole post 101 with a longer bonding interface 17, thus ensuring that the bonding force between the first metal post 1 and the second metal layer 2 matches the dimensions of the pole post 101, thereby improving the structural reliability of the pole post 101.

[0130] It is understood that the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes, but is not limited to, 1φb0, 1.2φb0, 1.5φb0, 1.8φb0, 2φb0, 2.2φb0, 2.4φb0, 2.5φb0, 2.8φb0, 3φb0, 3.5φb0, 3.6φb0, 4φb0, 4.3φb0, 4.8φb0, and 5φb0.

[0131] In one embodiment, φb0 ≤ 4 mm, and 3.6φb0 ≤ Lb ≤ 5φb0. 4 mm < φb0 < 8 mm, and 3φb0 ≤ Lb ≤ 3.6φb0. φb0 ≥ 8 mm, and 1φb0 ≤ Lb ≤ 3φb0.

[0132] It is understood that when φb0≤4mm, the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes, but is not limited to, 3.6φb0, 3.7φb0, 3.8φb0, 3.9φb0, 4φb0, 4.1φb0, 4.2φb0, 4.3φb0, 4.4φb0, 4.5φb0, 4.6φb0, 4.7φb0, 4.8φb0, 4.9φb0, and 5φb0.

[0133] When 4mm < φb0 < 8mm, the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes, but is not limited to, 3φb0, 3.1φb0, 3.1φb0, 3.2φb0, 3.2φb0, 3.3φb0, 3.3φb0, 3.4φb0, 3.4φb0, 3.4φb0, 3.5φb0, 3.5φb0, 3.5φb0, 3.6φb0, and 3.6φb0.

[0134] When φb0 ≥ 8 mm, the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes, but is not limited to, 1φb0, 1.2φb0, 1.5φb0, 1.8φb0, 2φb0, 2.3φb0, 2.3φb0, 2.4φb0, 2.4φb0, 2.5φb0, 2.5φb0, 2.6φb0, 2.6φb0, 2.7φb0, 2.7φb0, 2.8φb0, 2.8φb0, 2.9φb0, and 3φb0.

[0135] It is understandable that the larger the size of the pole post 101, the smaller the ratio of the length Lb of the interface 17 to the outer diameter φb0 of the cylinder 27. Conversely, the smaller the size of the pole post 101, the larger the ratio of the length Lb of the interface 17 to the outer diameter φb0 of the cylinder 27.

[0136] Please see Figure 6In one embodiment, there are two flanges 28. The second metal layer 2 also includes two transition portions 281. The two transition portions 281 are connected to the end face of the cylinder 27 near the second segment 15. The two transition portions 281 and the two flanges 28 are staggered along the circumference of the pole post 101, and the two ends of the flanges 28 along the circumference of the pole post 101 are respectively connected to the two transition portions 281. The transition portions 281 are embedded in the end face of the second segment 15 facing the first segment 14. The interface 17 between part of the transition portion 281 and the second segment 15 is located on the circumferential surface of the second segment 15. In this way, the structural symmetry of the pole post 101 can be improved, and the structural strength of the second metal layer 2 at the flanges 28 can be improved, which is beneficial to improving the structural strength of the pole post 101.

[0137] Please see Figure 5 and 5 In one embodiment, the second segment 15 has a rectangular cross-section. Two flanges 28 are spaced apart along the long side of the rectangle. The flanges 28 extend along the wide side of the rectangle. Two transition portions 281 are spaced apart along the narrow side of the rectangle. The transition portions 281 extend along the long side of the rectangle. It can be understood that the pole post 101 is smaller in the width direction of the rectangle, which is not conducive to forming the flanges 28.

[0138] In this embodiment, the above-mentioned configuration enables the directional pole 101 to have a flange 28 structure, which helps to improve the reliability of the connection between the first metal pole 1 and the second metal layer 2, and also makes the connection structure between the first metal pole 1 and the second metal layer 2 match the overall shape of the pole 101, thereby reducing the molding difficulty of the pole 101.

[0139] Please see Figure 5 In one embodiment, the end face of the transition portion 281 away from the axis of the pole post 101 is coplanar with the side wall containing the long side of the second segment 15. This makes the surface structure of the pole post 101 regular, which is beneficial for assembly with other components.

[0140] Please see Figure 2 or Figure 3 In one embodiment, a bonding interface 17 is formed at the contact point between the first metal post 1 and the second metal layer 2. The post 101 includes a metal hybrid layer 192. The metal hybrid layer 192 extends along the bonding interface 17 and encloses the bonding interface 17. The metal hybrid layer 192 includes a first metal material and a second metal material mixed together. The thickness of the metal hybrid layer 192 is Dc, and the thickness of the metal hybrid layer 192 is non-uniform.

[0141] It can be understood that a portion of the metal hybrid layer 192 in the thickness direction is located within the first metal pillar 1, and another portion of the metal hybrid layer 192 in the thickness direction is located within the second metal layer 2.

[0142] It is understandable that under the pressure of the piercing, the atoms at the contact points between the first metal pillar 1 and the second metal layer 2 approach each other, causing one to diffuse into the other, so as to form a metal mixture layer 192 in which the first metal and the second metal are mixed together.

[0143] The uneven thickness of the metal hybrid layer 192 refers to the fact that at least two parts of the metal hybrid layer 192 have the same thickness dimension.

[0144] In this embodiment, by forming a metal hybrid layer 192 extending along the bonding interface 17, the interlocking force between the first metal pillar 1 and the second metal layer 2 on their opposing surfaces can be improved. That is, an interlocking connection structure consisting of many protrusions and many recesses can be formed on the two metal surfaces, thereby making the connection between the first metal pillar 1 and the second metal layer 2 tighter and more reliable, and improving the ability to resist the separation between the first metal pillar 1 and the second metal layer 2.

[0145] Please see Figure 2 or Figure 3 In one embodiment, the thickness dimension Dc satisfies: 1μm≤Dc≤8μm.

[0146] It is understood that the thickness dimensions Dc of the metal hybrid layer 192 include, but are not limited to, 1μm, 1.2μm, 1.5μm, 2.1μm, 2.7μm, 3.3μm, 3.8μm, 4.2μm, 4.6μm, 5.1μm, 5.5μm, 6.0μm, 6.4μm, 6.8μm, 7.2μm, 7.9μm, and 8μm.

[0147] It is understandable that limiting the thickness dimension Dc of the metal mixing layer 192 can, on the one hand, ensure the material mixing depth between the first metal pillar 1 and the second metal layer 2, so as to ensure the reliability of the bonding between the first metal pillar 1 and the second metal layer 2; on the other hand, it can avoid the metal mixing layer 192 being too deep, which would result in a higher cost for molding the pole pillar 101.

[0148] Please see Figure 1 and Figure 2In one embodiment, the metal hybrid layer 192 includes a first hybrid portion 1921 and a second hybrid portion 1922. The first hybrid portion 1921 is formed by mixing the material of the bottom wall of the cylinder 27 with the material of the end face of the first segment 14 away from the second segment 15. The second hybrid portion 1922 is formed by mixing the material of the inner circumferential surface of the cylinder 27 near the flange 28 with the material of the outer circumferential surface of the first segment 14 near the second segment 15. The thickness of the first hybrid portion 1921 is greater than the thickness of the second hybrid portion 1922. This improves the bonding force between the first metal pillar 1 and the second metal layer 2 in the axial direction of the pole post 101, thereby enhancing the reliability of the bond between the first metal pillar 1 and the second metal layer 2.

[0149] Wherein, the metal mixed layer 192 is a metallurgical layer, or the metal mixed layer 192 is an alloy layer in which the first metal material and the second metal material are interlocked.

[0150] Please see Figure 7 , Figure 7 This is a schematic diagram of another second metal layer 2 provided in an embodiment of this application. In one embodiment, the flange 28 extends in a ring shape along the circumference of the first segment 14. In this way, the structural symmetry of the pole post 101 can be improved, thereby improving the stress state of the pole post 101 and thus improving the structural reliability of the pole post 101.

[0151] Please see Figure 2 or Figure 3 In one embodiment, the diameter φb1 of the end of the first segment 14 near the second segment 15 is smaller than the diameter φb2 of the end of the first segment 14 away from the second segment 15. This causes the side of the flange 28 near the axis to engage with the first metal post 1 along the axis of the pole post 101 to prevent the first segment 14 from coming out of the cylinder 27.

[0152] Please see Figure 8 or Figure 9 In one embodiment, the end face of the second segment 15 facing the first segment 14 is provided with a fitting groove 16. The flange 28 fits into the fitting groove 16. A gap a29 exists between the flange 28 and the fitting groove 16. Specifically, the gap a29 is located between the end of the flange 28 away from the axis of the pole post 101 and the wall of the fitting groove 16. This gap a29 can compensate for the mutual compression caused by the thermal expansion of the first metal pole 1 and the second metal layer 2 during the welding heating process of the pole post 101, thereby improving the stress state of the first metal pole 1 and the second metal layer 2.

[0153] Specifically, along the axial direction of the pole post 101 and in the direction close to the axis of the pole post 101, the size of the gap a29 in the radial direction of the pole post 101 gradually decreases. In this way, stress concentration at the joint between the first metal pole 1 and the second metal layer 2 can be avoided, thereby improving the stress state of the pole post 101.

[0154] Additionally, the side of the groove wall of the fitting groove 16 away from the axis of the pole post 101 smoothly transitions to the end face of the first segment 14 facing the second segment 15. The surface of the flange 28 away from the axis of the pole post 101 smoothly transitions to the surface of the flange 28 facing away from the first segment 14.

[0155] Please see Figure 8 or Figure 9 In one embodiment, the second segment 15 has a thickness dimension Da in the axial direction of the pole post 101; wherein the dimension of the gap a29 in the radial direction of the pole post 101 is La, satisfying: 0 < La ≤ 10% Da; and / or, the dimension of the gap a29 in the axial direction of the pole post 101 is Ha3, satisfying: 0 < Ha3 ≤ 40% Da.

[0156] Specifically, the radial dimension of the gap a29 in the pole post 101 is La, satisfying: 0 < La ≤ 10% Da; or, the axial dimension of the gap a29 in the pole post 101 is Ha3, satisfying: 0 < Ha3 ≤ 40% Da; or, the radial dimension of the gap a29 in the pole post 101 is La, satisfying: 0 < La ≤ 10% Da, and the axial dimension of the gap a29 in the pole post 101 is Ha3, satisfying: 0 < Ha3 ≤ 40% Da.

[0157] It is understood that the radial dimension La of the gap a29 on the pole post 101 includes, but is not limited to, 1%Da, 2%Da, 3%Da, 4%Da, 5%Da, 6%Da, 7%Da, 8%Da, 9%Da, and 10%Da.

[0158] It is understood that the dimensions Ha3 of the gap a29 in the axial direction of the pole post 101 include, but are not limited to, 3% Da, 6% Da, 9% Da, 12% Da, 15% Da, 18% Da, 21% Da, 24% Da, 27% Da, 30% Da, 33% Da, 36% Da, 39% Da, and 40% Da.

[0159] In this embodiment, by limiting the radial dimension La of the gap a29 in the pole post 101, the gap a29 can be prevented from being too wide and reducing the bonding between the first metal pole 1 and the second metal layer 2, thereby helping to ensure the structural reliability of the pole post 101.

[0160] In this embodiment, by limiting the dimension Ha3 of the gap a29 in the axial direction of the pole post 101, the gap a29 can be prevented from being too high, which would reduce the bonding between the first metal pole 1 and the second metal layer 2, thereby helping to ensure the structural reliability of the pole post 101.

[0161] Please see Figure 10 , Figure 10This is a schematic diagram of the structure of the third type of pole post 101 provided in the embodiments of this application. In one embodiment, a mating groove 271 is provided at the end of the cylinder 27 away from the second section 15.

[0162] It is understood that the current collector 120 has a protrusion 121 protruding from the terminal post 101, and the protrusion 121 is inserted into the mating groove 271. In this way, the mating area between the current collector 120 and the terminal post 101 can be increased by the mating groove 271 and the protrusion 121 to improve the current carrying capacity. At the same time, the structure of the mating groove 271 and the protrusion 121 can improve the positioning of the current collector 120 on the terminal post 101, thereby improving the assembly efficiency.

[0163] Among them, the current collector 120 connects the electrode tab to the electrode post 101.

[0164] Please see Figure 10 In one embodiment, the first segment 14 has a mating bottom wall 141 that is away from the second segment 15, and the bottom wall of the cylinder 27 protrudes toward the mating bottom wall 141 to be embedded in the mating bottom wall 141.

[0165] It is understood that the mating groove 271 can be formed by pressing, so that the bottom wall of the cylinder 27 protrudes into the mating bottom wall 141 and is embedded in the mating bottom wall 141. In this way, the area of ​​the joint surface between the first metal pillar 1 and the second metal layer 2 can be increased, thereby improving the reliability of the joint between the first metal pillar 1 and the second metal layer 2.

[0166] Please see Figure 10 In one embodiment, the first segment 14 has a mating bottom wall 141 that is away from the second segment 15. The periphery of the mating bottom wall 141 protrudes towards the periphery of the bottom wall of the cylinder 27 to be embedded in the bottom wall of the cylinder 27. In this way, the area of ​​the bonding surface between the first metal pillar 1 and the second metal layer 2 can be increased, thereby improving the reliability of the bonding between the first metal pillar 1 and the second metal layer 2.

[0167] Please see Figure 1 or Figure 10 In one embodiment, the diameter of the end of the cylinder 27 furthest from the second segment 15 is smaller than the diameter of the end of the cylinder 27 closest to the second segment 15. This effectively prevents the laser from passing through the gap a29 between the cylinder 27 and other components when the cylinder 27 is laser-welded to the other components, thus preventing the components located on the side of the cylinder 27 closest to the second segment 15 from being burned.

[0168] For example, when the seal 130 is fitted onto the cylinder 27, by making the diameter of the end of the cylinder 27 away from the second section 15 smaller than the diameter of the end of the cylinder 27 close to the second section 15, when welding the cylinder 27 to the manifold 120, the portion of the cylinder 27 with a larger diameter can block the laser, so as to prevent the laser from passing through the fitting gap a29 between the cylinder 27 and the manifold 120 and irradiating the sealing ring.

[0169] Please see Figure 1 or Figure 10 The specific implementation structure regarding the diameter of the end of the cylinder 27 furthest from the second segment 15 being smaller than the diameter of the end of the cylinder 27 closest to the second segment 15 can be as follows. Specifically, in one embodiment, the outer circumferential surface of the cylinder 27 is a conical surface, or a stepped groove b272 is provided at the end of the outer circumferential surface of the cylinder 27 furthest from the second segment 15, and the stepped groove b272 extends in an annular shape along the circumference of the cylinder 27. This makes the outer circumferential structure of the cylinder 27 simple and easy to manufacture.

[0170] It is understandable that when the diameter of the end of the cylinder 27 furthest from the second section 15 is smaller than the diameter of the end of the cylinder 27 closest to the second section 15, the aforementioned outer diameter of the cylinder 27 refers to the maximum diameter of the cylinder 27.

[0171] Please see Figure 11 , Figure 11 This is a schematic diagram of the structure of the fourth type of pole post 101 provided in the embodiments of this application. In one embodiment, the pole post 101 further includes a base plate 1019. The base plate 1019 is connected to the end of the cylinder 27 away from the second section 15.

[0172] Specifically, the base plate 1019 is welded to the cylinder 27, or the pole post 101 is riveted to the base plate 1019.

[0173] It is understood that the base plate 1019 can cooperate with the cover plate 110 of the battery cell to press the seal 130 between them, thereby achieving a sealed fit between the terminal post 101 and the cover plate 110.

[0174] Please see Figure 11 In one embodiment, a base plate 1019 is fitted onto a cylindrical body 27. The base plate 1019 is riveted to the cylindrical body 27. A pre-punched hole 273 is provided at the end of the cylindrical body 27 away from the second segment 15. The diameter of the pre-punched hole 273 gradually increases along the direction away from the second segment 15. Thus, when connecting the pole post 101 to the base plate 1019, a tool can be used to press the pre-punched hole 273, causing the second metal layer 2 to expand radially outward, thereby reducing the fitting clearance a29 between the pole post 101 and the base plate 1019, facilitating the riveting of the pole post 101 to the base plate 1019.

[0175] It is understandable that when a mating groove 271 is provided at the end of the cylinder 27 away from the second section 15, the pre-punched hole 273 is provided at the opening of the mating groove 271.

[0176] In one embodiment, a stepped groove b272 is provided at the end of the cylinder 27 away from the second segment 15. The stepped groove b272 extends in a ring shape around the circumference of the cylinder 27. The bottom plate 1019 is fitted into the stepped groove b272. In this way, the step groove b272 increases the mating structure between the bottom plate 1019 and the cylinder 27, which facilitates the installation of the bottom plate 1019 onto the cylinder 27, thereby improving assembly efficiency.

[0177] In one embodiment, the base plate 1019 is welded to the cylinder 27. This improves the stability of the connection between the base plate 1019 and the cylinder 27.

[0178] It is understandable that when welding the pole post 101 to the base plate 1019, a tooling can be used to pre-punch the hole 273, causing the second metal layer 2 to expand radially outward. This reduces the mating clearance a29 between the pole post 101 and the base plate 1019, allowing the pole post 101 to be riveted to the base plate 1019. Then, the pole post 101 is welded to the base plate 1019. Thus, the riveting action before welding improves the welding success rate and quality between the pole post 101 and the base plate 1019.

[0179] Please see Figure 1 or Figure 5 or Figure 10 In one embodiment, the second segment 15 is configured to be located outside the battery cell 1000. The end of the cylinder 27 away from the second segment 15 is configured to be connected to the current collector 120 so that the terminal post 101 is clamped onto the cover plate 110 of the battery cell 1000 by the current collector 120 and the second segment 15.

[0180] It is understandable that the second segment 15 is located on one side of the cover plate 110, and the manifold 120 is located on the other side of the cover plate 110.

[0181] It is understandable that in a cylindrical battery cell, the current collector 120 can be a current collector plate, while in a prismatic battery cell, the current collector 120 can be a current collector plate or a current collector pin.

[0182] In this embodiment, the base plate 1019 is eliminated by the above-described configuration, thereby reducing the number of components within the battery cell 1000. This not only reduces the weight of the battery cell 1000 but also allows the space originally used for the base plate 1019 to be used for electrode assemblies, thus improving the energy density of the battery cell 1000.

[0183] Please see Figure 12 or Figure 13 or Figure 14 or Figure 15 or Figure 16 , Figure 12 This is a structural schematic diagram of the first cover plate assembly 100 provided in the embodiments of this application. Figure 13 This is a structural schematic diagram of the second cover plate assembly 100 provided in the embodiments of this application. Figure 14 This is a structural schematic diagram of the third cover plate assembly 100 provided in the embodiments of this application. Figure 15 This is a structural schematic diagram of the fourth cover plate assembly 100 provided in the embodiments of this application. Figure 16 This is a structural schematic diagram of the fifth cover plate assembly 100 provided in the embodiments of this application. Accordingly, the embodiments of this application provide a cover plate assembly 100, which includes a cover plate 110 and the aforementioned pole post 101, the pole post 101 being disposed on the cover plate 110.

[0184] It is understood that the pole post 101 may include the base plate 1019, such as Figures 12 to 15 As shown. The pole post 101 may also be without the base plate 1019, and can be directly clamped to the cover plate via the current collector 120 and the second section 15, as shown. Figure 16 As shown.

[0185] In this embodiment, by employing the pole post 101 provided in some embodiments of this application, on the one hand, the thickness of the edge of the second segment 15 can be increased to ensure the welding thickness of the edge of the second segment 15. This allows the edge of the second segment 15 to have more material to impede the heat transfer during welding with other components, effectively preventing the second segment 15 from being welded through. On the other hand, the thickness Hb of the edge of the flange 28 can be reduced by overburdening, allowing the material at the edge of the flange 28 to flow towards the axis of the pole post 101. This results in more material at the end of the flange 28 near the axis, which helps to increase the depth of the second metal layer 2 embedded in the first metal post 1 near the axis. Thus, the reliability of the connection between the first metal post 1 and the second metal layer 2 can be improved, thereby enhancing the structural reliability of the cover plate assembly 100.

[0186] Please see Figure 12 or Figure 13 or Figure 14 or Figure 15 or Figure 16 In one embodiment, the cover plate assembly 100 further includes a first insulating member 112 and a second insulating member 113. The first insulating member 112 is disposed on one side of the cover plate 110. The second insulating member 113 is disposed on the other side of the cover plate 110. The second segment 15 and the flange 28 are located on the side of the first insulating member 112 opposite to the cover plate 110.

[0187] It can be understood that the first insulating component 112 is the upper plastic component, and the second insulating component 113 is the lower plastic component. The first insulating component 112 insulates and isolates the second section 15 and the flange 28 from the cover plate 110. The second insulating component 113 insulates and isolates the cover plate 110 from the current collector 120, the tab, and the electrode assembly, etc.

[0188] Please see Figures 12 to 15 In one embodiment, the cover assembly 100 further includes a seal 130. The seal 130 is disposed between the flange 28 and the cover 110, such as... Figure 14 and Figure 15 As shown; or, the seal 130 is located between the base plate 1019 and the cover plate 110, and the base plate 1019 is connected to the end of the cylinder 27 away from the second section 15, as shown. Figure 12 and Figure 13 As shown.

[0189] It is understood that the seal 130 can be located between the base plate 1019 and the cover plate 110, or between the flange 28 and the cover plate 110. The specific location of the seal 130 is selected according to the application scenario.

[0190] Please see Figure 17 , Figure 17 This is a schematic diagram of the structure of the first insulating member 112 provided in an embodiment of this application. In one embodiment, the surface of the first insulating member 112 facing the second segment 15 is provided with an exhaust groove 1121. The two ends of the exhaust groove 1121 extend to the inner and outer peripheral surfaces of the first insulating member 112, respectively. The exhaust groove 1121 facilitates the release of gas inside the battery cell 1000 after the gas pressure inside the battery cell 1000 reaches a certain threshold. The gas passes through the sealing member 130 to the space between the flange 28 and the exhaust groove 1121, and is discharged through the exhaust groove 1121, thereby facilitating the depressurization of the battery cell 1000.

[0191] In addition, the terminal has a non-circular cross-section, and a limiting groove is provided on the first insulating member 112. At least a portion of the terminal is located in the limiting groove and is in contact with the inner wall of the limiting groove. In this way, the terminal can be prevented from twisting by the first insulating member 112, thereby improving the torsional strength of the cover plate assembly 100.

[0192] For example, the terminal has a rectangular cross-section and beveled corners at all four corners.

[0193] In embodiments of this application, the seal 130 may be disposed between the cover plate 110 and the flange 28, such as... Figure 15 As shown, the seal 130 can also be disposed between the base plate 1019 and the cover plate 110, such as... Figure 12 and Figure 13As shown. The cylinder 27 can be welded to the base plate 1019 or riveted to the base plate 1019. When welding the cylinder 27 to the base plate 1019, the cylinder 27 can be riveted to the base plate 1019 first, and then welded together. To achieve riveting, the bottom of the cylinder 27 is provided with pre-punched holes 273, such as... Figure 10 and Figure 11 As shown. A mating groove 271 can be provided at the bottom of the cylinder 27 to mate with the protrusion 121 on the collector 120, such as... Figure 10 and Figure 13 As shown. The bottom of the cylinder 27 can also be a flat surface, such as... Figure 1 , Figure 12 and Figure 15 As shown. The pole may include a base plate, such as Figure 12 Character Figure 15 As shown, the bottom plate 1019 may not be provided at the bottom of the pole post 101, such as... Figure 16 As shown. The various settings and combinations described above are configured according to the actual application scenario, and this embodiment does not limit them.

[0194] Please see Figure 8 or Figure 9 In one embodiment, when the second segment 15 and the flange 28 are configured to be located outside the battery cell, the second segment 15 has a first surface 1013 adjacent to the first segment 14. The first surface 1013 includes a first region 1015 located on the outer peripheral side of the flange 28. The surface of the flange 28 facing away from the second segment 15 is a second region 1016. There is a height difference between the first region 1015 and the second region 1016. Both the first region 1015 and the second region 1016 are pressed against the first insulating member 112.

[0195] It is understood that one of the first zone 1015 and the second zone 1016 protrudes outward along the axial direction of the pole post 101 to form a height difference.

[0196] For example, along the axial direction of the column, the first region 1015 protrudes outward from the first surface 1013. Alternatively, along the axial direction of the pole post 101, the second region 1016 protrudes outward from the plane containing the first surface 1013.

[0197] It is understandable that the cross-section of the second segment 15 can be cylindrical, polygonal, or irregular.

[0198] It is understood that the first region 1015 and the second region 1016 abut against the first insulating member 112, so that the first insulating member 112 is subjected to axial pressure, thereby achieving the sealing of the mating surface between the pole post 101 and the first insulating member 112. The first region 1015 and the second region 1016 have a height difference, so that the one closer to the first insulating member 112 exerts a greater compressive force on the first insulating member 112.

[0199] In this embodiment, by creating a height difference between the first region 1015 and the second region 1016, the region closer to the first insulator 112 exerts a greater compressive force on the first insulator 112. This locally increases the compressive force of the electrode post 101 on the first insulator 112, thereby improving the sealing between the electrode post 101 and the first insulator 112 while controlling the amount of material used in the electrode post 101, thus enhancing the reliability of the battery cell 1000.

[0200] In addition, when the first region 1015 protrudes outward along the axial direction of the pole post 101, it can improve the sealing performance of the outer periphery of the pressing surface between the pole post 101 and the first insulating member 112, thereby effectively preventing external debris and impurities from entering between the pole post 101 and the first insulating member 112, so as to ensure the stability of the sealing structure between the pole post 101 and the first insulating member 112.

[0201] Meanwhile, when the second region 1016 protrudes outward along the axial direction of the pole post 101, the inner circumferential side of the first insulating member 112 is subjected to greater pressure, thereby increasing the deformation of the inner circumferential side of the first insulating member 112, so that the periphery of the first insulating member 112 tilts towards the end face of the second segment 15, which helps to improve the sealing performance between the pole post 101 and the first insulating member 112 at the periphery.

[0202] Please see Figure 8 In one embodiment, along the axial direction of the pole post 101, the first region 1015 protrudes outward along the axial direction of the pole post 101, and the thickness dimension of the first region 1015 protruding relative to the second region 1016 is Ha1. The second segment 15 has a thickness dimension Da in the axial direction of the pole post 101, satisfying 0 < Ha1 ≤ 15% Da.

[0203] It is understood that the thickness dimension Ha1 of the first zone 1015 protruding outward is not limited to 1%Da, 2%Da, 3%Da, 4%Da, 5%Da, 6%Da, 7%Da, 8%Da, 9%Da, 10%Da, 11%Da, 12%Da, 13%Da, 14%Da, and 15%Da.

[0204] For example, the thickness dimension Da of the pole 101 is 2 mm, Ha1 = 10% Da = 0.2 mm.

[0205] In this embodiment, by limiting the material used in the first region 1015, the amount of material protruding can be controlled, which is conducive to controlling the weight of the pole post 101. On the other hand, the thickness Ha1 of the first region 1015 protruding is too large, which would make it difficult to fit the pole post 101 with the first insulating member 112 and make the dimensional chain more complex.

[0206] When the first zone 1015 protrudes outward along the axial direction of the pole post 101, an exhaust groove can be provided on the side of the first insulating member 112 away from the cover plate 110. In this way, while improving the sealing between the pole post 101 and the cover plate 110, the flow of gas between the first insulating member 112 and the second zone 1016 can also be improved, thereby improving the exhaust effect.

[0207] In one embodiment, 2%Da≤Ha1≤15%Da. This makes the crimping of the first region 1015 onto the first insulating member 112 more obvious, which helps to significantly improve the sealing effect between the pole post 101 and the first insulating member 112 due to the protrusion of the first region 1015.

[0208] Please see Figure 9 In one embodiment, along the axial direction of the pole post 101, the second region 1016 protrudes outward along the axial direction of the pole post 101. The thickness of the second region 1016 protruding relative to the first region 1015 is Ha2. The second segment 15 has a thickness Da in the axial direction of the pole post 101, satisfying 0 < Ha2 ≤ 15% Da.

[0209] It is understood that the thickness dimension Ha2 of the second zone 1016 protruding outward includes, but is not limited to, 1%Da, 2%Da, 3%Da, 4%Da, 5%Da, 6%Da, 7%Da, 8%Da, 9%Da, 10%Da, 11%Da, 12%Da, 13%Da, 14%Da, and 15%Da.

[0210] For example, the second segment 15 has a circumferential dimension Da of 2 mm in the pole post 101, and Ha2 = 10% Da = 0.2 mm.

[0211] In this embodiment, by limiting the material used in the second region 1016, the amount of material protruding can be controlled to control the weight of the pole post 101. On the other hand, the thickness Ha2 of the second region 1016 protruding can be avoided from being too large, which would make it difficult to fit the pole post 101 with the first insulating member 112 and make the dimensional chain more complex.

[0212] In one embodiment, 2%Da≤Ha2≤15%Da. This makes the crimping of the second region 1016 onto the first insulating member 112 more obvious, which helps to significantly improve the sealing effect between the pole post 101 and the first insulating member 112 due to the protrusion of the second region 1016.

[0213] In one embodiment, the first region 1015 protrudes outward along the axial direction of the pole post 101 to form a first protrusion 1017, and the first protrusion 1017 extends in a ring shape along the circumferential direction of the pole post 101; or, the second region 1016 protrudes outward along the axial direction of the pole post 101 to form a second protrusion 1018, and the second protrusion 1018 extends in a ring shape along the circumferential direction of the pole post 101.

[0214] In this embodiment, by making the first protrusion 1017 extend into a ring along the circumference of the electrode post 101, the uniformity of stress on the electrode post 101 and the first insulating member 112 can be improved, which is conducive to improving the stress state of the battery cell 1000 and avoiding stress concentration.

[0215] In addition, by making the second protrusion 1018 extend into a ring along the circumference of the electrode post 101, the uniformity of stress on the electrode post 101 and the first insulating member 112 can be improved, which is conducive to improving the stress state of the battery cell 1000 and avoiding stress concentration.

[0216] Please see Figure 18 , Figure 18 This is a schematic diagram of the structure of a battery cell 1000 provided in an embodiment of this application. Accordingly, an embodiment of this application provides a battery cell 1000, including a housing 1100, an electrode assembly, and the aforementioned cover assembly 100; the housing 1100 has a receiving cavity; the electrode assembly is disposed in the receiving cavity, and the electrode assembly includes tabs; the cover 110 is connected to the housing 1100 and closes the opening of the receiving cavity, and the electrode post 101 is connected to the tabs.

[0217] It is understood that the electrode assembly includes at least a positive electrode plate, a separator, and a negative electrode plate stacked sequentially. The positive electrode plate can be connected to the positive electrode post 101 via a positive electrode tab, and the negative electrode tab can be connected to the negative electrode post 101 via a negative electrode plate.

[0218] The 1000 battery cells can specifically be cylindrical battery cells, prismatic battery cells, pouch battery cells, blade battery cells, etc.

[0219] In this embodiment, by employing the cover plate assembly 100 provided in some embodiments of this application, on the one hand, the thickness of the edge of the second segment 15 can be increased to ensure the welding thickness of the edge of the second segment 15. This allows the edge of the second segment 15 to have more material to impede the heat transfer during welding with other components, effectively preventing the second segment 15 from being welded through. On the other hand, the thickness Hb of the edge of the flange 28 can be reduced by pressing, allowing the material at the edge of the flange 28 to flow towards the axis of the electrode post 101. This results in more material at the end of the flange 28 near the axis, which helps to increase the depth of the second metal layer 2 embedded in the first metal post 1 near the axis. Thus, the reliability of the connection between the first metal post 1 and the second metal layer 2 can be improved, thereby enhancing the structural reliability of the battery cell 1000.

[0220] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An electrode post, characterized in that, include: The first metal column includes a first segment and a second segment connected together, wherein the outer diameter of the first segment is smaller than the outer diameter of the second segment; The second metal layer includes a cylindrical body and a flange, the cylindrical body covering the first section, the flange being connected to the end of the cylindrical body near the second section, and the flange extending radially along the pole post and embedded in the end face of the second section facing the first section; Wherein, along the axial direction of the pole post, the flange has a thickness dimension Hb, and at least a portion of the flange's thickness dimension Hb increases as it approaches the axis of the pole post.

2. The pole post according to claim 1, characterized in that, In the longitudinal section of the pole post through the flange, along the axial direction close to the pole post, the joint interface formed by the flange and the second segment includes a first segment, a second segment and a third segment connected in sequence. The curvature of the second line segment is less than the curvature of the first line segment and the curvature of the third line segment.

3. The pole post according to claim 2, characterized in that, The curvature of the third line segment is greater than that of the first line segment.

4. The pole post according to claim 3, characterized in that, The curvature of the first line segment is 2×10 -4 mm -1 ~8×10 -4 mm -1 The curvature of the third line segment is 7×10. -3 mm -1 ~1.2×10 -2 mm -1 .

5. The pole post according to claim 2, characterized in that, The curvature of the second line segment is less than or equal to 1×10 - 4 mm -1 .

6. The pole post according to claim 2, characterized in that, In the longitudinal section, along the axial direction of the pole post, the interface formed between the surface of the second metal layer near the axis of the pole post and the outer peripheral surface of the first metal post includes a fourth segment and a fifth segment, the two ends of the fourth segment being connected to the third segment and the fifth segment respectively. The curvature of the fourth line segment is less than the curvature of the third line segment and the curvature of the fifth line segment.

7. The pole post according to claim 6, characterized in that, The curvature of the first line segment is less than the curvature of the fifth line segment.

8. The pole post according to claim 7, characterized in that, The curvature of the first line segment is 3×10 -4 mm -1 ~9.5×10 -4 mm -1 The curvature of the third line segment is 5×10. -4 mm -1 ~2×10 -3 mm -1 The curvature of the fifth line segment is 7×10. - 4 mm -1 ~3×10 -3 mm -1 .

9. The pole post according to claim 6, characterized in that, The curvature of the fourth line segment is less than or equal to 1×10⁻⁶. - 4 mm -1 .

10. The pole post according to any one of claims 6-9, characterized in that, In the longitudinal section of the pole post, the first metal post has multiple forging flow lines, and the contact area between the first metal post and the second metal layer forms a bonding interface. The first metal column has a bonding region close to the second metal layer, and a plurality of forging flow lines in the bonding region extend along the bonding interface; the bonding region includes a tight region, and the spacing of the plurality of forging flow lines in the tight region is smaller than the spacing of the plurality of forging flow lines in the remaining regions of the bonding region; The dense region includes a first dense region, a second dense region, and a third dense region. Along the thickness direction of the second metal layer, the first dense region and the second dense region are respectively positioned opposite to the third line segment and the fifth line segment. The third dense region is located at the axis of the first metal column and is positioned away from the bottom wall of the cylinder.

11. The pole post according to any one of claims 2-9, characterized in that, The two endpoints of the second line segment are point U and point V, respectively; the straight line UV forms an angle W with the radial direction of the pole on the side away from the flange, satisfying: 0 < W ≤ 20°.

12. The pole post according to any one of claims 1-9, characterized in that, The outer diameter of the second segment is Rb1, and the maximum radius of the flange is Rb2, satisfying the following condition: 65%Rb1≤Rb2≤93%Rb1.

13. The pole post according to any one of claims 1-9, characterized in that, There are multiple flanges, which are arranged sequentially along the circumference of the pole post, and at least two flanges are arranged opposite each other along the radial direction of the pole post.

14. The pole post according to any one of claims 1-9, characterized in that, In the axial section of the pole, the length of the interface formed by the contact between the first metal pole and the second metal layer is Lb, and the outer diameter of the cylinder is φb0, satisfying: 1φb0≤Lb≤5φb0.

15. The pole post according to claim 14, characterized in that, φb0≤4mm, and 3.6φb0≤Lb≤5φb0; 4mm < φb0 < 8mm, and 3φb0 ≤ Lb ≤ 3.6φb0; φb0≥8mm, and 1φb0≤Lb≤3φb0.

16. The pole post according to any one of claims 1-9, characterized in that, The second metal layer further includes two transition portions, which are connected to the end face of the cylinder near the second section. The two transition portions and the two flanges are staggered along the circumference of the pole post, and the two ends of the flanges along the circumference of the pole post are respectively connected to the two transition portions. The transition portion is embedded in the end face of the second segment facing the first segment, and part of the interface between the transition portion and the second segment is located on the circumferential surface of the second segment.

17. The pole post according to claim 16, characterized in that, The second segment has a rectangular cross-section. The two flanges are spaced apart along the long side of the rectangle and extend along the wide side of the rectangle. The two transition portions are spaced apart along the narrow side of the rectangle and extend along the long side of the rectangle.

18. The pole post according to claim 17, characterized in that, The end face of the transition section away from the axis of the pole post is coplanar with the side wall where the long side of the second segment is located.

19. The pole post according to any one of claims 1-9, characterized in that, The contact area between the first metal post and the second metal layer forms a bonding interface; the pole post includes a metal hybrid layer that extends along the bonding interface and covers the bonding interface; the metal hybrid layer includes a first metal material and a second metal material that are mixed together. The thickness of the metal hybrid layer is Dc, and the thickness of the metal hybrid layer is non-uniform.

20. The pole post according to claim 19, characterized in that, The thickness dimension Dc satisfies: 1μm≤Dc≤8μm.

21. The pole post according to claim 19, characterized in that, The metal hybrid layer includes a first hybrid part and a second hybrid part. The first hybrid part is formed by mixing the material of the bottom wall of the cylinder with the material of the end face of the first section away from the second section. The second hybrid part is formed by mixing the material of the inner circumferential surface of the cylinder near the flange with the material of the outer circumferential surface of the first section near the second section. The thickness of the first mixing section is greater than the thickness of the second mixing section.

22. The pole post according to claim 19, characterized in that, The metal composite layer is a metallurgical layer, or the metal composite layer is an alloy layer in which a first metal material and a second metal material are intercalated.

23. The pole post according to any one of claims 1-9, characterized in that, The flange extends in a ring shape along the circumference of the first segment.

24. The pole post according to any one of claims 1-9, characterized in that, The diameter of the end of the first segment closer to the second segment is smaller than the diameter of the end of the first segment farther from the second segment.

25. The pole post according to any one of claims 1-9, characterized in that, The second segment has a fitting groove on its end face facing the first segment, and the flange fits into the fitting groove; there is a gap a between the flange and the fitting groove.

26. The pole post according to claim 25, characterized in that, The gap a is located between the end of the flange away from the axis of the pole and the groove wall of the fitting groove.

27. The pole post according to claim 26, characterized in that, The second segment has a thickness dimension Da in the axial direction of the pole post; Wherein, the dimension of the gap a in the radial direction of the pole post is La, which satisfies: 0 < La ≤ 10% Da; And / or, the gap a has a dimension of Ha3 in the axial direction of the pole post, satisfying: 0 < Ha3 ≤ 40% Da.

28. The pole post according to any one of claims 1-9, characterized in that, A mating groove is provided at the end of the cylinder away from the second section.

29. The pole post according to claim 28, characterized in that, The first segment has a mating bottom wall that is away from the second segment, and the bottom wall of the cylinder protrudes toward the mating bottom wall to be embedded in the mating bottom wall.

30. The pole post according to claim 28, characterized in that, The first segment has a mating bottom wall that is away from the second segment, and the periphery of the mating bottom wall protrudes toward the periphery of the bottom wall of the cylinder to be embedded in the bottom wall of the cylinder.

31. The pole post according to any one of claims 1-9, characterized in that, The diameter of the end of the cylinder furthest from the second section is smaller than the diameter of the end of the cylinder closest to the second section.

32. The pole post according to claim 31, characterized in that, The outer circumferential surface of the cylinder is a conical surface, or a stepped groove b is provided at one end of the outer circumferential surface of the cylinder away from the second section, and the stepped groove b extends in a ring shape along the circumference of the cylinder.

33. The pole post according to any one of claims 1-9, characterized in that, The pole also includes a base plate; the base plate is connected to the end of the cylinder away from the second section.

34. The pole piece according to claim 33, characterized in that, The bottom plate is sleeved on the cylinder and riveted to the cylinder; The cylinder has a pre-punched hole at the end away from the second section, and the diameter of the pre-punched hole gradually increases along the direction away from the second section.

35. The pole piece according to claim 34, characterized in that, A stepped groove b is provided at one end of the cylinder away from the second section. The stepped groove b extends in a ring around the circumference of the cylinder, and the bottom plate is fitted into the stepped groove b.

36. The pole post according to claim 34 or 35, characterized in that, The base plate is welded to the cylinder.

37. The pole post according to any one of claims 1-9, characterized in that, The second section is configured to be located outside the battery cell, and the end of the cylinder away from the second section is configured to be connected to the current collector so that the terminal post is clamped to the cover plate of the battery cell through the current collector and the second section.

38. A cover plate assembly, characterized in that, include: Cover plate; And a pole as claimed in any one of claims 1 to 37, the pole passing through the cover plate.

39. The cover plate assembly according to claim 38, characterized in that, The cover plate assembly also includes: A first insulating element is disposed on one side of the cover plate; A second insulating element is disposed on the other side of the cover plate; The second segment and the flange are located on the side of the first insulating member away from the cover plate.

40. The cover plate assembly according to claim 39, characterized in that, The cover plate assembly further includes a seal disposed between the flange and the cover plate; Alternatively, the seal is located between the base plate and the cover plate, and the base plate is connected to the end of the cylinder away from the second section.

41. The cover plate assembly according to claim 39, characterized in that, The surface of the first insulating member facing the second segment is provided with an exhaust groove, and the two ends of the exhaust groove extend to the inner and outer peripheral surfaces of the first insulating member, respectively.

42. The cover plate assembly according to claim 39, characterized in that, The second segment has a first surface close to the first segment, the first surface including a first region located on the outer periphery of the flange; the surface of the flange facing away from the second segment is a second region; There is a height difference between the first area and the second area, and both the first area and the second area are pressed against the first insulating component.

43. The cover plate assembly according to claim 42, characterized in that, Along the axial direction of the pole post, the first region protrudes outward along the axial direction of the pole post to form the height difference, and the thickness dimension of the first region protruding relative to the second region is Ha1. The second segment has a thickness dimension Da in the axial direction of the pole post, satisfying 0 < Ha1 ≤ 15% Da.

44. The cover plate assembly according to claim 43, characterized in that, 2%Da≤Ha1≤15%Da.

45. The cover plate assembly according to claim 42, characterized in that, Along the axial direction of the pole post, the second region protrudes outward along the axial direction of the pole post to form the height difference, and the thickness dimension of the second region protruding relative to the first region is Ha2. The second segment has a thickness dimension Da in the axial direction of the pole post, satisfying 0 < Ha2 ≤ 15% Da.

46. ​​The cover plate assembly according to claim 45, characterized in that, 2%Da≤Ha2≤15%Da.

47. The cover plate assembly according to claim 42, characterized in that, The first region protrudes outward along the axial direction of the pole post to form a first protrusion, and the first protrusion extends in a ring shape along the circumference of the pole post. or, The second region protrudes outward along the axial direction of the pole post to form a second protrusion, and the second protrusion extends in a ring shape along the circumference of the pole post.

48. A single battery cell, characterized in that, include: The shell has a receiving cavity; An electrode assembly is disposed in the receiving cavity, the electrode assembly including tabs; And the cover plate assembly as described in any one of claims 38 to 47, wherein the cover plate is connected to the housing and closes the opening of the receiving cavity, and the pole post is connected to the pole lug.

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