Pole, cover plate assembly and battery monomer

Abstract

The invention 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] The present application relates to the field of battery technology, and in particular to a pole, a cover plate assembly and a battery cell. Background Art

[0002] The pole is an important component that connects the inside and outside of a battery cell (also called a battery cell). One end of the pole is connected to the circuit outside the battery cell, for example, the pole is connected to the module bar, and the other end of the pole is connected to the internal circuit of the battery cell, for example, the pole is connected to the pole ear in the electrode assembly through the current collector.

[0003] In order to reduce the cost and weight of battery cells, the external circuit of the battery cell uses aluminum material for current transmission. However, in the battery cell, the negative electrode current collector and the negative electrode sheet are made of the same material, which is copper. Therefore, in order to improve the conductivity of the pole and control the weight and cost of the battery cell, a copper-aluminum composite pole is used to connect the negative electrode current collector and the external circuit. The copper material of the copper-aluminum composite pole is connected to the negative electrode current collector, and the aluminum material of the copper-aluminum composite pole is connected to the external circuit.

[0004] Since copper and aluminum have different melting points and different material fluidity, the reliability of the connection between the copper and aluminum of the pole is poor, which makes it easy for the copper and aluminum to separate from each other. Summary of the invention

[0005] The embodiments of the present application provide a pole, a cover plate assembly and a battery cell, which can improve the reliability of the bonding between the copper material and the aluminum material of the pole.

[0006] In the first aspect, an embodiment of the present application provides a pole, which includes a first metal pole and a second metal layer; the first metal pole includes a first section and a second section connected to each other, the outer diameter of the first section is smaller than the outer diameter of the second section; the second metal layer includes a cylinder and a flange, the cylinder covers the first section, the flange is connected to the end face of the cylinder close to the second section, the flange extends along the radial direction of the pole and is embedded in the end of the second section facing the first section; wherein, in the axial direction of the pole, the flange has a thickness dimension Hb, and the thickness dimension Hb of at least part of the flange increases as it approaches the axis of the pole.

[0007] In one embodiment, in the longitudinal section of the pole through the flange, along the axial direction close to the pole, the bonding 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 smaller 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 -4mm -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 .

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

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

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

[0013] In one embodiment, 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 .

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

[0015] In one embodiment, in the longitudinal section of the pole, the first metal pole has a plurality of forged streamlines, and the contact portion between the first metal pole and the second metal layer forms a bonding interface; the first metal pole has a bonding area close to the second metal layer, and a plurality of forged streamlines in the bonding area extend along the bonding interface; the bonding area includes a tight zone, and the spacing between the plurality of forged streamlines in the tight zone is smaller than the spacing between the plurality of forged streamlines in the remaining areas of the bonding area; wherein the tight zone includes a first dense zone, a second dense zone and a third dense zone, and along the thickness direction of the second metal layer, the first dense zone and the second dense zone are respectively arranged opposite to the third line segment and the fifth line segment; the third dense zone is located at the axis of the first metal pole and is arranged 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 section 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, and the multiple flanges are arranged in sequence along the circumference of the pole, and at least two flanges are arranged opposite to each other along the radial direction of the pole.

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

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

[0021] In one embodiment, there are two flanges, and the second metal layer also includes two transition parts, the two transition parts are connected to the end surface of the cylinder close to the second section, the two transition parts and the two flanges are staggered along the circumference of the pole, and the two ends of the flanges along the circumference of the pole are respectively connected to the two transition parts; wherein, the transition part is embedded in the end surface of the second section facing the first section, and the bonding interface between part of the transition part and the second section is located on the circumference of the second section.

[0022] In one embodiment, the cross-section of the second section is a rectangle, the two flanges are arranged at intervals along the direction of the long side of the rectangle, the flanges extend along the wide side of the rectangle, the two transition portions are arranged at intervals along the direction of the narrow side of the rectangle, and the transition portions extend along the long side of the rectangle.

[0023] In one embodiment, an end surface of the transition portion away from the axis of the pole is coplanar with a side wall where the long side of the second section is located.

[0024] In one embodiment, a bonding interface is formed at a contact portion between the first metal column and the second metal layer; the pole includes a metal mixed layer, the metal mixed layer extends along the bonding interface, and the metal mixed layer covers the bonding interface, and the metal mixed layer includes a first metal material and a second metal material that are mixed with each other; wherein the thickness dimension of the metal mixed layer is Dc, and the thickness of the metal mixed layer is uniform.

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

[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 and the material of the end face of the first section away from the second section, and the second mixing portion is formed by mixing the material of the inner circumference of the cylinder close to the flange and the material of the outer circumference of the first section close to the second section; wherein the thickness of the first mixing portion is greater than the thickness of the second mixing portion.

[0027] In one embodiment, the metal mixed layer is a metallurgical layer, or the metal mixed layer is an alloy layer in which a first metal material and a second metal material are embedded with each other.

[0028] In one embodiment, the flange extends in a ring shape along the circumference of the first section.

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

[0030] In one embodiment, an engaging groove is provided on the end surface of the second section facing the first section, and the flange is engaged with the engaging groove; there is a gap a between the flange and the engaging groove.

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

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

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

[0034] In one embodiment, the first section has a matching bottom wall away from the second section, and the bottom wall of the cylinder is protruded toward the matching bottom wall to be embedded in the matching bottom wall.

[0035] In one embodiment, the first section has a matching bottom wall away from the second section, and the periphery of the matching 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, a diameter of an end of the barrel far from the second section is smaller than a diameter of an end of the barrel close to the second section.

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

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

[0039] In one embodiment, the bottom plate is sleeved on the cylinder and riveted to the cylinder; wherein a pre-punched hole is provided at one end of the cylinder away from the second section, and the aperture of the pre-punched hole gradually increases in a direction away from the second section.

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

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

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

[0043] In a second aspect, an embodiment of the present application provides a cover plate assembly, which includes a cover plate and the aforementioned pole, wherein the pole is disposed on the cover plate.

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

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

[0046] In one embodiment, a venting groove is provided on a surface of the first insulating member facing the second section, and two ends of the venting groove extend to the inner circumference and the outer circumference of the first insulating member respectively.

[0047] In one embodiment, the second section has a first surface close to the first section, and the first surface includes a first area located on the outer peripheral side of the flange; the surface of the flange facing away from the second section is the second area; wherein there is a height difference between the first area and the second area, and both the first area and the second area are crimped with the first insulating member.

[0048] In one embodiment, along the axial direction of the pole, the first area protrudes outward along the axial direction of the pole to form a height difference, and the thickness dimension of the first area protruding relative to the second area is Ha1, and the second section has a thickness dimension Da in the axial direction of the pole, 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, the second area protrudes outward along the axial direction of the pole to form a height difference, and the thickness dimension of the second area protruding relative to the first area is Ha2, and the second section has a thickness dimension Da in the axial direction of the pole, satisfying 0<Ha2≤15%Da.

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

[0052] In one embodiment, the first zone protrudes outward along the axial direction of the pole to form a first protruding portion, and the first protruding portion extends in a ring shape along the circumference of the pole; or, the second zone protrudes outward along the axial direction of the pole to form a second protruding portion, and the second protruding portion extends in a ring shape along the circumference of the pole.

[0053] In the third aspect, an embodiment of the present application provides a battery cell, including a shell, an electrode assembly and the aforementioned cover assembly; the shell has a accommodating cavity; the electrode assembly is arranged in the accommodating cavity, and the electrode assembly includes a pole ear; the cover plate is connected to the shell and closes the opening of the accommodating cavity, and the pole is connected to the pole ear.

[0054] Beneficial effects of the embodiments of the present application:

[0055] In the embodiment of the present application, by increasing the thickness dimension Hb of at least part of the flange as it approaches the axis of the pole, on the one hand, it is helpful to increase the thickness of the edge of the second section to ensure the welding thickness of the edge of the second section, so that when the edge of the second section is welded with other components, the edge of the second section has more material to block the welding heat transfer, so as to effectively avoid welding through the second section; on the other hand, the thickness dimension Hb of the edge of the flange can be reduced by piercing, so that the material of the edge of the flange flows toward the axis of the pole, so that the end of the flange close to the axis has more material, so as to facilitate increasing the depth of the second metal layer close to the axis embedded in the first metal column. In this way, the reliability of the combination between the first metal column and the second metal layer can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 is a schematic structural diagram of a first type of pole provided in an embodiment of the present application;

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

[0059] Figure 3 The embodiments of this application provide Figure 1 A magnified view of another structure at A;

[0060] Figure 4 is a schematic diagram of a forging streamline of a first metal column provided in an embodiment of the present application;

[0061] Figure 5 is a schematic diagram of the structure of the second pole provided in an embodiment of the present application;

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

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

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

[0065] Fig. 9 yes Figure 1 A magnified view of another structure at B in the middle;

[0066] Fig.10 is a schematic structural diagram of a third type of pole provided in an embodiment of the present application;

[0067] Fig.11 is a schematic structural diagram of a fourth type of pole provided in an embodiment of the present application;

[0068] Fig.12 is a structural schematic diagram of a first cover plate assembly provided in an embodiment of the present application;

[0069] Fig.13 is a structural schematic diagram of a second cover plate assembly provided in an embodiment of the present application;

[0070] Fig.14 is a structural schematic diagram of a third cover plate assembly provided in an embodiment of the present application;

[0071] Fig.15 is a structural schematic diagram of a fourth cover plate assembly provided in an embodiment of the present application;

[0072] Fig.16 is a structural schematic diagram of a fifth cover plate assembly provided in an embodiment of the present application;

[0073] Fig.17 is a schematic structural diagram of a first insulating member provided in an embodiment of the present application;

[0074] Fig.18 It is a schematic diagram of the structure of a battery cell provided in an embodiment of the present application.

[0075] Description of reference numerals:

[0076] 101-pole; 1013-first surface; 1015-first area; 1016-second area; 1017-first convex portion; 1018-second convex portion; 1019-bottom plate;

[0077] 1-first metal column; 14-first section; 141-matching bottom wall; 15-second section; 16-fitting 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-bonding interface; 18-forging streamline; 19-bonding area; 191-tight area; 1911-first dense area; 1912-second dense area; 1913-third dense area; 192-metal mixed layer; 1921-first mixed part; 1922-second mixed part;

[0078] 2-second metal layer; 27-cylinder; 271-matching groove; 272-step groove b; 273-pre-punching hole; 28-flanging; 281-transition part; 29-gap a;

[0079] 100-cover plate assembly; 110-cover plate; 112-first insulating member; 1121-exhaust groove; 113-second insulating member; 120-current collecting member; 121-convex hull; 130-sealing member;

[0080] 1000-battery cell; 1100-housing. DETAILED DESCRIPTION

[0081] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0082] In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction 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 clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

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

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

[0086] See also Figure 1 , Figure 1 : is a schematic diagram of the structure of the first pole 101 provided by an embodiment of the present application. An embodiment of the present application provides a pole 101. The pole 101 includes a first metal column 1 and a second metal layer 2. The first metal column 1 includes a first section 14 and a second section 15 connected to each other. The outer diameter of the first section 14 is smaller than the outer diameter of the second section 15. The second metal layer 2 includes a cylinder 27 and a flange 28. The cylinder 27 covers the first section 14. The flange 28 is connected to the end face of the cylinder 27 close to the second section 15. The flange 28 extends along the radial direction of the pole 101 and is embedded in the end of the second section 15 facing the first section 14. Among them, in the axial direction of the pole 101, the flange 28 has a thickness dimension Hb. The thickness dimension Hb of at least part of the flange 28 increases as it approaches the axis of the pole 101.

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

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

[0089] It can be understood that the diameter of the second section 15 is greater than the diameter of the first section 14 , so that the flange 28 can be embedded in the end surface of the second section 15 facing the first section 14 .

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

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

[0092] Optionally, the mobility of the first metal is greater than the mobility of the second metal.

[0093] Optionally, the second metal has a harderness than the first metal.

[0094] It can be understood that when the pole 101 is applied to a battery cell, the first section 14 and the flange 28 can be located outside the battery cell to serve as the output electrode of the battery cell. At this time, the material of the second metal layer 2 is consistent with the material of the negative electrode current collector. The material of the first metal column 1 can be aluminum. The first section 14 and the flange 28 can also be located inside the battery cell to prevent the pole 101 from detaching from the cover 110 of the battery cell when the high pressure inside the battery cell is high. At this time, the material of the first metal column 1 is consistent with 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 dimension Hb of at least part of the flange 28 as it approaches the axis of the pole 101, on the one hand, it is helpful to increase the thickness of the edge of the second section 15 to ensure the welding thickness of the edge of the second section 15, so that when the edge of the second section 15 is welded with other components, the edge of the second section 15 has more material to block the welding heat transfer, so as to effectively avoid welding through the second section 15; on the other hand, the thickness dimension Hb of the edge of the flange 28 can be reduced by piercing, so that the material of the edge of the flange 28 flows toward the axis of the pole 101, so that the end of the flange 28 close to the axis has more material, so as to facilitate increasing the depth of the second metal layer 2 close to the axis embedded in the first metal column 1. In this way, the reliability of the combination between the first metal column 1 and the second metal layer 2 can be improved.

[0096] In addition, by allowing the material at the edge of the flange 28 to flow toward the axis of the pole 101 so that the end of the flange 28 close to the axis has more material, it also helps to increase the depth dimension of the second metal layer 2 radially invading the first metal column 1, so that the side of the flange 28 close to the axis can be matched with the first metal column 1 along the axis of the pole 101 to prevent the first section 14 from escaping from the cylinder 27.

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

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

[0099] Specifically, the concave sides of the first line segment 161 and the third line segment 163 face away from the second segment 15 .

[0100] In this embodiment, through the above arrangement, firstly, the part where the flange 28 is formed by the first line segment 161 can smoothly connect the side of the flange 28 away from the second section 15 with the surface where the flange 28 is embedded in the second section 15, secondly, the thickness dimension Hb can be smoothly increased through the part where the second line segment 162 is formed, and thirdly, the surface where the flange 28 is embedded in the second section 15 can be smoothly transitioned to the inner wall of the cylinder 27 through the third line segment 163. In this way, the stress concentration at the matching part between the flange 28 and the first metal column 1 can be improved to improve the stress state of the pole 101, thereby improving the reliability of the combination between the first metal column 1 and the second metal layer 2.

[0101] In one embodiment, the curvature of the third line segment 163 is greater than the curvature of the first line segment 161. It can be understood that such a configuration makes the radius of the end of the flange 28 away from the axis of the pole 101 larger, while the radius of the end of the flange 28 close to the axis of the pole 101 is smaller. In this way, the convexity of the end of the flange 28 away from the axis of the pole 101 can be reduced to reduce the material of the end of the flange 28 away from the axis of the pole 101, so that more material of the flange 28 can flow toward the axis of the pole 101. At the same time, the end of the flange 28 close to the pole 101 can have more material, so as to facilitate the increase in the depth of the second metal layer 2 inserted into the first metal column 1. In this way, the reliability of the combination can be improved.

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

[0103] It can be understood that the curvature of the first line segment 161 includes but is not limited to 2×10 -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 includes 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, through the above-mentioned limitation, the first line segment 161 can relatively smoothly connect the surface of the flange 28 facing away from the second segment 15 and the surface where the flange 28 and the second segment 15 are embedded, and the third line segment 163 can relatively smoothly connect the surface where the flange 28 and the second segment 15 are embedded and the inner surface of the cylinder 27.

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

[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 respectively located on both sides of the joint surface between the flange 28 and the second segment 15. 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, and the center of the first line segment 161 and the center of the third line segment 163 are located on the side of the joint surface between the flange 28 and the second segment 15 close to the first segment 14.

[0108] Based on the structure of the joint surface between the flange 28 and the second section 15 provided in the above embodiment, the embodiment of the present application further describes the structure of the joint surface between the flange 28 and the second section 15 as follows.

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

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

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

[0112] In this embodiment, through the above arrangement, the material of the flange 28 at the fourth line segment 164 can be reduced, so that the material originally located at the fourth line segment 164 flows at least to the fifth line segment 165 based on the pier pressure, which is conducive to the fifth line segment 165 protruding radially toward the axis of the pole 101, thereby increasing the depth of the second metal layer 2 near the axis embedded in the first metal column 1. In this way, the side of the flange 28 near the axis can be matched with the first metal column 1 along the axis of the pole 101 to prevent the first section 14 from escaping 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. It can be understood that such a setting makes the radius of the end of the flanging 28 away from the axis of the terminal post 101 larger, while the radius of the end of the flanging 28 close to the axis of the terminal post 101 smaller. In this way, the convexity of the end of the flanging 28 away from the axis of the terminal post 101 can be reduced to reduce the material at the end of the flanging 28 away from the axis of the terminal post 101, so that more material of the flanging 28 can flow towards the axis of the terminal post 101. At the same time, it can make the end of the flanging 28 close to the terminal post 101 have more material, which is beneficial to increasing the depth of insertion of the second metal layer 2 into the first metal post 1. In this way, it is beneficial to improve the reliability of the bonding.

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

[0115] It can be understood that the curvature of the first line segment 161 includes but is not limited to 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 、9×10 -4 mm -1 、9.5×10 -4 mm -1 .

[0116] It can be understood 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 can be understood that the curvature of the fifth line segment 165 includes but 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, through the above-mentioned limitation, the first line segment 161 can relatively smoothly connect the surface of the flange 28 facing away from the second segment 15 with the surface where the flange 28 and the second segment 15 are embedded, and the third line segment 163 and the fifth line segment 165 can relatively smoothly connect the surface where the flange 28 and the second segment 15 are embedded with the inner surface of the cylinder 27.

[0119] In one embodiment, the curvature of the fourth line segment 164 is less than or equal to 1×10 -4 mm -1 Thus, the curvature relative to the fourth line segment 164 is greater than 1×10 -4 mm -1 In terms of the structure, such a setting can reduce the material of the portion of the flange 28 forming the fourth line segment 164, so that the material of this portion can flow to the fifth line segment 165, so as to facilitate the end of the flange 28 close to the axis to have more material, thereby increasing the depth of the second metal layer 2 close to the axis embedded in the first metal column 1.

[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 respectively located on both sides of the joint surface between the flange 28 and the second segment 15. 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, and the center of the third line segment 163 and the center of the fifth line segment 165 are located on the side of the joint surface between the flange 28 and the second segment 15 close to the connection between the flange 28 and the cylinder 27.

[0121] See also Figure 4 , Figure 41 is a schematic diagram of forging streamlines 18 of the first metal column 1 provided in an embodiment of the present application. In one embodiment, in the longitudinal section of the pole 101, the first metal column 1 has a plurality of forging streamlines 18. The contact portion between the first metal column 1 and the second metal layer 2 forms a bonding interface 17; the first metal column 1 has a bonding area 19 close to the second metal layer 2, and a plurality of forging streamlines 18 in the bonding area 19 extend along the bonding interface 17. The bonding area 19 includes a tight zone 191, and the spacing between multiple forging streamlines 18 in the tight zone 191 is smaller than the spacing between multiple forging streamlines 18 in other areas of the bonding area 19; wherein, the tight zone 191 includes a first dense zone 1911, a second dense zone 1912 and a third dense zone 1913, and along the thickness direction of the second metal layer 2, the first dense zone 1911 and the second dense zone 1912 are respectively arranged opposite to the third line segment 163 and the fifth line segment 165; the third dense zone 1913 is located at the axis of the first metal column 1 and is arranged away from the bottom wall of the cylinder 27.

[0122] It can be understood that the metal grains of the first metal material located in the tight zone 191 are highly refined and arranged more closely, so that the first metal material located in the tight zone 191 has an enhanced ability to hinder dislocation movement, thereby improving the strength and hardness of the first metal column 1 to enhance the structural reliability of the pole 101.

[0123] In addition, the first dense area 1911 and the second dense area 1912 are respectively arranged opposite to the third line segment 163 and the fifth line segment 165, so that the first dense area 1911 and the second dense area 1912 can clamp the flange 28, thereby improving the reliability of the connection between the first metal column 1 and the second metal layer 2.

[0124] See also Figure 2 or Figure 3 In one embodiment, the two end points of the second line segment 162 are point U and point V respectively; the straight line UV forms an angle W with the radial direction of the pole 101 on the side away from the flange 28, satisfying: 0<W≤20°. In this way, the steepness of the bonding surface between the first metal column 1 and the second metal layer 2 between point U and point V can be controlled. In this way, the bonding surface between the first metal column 1 and the second metal layer 2 between point U and point V is relatively gentle, so that under the premise that the maximum thickness of the flange 28 is constant, the first metal column 1 and the second metal layer 2 can have a larger bonding surface in the axial direction, so as to improve the reliability of the bonding between the first metal column 1 and the second metal layer 2.

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

[0126] It can be 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, through the above-mentioned limitation, on the one hand, the radial dimension of the flange 28 and the second section 15 can be guaranteed, so that there is a sufficient radial bonding dimension between them, which can help to ensure the reliability of the bonding between the first metal column 1 and the second metal layer 2; on the other hand, it can avoid the radial dimension of the flange 28 being too large to affect the thickness of the second section 15, so as to ensure the smooth welding of the second section 15 with other components, so as to avoid the second section 15 being welded through and affecting the reliability of the bonding between the second section 15 and the flange 28.

[0128] See also Figure 5 and Figure 6 , Figure 5 is a schematic structural diagram of a second pole 101 provided in an embodiment of the present application, Figure 6 2 is a schematic diagram of the structure of the second metal layer 2 provided in an embodiment of the present application. In one embodiment, there are multiple flanges 28. Multiple flanges 28 are arranged in sequence along the circumference of the pole 101. At least two flanges 28 are arranged opposite to each other along the radial direction of the pole 101. In this way, the reliability of the combination between the first metal column 1 and the second metal layer 2 can be improved, and the structural symmetry of the pole 101 can be improved, so as to improve the stress state of the pole 101.

[0129] In one embodiment, in the axial cross section of the pole 101, the length of the bonding interface 17 formed by the first metal column 1 and the second metal layer 2 contacting each other is Lb, and the outer diameter of the cylinder 27 is φb0, which satisfies: 1φb0≤Lb≤5φb0. In this way, the larger the pole 101, the longer the bonding interface 17, so that the bonding force between the first metal column 1 and the second metal layer 2 can match the size of the pole 101, thereby improving the structural reliability of the pole 101.

[0130] It can be 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 can be understood that when φb0 ≤ 4 mm, the length Lb of the bonding interface 17 formed by the mutual contact of the first metal column 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, 5φb0.

[0133] When 4 mm < φb0 < 8 mm, the length Lb of the bonding interface 17 formed by the mutual contact of the first metal column 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, 3.6φb0.

[0134] When φb0 ≥ 8 mm, the length Lb of the bonding interface 17 formed by the mutual contact of the first metal column 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, 3φb0.

[0135] It can be understood that the larger the size of the pole column 101, the smaller the ratio of the length Lb of the bonding interface 17 to the outer diameter φb0 of the cylinder 27. The smaller the size of the pole column 101, the larger the ratio of the length Lb of the bonding interface 17 to the outer diameter φb0 of the cylinder 27.

[0136] Please refer to 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 surface of the cylinder 27 close to the second section 15. The two transition portions 281 and the two flanges 28 are staggered along the circumference of the pole 101, and the two ends of the flanges 28 along the circumference of the pole 101 are respectively connected to the two transition portions 281. Among them, the transition portion 281 is embedded in the end surface of the second section 15 facing the first section 14. The bonding interface 17 between the partial transition portion 281 and the second section 15 is located on the circumferential surface of the second section 15. In this way, the structural symmetry of the pole 101 can be improved, and the structural strength of the second metal layer 2 at the flange 28 can be improved, so as to improve the structural strength of the pole 101.

[0137] See also Figure 5 and 5 In one embodiment, the cross section of the second section 15 is a rectangle. The two flanges 28 are arranged at intervals along the direction where the long side of the rectangle is located. The flanges 28 extend along the wide side of the rectangle. The two transition portions 281 are arranged at intervals along the direction where the narrow side of the rectangle is located. The transition portion 281 extends along the long side of the rectangle. It can be understood that in the width direction of the rectangle, the size of the pole 101 is small, which is not conducive to forming the flanges 28.

[0138] In this embodiment, through the above-mentioned setting, the direction pole 101 can have a flange 28 structure to improve the reliability of the connection between the first metal column 1 and the second metal layer 2, and the connection structure between the first metal column 1 and the second metal layer 2 can be matched with the overall shape of the pole 101 to reduce the difficulty of forming the pole 101.

[0139] See also Figure 5 In one embodiment, the end surface of the transition portion 281 away from the axis of the pole 101 is coplanar with the side wall where the long side of the second section 15 is located. In this way, the surface structure of the pole 101 is regular, which is convenient for assembly with other components.

[0140] See also Figure 2 or Figure 3 In one embodiment, the contact portion between the first metal column 1 and the second metal layer 2 forms a bonding interface 17. The pole 101 includes a metal mixed layer 192. The metal mixed layer 192 extends along the bonding interface 17, and the metal mixed layer 192 covers the bonding interface 17. The metal mixed layer 192 includes a first metal material and a second metal material mixed with each other. The thickness of the metal mixed layer 192 is Dc, and the thickness of the metal mixed layer 192 is uneven.

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

[0142] It can be understood that under the pressure of the ramming, the atoms in the contact area between the first metal column 1 and the second metal layer 2 approach each other and diffuse one in the other to form a metal mixed layer 192 in which the first metal and the second metal are mixed.

[0143] The non-uniform thickness of the metal mixed layer 192 means that the thickness of at least two parts of the metal mixed layer 192 is the same.

[0144] In this embodiment, by forming a metal mixed layer 192 extending along the bonding interface 17, the bite force between the first metal column 1 and the second metal layer 2 on the opposite surfaces of each other can be improved, that is, an interlocking connection structure composed of a plurality of protrusions and a plurality of recesses that are mutually embedded can be formed on the surfaces of the two metals, thereby making the connection between the first metal column 1 and the second metal layer 2 tighter and more reliable, and improving the ability to resist separation between the first metal column 1 and the second metal layer 2.

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

[0146] It can be understood that the thickness dimension Dc of the metal mixed layer 192 includes but is 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 can be understood that the limitation on the thickness dimension Dc of the metal mixed layer 192 can, on the one hand, ensure the material mixing depth between the first metal column 1 and the second metal layer 2, so as to ensure the reliability of the bonding between the first metal column 1 and the second metal layer 2; on the other hand, it can avoid the depth dimension of the metal mixed layer 192 being too large, which will lead to a higher cost for forming the electrode column 101.

[0148] See also Figure 1 and Figure 2, in one embodiment, the metal mixing layer 192 includes a first mixing portion 1921 and a second mixing portion 1922. The first mixing portion 1921 is formed by mixing the material of the bottom wall of the cylinder 27 and the material of the end face of the first section 14 away from the second section 15. The second mixing portion 1922 is formed by mixing the material of the portion of the inner peripheral surface of the cylinder 27 near the flanging 28 and the material of the portion of the outer peripheral surface of the first section 14 near the second section 15. Wherein, the thickness of the first mixing portion 1921 is greater than the thickness of the second mixing portion 1922. In this way, the bonding force between the first metal column 1 and the second metal layer 2 in the axial direction of the terminal post 101 can be improved, so as to improve the reliability of the bonding between the first metal column 1 and the second metal layer 2.

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

[0150] Please refer to Figure 7 , Figure 7 is another structural schematic diagram of the second metal layer 2 provided by the embodiment of the present application. In one embodiment, the flanging 28 extends circumferentially along the first section 14 to form a ring. In this way, the structural symmetry of the terminal post 101 can be improved to improve the stress state of the terminal post 101, thereby improving the structural reliability of the terminal post 101.

[0151] Please refer to Figure 2 or Figure 3 , in one embodiment, the diameter φb1 of one end of the first section 14 close to the second section 15 is smaller than the diameter φb2 of the end of the first section 14 away from the second section 15. In this way, the side of the flanging 28 close to the axis is in blocking fit with the first metal column 1 along the axis of the terminal post 101, so as to prevent the first section 14 from coming out of the cylinder 27.

[0152] Please refer to Figure 8 or Fig. 9 , in one embodiment, a fitting groove 16 is provided on the end face of the second section 15 facing the first section 14. The flanging 28 is fitted with the fitting groove 16. Wherein, there is a gap a29 between the flanging 28 and the fitting groove 16. Specifically, the gap a29 is located between the end of the flanging 28 away from the axis of the terminal post 101 and the groove wall of the fitting groove 16. This gap a29 can compensate for the influence of the mutual extrusion of the first metal column 1 and the second metal layer 2 due to thermal expansion during the welding of the terminal post 101, so as to facilitate improving the stress state of the first metal column 1 and the second metal layer 2.

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

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

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

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

[0157] It can be understood that the dimension La of the gap a29 in the radial direction of the pole 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 can be understood that the dimension Ha3 of the gap a29 in the axial direction of the pole 101 includes but is 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 of the pole 101 , it is possible to avoid the gap a29 being too wide to reduce the bonding between the first metal column 1 and the second metal layer 2 , thereby facilitating the structural reliability of the pole 101 .

[0160] In this embodiment, by limiting the dimension Ha3 of the gap a29 in the axial direction of the pole 101 , it is possible to avoid the gap a29 being too high to reduce the bonding between the first metal column 1 and the second metal layer 2 , thereby facilitating the structural reliability of the pole 101 .

[0161] See also Fig.10 , Fig.101 is a schematic diagram of the structure of the third pole 101 provided in an embodiment of the present application. In one embodiment, a matching groove 271 is provided at one end of the cylinder 27 away from the second section 15 .

[0162] It can be understood that the current collector 120 is provided with a convex bump 121 protruding toward the pole 101, and the convex bump 121 is inserted into the matching groove 271. In this way, the matching area between the current collector 120 and the pole 101 can be increased by the matching groove 271 and the convex bump 121, so as to improve the current flow capacity, and the positioning of the current collector 120 on the pole 101 can be improved by the matching groove 271 and the convex bump 121 structure, so as to improve the assembly efficiency.

[0163] The current collector 120 connects the pole lug to the pole 101 .

[0164] See also Fig.10 In one embodiment, the first section 14 has a matching bottom wall 141 away from the second section 15 , and the bottom wall of the cylinder 27 protrudes toward the matching bottom wall 141 to be embedded in the matching bottom wall 141 .

[0165] It can be understood that the matching groove 271 can be formed by ramming so that the bottom wall of the cylinder 27 is protruded toward the matching bottom wall 141 to be embedded in the matching bottom wall 141. In this way, the area of ​​the bonding surface between the first metal column 1 and the second metal layer 2 can be increased, thereby improving the reliability of the bonding between the first metal column 1 and the second metal layer 2.

[0166] See also Fig.10 In one embodiment, the first section 14 has a matching bottom wall 141 away from the second section 15, and the periphery of the matching bottom wall 141 is protruded toward 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 column 1 and the second metal layer 2 can be increased, thereby improving the reliability of the bonding between the first metal column 1 and the second metal layer 2.

[0167] See also Figure 1 or Fig.10 In one embodiment, the diameter of the end of the cylinder 27 away from the second section 15 is smaller than the diameter of the end of the cylinder 27 close to the second section 15. In this way, when the cylinder 27 and other components are laser welded together, the laser can be effectively prevented from passing through the gap a29 between the cylinder 27 and other components, thereby preventing the components located on the side of the cylinder 27 close to the second section 15 from being burned.

[0168] For example, when the seal 130 is sleeved on 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 the cylinder 27 and the current collecting member 120 are welded, the part of the cylinder 27 with a larger diameter can block the laser to prevent the laser from passing through the fitting gap a29 between the cylinder 27 and the current collecting member 120 and irradiating the sealing ring.

[0169] See also Figure 1 or Fig.10 The specific implementation structure of the diameter of the end of the cylinder 27 away from the second section 15 is smaller than the diameter of the end of the cylinder 27 close to the second section 15 can be the following structure. Specifically, in one embodiment, the outer peripheral surface of the cylinder 27 is a conical surface, or a step groove b272 is provided at the end of the outer peripheral surface of the cylinder 27 away from the second section 15, and the step groove b272 extends in a ring shape along the circumference of the cylinder 27. In this way, the outer peripheral structure of the cylinder 27 is simple and easy to manufacture.

[0170] It can be understood that when the diameter of the end of the cylinder 27 away from the second section 15 is smaller than the diameter of the end of the cylinder 27 close to the second section 15 , the aforementioned outer diameter of the cylinder 27 refers to the maximum diameter of the cylinder 27 .

[0171] See also Fig.11 , Fig.11 1 is a schematic diagram of the structure of the fourth pole 101 provided in an embodiment of the present application. In one embodiment, the pole 101 further includes a bottom plate 1019. The bottom plate 1019 is connected to an end of the cylinder 27 away from the second section 15.

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

[0173] It can be understood that the bottom plate 1019 can cooperate with the cover plate 110 of the battery cell to compress the seal 130 therebetween, thereby achieving a sealed fit between the pole 101 and the cover plate 110 .

[0174] See also Fig.11 In one embodiment, the bottom plate 1019 is sleeved on the cylinder 27. The bottom plate 1019 is riveted to the cylinder 27. A pre-punched hole 273 is provided at one end of the cylinder 27 away from the second section 15. The aperture of the pre-punched hole 273 gradually increases in the direction away from the second section 15. In this way, when the pole 101 is connected to the bottom plate 1019, the pre-punched hole 273 can be squeezed by a tool to make the second metal layer 2 expand radially outward, thereby reducing the matching gap a29 between the pole 101 and the bottom plate 1019, so as to facilitate the riveting of the pole 101 and the bottom plate 1019.

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

[0176] In one embodiment, a step groove b272 is provided at one end of the cylinder 27 away from the second section 15. The step groove b272 extends in a ring shape around the circumference of the cylinder 27. The bottom plate 1019 is sleeved in the step groove b272. In this way, the matching structure between the bottom plate 1019 and the cylinder 27 can be increased by the step groove b272, so as to facilitate the installation of the bottom plate 1019 on the cylinder 27, thereby improving the assembly efficiency.

[0177] In one embodiment, the bottom plate 1019 is welded to the cylinder 27. In this way, the stability of the connection between the bottom plate 1019 and the cylinder 27 can be improved.

[0178] It can be understood that when welding the pole 101 to the bottom plate 1019, the pre-punching hole 273 can be firstly pressed by tooling to make the second metal layer 2 expand radially outward, thereby reducing the matching gap a29 between the pole 101 and the bottom plate 1019, so as to rivet the pole 101 to the bottom plate 1019. Then the pole 101 is welded to the bottom plate 1019. In this way, the riveting action before welding is conducive to improving the welding superiority rate of the pole 101 and the bottom plate 1019, and improving the welding quality between the pole 101 and the bottom plate 1019.

[0179] See also Figure 1 or Figure 5 or Fig.10 In one embodiment, the second section 15 is configured to be located outside the battery cell 1000. One end of the barrel 27 away from the second section 15 is configured to be connected to the current collector 120, so that the pole 101 is clamped on the cover plate 110 of the battery cell 1000 through the current collector 120 and the second section 15.

[0180] It can be understood that the second section 15 is located on one side of the cover plate 110 , and the current collecting member 120 is located on the other side of the cover plate 110 .

[0181] It can be understood that in a cylindrical battery cell, the current collecting member 120 can be a current collecting plate, and in a square shell battery cell, the current collecting member 120 can be a current collecting sheet or a current collecting foot.

[0182] In this embodiment, the bottom plate 1019 is eliminated through the above arrangement, thereby reducing the number of components in the battery cell 1000. In this way, not only the weight of the battery cell 1000 can be reduced, but also the space originally used for arranging the bottom plate 1019 can be used for arranging the electrode assembly, thereby facilitating the improvement of the capacity density of the battery cell 1000.

[0183] See also Fig.12 or Fig.13 or Fig.14 or Fig.15 or Fig.16 , Fig.12 is a structural schematic diagram of a first cover plate assembly 100 provided in an embodiment of the present application, Fig.13 is a structural schematic diagram of a second cover plate assembly 100 provided in an embodiment of the present application, Fig.14 is a schematic structural diagram of a third cover plate assembly 100 provided in an embodiment of the present application. Fig.15 is a structural schematic diagram of a fourth cover plate assembly 100 provided in an embodiment of the present application, Fig.16 1 is a schematic diagram of the structure of the fifth cover plate assembly 100 provided in the embodiment of the present application. Accordingly, the embodiment of the present application provides a cover plate assembly 100, which includes a cover plate 110 and the aforementioned pole 101, and the pole 101 is disposed on the cover plate 110.

[0184] It is understood that the pole 101 may include a bottom plate 1019, such as Figures 12 to 15 The pole 101 may also be without the bottom plate 1019 and directly clamped on the cover plate by the current collector 120 and the second section 15, as shown in FIG. Fig.16 shown.

[0185] In this embodiment, by adopting the pole 101 provided by some embodiments of the present application, on the one hand, the thickness of the edge of the second section 15 can be increased to ensure the welding thickness of the edge of the second section 15, so that when the edge of the second section 15 is welded with other components, the edge of the second section 15 has more material to block the welding heat transfer, so as to effectively avoid welding through the second section 15; on the other hand, the thickness dimension Hb of the edge of the flange 28 can be reduced by piercing, so that the material of the edge of the flange 28 flows toward the axis of the pole 101, so that the end of the flange 28 close to the axis has more material, so as to facilitate the increase of the depth of the second metal layer 2 close to the axis embedded in the first metal column 1. In this way, the reliability of the combination between the first metal column 1 and the second metal layer 2 can be improved, so as to improve the structural reliability of the cover plate assembly 100.

[0186] See also Fig.12 or Fig.13 or Fig.14 or Fig.15 or Fig.16 In one embodiment, the cover 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 110. The second insulating member 113 is disposed on the other side of the cover 110. The second section 15 and the flange 28 are located on the side of the first insulating member 112 away from the cover 110.

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

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

[0189] It is understandable that the seal 130 may be disposed between the bottom 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] See also Fig.17 , Fig.17 1 is a schematic diagram of the structure of the first insulating member 112 provided in an embodiment of the present application. In one embodiment, a venting groove 1121 is provided on the surface of the first insulating member 112 facing the second section 15. The two ends of the venting groove 1121 extend to the inner circumference and the outer circumference of the first insulating member 112, respectively. The venting groove 1121 facilitates the gas inside the battery cell 1000 to pass through the seal 130 to between the flange 28 and the venting groove 1121 after the air pressure inside the battery cell 1000 reaches a certain threshold, and is discharged through the venting groove 1121, so as to facilitate the pressure relief of the battery cell 1000.

[0191] In addition, the cross section of the terminal is non-circular, and a limiting groove is provided on the first insulating member 112, and at least part of the terminal is located in the limiting groove and fits with the inner wall of the limiting groove. In this way, the first insulating member 112 can prevent the terminal from twisting, thereby improving the torsional strength of the cover assembly 100.

[0192] Exemplarily, the terminal has a rectangular cross section, and four corners are provided with bevel chamfers.

[0193] In an embodiment of the present application, the seal 130 may be disposed between the cover plate 110 and the flange 28. Fig.15 As shown, the seal 130 may also be disposed between the bottom plate 1019 and the cover plate 110, as shown in FIG. Fig.12 and Fig.13As shown. The cylinder 27 can be welded to the bottom plate 1019 or riveted to the bottom plate 1019. When welding the cylinder 27 to the bottom plate 1019, the cylinder 27 and the bottom plate 1019 can be riveted first and then welded together. In order to achieve riveting, a pre-punched hole 273 is provided at the bottom of the cylinder 27. Fig.10 and Fig.11 The bottom of the cylinder 27 may be provided with a matching groove 271 to match with the convex bump 121 on the current collecting member 120, as shown in FIG. Fig.10 and Fig.13 The bottom of the cylinder 27 may also be a plane, such as Figure 1 , Fig.12 and Fig.15 The pole may include a base plate, such as Fig.12 Character Fig.15 As shown, the bottom plate 1019 may not be provided at the bottom of the pole 101. Fig.16 The above-mentioned configuration modes and their combinations are set according to actual application scenarios, and this embodiment does not limit this.

[0194] See also Figure 8 or Fig. 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 close to the first segment 14. The first surface 1013 includes a first area 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 the second area 1016. There is a height difference between the first area 1015 and the second area 1016. The first area 1015 and the second area 1016 are both crimped with the first insulating member 112.

[0195] It can be understood that one of the first area 1015 and the second area 1016 is protruded outward along the axial direction of the pole 101 to form a height difference.

[0196] Exemplarily, along the axial direction of the column, the first area 1015 is protruded outward from the first surface 1013. Alternatively, along the axial direction of the pole 101, the second area 1016 is protruded outward from the plane where the first surface 1013 is located.

[0197] It can be understood that the cross section of the second section 15 can be cylindrical, polygonal or irregular.

[0198] It can be understood that the first area 1015 and the second area 1016 are in contact with the first insulating member 112, so that the first insulating member 112 is axially compressed, thereby achieving sealing of the mating surface between the pole 101 and the first insulating member 112. There is a height difference between the first area 1015 and the second area 1016, so that the one closer to the first insulating member 112 exerts a greater pressure on the first insulating member 112.

[0199] In this embodiment, a height difference is provided between the first area 1015 and the second area 1016 so that the one closer to the first insulating member 112 exerts a greater pressure on the first insulating member 112. In this way, the pressure of the pole 101 on the first insulating member 112 can be partially increased, thereby improving the sealing between the pole 101 and the first insulating member 112 while controlling the material usage of the pole 101, so as to improve the reliability of the battery cell 1000.

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

[0201] At the same time, when the second zone 1016 protrudes outward along the axial direction of the pole 101, the inner circumference of the first insulating member 112 can be subjected to greater pressure, thereby increasing the deformation of the inner circumference of the first insulating member 112, so that the periphery of the first insulating member 112 is tilted toward the end face of the second section 15, so as to improve the sealing between the pole 101 and the first insulating member 112 at the periphery.

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

[0203] It can be understood that the outwardly protruding thickness dimension Ha1 of the first zone 1015 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.

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

[0205] In this embodiment, through the above-mentioned limitation, on the one hand, the amount of material protruding from the first zone 1015 can be controlled to facilitate controlling the weight of the pole 101; on the other hand, it can avoid that the thickness dimension Ha1 protruding from the first zone 1015 is too large, which leads to greater difficulty in matching between the pole 101 and the first insulating member 112 and a more complicated dimensional chain.

[0206] When the first area 1015 is convexly arranged outwardly along the axial direction of the pole 101, an exhaust groove may be arranged on the side of the first insulating member 112 away from the cover plate 110. In this way, on the basis of improving the sealing between the pole 101 and the cover plate 110, the flow of the gas between the first insulating member 112 and the second area 1016 may be improved, thereby facilitating the improvement of the exhaust effect.

[0207] In one embodiment, 2%Da≤Ha1≤15%Da. In this way, the first region 1015 can be more obviously pressed against the first insulating member 112, so that the convexity of the first region 1015 can significantly improve the sealing between the pole 101 and the first insulating member 112.

[0208] See also Fig. 9 In one embodiment, along the axial direction of the pole 101, the second area 1016 is protruded outward along the axial direction of the pole 101. The thickness dimension of the second area 1016 protruding relative to the first area 1015 is Ha2. The second section 15 has a thickness dimension Da in the axial direction of the pole 101, satisfying 0<Ha2≤15%Da.

[0209] It can be understood that the outwardly protruding thickness dimension Ha2 of the second zone 1016 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] Exemplarily, the size Da of the second section 15 in the circumferential direction of the pole 101 is 2 mm, Ha2=10%Da=0.2 mm.

[0211] In this embodiment, through the above-mentioned limitation, on the one hand, the amount of material protruding from the second zone 1016 can be controlled to facilitate controlling the weight of the pole 101; on the other hand, it can avoid the thickness dimension Ha2 protruding from the second zone 1016 being too large, which would cause greater difficulty in matching between the pole 101 and the first insulating member 112 and a more complex dimensional chain.

[0212] In one embodiment, 2%Da≤Ha2≤15%Da. In this way, the second area 1016 can be more obviously pressed against the first insulating member 112, so that the convex arrangement of the second area 1016 can improve the sealing between the pole 101 and the first insulating member 112 more obviously.

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

[0214] In this embodiment, by extending the first protruding portion 1017 into a ring shape along the circumference of the pole 101 , the force uniformity of the pole 101 and the first insulating member 112 can be improved, thereby improving the force state of the battery cell 1000 and avoiding stress concentration.

[0215] In addition, by extending the second protruding portion 1018 into a ring shape along the circumference of the pole 101 , the force uniformity of the pole 101 and the first insulating member 112 can be improved, so as to improve the force state of the battery cell 1000 and avoid stress concentration.

[0216] See also Fig.18 , Fig.18 1 is a schematic diagram of the structure of a battery cell 1000 provided in an embodiment of the present application. Accordingly, an embodiment of the present application provides a battery cell 1000, comprising 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 a tab; the cover 110 is connected to the housing 1100 and closes the opening of the receiving cavity, and the pole 101 is connected to the tab.

[0217] It can be understood that the electrode assembly includes at least a positive electrode sheet, a separator and a negative electrode sheet stacked in sequence. The positive electrode sheet can be connected to the positive electrode column 101 through a positive electrode tab, and the negative electrode tab can be connected to the negative electrode column 101 through a negative electrode sheet.

[0218] The battery cell 1000 may specifically be a cylindrical battery cell 1000 , a square-shell battery cell 1000 , a soft-pack battery cell 1000 , a blade battery cell 1000 , or the like.

[0219] In this embodiment, by adopting the cap plate assembly 100 provided in some embodiments of the present application, on the one hand, the thickness of the edge of the second section 15 can be increased to ensure the welding thickness of the edge of the second section 15, so that when the edge of the second section 15 is welded with other components, the edge of the second section 15 has more material to block the welding heat transfer, so as to effectively avoid welding through the second section 15; on the other hand, the thickness dimension Hb of the edge of the flange 28 can be reduced by piercing, so that the material of the edge of the flange 28 flows toward the axis of the pole 101, so that the end of the flange 28 close to the axis has more material, so as to facilitate the increase of the depth of the second metal layer 2 close to the axis embedded in the first metal column 1. In this way, the reliability of the combination between the first metal column 1 and the second metal layer 2 can be improved, so as to improve the structural reliability of the battery cell 1000.

[0220] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A pole, characterized in that: include: A first metal column, comprising a first section and a second section connected to each other, wherein an outer diameter of the first section is smaller than an outer diameter of the second section; A second metal layer includes a cylinder and a flange, wherein the cylinder covers the first section, the flange is connected to an end of the cylinder close to the second section, and the flange extends along the radial direction of the pole and is embedded in an end surface of the second section facing the first section; In the axial direction of the pole, the flange has a thickness dimension Hb, and the thickness dimension Hb of at least a portion of the flange increases as it approaches the axis of the pole.

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

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

4. The pole 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 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 according to claim 2, characterized in that: In the longitudinal section, along the axial direction of the pole, a bonding interface formed between a surface of the second metal layer close to the axis of the pole and an outer peripheral surface of the first metal pole comprises a fourth line segment and a fifth line segment, and two ends of the fourth line segment are respectively connected to the third line segment and the fifth line segment; The curvature of the fourth line segment is smaller than the curvature of the third line segment and the curvature of the fifth line segment.

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

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

10. The pole according to any one of claims 6 to 9, characterized in that: In the longitudinal section of the pole, the first metal column has a plurality of forging flow lines, and the contacting portion between the first metal column and the second metal layer forms a bonding interface; The first metal column has a bonding area close to the second metal layer, and a plurality of the forging streamlines in the bonding area extend along the bonding interface; the bonding area includes a compact area, and a spacing between the plurality of the forging streamlines in the compact area is smaller than a spacing between the plurality of the forging streamlines in the remaining area of ​​the bonding area; Among them, the dense area includes a first dense area, a second dense area and a third dense area. Along the thickness direction of the second metal layer, the first dense area and the second dense area are respectively arranged opposite to the third line segment and the fifth line segment; the third dense area is located at the axis of the first metal column and is arranged away from the bottom wall of the cylinder.

11. The pole according to any one of claims 2 to 9, characterized in that: 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°.

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

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

14. The pole according to any one of claims 1 to 9, characterized in that: In the axial cross section of the pole, the length of the bonding interface formed by the first metal pole and the second metal layer contacting each other is Lb, and the outer diameter of the cylinder is φb0, which satisfies: 1φb0≤Lb≤5φb0.

15. The pole 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 according to any one of claims 1 to 9, characterized in that: The second metal layer further includes two transition parts, the two transition parts are connected to the end surface of the cylinder close to the second section, the two transition parts and the two flanges are staggered along the circumference of the pole, and the two ends of the flange along the circumference of the pole are respectively connected to the two transition parts; The transition portion is embedded in the end surface of the second section facing the first section, and a portion of the bonding interface between the transition portion and the second section is located on the circumferential surface of the second section.

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

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

19. The pole according to any one of claims 1 to 9, characterized in that: The contact portion between the first metal column and the second metal layer forms a bonding interface; the pole comprises a metal mixed layer, the metal mixed layer extends along the bonding interface, and the metal mixed layer covers the bonding interface, and the metal mixed layer comprises a first metal material and a second metal material mixed with each other; The thickness of the metal mixed layer is Dc, and the thickness of the metal mixed layer is uneven.

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

21. The pole according to claim 19, characterized in that The metal mixed layer comprises a first mixed portion and a second mixed portion, wherein the first mixed portion is formed by mixing the material of the bottom wall of the cylinder and the material of the end surface of the first section away from the second section, and the second mixed portion is formed by mixing the material of the portion of the inner circumference of the cylinder close to the flange and the material of the portion of the outer circumference of the first section close to the second section; Wherein, the thickness of the first mixing portion is greater than the thickness of the second mixing portion.

22. The pole according to claim 19, characterized in that The metal mixed layer is a metallurgical layer, or the metal mixed layer is an alloy layer in which a first metal material and a second metal material are embedded with each other.

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

24. The pole according to any one of claims 1 to 9, characterized in that: A diameter of an end of the first segment close to the second segment is smaller than a diameter of an end of the first segment far from the second segment.

25. The pole according to any one of claims 1 to 9, characterized in that: An engaging groove is arranged on the end surface of the second section facing the first section, and the flange is engaged with the engaging groove; there is a gap a between the flange and the engaging groove.

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

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

28. The pole according to any one of claims 1 to 9, characterized in that: A matching groove is arranged at one end of the cylinder away from the second section.

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

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

31. The pole according to any one of claims 1 to 9, characterized in that: A diameter of an end of the cylinder away from the second section is smaller than a diameter of an end of the cylinder close to the second section.

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

33. The pole according to any one of claims 1 to 9, characterized in that: The pole further comprises a bottom plate; the bottom plate is connected to an end of the cylinder away from the second section.

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

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

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

37. The pole according to any one of claims 1 to 9, characterized in that The second section is configured to be located outside the battery cell, and one end of the cylinder away from the second section is configured to be connected to a current collector, so that the pole is clamped on 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 the pole according to any one of claims 1 to 37, wherein the pole is penetrated 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 member, disposed on one side of the cover plate; A second insulating member, disposed on the other side of the cover plate; Wherein, the second section and the flange are located on a side of the first insulating member facing away from the cover plate.

40. The cover plate assembly according to claim 39, characterized in that The cover plate assembly further comprises a sealing member, wherein the sealing member is disposed between the flange and the cover plate; Alternatively, the sealing member is located between the bottom plate and the cover plate, and the bottom plate is connected to an end of the cylinder away from the second section.

41. The cover plate assembly according to claim 39, characterized in that An exhaust groove is provided on a surface of the first insulating member facing the second section, and two ends of the exhaust groove extend to the inner circumferential surface and the outer circumferential surface of the first insulating member respectively.

42. The cover plate assembly according to claim 39, characterized in that The second section has a first surface close to the first section, the first surface includes a first area located on the outer peripheral side of the flange; the surface of the flange facing away from the second section is the second area; There is a height difference between the first area and the second area, and both the first area and the second area are crimped to the first insulating member.

43. The cover plate assembly according to claim 42, characterized in that Along the axial direction of the pole, the first area protrudes outward along the axial direction of the pole to form the height difference, and the thickness dimension of the first area protruding relative to the second area is Ha1, and the second section has a thickness dimension Da in the axial direction of the pole, 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, the second area protrudes outward along the axial direction of the pole to form the height difference, and the thickness dimension of the second area protruding relative to the first area is Ha2, and the second section has a thickness dimension Da in the axial direction of the pole, 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 area is convex outwardly along the axial direction of the pole to form a first convex portion, and the first convex portion extends in a ring shape along the circumference of the pole; or, The second area is protruded outwardly along the axial direction of the pole to form a second protruding portion, and the second protruding portion extends in a ring shape along the circumferential direction of the pole.

48. A battery cell, characterized in that: include: A housing having a receiving cavity; An electrode assembly is disposed in the accommodating cavity, and the electrode assembly includes a pole ear; And the cover plate assembly as described in any one of claims 38 to 47, wherein the cover plate is connected to the shell and closes the opening of the accommodating cavity, and the pole is connected to the pole ear.

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