Conductive structure and preparation method thereof, cover plate assembly and battery monomer

Abstract

The invention provides a conductive structure and a preparation method thereof, a cover plate assembly and a battery cell. The conductive structure comprises a first metal column having a first end and a second end which are opposite to each other; the second metal layer is combined on the surface of the first metal column, and the second metal layer wraps the first end and extends towards the second end. According to the conductive structure, the second metal layer combined on the surface of the first metal column is arranged to extend from the surface of the first end of the first metal column to the second end, namely, the end face of the first end of the first metal column and at least part of the side face of the first metal column are covered by the second metal layer; the bonding area of the second metal layer and the first metal column can be effectively increased, the overcurrent capability of the conductive structure is ensured, the bonding strength of the second metal layer and the first metal column is improved, and the risk that the second metal layer falls off is reduced.

Description

[0001] This application claims the priority of the Chinese patent application with application number 202411252093.7 filed with the Chinese Patent Office on September 6, 2024. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a conductive structure, a method for preparing a conductive structure, a cover plate assembly, and a battery cell. Background Art

[0003] The pole is an important component that connects the inside and outside of the battery cell (also called a battery cell). Usually, one end of the pole is connected to the circuit outside the battery cell, such as being connected to the module bar, and the other end of the pole is connected to the internal circuit of the battery cell, such as being connected to the pole ear in the electrode assembly through a current collector. At present, most poles are made of a single metal material, such as aluminum for the positive pole and copper for the negative pole. However, poles made of a single metal material are prone to welding difficulties. Taking the negative pole as a pure copper pole as an example, when the pure copper pole and the terminal block are laser welded, in order to reduce the cost and weight of the battery cell, the material of the terminal block is generally aluminum. Due to the different melting points between copper and aluminum, laser welding is prone to failure, resulting in cracking.

[0004] In order to reduce the difficulty of welding, a composite pole is designed in the related art. The composite pole includes two metal layers stacked up and down and made of different materials. The different metal layers are combined together by friction welding or stamping. Taking the composite pole as a negative pole as an example, the composite pole includes an aluminum layer and a copper layer. However, the bonding strength between the different metal layers in this composite pole is limited, which causes the metal layer connected to the electrode assembly to easily fall off and fall into the battery cell, thereby causing the battery cell to fail. Summary of the invention

[0005] The embodiments of the present application provide a conductive structure and a preparation method thereof, a cover plate assembly, and a battery cell, which can improve the technical problem that the metal layer in the composite pole is easy to fall off.

[0006] In a first aspect, an embodiment of the present application provides a conductive structure, including:

[0007] a first metal post having opposing first and second ends;

[0008] The second metal layer is bonded to the surface of the first metal column, and the second metal layer covers the first end and extends to the second end.

[0009] In one embodiment, the second metal layer is damascened with the first metal pillar.

[0010] In one embodiment, an end portion of the second metal layer is embedded in the first metal pillar.

[0011] In one embodiment, a gap is formed between an end of the second metal layer and the first metal column.

[0012] In one embodiment, an end face and a transition face connected in sequence are formed at the end of the second metal layer, and a gap is formed only between the end face, the transition face and the first metal column, wherein the side of the end face away from the transition face is connected to the outer surface of the second metal layer, and the transition face is bent from the end face to the first metal column.

[0013] In one embodiment, the average spacing of the gaps is less than 0.1 mm.

[0014] In one embodiment, the end of the second metal layer includes a first extension segment and / or a second extension segment, the first extension segment extends along a first direction, the second extension segment extends along a second direction, and the first direction intersects with the second direction.

[0015] In one embodiment, the conductive structure is a pole, and a support surface is formed on the end of the second metal layer, and the support surface is used to support the terminal pressing block.

[0016] In one embodiment, the supporting surface is an inclined surface, and along a direction away from the first end, the inclined surface gradually approaches the outer side surface of the first metal column from the outer side surface of the second metal layer.

[0017] In one embodiment, the inclined surface is an inclined straight surface, and the angle between the inclined straight surface and the outer side surface of the second metal layer is 110° to 130°.

[0018] In one embodiment, the support surface is a step surface, and the step surface includes a first sub-step surface and a second sub-step surface connected in sequence, the number of the first sub-step surfaces is greater than or equal to 1, and the number of the second sub-step surfaces is greater than or equal to 1.

[0019] In one embodiment, along the axial direction of the pole, the height of the second sub-step surface is greater than or equal to 0.2 mm, and / or, along the radial direction of the pole, the width of the first sub-step surface is greater than or equal to 0.2 mm.

[0020] In one embodiment, along the radial direction of the pole, the width of the supporting surface is greater than or equal to 0.3 mm and less than or equal to the thickness of the second metal layer.

[0021] In one embodiment, the first metal column protrudes radially to form a boss, and the second metal layer at least extends to the boss.

[0022] In one embodiment, the boss is located at the first end, and the boss is completely covered in the second metal layer.

[0023] In one embodiment, the conductive structure is an integrated pole and a current collector, wherein the boss is the current collector, and the current collector is used to be connected to the pole lug.

[0024] In one embodiment, the boss is far away from the first end, and a radial dimension of the boss is greater than a radial dimension of the first end.

[0025] In one embodiment, the boss is located at the second end, and a portion of the boss is exposed outside the second metal layer.

[0026] In one embodiment, the conductive structure is an integrated pole and a terminal pressing block, wherein the boss is the terminal pressing block.

[0027] In one embodiment, the second metal layer includes a first section, a second section and a third section, the first section corresponds to the end face of the first end, the second section corresponds to the side face of the first end, the third section corresponds to a side surface of the boss close to the first end, and the second section connects the first section and the third section.

[0028] In one embodiment, the third section is formed as an end portion of the second metal layer, and the third section is embedded in the boss.

[0029] In one embodiment, the average thickness of the first section is greater than the average thickness of the second section, and the average thickness of the second section is greater than the average thickness of the third section.

[0030] In one embodiment, the average thickness of the second section is greater than half of the average thickness of the first section, and / or the average thickness of the third section is greater than half of the average thickness of the second section.

[0031] In one embodiment, the thickness of a portion of the second section close to the third section is greater than the thickness of a portion of the second section close to the first section.

[0032] In one embodiment, the end surface of the first end is partially concave to form a groove, and the first section includes a first sub-segment, a second sub-segment and a third sub-segment connected in sequence, the first sub-segment is located outside the groove, the second sub-segment is located on the side wall of the groove, and the third sub-segment is located on the bottom wall of the groove.

[0033] In one embodiment, a vertical distance between an outer surface of the first subsegment and an outer surface of the third subsegment is less than or equal to 2.5 mm.

[0034] In one embodiment, the average thickness of the first subsection is greater than or equal to 0.5 mm, and / or the average thickness of the second subsection is greater than or equal to 0.5 mm.

[0035] In one embodiment, the second subsegment extends obliquely from the first subsegment toward the third subsegment, and the inclination angle of the second subsegment is greater than or equal to 15° and less than or equal to 60°.

[0036] In one embodiment, the boss is located between the first end and the second end, and the radial dimension of the boss is greater than the radial dimension of the second end.

[0037] In one embodiment, the second metal layer further includes a fourth section, the fourth section corresponds to a side surface of the boss, and the fourth section is connected to the third section.

[0038] In one embodiment, along the axial direction of the first metal column, the distance between the outer surface of the third section and the end of the fourth section away from the first end is a, and along the radial direction of the first metal column, the distance between the outer surface and the inner surface of the fourth section is e, wherein a>e>0.5mm.

[0039] In one embodiment, the second metal layer further includes a fifth section, the fifth section corresponds to a side surface of the boss away from the first end, and the fourth section connects the fifth section and the third section.

[0040] In one embodiment, along the axial direction of the first metal column, the distance between the inner surface of the fifth section and the inner surface of the third section is b, and b>0.5 mm.

[0041] In one embodiment, along the axial direction of the first metal column, the distance between the outer surface of the third segment and the outer surface of the fifth segment is h2; along the radial direction of the first metal column, the distance between the outer surface of the fourth segment and the root of the boss on the side close to the second end is c, and the distance between the outer surface of the fourth segment and the end of the fifth segment close to the central axis of the first metal column is d; wherein, c>h2 and d≥2 / 3c, or, c≤h2 and d>0.5mm.

[0042] In one embodiment, the fourth section and the fifth section are formed as free ends of the bosses wrapped with an inverted buckle layer, and along the axial direction of the first metal column, the distance between the outer surface of the third section and the outer surface of the inverted buckle layer is K1, the thickness of the inverted buckle layer is K2, f=K2 / K1, where f is greater than or equal to 0.3 and less than 1.

[0043] In one embodiment, the edge of the end face of the first end is concave to form a first step portion, and the second metal layer also includes a second step portion, which matches the first step portion, is connected between the first section and the second section, and is used to connect to the pole ear.

[0044] In one embodiment, the second step portion has a first step surface and a second step surface connected, and in the radial direction of the first metal column, the width of the first step surface is greater than or equal to 0.5 mm, and in the axial direction of the first metal column, the height of the second step surface is greater than or equal to 0.4 mm.

[0045] In one embodiment, the first metal column is an aluminum column, and the second metal layer is a copper layer.

[0046] In one embodiment, the average thickness of the second metal layer is 0.1 mm-3 mm.

[0047] In one embodiment, the bonding interface between the second metal layer and the first metal column has an uneven microstructure.

[0048] In one embodiment, the diameter of the conductive structure is less than or equal to 30 mm.

[0049] In one embodiment, the first metal column 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 end of the first section away from the second section is the first end, and the end of the second section away from the first section is the second end; the second metal layer includes a cylinder and a flange, the cylinder covers the first section, the flange is connected to the end surface of the cylinder close to the second section, the flange extends along the radial direction of the conductive structure and is embedded in the end of the second section facing the first section; wherein, in the axial direction of the conductive structure, 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 conductive structure.

[0050] In one embodiment, in the longitudinal section of the conductive structure through the flange, along the axial direction close to the conductive structure, 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.

[0051] In one embodiment, the curvature of the third line segment is greater than the curvature of the first line segment.

[0052] In one embodiment, 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 .

[0053] In one embodiment, the curvature of the second line segment is less than or equal to 1×10 -4 mm -1 .

[0054] In one embodiment, in a longitudinal cross-section, along the axial direction of the conductive structure, a bonding interface formed between a surface of the second metal layer close to the axis of the conductive structure and an outer peripheral surface of the first metal column 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.

[0055] In one embodiment, the curvature of the first line segment is smaller than the curvature of the fifth line segment.

[0056] 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 .

[0057] In one embodiment, the curvature of the fourth line segment is less than or equal to 1×10 -4 mm -1 .

[0058] In one embodiment, in the longitudinal section of the conductive structure, the first metal column has a plurality of forged streamlines, and the contact 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 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 column and is arranged away from the bottom wall of the cylinder.

[0059] In one embodiment, two endpoints of the second line segment are point U and point V respectively; the straight line UV and the radial direction of the conductive structure form an angle W on the side away from the flange, satisfying: 0<W≤20°.

[0060] 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.

[0061] In one embodiment, there are a plurality of flanges, the plurality of flanges are sequentially arranged along the circumference of the conductive structure, and at least two flanges are oppositely arranged along the radial direction of the conductive structure.

[0062] In one embodiment, in the axial cross section of the conductive structure, the length of the bonding interface formed by the first metal column and the second metal layer contacting each other is Lb, and the outer diameter of the cylinder is φb0, satisfying: 1φb0≤Lb≤5φb0.

[0063] In one embodiment, φb0≤4mm, and 3.6φb0≤Lb≤5φb0; 4mm<φb0<8mm, and 3φb0≤Lb≤3.6φb0; φb0≥8mm, and 1φb0≤Lb≤3φb0.

[0064] In one embodiment, the second metal layer also includes a transition portion, which is connected to the end surface of the cylinder close to the second section; wherein the transition portion is embedded in the end surface of the second section facing the first section, and a bonding interface between part of the transition portion and the second section is located on the circumferential surface of the second section.

[0065] 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.

[0066] In one embodiment, an end surface of the transition portion away from the axis of the conductive structure is coplanar with a side wall where the long side of the second section is located.

[0067] In one embodiment, a bonding interface is formed at the contact portion between the first metal pillar and the second metal layer; the conductive structure 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.

[0068] In one embodiment, the thickness dimension Dc satisfies: 1 μm≤Dc≤8 μm.

[0069] 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.

[0070] 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.

[0071] In one embodiment, the flange extends in a ring shape along the circumference of the first section.

[0072] 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.

[0073] 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.

[0074] In one embodiment, the gap a is located between an end of the flange away from the axis of the conductive structure and a slot wall of the engaging slot.

[0075] In one embodiment, the second section has a thickness dimension Da in the axial direction of the conductive structure; wherein the dimension of the gap a in the radial direction of the conductive structure is La, satisfying: 0<La≤10%Da; and / or, the dimension of the gap a in the axial direction of the conductive structure is Ha3, satisfying: 0<Ha3≤40%Da.

[0076] In one embodiment, a matching groove is provided at one end of the cylinder away from the second section.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] In one embodiment, in the longitudinal section of the first metal column, a side line of a portion of the second segment is an oblique line that is disposed at an acute angle to the axis of the first metal column.

[0082] In one embodiment, in the longitudinal section of the first metal column, the side line corresponding to the circumferential surface of the second section is a slanted line; and / or the second section has a second surface facing away from the second metal layer, and in the longitudinal section of the first metal column, the side line corresponding to the portion of the second surface close to the edge is a slanted line.

[0083] In one embodiment, the end surface of the second section facing away from the first section is provided with an inner shrinkage hole, the inner shrinkage hole extends along the axis of the first metal column, and the inner shrinkage hole is arranged close to the axis of the first metal column; wherein the aperture of the inner shrinkage hole decreases as it approaches the first section.

[0084] In one embodiment, the conductive structure further includes a second metal strip, which is disposed on the circumference of the second segment and away from the first segment, and extends in a ring shape along the circumference of the second segment.

[0085] In one embodiment, the conductive structure is a pole of a battery cell, and at least the end of the flange is configured to be located on a side of the cover plate of the battery cell that is away from the electrode assembly of the battery cell.

[0086] In one embodiment, the second end of the first metal column is provided with an extension portion extending toward the first end, and the extension portion at least covers a portion of the end portion of the second metal layer.

[0087] In one embodiment, at least two sides of the second metal layer are covered by extension portions, and the two extension portions have different thicknesses.

[0088] In one embodiment, the first metal column includes a first section and a second section connected in sequence, the outer diameter of the first section is smaller than the outer diameter of the second section, the second section has a first surface close to the first section, the end of the first section away from the second section is the first end, and the end of the second section away from the first section is the second end; wherein one end of the extension portion is connected to the circumferential surface of the second section, and the other end extends toward the first end.

[0089] In one embodiment, the diameter of the second section is φd, and along the radial direction of the first metal column, the extension portion has a thickness dimension Dd, satisfying: 0<Dd≤0.3φd.

[0090] In a second aspect, an embodiment of the present application further provides a method for preparing a conductive structure, comprising:

[0091] Providing a blank, the blank comprising a first layer and a second layer, the first layer comprising a first metal, and the second layer comprising a second metal;

[0092] Placing the blank in the cavity of the first cold heading die, and stacking the first layer and the second layer in sequence from the outside to the inside of the cavity;

[0093] The blank is subjected to a first cold heading treatment. With the help of a strong beam of the first cold heading die, when the first layer squeezes the second layer, the first layer is deformed and invades the second layer, and the second layer is thinned and extends to the peripheral side of the first layer.

[0094] In one embodiment, in the blank, the first layer and the second layer are laminated and combined together.

[0095] In one embodiment, a blank is provided, comprising:

[0096] Providing a composite board, the composite board comprising a first layer and a second layer that are laminated and bonded;

[0097] The composite board is punched to obtain a blank.

[0098] In one embodiment,

[0099] Before placing the blank into the cavity, the blank is screened so that the second layer of the blank faces the bottom wall of the cavity when the blank is loaded into the cavity.

[0100] In one embodiment, the method for preparing the conductive structure further includes: after performing the first cold heading treatment on the blank, placing it in a second cold heading die, and extruding a surface of the first layer facing away from the second layer.

[0101] In a third aspect, an embodiment of the present application further provides a cover plate assembly, comprising:

[0102] Cover plate; the conductive structure mentioned above or the conductive structure prepared by the method for preparing the conductive structure mentioned above, the conductive structure is penetrated on the cover plate.

[0103] In one embodiment, the conductive structure is a pole or the conductive structure is an integrated pole and a terminal block;

[0104] The cover plate assembly also includes a current collecting piece, which is located on one side of the cover plate and welded to the conductive structure.

[0105] In one embodiment, the cover plate assembly further comprises:

[0106] A first insulating member is disposed between the conductive structure and the cover plate,

[0107] A second insulating member is disposed between the cover plate and the current collecting member; and / or,

[0108] The cover plate assembly further includes a sealing member, which is disposed between the cover plate and the conductive structure.

[0109] In one embodiment, the sealing member is located on a side of the cover plate close to the first insulating member; or, the sealing member is located on a side of the cover plate close to the second insulating member.

[0110] In one embodiment, a venting groove is provided on a surface of the first insulating member facing away from the cover plate, and two ends of the venting groove extend to the inner circumference and the outer circumference of the first insulating member respectively.

[0111] In one embodiment, the first metal column 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 end of the first section away from the second section is the first end, and the end of the second section away from the first section is the second end; the second metal layer includes a cylinder and a flange, the cylinder covers the first section, the flange is connected to the end of the cylinder close to the second section, the flange extends along the radial direction of the conductive structure and is embedded in the end surface of the second section facing the first section; the second section and the flange are located on the side of the first insulating member away from the cover plate; 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 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.

[0112] In one embodiment, along the axial direction of the first metal column, the first region protrudes outward along the axial direction of the conductive structure to form a height difference, and the thickness dimension of the first region protruding relative to the second region is Ha1, and the second section has a thickness dimension Da in the axial direction of the conductive structure, satisfying 0<Ha1≤15%Da.

[0113] In one embodiment, 2%Da≤Ha1≤15%Da.

[0114] In one embodiment, along the axial direction of the first metal column, the second region protrudes outward along the axial direction of the conductive structure to form a height difference, and the thickness dimension of the second region protruding relative to the first region is Ha2, and the second section has a thickness dimension Da in the axial direction of the conductive structure, satisfying 0<Ha2≤15%Da.

[0115] In one embodiment, 2%Da≤Ha2≤15%Da.

[0116] In one embodiment, the first zone protrudes outward along the axial direction of the conductive structure to form a first protruding portion, and the first protruding portion extends in a ring shape along the circumferential direction of the conductive structure; or, the second zone protrudes outward along the axial direction of the conductive structure to form a second protruding portion, and the second protruding portion extends in a ring shape along the circumferential direction of the conductive structure.

[0117] In one embodiment, the conductive structure further includes a bottom plate; the second metal layer includes a cylinder, the cylinder covers the first end and extends toward the second end; the bottom plate is connected to an end of the cylinder away from the second end.

[0118] 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 end, and the aperture of the pre-punched hole gradually increases in a direction away from the second end.

[0119] In one embodiment, a step groove b is provided at one end of the cylinder away from the second end. 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.

[0120] In one embodiment, the bottom plate is welded to the cylinder.

[0121] In one embodiment, the first metal column 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 end of the first section away from the second section is the first end, and the end of the second section away from the first section is the second end; the second metal layer includes a cylinder, and the cylinder covers the first section; wherein the second section is configured to be located outside the battery cell, and the end of the cylinder away from the second section is configured to be connected to the current collector, so that the conductive structure is clamped on the cover plate of the battery cell through the current collector and the second section.

[0122] In a fourth aspect, an embodiment of the present application further provides a battery cell, comprising:

[0123] A housing having a receiving cavity;

[0124] The electrode assembly is arranged in the accommodating cavity, and the electrode assembly includes a pole ear;

[0125] The aforementioned cover plate assembly is connected to the shell and closes the opening of the accommodating cavity, and the conductive structure is connected to the pole ear.

[0126] Beneficial effects of the embodiments of the present application:

[0127] In an embodiment of the present application, the conductive structure is configured such that the second metal layer bonded to the surface of the first metal column extends from the surface of the first end of the first metal column to the second end. That is, the end face of the first end of the first metal column and at least part of the side face of the first metal column are covered by the second metal layer. Compared with the form of only setting the second metal layer on the end face of one end of the first metal column, the bonding area between the second metal layer and the first metal column can be effectively increased, thereby ensuring the current carrying capacity of the conductive structure, improving the bonding strength between the second metal layer and the first metal column, and reducing the risk of the second metal layer falling off. BRIEF DESCRIPTION OF THE DRAWINGS

[0128] 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.

[0129] Figure 1 is a schematic diagram of the main structure of a first conductive structure provided in an embodiment of the present application;

[0130] Figure 2 yes Figure 1 A schematic cross-sectional structure diagram of a conductive structure in FIG.

[0131] Figure 3 yes Figure 2 Enlarged view of part A in the middle;

[0132] Figure 4 is a schematic diagram of the main structure of a second conductive structure provided in an embodiment of the present application;

[0133] Figure 5 yes Figure 4 A schematic cross-sectional structure diagram of a conductive structure in FIG.

[0134] Figure 6 is a schematic diagram of the three-dimensional structure of a third conductive structure provided in an embodiment of the present application;

[0135] Figure 7 yes Figure 6 A schematic cross-sectional structure diagram of a conductive structure in FIG.

[0136] Figure 8 yes Figure 6 A schematic cross-sectional structure diagram of a cover plate assembly formed by assembling the conductive structure in the cover plate;

[0137] Fig. 9 yes Figure 8 An exploded view of the cover assembly in FIG.

[0138] Fig.10 is a schematic cross-sectional structure diagram of a fourth conductive structure provided in an embodiment of the present application;

[0139] Fig.11 yes Fig.10 Enlarged view of middle part B;

[0140] Fig.12 is a schematic cross-sectional structure diagram of a fifth conductive structure provided in an embodiment of the present application;

[0141] Fig.13 yes Fig.12 Enlarged view of the middle C part;

[0142] Fig.14 yes Fig.12 A schematic cross-sectional structure diagram of a conductive module formed by assembling a conductive structure in the embodiment and a terminal pressing block;

[0143] Fig.15 yes Fig.14 A schematic diagram of the cross-sectional structure of the middle terminal pressing block;

[0144] Fig.16 is a schematic diagram of the three-dimensional structure of a sixth conductive structure provided in an embodiment of the present application;

[0145] Fig.17 yes Fig.16 A schematic cross-sectional structure diagram of a conductive structure in FIG.

[0146] Fig.18 yes Fig.16 An exploded view of a cover plate assembly formed by assembling the conductive structure on the cover plate;

[0147] Fig.19 is a schematic cross-sectional structure diagram of a seventh conductive structure provided in an embodiment of the present application;

[0148] Fig. 20 yes Fig.19 Enlarged view of the middle D part;

[0149] Fig.21 is a schematic cross-sectional structure diagram of an eighth conductive structure provided in an embodiment of the present application;

[0150] Fig. 22 yes Fig.21 Enlarged view of the middle E part;

[0151] Fig.23 is a schematic cross-sectional structure diagram of a ninth conductive structure provided in an embodiment of the present application;

[0152] Fig.24 yes Fig.23 Enlarged view of the middle F part;

[0153] Fig.25 is a schematic diagram of a three-dimensional structure of a tenth conductive structure provided in an embodiment of the present application at a certain viewing angle;

[0154] Fig.26 yes Fig.25 A schematic diagram of the three-dimensional structure of the conductive structure in another viewing angle;

[0155] Fig. 27 yes Fig.25 A schematic cross-sectional view of a conductive structure in FIG.

[0156] Fig.28 yes Fig. 27 Enlarged view of the middle G section;

[0157] Fig.29 is a schematic structural diagram of an eleventh conductive structure provided in an embodiment of the present application;

[0158] Fig.30 yes Fig.29 The enlarged view of point A in the middle;

[0159] Fig.31 The embodiments of this application provide Fig.29 A magnified view of another structure at A;

[0160] Fig.32 is a schematic diagram of a forging streamline of a first metal column provided in an embodiment of the present application;

[0161] Fig.33 is a schematic structural diagram of a twelfth conductive structure provided in an embodiment of the present application;

[0162] Fig.34 is a schematic structural diagram of a second metal layer provided in an embodiment of the present application;

[0163] Fig.35 is a schematic structural diagram of another second metal layer provided in an embodiment of the present application;

[0164] Fig.36 yes Fig.29 The enlarged view of point B in the middle;

[0165] Fig.37 yes Fig.29 A magnified view of another structure at B in the middle;

[0166] Fig.38 is a schematic structural diagram of a thirteenth conductive structure provided in an embodiment of the present application;

[0167] Fig.39 is a schematic structural diagram of a fourteenth conductive structure provided in an embodiment of the present application;

[0168] Fig.40is a structural schematic diagram of a first cover plate assembly provided in an embodiment of the present application;

[0169] Fig.41 is a structural schematic diagram of a second cover plate assembly provided in an embodiment of the present application;

[0170] Fig.42 is a structural schematic diagram of a third cover plate assembly provided in an embodiment of the present application;

[0171] Fig.43 is a structural schematic diagram of a fourth cover plate assembly provided in an embodiment of the present application;

[0172] Fig.44 is a structural schematic diagram of a fifth cover plate assembly provided in an embodiment of the present application;

[0173] Fig.45 is a schematic structural diagram of a first insulating member provided in an embodiment of the present application;

[0174] Fig.46 is a schematic structural diagram of a fifteenth conductive structure provided in an embodiment of the present application;

[0175] Fig.47 is a schematic structural diagram of a sixteenth conductive structure provided in an embodiment of the present application;

[0176] Fig.48 is a structural schematic diagram of a seventeenth conductive structure provided in an embodiment of the present application;

[0177] Fig.49 is a schematic structural diagram of an eighteenth conductive structure provided in an embodiment of the present application;

[0178] Fig.50 is a schematic diagram of the cross-sectional structure of a battery cell provided in an embodiment of the present application;

[0179] Fig.51 It is a schematic diagram of the structure of a battery cell provided in an embodiment of the present application.

[0180] The reference numerals are as follows:

[0181] 10. Conductive structure; 101. Pole; 1011- Second metal strip; 1012- Inner shrinkage hole; 1013. First surface; 1014- Second surface; 1015. First area; 1016. Second area; 1017. First convex portion; 1018. Second convex portion; 1019. Bottom plate;

[0182] 102. Terminal pressing block;

[0183] 1. First metal column; 14. First section; 141. Matching bottom wall; 15. Second section; 151. Extension; 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;

[0184] 11, first end; 11a, first step portion; 11b, groove;

[0185] 12. Second end;

[0186] 13. Boss;

[0187] 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;

[0188] 20, end; 201, first extension section; 202, second extension section; 20a, gap; 20b, end surface; 20c, transition surface;

[0189] 203, support surface;

[0190] 2031, inclined surface;

[0191] 2032, step surface; 20321, first sub-step surface; 20322, second sub-step surface;

[0192] 21, first section; 211, first subsection; 212, second subsection; 213, third subsection;

[0193] 22. Section 2;

[0194] 23. The third section;

[0195] 24. Section 4;

[0196] 25. Section 5;

[0197] 251, reverse buckle layer;

[0198] 26, second step portion; 261, first step surface; 262, second step surface;

[0199] 100. Cover plate assembly;

[0200] 110, cover plate; 112, first insulating member; 1121, exhaust groove; 113, second insulating member; 114, mounting hole; 115, injection hole;

[0201] 120, current collecting member; 121, convex hull;

[0202] 130. Seals;

[0203] 140. Explosion-proof valve;

[0204] 1000, battery cell;

[0205] 1100, housing; 1110, accommodating chamber;

[0206] 1200. Electrode assembly; 1210. Tab. DETAILED DESCRIPTION

[0207] 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.

[0208] 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.

[0209] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0210] 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, an electrical connection, or mutual communication; 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.

[0211] The terms "comprises," "includes," or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0212] 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.

[0213] To facilitate understanding of the scheme of the present application, the spline curves and arrows used in the drawings are explained here: the components indicated by the spline curves without arrows are solid components, that is, components with solid structures; the components indicated by the spline curves with arrows are virtual components, that is, components without solid structures.

[0214] Since the composite pole includes metal layers of different materials, usually different metals have different thermal expansion coefficients, which leads to a decrease in the bonding strength between the metal layers in the composite pole under high temperature working environment, and the metal layers are easily separated and fall off. In addition, the bonding strength between the metal layers in the composite pole is affected by the bonding area. When the diameter of the composite pole is small, the metal layers in the composite pole are also easy to fall off.

[0215] In order to solve the problem that the metal layer in the composite pole is easy to fall off and thus cause the battery cell to fail, the embodiments of the present application provide a conductive structure, a method for preparing the conductive structure, a cover plate assembly and a battery cell, such as Figures 1 to 51 shown.

[0216] In a first aspect, an embodiment of the present application provides a conductive structure, which is used to connect the internal circuit of a battery cell with the circuit outside the battery cell (external circuit for short), so as to connect the battery cell with the external circuit, so as to realize that the external circuit supplies power to the battery cell (i.e., charging the battery cell), or the battery cell supplies power to the external circuit (i.e., discharging the battery cell). In detail, the conductive structure can be used to be assembled on the cover plate of the battery cell.

[0217] Specifically, see Figures 1 to 28The conductive structure 10 includes a first metal column 1 and a second metal layer 2, and the second metal layer 2 is bonded to the surface of the first metal column 1. The first metal column 1 has two opposite ends, namely a first end 11 and a second end 12; the second metal layer 2 covers the first end 11 and extends to the second end 12.

[0218] Optionally, the second metal layer 2 is used to connect with the pole tab, wherein the pole tab can be a pole tab welded on the electrode assembly, or can be an uncoated area on the pole piece that is not coated with active material.

[0219] The conductive structure 10 includes a first metal column 1 and a second metal layer 2. It can be understood that the first metal column 1 can be a columnar structure, and the material of the first metal column 1 includes a first metal; the second metal layer 2 can be 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. Optionally, the electrical conductivity of the second metal is greater than the electrical conductivity of the first metal, that is, the electrical conductivity of the second metal is better than the electrical conductivity of the first metal. Optionally, the fluidity of the first metal is greater than the fluidity of the second metal. Optionally, the hardness of the second metal is better than the hardness of the first metal.

[0220] The second metal layer 2 is bonded to the surface of the first metal column 1, which means that the second metal layer 2 is located on the outer surface of the first metal column 1, and the second metal layer 2 is also bonded to the first metal column 1. The bonding here means that the second metal layer 2 and the first metal column 1 will not separate simply under the action of internal force. For example, the second metal layer 2 and the first metal column 1 are physically bonded together. As an example, the second metal layer 2 and the first metal column 1 can be bonded together by cold heading, or the second metal layer 2 and the first metal column 1 are composite metal plates.

[0221] It can be understood that the second metal layer 2 wraps the surface of the first end 11, and the second metal layer 2 extends from the surface of the first end 11 to the second end 12. The second metal layer 2 extends from the first end 11 to the second end 12, specifically, the end 20 of the second metal layer 2 extends to the second end 12, which may be the end 20 of the second metal layer 2 extending to the second end 12, or the end 20 of the second metal layer 2 extending to a position between the first end 11 and the second end 12. Optionally, the end 20 of the second metal layer 2 extends to the second end 12, but the second metal layer 2 does not completely wrap the second end 12, that is, the second end 12 is at least partially exposed outside the second metal layer 2, so that the second end 12 is directly connected to other components. Here, the end 20 of the second metal layer 2 refers to the edge of the second metal layer 2. The second metal layer 2 is used to connect to the pole ear, and the second metal layer 2 may be directly connected to the pole ear, or the second metal layer 2 may be connected to the pole ear through other intermediate components (such as the current collector 120). As an example, the second metal layer 2 is used to weld with the current collector 120, and the current collector 120 is welded with the tab. Here, the tab refers to the metal conductor that leads the positive and negative electrodes from the battery cell (i.e., the battery cell). As an example, the current collector 120 includes at least one of a current collecting disc and a connecting sheet.

[0222] When the conductive structure 10 is applied to a battery cell, the first end 11 of the first metal column 1 is directed toward the interior of the battery cell, while the second end 12 is directed toward the exterior of the battery cell. The second metal layer 2 wraps the first end 11 of the first metal column 1 and extends from the first end 11 to the second end 12. Thus, the second metal layer 2 can also serve as a protective layer to separate the first end 11 of the first metal column 1 from the electrolyte in the battery cell, thereby reducing the risk of the first end 11 being corroded by the electrolyte.

[0223] The conductive structure 10 provided in the embodiment of the present application is configured such that the second metal layer 2 bonded to the surface of the first metal column 1 is extended from the surface of the first end 11 of the first metal column 1 to the second end 12. That is, the end face of the first end 11 of the first metal column 1 and at least part of the side face of the first metal column 1 are covered by the second metal layer 2. Compared with the form of only arranging the second metal layer 2 on the end face of one end of the first metal column 1, the bonding area between the second metal layer 2 and the first metal column 1 can be effectively increased, thereby ensuring the overcurrent capability (referred to as overcurrent capability) of the conductive structure 10, improving the bonding strength between the second metal layer 2 and the first metal column 1, and reducing the risk of the second metal layer 2 falling off.

[0224] In addition to increasing the bonding area between the second metal layer 2 and the first metal column 1, the second metal layer 2 is configured to extend from the first end 11 of the first metal column 1 to the second end 12, shortening the distance between the second metal layer 2 and the second end 12, thereby shortening the current flow path, and also improving the current carrying capacity of the conductive structure 10.

[0225] In some embodiments, see Figure 2 , Figure 5 , Figure 7 , Fig.10 , Fig.15 , Fig.17 , Fig.19 , Fig.21 , Fig.23 and Fig. 27 , the second metal layer 2 is inlaid with the first metal column 1. Part of the second metal layer 2 can be embedded in the first metal column 1, or part of the first metal column 1 can be embedded in the second metal layer 2. By inlaying the second metal layer 2 with the first metal column 1, the bonding area between the second metal layer 2 and the first metal column 1 can be increased to a certain extent, the overcurrent capacity of the conductive structure 10 can be improved, and the risk of separation of the second metal layer 2 and the first metal column 1 can be reduced.

[0226] In some embodiments, see Figure 2 , Figure 5 , Figure 7 , Fig.10 , Fig.15 , Fig.17 and Fig.19 , the end 20 of the second metal layer 2 is embedded in the first metal column 1. Since the combination of the end 20 of the second metal layer 2 and the first metal column 1 is usually prone to form a weak point, by embedding the end 20 of the second metal layer 2 in the first metal column 1, the area of ​​the end 20 of the second metal layer 2 combined with the first metal column 1 is increased, the current capacity is improved, and the bonding strength is increased. In addition, the end 20 of the second metal layer 2 is hidden in the first metal column 1, reducing the external force on the end 20 of the second metal layer 2. The risk of peeling off the second metal layer 2. Here, the end 20 of the second metal layer 2 is embedded in the first metal column 1, and the end 20 of the second metal layer 2 can be partially embedded in the first metal column 1, or the end 20 of the second metal layer 2 can be completely embedded in the first metal column 1.

[0227] In some embodiments, see Figure 2 and Figure 3 , there is a gap 20a between the end 20 of the second metal layer 2 and the first metal column 1. Since the material of the first metal column 1 is the first metal, and the material of the second metal layer 2 is the second metal, the first metal and the second metal are different, and the thermal expansion coefficients of different metals are different. In this way, under high temperature conditions, the gap 20a can provide a buffer space for the one with a larger volume expansion between the first metal column 1 and the second metal layer 2, and the first metal column 1 and the end 20 of the second metal layer 2 are tightly pressed together, reducing the risk of the second metal layer 2 being separated from the first metal column 1 due to volume expansion.

[0228] In some embodiments, see Figure 3 , the average spacing W1 of the gap 20a between the end 20 of the second metal layer 2 and the first metal column 1 is less than 0.1mm. The average spacing W1 here refers to the average spacing distance between the end 20 of the second metal layer 2 and the first metal column 1. The average spacing W1 should not be too large, otherwise it will affect the bonding effect between the first metal column 1 and the second metal layer 2, and it is difficult to achieve tightness between the first metal column 1 and the end 20 of the second metal layer 2 at high temperature. As an example, W1 is 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm or 0.1mm.

[0229] In some embodiments, see Figure 3 , an end face 20b and a transition face 20c are formed on the end 20 of the second metal layer 2, and the end face 20b and the transition face 20c are connected in sequence. Between the second metal layer 2 and the first metal column 1, a gap 20a is formed only between the end face 20b and the transition face 20c and the first metal column 1. The side of the end face 20b away from the transition face 20c is connected to the outer surface of the second metal layer 2, and the transition face 20c is bent and transitioned from the end face 20b to the first metal column 1. The outer surface of the second metal layer 2 refers to the surface of the second metal layer 2 exposed to the outside, and usually the outer surface of the second metal layer 2 is opposite to the first metal column 1. As an example, the transition face 20c is an arc surface, and the distance between the transition face 20c and the first metal column 1 becomes smaller along the direction approaching the first metal column 1. By forming the gap 20a only between the end face 20b and the transition face 20c and the first metal column 1, the bonding area between the second metal layer 2 and the first metal column 1 is guaranteed.

[0230] In some embodiments, the end portion 20 of the second metal layer 2 may also be configured not to be embedded in the first metal column 1 .

[0231] In some embodiments, see Figure 7 , the end 20 of the second metal layer 2 includes a first extension segment 201 and / or a second extension segment 202. Here, the first extension segment 201 refers to the portion of the end 20 of the second metal layer 2 extending along the first direction, and the second extension segment 202 refers to the portion of the end 20 of the second metal layer 2 extending along the second direction, wherein the first direction intersects with the second direction. Optionally, the first direction is perpendicular to the second direction. As an example, the first direction is the radial direction of the first metal column 1, and the second direction is the axial direction of the first metal column 1. That is to say, the end 20 of the second metal layer 2 can extend in different directions on the surface or inside of the first metal column 1, and can extend in a straight line or in a bent manner.

[0232] In some embodiments, see Figures 6 to 15, the conductive structure 10 is a pole 101, and a support surface 203 is formed on the end 20 of the second metal layer 2, and the support surface 203 is used to support the terminal block 102. That is to say, the pole 101 and the terminal block 102 are separately arranged. Here, the pole 101 and the terminal block 102 are both components in the battery cell, wherein the pole 101 is usually partially located inside the battery cell and connected to the electrode assembly, and partially located outside the battery cell, and the terminal block 102 is located outside the battery cell and connected to the pole 101. The terminal block 102 fixes the pole 101 to the cover plate 110, and the terminal block 102 can also be used to electrically connect to an external structure, for example, the terminal block 102 is connected to a module bar. A support surface 203 is provided on the end 20 of the second metal layer 2, and the support surface 203 is used to support the terminal block 102. Specifically, the support surface 203 is connected to the outer side surface of the second metal layer 2, and the outer surface of the second metal layer 2 includes the outer side surface of the second metal layer 2 and the support surface 203, that is, the support surface 203 is a partial outer surface of the second metal layer 2. Optionally, the support surface 203 can be at least one of a stepped surface, a straight surface, and a curved surface. When the pole 101 is connected to the terminal block 102, the terminal block 102 is supported on the support surface 203, and when laser welding is used to weld the gap between the pole 101 and the terminal block 102, the support surface 203 can be formed as the bottom surface of the gap and block the laser during welding, thereby reducing the risk of laser penetration.

[0233] In some embodiments, see Figures 12 to 15 , the support surface 203 is an inclined surface 2031, and in the direction away from the first end 11, the inclined surface 2031 gradually approaches the outer side surface of the first metal column 1 from the outer side surface of the second metal layer 2. Here, the inclined surface 2031 can be an inclined straight surface or an inclined curved surface. As an example, the inclined curved surface is an inclined arc surface, and the inclined arc surface here can be an arc surface that arches in the direction away from the second metal layer 2, and the inclined arc surface can also be an arc surface that sinks in the direction close to the second metal layer 2. By setting the support surface 203 as the inclined surface 2031, and in the direction away from the first end 11, the inclined surface 2031 gradually approaches the first metal column 1, so that when the terminal pressing block 102 is supported on the inclined surface 2031, the terminal pressing block 102 will generate a radial inward partial pressure on the inclined surface 2031 along the pole 101, so that the end 20 of the second metal layer 2 is more closely attached to the first metal column 1, reducing the risk of the second metal layer 2 detaching.

[0234] In some embodiments, see Fig.13, the inclined surface 2031 is an inclined straight surface, and the angle α between the inclined straight surface and the outer side surface of the second metal layer 2 is 110° to 130°. The angle α in the above range can form a deformed interlocking bonding interface between the second metal layer 2 and the first metal column 1 under the radial inward partial pressure applied by the terminal block 102, thereby improving the bonding effect between the second metal layer 2 and the first metal column 1. As an example, the angle α is 110°, 115°, 120°, 125° or 130°.

[0235] In some embodiments, see Figures 6 to 11 , the support surface 203 is a step surface 2032, and the step surface 2032 includes a first sub-step surface 20321 and a second sub-step surface 20322 connected in sequence. Here, the first sub-step surface 20321 refers to a surface extending along the first direction, and the second sub-step surface 20322 refers to a surface extending along the second direction, wherein the first direction intersects the second direction. Optionally, the first direction is perpendicular to the second direction. As an example, the first direction is the radial direction of the first metal column 1, and the second direction is the axial direction of the first metal column 1. Optionally, the second sub-step surface 20322 and the first sub-step surface 20321 are both straight surfaces. The number of the second sub-step surfaces 20322 is greater than or equal to 1, and the number of the first sub-step surfaces 20321 is greater than or equal to 1. In other words, the number of the second sub-step surfaces 20322 can be one or more, and the number of the first sub-step surfaces 20321 can also be one or more. Here, multiple refers to two or more. When the number of the second sub-step surfaces 20322 is one and the number of the first sub-step surfaces 20321 is also one, the obtained step surface 2032 is a single-step surface; when the number of at least one of the second sub-step surfaces 20322 and the first sub-step surfaces 20321 is more than one, the obtained step surface 2032 is a multi-step surface. As an example, the number of the second sub-step surfaces 20322 is two and the number of the first sub-step surfaces 20321 is also two. In a single-step surface, the second sub-step surface 20322 is connected to the first sub-step surface 20321 in sequence. In a multi-step surface, the second sub-step surface 20322 is connected to the first sub-step surface 20321 alternately in sequence. By setting the support surface 203 as the step surface 2032, the stability of the fit between the terminal block 102 and the pole 101 can be improved, and the risk of laser penetration during laser welding can be reduced.

[0236] In some embodiments, see Fig.11, along the radial direction of the pole 101, the width W21 of the first sub-step surface 20321 is greater than or equal to 0.2 mm. The width W21 of the first sub-step surface 20321 should not be too small, otherwise the step surface is difficult to form and the step surface is easily damaged. As an example, the width W21 of the first sub-step surface 20321 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm or 0.7 mm.

[0237] In some embodiments, see Fig.11 , along the axial direction of the pole 101, the height H21 of the second sub-step surface 20322 is greater than or equal to 0.2 mm. The height H21 of the second sub-step surface 20322 should not be too small, otherwise the step surface is difficult to form and the step surface is easily damaged. As an example, the height H21 of the second sub-step surface 20322 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm or 0.7 mm.

[0238] In some embodiments, see Fig.13 , along the radial direction of the pole 101, the width W2 of the support surface 203 is greater than or equal to 0.3mm and less than or equal to the thickness of the second metal layer 2. In the radial direction of the pole 101, the maximum value of the width W2 of the support surface 203 is subject to the thickness of the second metal layer 2, but the minimum value of the width W2 of the support surface 203 is related to the design of the support surface 203, and its minimum value should not be too small, otherwise it will affect the supporting effect of the support surface 203 on the terminal block 102, and further affect the effect of the second metal layer 2 blocking the laser during laser welding. As an example, the width W2 of the support surface 203 is 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm, 2.2mm, 2.5mm, 2.8mm or 3.0mm.

[0239] In some embodiments, see Fig.14 The conductive structure 10 is a pole 101, the pole 101 and the terminal block 102 are connected to form a conductive module 10a, and the end 20 of the second metal layer 2 is sandwiched between the first metal column 1 and the terminal block 102. The end 20 is formed as a clamping portion 2a, and the clamping portion 2a is sandwiched between the first metal column 1 and the terminal block 102, that is, part of the second metal layer 2 is sandwiched between the first metal column 1 and the terminal block 102.

[0240] Part of the second metal layer 2 (i.e., the end 20) is clamped between the first metal column 1 and the terminal block 102. On the one hand, the first metal column 1 and the terminal block 102 limit the end 20 to prevent the second metal layer 2 from separating from the first metal column 1. On the other hand, due to the ductility of the metal, when the first metal column 1 and the terminal block 102 clamp the end 20, the first metal and the second metal will invade each other, making the second metal layer 2 and the first metal column 1 more tightly combined. The dual effects jointly reduce the risk of the second metal layer 2 separating from the first metal column 1.

[0241] In some embodiments, see Fig.15 , a through hole 1021 is provided on the terminal pressing block 102, and the terminal pressing block 102 is sleeved on the pole 101 through the through hole 1021. That is, the pole 101 is penetrated on the terminal pressing block 102 through the through hole 1021. As an example, one end of the pole 101 (specifically the first end 11 of the first metal column 1) extends into the through hole 1021, and the terminal pressing block 102 is sleeved on one end of the pole 101. By sleeve-mounting the terminal pressing block 102 on the pole 101, the height of the conductive module 10a can be appropriately reduced, and the terminal pressing block 102 can also limit the pole 101.

[0242] In some embodiments, the terminal pressing block 102 is sleeved on the first metal column 1 through the through hole 1021. The hole walls 1022 of some through holes 1021 may be in direct contact with the first metal column 1, or the hole walls 1022 of all through holes 1021 may be in direct contact with the first metal column 1, that is, there is no second metal layer 2 between the hole walls 1022 of the through holes 1021 and the first metal column 1. By sleeved the terminal pressing block 102 on the first metal column 1 through the through hole 1021, it is convenient to weld the terminal pressing block 102 and the first metal column 1, for example, by laser welding.

[0243] In some embodiments, the through hole 1021 is interference fit with the pole 101. In this way, the terminal block 102 can be tightly fitted with the pole 101, and the thrust resistance and torsion resistance of the pole 101 can be improved. At the same time, the interference fit method does not require the introduction of other connecting components, has a simple structure, and has a high reliability of the connection method.

[0244] In some embodiments, the terminal pressing block 102 is fixed to the pole 101 by riveting. As an example, the assembly process includes: inserting one end of the pole 101 into the through hole 1021 of the terminal pressing block 102, at which time the pole 101 and the through hole 1021 may be clearance-fitted, and then riveting the pole 101 and the through hole 1021 together by a riveting fixing process. In detail, during the process of riveting, the pole 101 can be squeezed along the axial direction of the pole 101 by using a riveting machine. The pole 101 will deform during the pressure process, and the pole 101 will shrink along the axial direction, but the pole 101 will expand radially. At this time, the part of the pole 101 located in the through hole 1021 will fill the gap between the pole 101 and the through hole 1021 and squeeze the hole wall 1022 of the through hole 1021, so as to achieve an interference fit between the pole 101 and the through hole 1021, and the part of the pole 101 located outside the through hole 1021 will form a stop step that cooperates with the terminal pressing block 102, that is, the pole 101 is equivalent to a rivet, which improves the reliability of the connection between the terminal pressing block 102 and the pole 101 and reduces the risk of the pole 101 being separated from the terminal pressing block 102. Optionally, during the process of riveting, the terminal pressing block 102 is fixed by a clamp and the terminal pressing block 102 cannot move.

[0245] In some embodiments, see Fig.15 , a mating surface 1023 matching the support surface 203 is formed on the hole wall 1022 of the through hole 1021. When the support surface 203 is an inclined surface 2031, the mating surface 1023 is an inclined mating surface 1023 adapted to the inclined surface 2031. When the support surface 203 is a step surface 2032, the mating surface 1023 is a step mating surface 1023 adapted to the step surface 2032. By utilizing the complementarity between the support surface 203 and the mating surface 1023, the stability of the fit between the terminal block 102 and the pole 101 is effectively improved, and the risk of laser penetration during laser welding is reduced. In addition, when the support surface 203 is an inclined straight surface, the inclined straight surface is adapted to the mating surface 1023, and can also play a guiding role, further improving the reliability of the fit between the terminal block 102 and the pole 101. In some embodiments, the clamping portion 2a is set to a ring shape, and the clamping portion 2a is connected to the periphery of the first metal column 1. By setting the clamping portion 2a in a ring shape, the contact area between the clamping portion 2a and the circumference of the first metal column 1 can be increased, the bonding area between the second metal layer 2 and the first metal column 1 can be increased, the risk of the second metal layer 2 falling off can be reduced, and the manufacturing difficulty of the pole 101 can also be effectively reduced. Of course, in other embodiments, the clamping portion 2a can also be provided to include a plurality of convex pieces, the plurality of convex pieces are spaced around the circumference of the first metal column 1, and the convex pieces are clamped between the first metal column 1 and the terminal block 102.

[0246] In some embodiments, see Figures 1 to 5 , Figures 16 to 28, the first metal column 1 protrudes radially to form a boss 13, and the second metal layer 2 extends at least to the boss 13. Specifically, a part of the first metal column 1 protrudes outward roughly along the radial direction of the first metal column 1 to form the boss 13. Optionally, the angular deviation between the boss 13 and the radial direction of the first metal column 1 is within ±15°. The second metal layer 2 extends at least to the boss 13, and the end 20 of the second metal layer 2 may extend to the boss 13, or the end 20 of the second metal layer 2 may extend beyond the boss 13, that is, the boss 13 may be completely wrapped in the second metal layer 2, or it may be partially wrapped in the second metal layer 2. When the end 20 of the second metal layer 2 extends to the boss 13, the end 20 of the second metal layer 2 may be embedded in the boss 13, or it may be located only on the surface of the boss 13.

[0247] As an example, see Figure 2 The boss 13 is far away from the first end 11 , the end 20 of the second metal layer 2 extends to a side of the boss 13 close to the first end 11 , and the end 20 of the second metal layer 2 is embedded in the boss 13 .

[0248] As an example, see Fig.23 The boss 13 is away from the first end 11 , and the end 20 of the second metal layer 2 extends to a side of the boss 13 away from the first end 11 .

[0249] By making the first metal column 1 radially protrude to form a boss 13, the boss 13 can be used to increase the outer surface area of ​​the first metal column 1, and the second metal layer 2 also partially or even completely covers the boss 13, so that the bonding area between the second metal layer 2 and the first metal column 1 is increased, the bonding force is enhanced, and the risk of the second metal layer 2 being separated from the first metal column 1 is reduced, while also improving the current carrying capacity of the conductive structure 10.

[0250] In addition, when the conductive structure 10 is applied to a battery cell, the boss 13 can serve as a stopping structure to cooperate with other components (such as the cover plate 110). At the same time, since the second metal layer 2 extends at least to the boss 13, the second metal layer 2 will be clamped between the boss 13 and the component that cooperates with the boss 13, thereby preventing the risk of the second metal layer 2 detaching from the first metal column 1.

[0251] In some embodiments, see Figure 4 and Figure 5 , the boss 13 is located at the first end 11, and the boss 13 is completely covered in the second metal layer 2. As an example, see Figure 5The conductive structure 10 is roughly in the shape of an inverted T. When the conductive structure 10 is assembled on the cover plate 110, the smaller end of the conductive structure 10 can be passed through the mounting hole 114 on the cover plate 110 from bottom to top until the boss 13 abuts against the cover plate 110, and the second metal layer 2 on the upper surface of the boss 13 is clamped between the boss 13 and the cover plate 110 to prevent the second metal layer 2 from falling off.

[0252] In some embodiments, see Figure 4 and Figure 5 The boss 13 is located at the first end 11, and the second metal layer 2 includes a first section and a second section, wherein the first section corresponds to the end face of the boss 13 (i.e., the first end 11), and the second section 22 at least covers the side surface of the boss 13 and the side surface of the boss 13 close to the second end 12, i.e., the boss 13 is completely enclosed in the second metal layer 2.

[0253] In some embodiments, see Figure 4 and Figure 5 , the conductive structure 10 is an integrated structure of a pole and a current collector, that is, the conductive structure 10 is an integrated pole 101 and a current collector 120, wherein the boss 13 is the current collector 120. By integrating the pole 101 and the current collector 120, the process of assembling the pole 101 and the current collector 120 can be omitted, thereby reducing the production cost of the battery cell. In addition, since the second metal layer 2 extends onto the boss 13, that is, the second metal layer 2 extends onto the current collector 120, there is no need to increase the volume of the pole 101. Only by reusing the current collector 120 can the bonding area of ​​the second metal layer 2 be greatly increased, the risk of the second metal layer 2 falling off can be reduced, and the current carrying capacity of the conductive structure 10 can be improved without bringing about the burden of volume and weight. The above-mentioned current collector 120 is also a component in the battery cell, and the current collector 120 is usually located inside the battery cell. That is, when the pole-current collector integrated structure is assembled on a battery cell, such as the cover plate 110 of the battery cell, the boss 13 is located inside the battery cell. The current collector 120 is also used to electrically connect to the tab of the electrode assembly.

[0254] In some embodiments, see Figures 1 to 3 , Figures 16 to 28 , the boss 13 is far away from the first end 11, and the radial dimension of the boss 13 is greater than the radial dimension of the first end 11. The boss 13 can be located at the second end 12, or between the first end 11 and the second end 12. As an example, see Figure 1When the boss 13 is located at the second end 12, the shape of the conductive structure 10 is roughly an upright T-shape. When the conductive structure 10 is assembled on the cover plate 110, the smaller end of the conductive structure 10 can be passed through the mounting hole on the cover plate 110 from top to bottom until the boss 13 abuts against the cover plate 110, and the second metal layer 2 on the lower surface of the boss 13 is clamped between the boss 13 and the cover plate 110 to prevent the second metal layer 2 from falling off.

[0255] In some embodiments, see Figures 1 to 3 , Figures 16 to 20 , the boss 13 is located at the second end 12, and the boss 13 is partially exposed outside the second metal layer 2. The boss 13 is located at the second end 12, and when the conductive structure 10 and the cover plate 110 are assembled, the boss 13 is usually located outside the cover plate 110. By setting the boss 13 to be partially exposed outside the second metal layer 2, it is convenient for the boss 13 to be directly connected to other components (such as a module bar).

[0256] In some embodiments, the conductive structure 10 is an integrated structure of a pole-terminal block, that is, the conductive structure 10 is an integrated pole 101 and a terminal block 102, wherein the boss 13 is the terminal block 102. By integrating the pole 101 and the terminal block 102, the process of assembling the pole 101 and the terminal block 102 can be omitted, thereby reducing the production cost of the battery cell. In addition, since the second metal layer 2 extends onto the boss 13, that is, the second metal layer 2 extends onto the terminal block 102, there is no need to increase the volume of the pole 101. The bonding area of ​​the second metal layer 2 can be greatly increased by reusing the terminal block 102, reducing the risk of the second metal layer 2 falling off, and improving the current carrying capacity of the conductive structure 10 without bringing the burden of volume and weight. When the pole-terminal block integrated structure is assembled on a battery cell, such as the cover plate 110 of the battery cell, the boss 13 is located outside the battery cell.

[0257] In some embodiments, see Figure 2 , Figures 16 to 28, the second metal layer 2 includes a first section 21, a second section 22 and a third section 23, wherein the first section 21 corresponds to the end face of the first end 11, the second section 22 corresponds to the side face of the first end 11, the third section 23 corresponds to the side surface of the boss 13 close to the first end 11, and the second section 22 connects the first section 21 and the third section 23. Here, the first section 21, the second section 22 and the third section 23 refer to three different parts of the second metal layer 2. Here, the end 20 of the second metal layer 2 may be located in the third section 23 or not. When the end 20 of the second metal layer 2 is not located in the third section 23, it means that the second metal layer 2 also includes other sections, i.e., other parts. Optionally, the number of sections of the second metal layer 2 is less than or equal to five, because the more sections, the greater the manufacturing difficulty and the higher the cost.

[0258] By setting the second metal layer 2 to include at least three sections, wherein the first section 21 and the second section 22 can wrap the first end 11 to protect the first end 11 and reduce the risk of the first end 11 being corroded by the electrolyte; and the third section 23 extends to the surface of the boss 13, the bonding area of ​​the second metal layer 2 can be further increased, the current carrying capacity of the conductive structure 10 can be improved, and the risk of the second metal layer 2 falling off can be reduced.

[0259] In some embodiments, see Figure 2 , Fig.17 and Fig.19 , the third section 23 is formed as the end 20 of the second metal layer 2, and the third section 23 is embedded in the boss 13. By setting the second metal layer 2 to include only three sections, the manufacturing difficulty of the conductive structure 10 can be reduced. At the same time, the third section 23 as the end 20 of the second metal layer 2 is also embedded in the boss 13, increasing the bonding area and ensuring the bonding strength of the second metal layer 2, so that the conductive structure 10 has a higher cost performance. In addition, in this way, under high temperature conditions, when the third section 23 expands, the first metal column 1 can limit the third section 23 from both ends of the third section 23, and the third section 23 can better achieve a tight fit with the first metal column 1, thereby improving the bonding strength of the second metal layer 2.

[0260] In some embodiments, see Figure 2, the average thickness d1 of the first section 21 is greater than the average thickness d2 of the second section 22, and the average thickness d2 of the second section 22 is greater than the average thickness d3 of the third section 23. That is, the first section 21, the second section 22 and the third section 23 satisfy the following thickness relationship: d1>d2>d3. When the conductive structure 10 is applied to the battery cell 1000, the first end 11 of the first metal column 1 is directed toward the inside of the battery cell 1000. In terms of the probability of contacting the electrolyte, the probability of the first section 21 is greater than the probability of the second section 22, and the probability of the second section 22 is greater than the probability of the third section 23. By setting the first section 21, the second section 22 and the third section 23 to have a decreasing average thickness in sequence, the risk of the first end 11 being corroded by the electrolyte can be reduced while controlling the cost.

[0261] In some embodiments, see Figure 2 , the average thickness d2 of the second section 22 is greater than half of the average thickness d1 of the first section 21. Within this range, the second metal layer 2 has both mechanical strength and cost advantages. As an example, the ratio of d2 to d1 is 0.5, 0.6, 0.7, 0.8 or 0.9.

[0262] In some embodiments, see Figure 2 , the average thickness d3 of the third section 23 is greater than half of the average thickness d2 of the second section 22. Within this range, the second metal layer 2 has both mechanical strength and cost advantages. As an example, the ratio of d3 to d2 is 0.5, 0.6, 0.7, 0.8 or 0.9.

[0263] In some embodiments, see Figure 2 The thickness d23 of the second section 22 near the third section 23 is greater than the thickness d21 of the second section 22 near the first section 21. In this way, the second section 22 near the third section 23 can play a buckle function, so that the second metal layer 2 and the first metal column 1 have better bonding strength at this position.

[0264] In some embodiments, see Fig.17 , Figures 21 to 28, the end surface of the first end 11 is partially concave to form a groove 11b, and the first section 21 includes a first sub-segment 211, a second sub-segment 212 and a third sub-segment 213 connected in sequence, the first sub-segment 211 is located outside the groove 11b, the second sub-segment 212 is located on the side wall of the groove 11b, and the third sub-segment 213 is located on the bottom wall of the groove 11b. The concave here means concave toward the inside of the first metal column 1. The end surface of the first end 11 forms a groove 11b, and the second metal layer 2 also matches the surface of the first end 11 to form a second sub-segment 212 and a third sub-segment 213 that fit the inner wall surface of the groove 11b. By providing a groove 11b on the end surface of the first end 11 and attaching the second metal layer 2 to the inner wall surface of the groove 11b, the bonding area between the second metal layer 2 and the first metal column 1 is increased, and the bonding strength is improved.

[0265] In some embodiments, see Fig.28 , the average thickness d2 of the second section 22 is greater than or equal to 0.5 mm. Generally, the larger the average thickness d2 of the second section 22, the higher the mechanical strength of the second section 22, and the better the corrosion resistance and fracture resistance. As an example, the average thickness d2 of the second section 22 is 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm or 2.5 mm.

[0266] In some embodiments, see Fig.28 , the average thickness d11 of the first subsegment 211 is greater than or equal to 0.5 mm. Generally, the greater the average thickness of the first subsegment 211, the higher the mechanical strength of the first subsegment 211, and the better the corrosion resistance and fracture resistance. As an example, the average thickness d11 of the first subsegment 211 is 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm or 2.5 mm.

[0267] In some embodiments, see Fig.17 , Fig.21 , Fig.23 and Fig. 27 , the vertical distance H2 between the outer surface of the first subsegment 211 and the outer surface of the third subsegment 213 is ≤2.5mm. As an example, H2 is 0.2mm, 0.5mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm or 2.5mm. The vertical distance H2 between the outer surface of the first subsegment 211 and the outer surface of the third subsegment 213 within the above range can ensure that the first metal column 1 and the second metal layer 2 have better bonding strength and the manufacturing difficulty of the conductive structure 10 is low.

[0268] In some embodiments, see Fig.21 and Fig.23 , the second sub-segment 212 extends obliquely from the first sub-segment 211 to the third sub-segment 213, and the inclination angle σ of the second sub-segment 212 satisfies the following condition: 15°≤σ≤60°. Here, the inclination angle σ refers to the inclination angle of the second sub-segment 212 relative to the plane extending in the radial direction of the first metal column 1. As an example, the inclination angle σ is 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60°. By controlling the inclination angle σ of the second sub-segment 212, the second sub-segment 212 can be smoothly transitioned from the first sub-segment 211 to the third sub-segment 213, alleviating the phenomenon that the stress concentration at the connection between the second sub-segment 212 and the first sub-segment 211 and the connection between the second sub-segment 212 and the third sub-segment 213 leads to the fracture of the second metal layer 2.

[0269] In some embodiments, see Figures 21 to 28 , the boss 13 is located between the first end 11 and the second end 12, and the radial dimension of the boss 13 is larger than the radial dimension of the second end 12. As an example, see Fig.21 and Fig.23 When the boss 13 is located between the first end 11 and the second end 12, the shape of the conductive structure 10 is roughly in the shape of a "Z" character. For this type of conductive structure 10, when the boss 13 is used as a stopper structure, the boss 13 can be clamped from both sides of the boss 13 to achieve a more stable fixation of the second metal layer 2. In order to prevent the conductive structure 10 from being too high, the boss 13 can be made thinner, and the second end 12 can be used to electrically connect with other components.

[0270] In some embodiments, see Figures 21 to 28 The second metal layer 2 further includes a fourth section 24, which corresponds to the side of the boss 13 and is connected to the third section 23. The fourth section 24 can further increase the bonding area between the second metal layer 2 and the first metal column 1. Here, the side of the boss 13 can be completely covered by the fourth section 24, or can be partially covered by the fourth section 24.

[0271] In some embodiments, see Fig. 22, along the axial direction of the first metal column 1, the distance between the outer surface of the third section 23 and the end of the fourth section 24 away from the first end 11 is a, and along the radial direction of the first metal column 1, the distance between the outer surface and the inner surface of the fourth section 24 is e, where a>e>0.5mm. Within this range, the bonding area between the fourth section 24 and the boss 13 is large, and the strength of the fourth section 24 itself is also large, which can not only improve the current carrying capacity of the conductive structure 10, but also improve the bonding strength between the second metal layer 2 and the first metal column 1. Along the axial direction of the first metal column 1, the distance between the outer surface of the third section 23 and the outer surface of the boss 13 is h1.

[0272] In some embodiments, see Figure 23 to Figure 28 The second metal layer 2 further includes a fifth section 25, the fifth section 25 corresponds to a side surface of the boss 13 away from the first end 11, and the fourth section 24 connects the fifth section 25 and the third section 23. The fifth section 25 can further increase the bonding area between the second metal layer 2 and the first metal column 1. Optionally, the end 20 of the second metal layer 2 is located in the fifth section 25.

[0273] In some embodiments, see Fig.24 , along the axial direction of the first metal column 1, the distance between the inner surface of the fifth section 25 and the inner surface of the third section 23 is b, b>0.5mm. Since the boss 13 is at least partially located between the inner surface of the fifth section 25 and the inner surface of the third section 23, by setting b>0.5mm, it is helpful to ensure the mechanical strength of the boss 13, especially when the boss 13 is used as a stop structure, the risk of the boss 13 breaking can be reduced.

[0274] In some embodiments, see Fig.24 , along the axial direction of the first metal column 1, the distance between the outer surface of the third section 23 and the outer surface of the fifth section 25 is h2; along the radial direction of the first metal column 1, the distance between the outer surface of the fourth section 24 and the root of the side of the boss 13 close to the second end 12 is c, and the distance between the outer surface of the fourth section 24 and the end of the fifth section 25 close to the central axis of the first metal column 1 is d; wherein c>h2 and d≥2 / 3c, or c≤h2 and d>0.5mm. Within the above range, the bonding strength between the second metal layer 2 and the first metal column 1 can be effectively improved.

[0275] In some embodiments, see Fig.28 The fourth section 24 and the fifth section 25 are formed such that the buckle layer 251 wraps the free end of the boss 13, and along the axial direction of the first metal column 1, the distance between the outer surface of the third section 23 and the outer surface of the buckle layer 251 is K1, and the thickness of the buckle layer 251 is K2, f=K2 / K1, where f is greater than or equal to 0.3 and less than 1. The buckle layer 251 can enhance the installation strength of the conductive structure 10.

[0276] In some embodiments, see Fig.19 , Fig. 20 , Figure 25 to Figure 28 , the edge of the end face of the first end 11 is concave to form a first step portion 11a, and the second metal layer 2 also includes a second step portion 26, which matches the first step portion 11a, is connected between the first section 21 and the second section 22, and is used to connect with the pole lug 1210. It can be foreseen that there will also be a step on one end of the conductive structure 10, which is formed by the second step portion 26 stacked on the first step portion 11a, which is equivalent to the first metal column 1 and the second metal layer 2 being concavely formed synchronously. The advantage of this arrangement is that the strong correlation between the area of ​​the second step portion 26 and the thickness of the second metal layer 2 is changed, and even if the thickness of the second metal layer 2 is very small, a sufficiently large second step portion 26 can be formed to ensure the effect of the second step portion 26 connecting with the pole lug. Optionally, the first step portion 11a is a sink located at the edge of the end face of the first end 11, and the sink is formed by the end face of the first end 11 sinking in the direction close to the second end 12. In the second metal layer 2, the first section 21, the second step portion 26 and the second section 22 are connected in sequence. Optionally, the second step portion 26 is used to weld with the current collector 120 connected to the pole tab. As an example, when welding the second step portion 26 with the current collector 120, the current collector 120 can be first sleeved on the conductive structure 10, and the current collector 120 and the second step portion 26 cooperate with each other, and the current collector 120 is welded to the second step portion 26 by laser welding. If the surface area of ​​the second step portion 26 is larger, the surface that can be welded between the second step portion 26 and the current collector 120 will be larger, and the larger the welding surface, the higher the reliability of welding.

[0277] In some embodiments, see Fig.19 , Fig. 20 and Fig.28, the second step portion 26 has a first step surface 261 and a second step surface 262 connected. Specifically, the second step portion 26 is L-shaped, the first step surface 261 is a surface on the second step portion 26 extending along the first direction, and the second step surface 262 is a surface on the second step portion 26 extending along the second direction. The first direction intersects with the second direction. Optionally, the first direction is perpendicular to the second direction. As an example, the first direction is the radial direction of the first metal column 1, and the second direction is the axial direction of the first metal column 1. In the radial direction of the first metal column 1, the width W31 of the first step surface 261 is ≥0.5mm. As an example, the width W31 of the first step surface 261 is 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm. In the axial direction of the first metal column 1, the height H31 of the second step surface 262 is ≥0.4mm. As an example, the height H31 of the second step surface 262 is 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1.0 mm. By increasing the width of the first step surface 261 and the height of the second step surface 262, it is possible to ensure that the second step portion 26 has a sufficient contact surface, thereby improving the flow capacity and connection strength.

[0278] In some embodiments, the first metal is aluminum, that is, the first metal column 1 is an aluminum column, and the second metal is copper, that is, the second metal layer 2 is a copper layer. Compared with copper, aluminum is cheaper, and by setting the conductive structure 10 to include an aluminum column and a copper layer, the cost of the conductive structure 10 can be effectively reduced. Exemplarily, the conductive structure 10 is a negative electrode column.

[0279] In some embodiments, the average thickness D1 of the second metal layer 2 is less than or equal to 3 mm. By making the second metal layer 2 thinner, the production cost of the conductive structure 10 can be effectively reduced, especially when the first metal column 1 is an aluminum column and the second metal layer 2 is a copper layer, the use of more expensive copper is reduced, and the cost of the conductive structure 10 is effectively reduced while also reducing the weight of the conductive structure 10. As an example, the average thickness D1 of the second metal layer 2 is 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.5 mm, 2.8 mm or 3.0 mm. Optionally, the average thickness D1 of the second metal layer 2 is less than or equal to 1.8 mm.

[0280] In some embodiments, the average thickness D1 of the second metal layer 2 is 0.2 mm to 1.5 mm. Generally, if the average thickness D1 of the second metal layer 2 is reduced, the current carrying capacity of the conductive structure 10 decreases, but the cost of the conductive structure 10 is reduced. By designing the average thickness D1 of the second metal layer 2 to be 0.2 mm to 1.5 mm, the conductive structure 10 can have both cost advantages and sufficient current carrying capacity within this range. As an example, the average thickness D1 of the second metal layer 2 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm.

[0281] In some embodiments, the bonding interface between the second metal layer 2 and the first metal column 1 has an uneven microstructure. This refers to the uneven fit between the surface of the second metal layer 2 and the surface of the first metal column 1 at the microscopic level. Optionally, the conductive structure 10 is a cold-headed part. As an example, the first metal column 1 is an aluminum column, the second metal layer 2 is a copper layer, and the conductive structure 10 is formed by cold heading of a copper-aluminum composite plate. Since the metal has ductility, during the cold heading process, under pressure, the first metal in the first metal column 1 and the second metal in the second metal layer 2 are deformed and invade each other, so that the bonding interface between the first metal column 1 and the second metal layer 2 is formed into a microscopically uneven wavy surface, which can further increase the bonding area between the first metal column 1 and the second metal layer 2 and improve the bonding strength.

[0282] In some embodiments, the diameter φ of the conductive structure 10 is less than or equal to 30 mm. The diameter φ of the conductive structure 10 should not be too large, otherwise it will increase the weight and cost of the battery cell. Optionally, 5 mm ≤ φ ≤ 30 mm, within which the conductive structure 10 has both better current carrying capacity and cost advantages. As an example, the diameter φ of the conductive structure 10 is 5 mm, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm.

[0283] In some embodiments, the diameter φ of the conductive structure 10 is less than or equal to 10 mm. By making the conductive structure 10 smaller, the production cost of the conductive structure 10 can be effectively reduced. As an example, the diameter φ of the conductive structure 10 is 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0284] In some embodiments, in the conductive structure 10, the ratio of the volume of the second metal layer 2 to the total volume of the conductive structure 10 is 5 vol% to 70 vol%. Within this range, the conductive structure 10 has better bonding strength, current carrying capacity and cost advantages. As an example, the volume of the second metal layer 2 accounts for 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol% or 70 vol%.

[0285] In some embodiments, in the conductive structure 10, the ratio of the volume of the second metal layer 2 to the total volume of the conductive structure 10 is 5 vol% to 40 vol%. Within this range, the conductive structure 10 has better bonding strength, current carrying capacity and cost advantages. As an example, the volume of the second metal layer 2 accounts for 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol% or 40 vol%.

[0286] In some embodiments, when the first metal pillar 1 is cut along a radial direction of the first metal pillar 1 , the cross-sectional shape of the first metal pillar 1 may be one of square, circular, hexagonal, and racetrack.

[0287] In some embodiments, the bonding area between the second metal layer 2 and the first metal column 1 is greater than or equal to 20 mm 2 The second metal layer 2 is bonded to the surface of the first metal column 1, and the surface where the second metal layer 2 and the first metal column 1 are in contact with each other is the bonding surface, also called the contact surface. The bonding area between the second metal layer 2 and the first metal column 1 refers to the area of ​​the surface where the second metal layer 2 and the first metal column 1 are in contact. As an example, the bonding area is 20mm 2 , 30mm 2 , 40mm 2 , 50mm 2 , 100mm 2 、150mm 2 , 200mm 2 、300mm 2 , 400mm 2 or 500mm 2 By increasing the bonding area, the current carrying capacity of the conductive structure 10 can be improved and the risk of the second metal layer 2 falling off can be reduced.

[0288] In some embodiments, the bonding area between the second metal layer 2 and the first metal column 1 is greater than or equal to 80 mm 2 As an example, the bonding area is 80mm 2 、90mm2 , 100mm 2 , 120mm 2 、130mm 2 、140mm 2 、150mm 2 , 200mm 2 , 250mm 2 、300mm 2 , 400mm 2 or 500mm 2 .

[0289] In some embodiments, the volume ratio of the second metal layer 2 to the first metal column 1 is 0.1 to 0.65. That is, the volume of the first metal column 1 is 1.54 to 10 times the volume of the second metal layer 2, that is, the volume content of the first metal column 1 in the conductive structure 10 is much greater than the volume content of the second metal layer 2. In the case where the bonding area of ​​the second metal layer 2 and the first metal column 1 is increased, the conductive structure 10 is ensured to still have sufficient current capacity, and the cost of the conductive structure 10 can be reduced by reducing the content of the second metal layer 2 in the conductive structure 10, especially when the first metal column 1 is an aluminum column and the second metal layer 2 is a copper layer. As an example, the volume ratio of the second metal layer 2 to the first metal column 1 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.65. Usually, the volume ratio of the second metal layer 2 to the first metal column 1 fluctuates with the size (e.g., diameter) of the conductive structure 10. The larger the size of the conductive structure 10, the smaller the volume ratio of the second metal layer 2 to the first metal column 1.

[0290] In some embodiments, see Figure 2 , on the appearance surface of the conductive structure 10, the ratio A of the surface area of ​​the second metal layer 2 to the surface area of ​​the first metal column 1 is greater than or equal to 0.25. Since the second metal layer 2 is combined with the surface of the first metal column 1, the surface of the second metal layer 2 exposed to the outside forms the appearance surface of the conductive structure 10; when the second metal layer 2 is not completely covered on the first metal column 1, the surface of the first metal column 1 exposed to the outside will also form the appearance surface of the conductive structure 10. It can be understood that on the appearance surface of the conductive structure 10, the surface area of ​​the second metal layer 2 is the area of ​​the surface of the second metal layer 2 exposed to the outside, and the surface area of ​​the first metal column 1 is the area of ​​the surface of the first metal column 1 exposed to the outside. Increasing the surface area of ​​the second metal layer 2 on the appearance surface of the conductive structure 10 is equivalent to increasing the area of ​​the second metal layer 2 covered on the first metal column 1, that is, increasing the bonding area between the second metal layer 2 and the first metal column 1. As an example, on the exterior surface of the conductive structure 10 , a ratio A of the surface area of ​​the second metal layer 2 to the surface area of ​​the first metal pillar 1 is 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5 or 3.

[0291] In some embodiments, the diameter φ of the conductive structure 10 is less than or equal to 10 mm, and the ratio A of the surface area of ​​the second metal layer 2 to the surface area of ​​the first metal column 1 is greater than or equal to 0.25 and less than or equal to 0.6. In order to facilitate the second end 12 to be directly connected to other components, the second end 12 is at least partially exposed outside the second metal layer 2. Generally, the smaller the diameter of the conductive structure 10, the smaller the surface area of ​​the conductive structure 10. In the case of φ≤10 mm, controlling 0.25≤A≤0.6 can ensure that the second end 12 has enough connection surface to connect with other components, and the bonding area is large enough, thereby ensuring the current carrying capacity of the conductive structure 10. As an example, φ is 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, and A is 0.25, 0.3, 0.4, 0.5 or 0.6.

[0292] In some embodiments, the diameter φ of the conductive structure 10 is greater than 10 mm and less than or equal to 30 mm, and the ratio of the surface area of ​​the second metal layer 2 to the surface area of ​​the first metal column 1 is greater than or equal to 0.75 and less than or equal to 2. As the diameter of the conductive structure 10 increases, the current carrying capacity of the conductive structure 10 is improved, but it will also increase the cost of the conductive structure 10 and bring volume and mass burdens. In the case of 10mm<φ≤30mm, the conductive structure 10 can have both cost advantages and better current carrying capacity. In addition, as the diameter of the conductive structure 10 increases, the surface area of ​​the conductive structure 10 also increases, and a portion of the conductive structure 10 is retained on the second end 12 to be exposed outside the second metal layer 2, and other areas can be covered with the second metal layer 2 to increase the bonding area. In the case of 10mm<φ≤30mm, controlling 0.75≤A≤2 can ensure that the bonding area is large enough, thereby ensuring the current carrying capacity of the conductive structure 10. As an example, φ is 10.1 mm, 11 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm, 24 mm, 26 mm, 28 mm or 30 mm, and A is 0.75, 0.8, 0.9, 1.0, 1.2, 1.5, 1.7, 1.85 or 2.

[0293] In addition to the conductive structure 10 provided in the above embodiment, the embodiment of the present application further provides a conductive structure 10 with the following structure.

[0294] See also Fig.29 , Fig.291 is a schematic diagram of the structure of the eleventh conductive structure 10 provided by an embodiment of the present application. An embodiment of the present application provides a conductive structure 10. The conductive structure 10 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 end of the first section 14 away from the second section 15 is the first end, and the end of the second section 15 away from the first section 14 is the second end. 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 surface of the cylinder 27 close to the second section 15. The flange 28 extends along the radial direction of the conductive structure 10 and is embedded in the end of the second section 15 facing the first section 14. In the axial direction of the conductive structure 10, 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 conductive structure 10.

[0295] 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.

[0296] 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.

[0297] 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 .

[0298] 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.

[0299] 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.

[0300] Optionally, the mobility of the first metal is greater than the mobility of the second metal.

[0301] Optionally, the second metal has a harderness than the first metal.

[0302] It can be understood that when the conductive structure 10 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 conductive structure 10 from escaping from the cover plate 110 of the battery cell when the high voltage is inside the battery cell. 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.

[0303] In this embodiment, by increasing the thickness dimension Hb of at least part of the flange 28 as it approaches the axis of the conductive structure 10, 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 conductive structure 10, 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.

[0304] In addition, by allowing the material at the edge of the flange 28 to flow toward the axis of the conductive structure 10 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 conductive structure 10 to prevent the first section 14 from escaping from the cylinder 27.

[0305] In one embodiment, the thickness dimension Hb of the flange 28 gradually increases along the direction close to the axis of the conductive structure 10. In the longitudinal section of the conductive structure 10 passing through the flange 28, along the direction close to the axis of the conductive structure 10, the bonding interface 17 formed by the flange 28 and the second segment 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 segment 14 and the inner wall of the cylinder 27.

[0306] 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.

[0307] Specifically, the concave sides of the first line segment 161 and the third line segment 163 face away from the second segment 15 .

[0308] In this embodiment, through the above arrangement, firstly, the part where the flange 28 is formed into the first line segment 161 can smoothly connect the side of the flange 28 away from the second segment 15 with the surface where the flange 28 is embedded in the second segment 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 segment 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 conductive structure 10, thereby improving the reliability of the combination between the first metal column 1 and the second metal layer 2.

[0309] 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 conductive structure 10 larger, while the radius of the end of the flange 28 close to the axis of the conductive structure 10 is smaller. In this way, the convexity of the end of the flange 28 away from the axis of the conductive structure 10 can be reduced to reduce the material of the end of the flange 28 away from the axis of the conductive structure 10, so that more material of the flange 28 can flow toward the axis of the conductive structure 10. At the same time, the end of the flange 28 close to the conductive structure 10 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.

[0310] 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 .

[0311] 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 -4mm -1 .

[0312] 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 .

[0313] 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.

[0314] 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.

[0315] 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.

[0316] 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.

[0317] See also Fig.31 , Fig.31 The embodiments of this application provide Fig.29An enlarged view of another structure at A of the conductive structure 10. In one embodiment, in the longitudinal section of the conductive structure 10 passing the flange 28, along the axial direction of the conductive structure 10, the bonding interface 17 formed between the surface of the second metal layer 2 close to the axis of the conductive structure 10 and the outer peripheral surface of the first metal column 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.

[0318] 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 conductive structure 10 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 .

[0319] 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 .

[0320] 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 conductive structure 10, 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 conductive structure 10 to prevent the first segment 14 from escaping from the cylinder 27.

[0321] In one embodiment, the curvature of the first line segment 161 is smaller than the curvature of the fifth line segment 165. It can be understood that such a configuration makes the radius of the end of the flange 28 away from the axis of the conductive structure 10 larger, while the radius of the end of the flange 28 close to the axis of the conductive structure 10 is smaller. In this way, the convexity of the end of the flange 28 away from the axis of the conductive structure 10 can be reduced to reduce the material of the end of the flange 28 away from the axis of the conductive structure 10, so that more material of the flange 28 can flow toward the axis of the conductive structure 10. At the same time, the end of the flange 28 close to the conductive structure 10 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.

[0322] 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 , the curvature of the fifth line segment 165 is 7×10 -4 mm -1 ~3×10 -3 mm -1 .

[0323] 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 .

[0324] 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 -4 mm -1 , 1×10 -3 mm -1 , 2×10 -3 mm -1 .

[0325] 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 .

[0326] 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.

[0327] 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.

[0328] 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.

[0329] See also Fig.32 , Fig.32 Schematic diagram of forging streamlines 18 of the first metal pillar 1 provided in an embodiment of the present application. In one embodiment, in a longitudinal section of the conductive structure 10, the first metal pillar 1 has a plurality of forging streamlines 18. The contact portion between the first metal pillar 1 and the second metal layer 2 forms a bonding interface 17; the first metal pillar 1 has a bonding 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.

[0330] It can be understood that the metal grains of the first metal material located in the tight area 191 are highly refined and arranged more closely, so that the ability of the first metal material located in the tight area 191 to hinder dislocation movement is enhanced, thereby improving the strength and hardness of the first metal column 1 to enhance the structural reliability of the conductive structure 10.

[0331] 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.

[0332] See also Fig.30 or Fig.31 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 conductive structure 10 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.

[0333] See also Fig.29 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.

[0334] 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.

[0335] 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.

[0336] See also Fig.33 and Fig.34 , Fig.33is a schematic structural diagram of a twelfth conductive structure 10 provided in an embodiment of the present application, Fig.34 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 conductive structure 10. At least two flanges 28 are arranged opposite to each other along the radial direction of the conductive structure 10. 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 conductive structure 10 can be improved, so as to improve the stress state of the conductive structure 10.

[0337] In one embodiment, in the axial cross section of the conductive structure 10, 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 conductive structure 10, 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 conductive structure 10, thereby improving the structural reliability of the conductive structure 10.

[0338] 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.

[0339] 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.

[0340] It can be understood that when φb0≤4mm, the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes but is not limited to 3.6φb0, 3.7φb0, 3.8φb0, 3.9φb0, 4φb0, 4.1φb0, 4.2φb0, 4.3φb0, 4.4φb0, 4.5φb0, 4.6φb0, 4.7φb0, 4.8φb0, 4.9φb0, and 5φb0.

[0341] When 4mm<φb0<8mm, the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes but is not limited to 3φb0, 3.1φb0, 3.1φb0, 3.2φb0, 3.2φb0, 3.3φb0, 3.3φb0, 3.4φb0, 3.4φb0, 3.4φb0, 3.5φb0, 3.5φb0, 3.5φb0, 3.6φb0, and 3.6φb0.

[0342] When φb0≥8mm, the length Lb of the bonding interface 17 formed by the contact between the first metal pillar 1 and the second metal layer 2 includes but is not limited to 1φb0, 1.2φb0, 1.5φb0, 1.8φb0, 2φb0, 2.3φb0, 2.3φb0, 2.4φb0, 2.4φb0, 2.5φb0, 2.5φb0, 2.6φb0, 2.6φb0, 2.7φb0, 2.7φb0, 2.8φb0, 2.8φb0, 2.9φb0, and 3φb0.

[0343] It can be understood that the larger the size of the conductive structure 10, 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 conductive structure 10, the larger the ratio of the length Lb of the bonding interface 17 to the outer diameter φb0 of the cylinder 27.

[0344] See also Fig.34 In one embodiment, the second metal layer 2 further includes a transition portion 281. The transition portion 281 is connected to the end surface of the cylinder 27 close to the second section 15. 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 conductive structure 10 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 conductive structure 10.

[0345] Specifically, there are two flanges 28 and two transition portions 281. The two transition portions 281 and the two flanges 28 are alternately arranged along the circumference of the conductive structure 10. Both ends of the flange 28 along the circumference of the conductive structure 10 are connected to the two transition portions 281 respectively.

[0346] See also Fig.33 and Fig.34 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 conductive structure 10 is small, which is not conducive to forming the flanges 28.

[0347] In this embodiment, through the above-mentioned setting, the directional conductive structure 10 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 match the overall shape of the conductive structure 10 to reduce the difficulty of forming the conductive structure 10.

[0348] See also Fig.33 In one embodiment, the end surface of the transition portion 281 away from the axis of the conductive structure 10 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 conductive structure 10 is regular, which is convenient for assembly with other components.

[0349] See also Fig.30 or Fig.31 In one embodiment, the contact portion between the first metal pillar 1 and the second metal layer 2 forms a bonding interface 17. The conductive structure 10 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.

[0350] 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 .

[0351] 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.

[0352] 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.

[0353] 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.

[0354] See also Fig.30 or Fig.31 In one embodiment, the thickness dimension Dc satisfies: 1 μm≤Dc≤8 μm.

[0355] 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.

[0356] 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 of forming and conductive structure 10.

[0357] See also Fig.29 and Fig.30 In one embodiment, the metal mixed layer 192 includes a first mixed portion 1921 and a second mixed portion 1922. The first mixed portion 1921 is formed by mixing the material of the bottom wall of the cylinder 27 and the material of the end surface of the first section 14 away from the second section 15. The second mixed portion 1922 is formed by mixing the material of the inner circumference of the cylinder 27 near the flange 28 and the material of the outer circumference of the first section 14 near the second section 15. The thickness of the first mixed portion 1921 is greater than the thickness of the second mixed portion 1922. In this way, the bonding force of the first metal column 1 and the second metal layer 2 in the axial direction of the conductive structure 10 can be improved to improve the reliability of the bonding between the first metal column 1 and the second metal layer 2.

[0358] The metal mixed layer 192 is a metallurgical layer, or the metal mixed layer 192 is an alloy layer in which a first metal material and a second metal material are embedded with each other.

[0359] See also Fig.35 , Fig.35 2 is a schematic diagram of the structure of another second metal layer 2 provided in an embodiment of the present application. In one embodiment, the flange 28 extends in a ring shape along the circumference of the first section 14. In this way, the structural symmetry of the conductive structure 10 can be improved to improve the stress state of the conductive structure 10, thereby improving the structural reliability of the conductive structure 10.

[0360] See also Fig.30 or Figure 3 In one embodiment, the diameter φb1 of the 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 flange 28 close to the axis is matched with the first metal column 1 along the axis of the conductive structure 10 to prevent the first section 14 from falling out of the cylinder 27.

[0361] See also Fig.36 or Fig.37 In one embodiment, the second section 15 is provided with an engaging groove 16 on the end surface facing the first section 14. The flange 28 is engaged with the engaging groove 16. There is a gap a29 between the flange 28 and the engaging groove 16. Specifically, the gap a29 is located between the end of the flange 28 away from the axis of the conductive structure 10 and the groove wall of the engaging groove 16. This gap a29 can compensate for the influence of the first metal column 1 and the second metal layer 2 being squeezed against each other due to thermal expansion during the welding and heating process of the conductive structure 10, so as to improve the stress state of the first metal column 1 and the second metal layer 2.

[0362] Specifically, along the axial direction of the conductive structure 10 and along the direction close to the axis of the conductive structure 10, the radial dimension of the gap a29 gradually decreases. In this way, stress concentration at the junction between the first metal column 1 and the second metal layer 2 can be avoided, thereby improving the stress state of the conductive structure 10.

[0363] In addition, the side of the groove wall of the embedding groove 16 away from the axis of the conductive structure 10 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 conductive structure 10 smoothly transitions to the surface of the flange 28 away from the first section 14.

[0364] Exemplarily, the width of gap a is less than or equal to 0.5 mm. The width of gap a is the distance between two surfaces on both sides of the gap. Specifically, the width of gap a is the distance between two surfaces forming the gap in the radial direction of the conductive structure 10.

[0365] See also Fig.36 or Fig.37 In one embodiment, the second section 15 has a thickness dimension Da in the axial direction of the conductive structure 10; wherein the dimension of the gap a29 in the radial direction of the conductive structure 10 is La, satisfying: 0<La≤10%Da; and / or, the dimension of the gap a29 in the axial direction of the conductive structure 10 is Ha3, satisfying: 0<Ha3≤40%Da.

[0366] Specifically, the size of the gap a29 in the radial direction of the conductive structure 10 is La, satisfying: 0<La≤10%Da, or, the size of the gap a29 in the axial direction of the conductive structure 10 is Ha3, satisfying: 0<Ha3≤40%Da, or, the size of the gap a29 in the radial direction of the conductive structure 10 is La, satisfying: 0<La≤10%Da, and the size of the gap a29 in the axial direction of the conductive structure 10 is Ha3, satisfying: 0<Ha3≤40%Da.

[0367] It can be understood that the dimension La of the gap a29 in the radial direction of the conductive structure 10 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.

[0368] It can be understood that the size Ha3 of the gap a29 in the axial direction of the conductive structure 10 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.

[0369] In this embodiment, by limiting the radial dimension La of the gap a29 of the conductive structure 10 , 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 conductive structure 10 .

[0370] In this embodiment, by limiting the axial dimension Ha3 of the gap a29 of the conductive structure 10 , 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 conductive structure 10 .

[0371] See also Fig.38 , Fig.38 13 is a schematic structural diagram of a thirteenth conductive structure 10 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 .

[0372] It can be understood that the current collector 120 is provided with a convex bump 121 protruding toward the conductive structure 10, 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 conductive structure 10 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 conductive structure 10 can be improved by the matching groove 271 and the convex bump 121 structure, so as to improve the assembly efficiency.

[0373] The current collecting member 120 connects the electrode tab to the conductive structure 10 .

[0374] See also Fig.38 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 .

[0375] 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.

[0376] See also Fig.38 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.

[0377] See also Fig.29 or Fig.38 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.

[0378] 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.

[0379] See also Fig.29 or Fig.38 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.

[0380] 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 .

[0381] See also Fig.47In one embodiment, in the longitudinal section of the first metal column 1, the side lines of part of the second section 15 are oblique lines arranged at an acute angle to the axis of the first metal column 1. In this way, the structural lines of the second section 15 can be increased, so that the second section 15 and the component connected thereto have more positioning structures, thereby facilitating the improvement of the reliability of the cooperation between the second section 15 and the component.

[0382] Exemplarily, in the longitudinal section of the first metal column 1, the sideline corresponding to the circumferential surface of the second section 15 is an oblique line. Specifically, the sideline corresponding to the circumferential surface of the second section 15 forms an acute angle γ1 with the axis of the first metal column 1 at the side of the second end 12 close to the second metal layer 2.

[0383] Exemplarily, the second section 15 has a second surface 1014 facing away from the second metal layer 2, and in the longitudinal section of the first metal column 1, the sideline corresponding to the portion of the second surface 1014 close to the edge is a slant line. Specifically, the sideline corresponding to the portion of the second surface 1014 close to the edge forms an acute angle γ2 with the axis of the first metal column 1 on the side of the second surface 1014 close to the first end 11.

[0384] See also Fig.48 In one embodiment, the end surface 20b of the second section 15 facing away from the first section 14 is provided with an inner shrinkage hole 1012. The inner shrinkage hole 1012 extends along the axis of the first metal column 1. The inner shrinkage hole 1012 is arranged near the axis of the first metal column 1. The diameter of the inner shrinkage hole decreases as it approaches the first section 14. In this way, the second section 15 can have more positioning structures with the component connected thereto, thereby facilitating the improvement of the reliability of the cooperation between the second section 15 and the component, and the surface area of ​​the second section 15 can be increased to facilitate heat conduction or heat dissipation.

[0385] See also Fig.49 In one embodiment, the conductive structure 10 further includes a second metal strip 1011. The second metal strip 1011 is disposed on the circumference of the second segment 15 and is disposed away from the first segment 14. The second metal strip 1011 extends in a ring shape along the circumference of the second segment 15. In this way, the conductivity of the second segment 15 can be improved, so as to facilitate the current flow capacity between the second segment 15 and the components connected thereto.

[0386] It can be understood that the material of the second metal strip 1011 is consistent with the material of the second metal layer 2 , and both can be copper materials.

[0387] In one embodiment, the conductive structure 10 is a pole 101 of a battery cell, and at least the end 20 of the flange 28 is configured to be located on the side of the cover plate 110 of the battery cell away from the electrode assembly 1200 of the battery cell. In this way, the flange 28 can be supported and limited by the cover plate 110, thereby effectively preventing the second metal layer 2 from being separated from the aluminum layer under the pulling of the internal components of the battery cell.

[0388] The second metal layer 2 is configured to be located inside the battery cell.

[0389] See also Fig.46 , Fig.46 1 is a schematic diagram of the structure of the fifteenth conductive structure 10 provided in an embodiment of the present application. In one embodiment, the second end of the first metal column 1 is provided with an extension portion 151 extending toward the first end. The extension portion 151 at least covers a portion of the end of the second metal layer 2. In this way, the area of ​​the mating surface between the first metal column 1 and the second metal layer 2 can be increased, thereby increasing the reliability of the combination between the first metal column 1 and the second metal layer 2.

[0390] For example, after the blanks for forming the first metal column 1 and the blanks for forming the second metal layer 2 are pressed together and shaped, a finished product is obtained, and the radially larger portion of the finished product is cut, and the cutting direction is from the second section to the first section. As the cutting is carried out, the extrusion force between the cutting blade and the first metal column 1 drives part of the first metal material to slide or flow toward the end of the second metal layer 2, thereby forming an extension 151 that covers part of the end of the second metal layer 2.

[0391] In one embodiment, at least two sides of the second metal layer 2 are covered by the extension portion 151. In this way, the symmetry of the extension portion 151 covering the second metal layer 2 can be improved, so as to improve the reliability of the combination between the first metal column 1 and the second metal layer 2.

[0392] In one embodiment, the thickness of the two extensions 151 is different. It can be understood that the battery pack includes a plurality of battery cells arranged in parallel. A pole is provided on each battery cell. When the conductive structure 10 is used as a pole, the heat it receives will vary depending on the position of the battery cell. Correspondingly, the temperature around the pole will also vary depending on the orientation. Based on this, the extension 151 of the portion of the pole that is heated more can be thickened according to the layout position of the battery cell, so that the portion of the pole that is heated more has better heat dissipation performance.

[0393] In one embodiment, the first metal column 1 includes a first section 14, a second section 15 and an extension portion 151 connected in sequence. The outer diameter of the first section 14 is smaller than the outer diameter of the second section 15. The second section 15 has a first surface 1013 close to the first section 14. The end of the first section 14 away from the second section 15 is the first end, and the end of the second section 15 away from the first section 14 is the second end. The second metal layer 2 covers the first section 14, and the end of the second metal layer 2 extends along the first surface 1013 toward the circumference of the second section 15. Among them, one end of the portion 151 is connected to the circumference of the second section 15, and the other end extends toward the first end. In this way, the conductive structure 10 can be a T-shaped structure, which is beneficial for the conductive structure 10 to have a structure that stops and cooperates with the cover plate 110 of the battery cell when it is used as a pole 101, so that the conductive structure 10 can be clamped on the cover plate 110 through the second section 15 in combination with the terminal block 102 or through the second section 15 in combination with the bottom plate 1019. In this way, the reliability of the cooperation between the conductive structure 10 and the cover plate 110 can be improved.

[0394] See also Fig.46 In one embodiment, the diameter of the second section is φd, and along the radial direction of the first metal column, the extension portion 151 has a thickness dimension Dd, satisfying: 0<Dd≤0.3φd.

[0395] It can be understood that the thickness dimension Dd includes but is not limited to 0.02φd, 0.05φd, 0.08φd, 0.1φd, 0.12φd, 0.14φd, 0.16φd, 0.18φd, 0.2φd, 0.22φd, 0.24φd, 0.26φd, 0.28φd, 0.29φd, and 0.3φd.

[0396] In this embodiment, the above limitation can avoid the thickness dimension Dd of the extension portion 151 being too large, which would result in a smaller radial bonding dimension between the first metal column 1 and the second metal layer 2, thereby ensuring the reliability of the bonding between the first metal column 1 and the second metal layer 2.

[0397] In a second aspect, the present application also provides a method for preparing a conductive structure 10. Specifically, the method for preparing the conductive structure 10 includes:

[0398] S10, providing a blank, wherein the blank comprises a first layer and a second layer, wherein the first layer comprises a first metal, and the second layer comprises a second metal;

[0399] S20, placing the blank in the cavity of the first cold heading die, and maintaining the first layer and the second layer stacked in sequence from the outside to the inside of the cavity;

[0400] S30, performing a first cold heading treatment on the blank, with the help of a strong beam of the first cold heading die, so that when the first layer squeezes the second layer, the first layer is deformed and invades the second layer, and the second layer is thinned and extends to the peripheral side of the first layer, thereby obtaining a semi-finished product;

[0401] S40 , performing a first shaping process on the semi-finished product to obtain a conductive structure 10 .

[0402] The blank includes a first layer and a second layer. The first layer includes a first metal, that is, the first layer is a metal layer, and the material of the first layer is the first metal; the second layer includes a second metal, that is, the second layer is also a metal layer, and the material of the second layer is the second metal. The first metal and the second metal are different. As an example, the first metal is aluminum and the second metal is copper. Optionally, the first layer and the second layer in the blank are stacked and combined together. Of course, in some cases, the first layer and the second layer in the blank can also be separable, because the subsequent first cold heading treatment can also make the first layer and the second layer combined together, so the first layer and the second layer in the blank are not necessarily required to be combined together.

[0403] The first cold heading die has a cavity, and the blank is placed in the cavity of the first cold heading die. Specifically, along the direction from the outside to the inside of the cavity, the first layer and the second layer are kept stacked in sequence, that is, the second layer is closer to the bottom wall of the cavity than the first layer, and the first layer is closer to the opening of the cavity than the second layer. When the blank is placed in the cavity, the blank can be completely contained in the cavity, or one end of the blank can extend into the cavity. The portion of the blank extending into the cavity can be exactly adapted to the size of the cavity, or it can be smaller than the cavity. The cavity can be of different shapes. Usually the shape of the cavity will affect the shape of the semi-finished product. As an example, when the cavity includes a first cavity segment and a second cavity segment connected, wherein the inner diameter of the first cavity segment is smaller than the inner diameter of the second cavity segment, the first cavity segment is cylindrical, and the second cavity segment is bowl-shaped.

[0404] The first cold heading process refers to the upsetting process of the blank. For example, the blank is punched using a cold heading device. Since the second layer of the blank is kept facing the inside of the cavity and the first layer of the blank is facing the outside of the cavity when the blank is placed in the cavity of the first cold heading die, the punch of the cold heading device acts directly on the first layer, that is, the blank is squeezed from the surface of the first layer facing away from the second layer. Since the first layer and the second layer are both metal layers, the metal has ductility, and when the blank is upset, the first layer and the second layer will deform and extend. For example, when the blank is upset along the axial direction of the blank, the first layer and the second layer extend along the radial direction of the blank.

[0405] Since the blank is placed in the cavity of the first cold heading die, the first cold heading die, specifically the side wall of the cavity, will exert a strong restraining effect on the blank, referred to as strong restraint, to regulate the direction in which the first layer and the second layer will deform and extend. Therefore, the first cold heading process can also be called strong restraint processing or cold heading forming. Usually, the thickness of the side wall of the cavity in the first cold heading die, the material of the first cold heading die, etc. will affect the strong restraint effect of the first cold heading die. As an example, the first cold heading die is a stainless steel die.

[0406] It can be understood that when the blank is upset, since the first layer and the second layer are stacked, the first layer will squeeze the second layer. However, due to the strong force of the first cold upsetting mold, the first layer is deformed due to pressure and invades the second layer. The second layer is deformed and thinned due to pressure and extends to the surrounding side of the first layer, that is, extends along the tiny gap between the first layer and the side wall of the cavity, to obtain a semi-finished product.

[0407] In order to improve the dimensional accuracy, shape or surface roughness of the semi-finished product and remove excess material, the semi-finished product is further subjected to a first shaping process to obtain a conductive structure 10 that meets the requirements. The first shaping process includes but is not limited to at least one of punching, polishing and grinding.

[0408] Optionally, the method for preparing the conductive structure 10 is used to prepare the conductive structure 10 provided in the first aspect, wherein the first layer can be deformed by upsetting to obtain the first metal column 1, and the second layer can be deformed by upsetting to obtain the second metal layer 2.

[0409] The preparation method of the conductive structure 10 provided in the embodiment of the present application combines the first layer and the second layer together by cold heading, and during the cold heading process, the deformation, extension and intrusion of the first layer and the second layer can make the bonding interface between the two become a microscopically uneven surface, so that the bonding surface area is increased and the bonding strength is enhanced. In addition, during the cold heading process, the second layer will extend to the peripheral side of the first layer, that is, the second layer is not only combined with the bottom surface of the first layer, but also combined with the side surface of the first layer, further increasing the bonding area between the two and enhancing the bonding strength.

[0410] In some embodiments, in the blank, the first layer and the second layer are stacked together. It can be understood that in the blank, the first layer is located on one side of the second layer, and the first layer and the second layer are combined together. By stacking the first layer and the second layer together first, it is convenient to load the first layer and the second layer together and put them into the mold cavity, thereby simplifying the manufacturing process of the conductive structure 10.

[0411] In some embodiments, in the blank, the ratio of the average thickness of the second layer to the average thickness of the blank is 0.1 to 0.2. That is, the average thickness of the first layer is much greater than the average thickness of the second layer. Usually, the second layer should not be too large, otherwise the second layer is not easy to extend, especially when the hardness of the second metal is greater than the hardness of the first metal, the manufacturing difficulty of the first cold heading process will be increased, and the second layer should not be too thin, otherwise the second layer is easy to tear during the cold heading process. As an example, the ratio of the average thickness of the second layer to the average thickness of the blank is 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 or 0.2.

[0412] In some embodiments, in the blank, the edge of the second layer protrudes from the edge of the first layer. The edge of the second layer appropriately protrudes from the edge of the first layer, so that when the blank is placed in the cavity of the first cold heading mold, a certain gap can be maintained between the side of the first layer and the inner wall of the cavity, and during the first cold heading process, the existence of the gap can promote extension to the peripheral side of the first layer, reducing the manufacturing difficulty.

[0413] In some embodiments, providing a blank includes preparing the blank, and the blank preparation process includes:

[0414] S11, providing a composite plate, wherein the composite plate includes a first layer and a second layer that are laminated and bonded together;

[0415] S12, punching the composite board to obtain a blank.

[0416] Optionally, the blank is in a columnar shape. As an example, when the first metal is aluminum and the second metal is copper, the composite plate is a copper-aluminum composite plate, which includes a copper layer and an aluminum layer stacked in layers. A copper-aluminum composite column, i.e., a blank, can be obtained by punching the copper-aluminum composite plate using a punching device.

[0417] The blank is obtained by adopting the composite plate method, the process is simple and the manufacturing is convenient.

[0418] In some embodiments, the method for preparing the conductive structure 10 further includes:

[0419] S13, before placing the blank into the mold cavity, performing a second shaping process on the blank.

[0420] It can be understood that shaping refers to adjusting the geometric shape, size, etc. of the blank.

[0421] In some embodiments, the method for preparing the conductive structure 10 further includes:

[0422] S14. Before placing the blank into the cavity, screen the blank so that when the blank is loaded into the cavity, the second layer faces the bottom wall of the cavity.

[0423] The conductive structure 10 is mass-produced during the preparation process. During the production process, the blank may lie down or turn in the opposite direction, which will affect the loading, especially the automatic loading. Therefore, the blank is screened before loading, and the blank that meets the requirements is screened for loading. Here, the reverse direction means that the orientation of the first layer and the second layer in the blank is opposite to the requirement. For example, when loading, the first layer of the blank is required to face upward and the second layer is required to face downward. If the first layer of the blank faces downward and the second layer faces upward, it is considered reverse.

[0424] As an example, a columnar blank can be placed in a screening plate, and the screening plate can be used to screen the blank so that the orientation of the first layer of the screened blank is consistent and meets the requirements.

[0425] In some embodiments, the method for preparing the conductive structure 10 further includes:

[0426] S31, after the blank is subjected to the first cold heading treatment, the blank subjected to the first cold heading treatment is placed in a second cold heading die, that is, the semi-finished product is placed in the second cold heading die, and the surface of the first layer facing away from the second layer is extruded.

[0427] Here, the semi-finished product is subjected to a second cold heading process, and the size and shape of the semi-finished product can be further adjusted by using a second cold heading die. If the second cold heading die used is different, the shape of the conductive structure 10 obtained in the end will also be different.

[0428] The preparation method of the conductive structure 10 provided in the embodiment of the present application can also effectively improve the production efficiency of the conductive structure 10, reduce material waste, and better control production costs. Moreover, the conductive structure 10 produced by this method is dimensionally stable and easy to meet the use requirements of the product.

[0429] In a third aspect, an embodiment of the present application further provides a cover plate assembly, which is used to cooperate with the shell of the battery cell to form a closed cavity, and the cavity is used to accommodate the electrode assembly of the battery cell.

[0430] Specifically, see Figure 8 , Fig. 9 and Fig.18 The cover plate assembly 100 includes a cover plate 110 and the aforementioned conductive structure 10 (which may be the conductive structure 10 provided by the first aspect, or the conductive structure 10 prepared by the method provided by the second aspect), and the conductive structure 10 is connected to the cover plate 110. Specifically, the conductive structure 10 is provided on the cover plate 110. The first metal column 1 may be provided on the cover plate 110, the second metal layer 2 may be provided on the cover plate 110, or the first metal column 1 and the second metal layer 2 may be provided on the cover plate 110 together.

[0431] Also, see Fig.40 or Fig.41 or Fig.42 or Fig.43 or Fig.44 , Fig.40 is a structural schematic diagram of a first cover plate assembly 100 provided in an embodiment of the present application, Fig.41 is a structural schematic diagram of a second cover plate assembly 100 provided in an embodiment of the present application, Fig.42 is a schematic structural diagram of a third cover plate assembly 100 provided in an embodiment of the present application. Fig.43 is a structural schematic diagram of a fourth cover plate assembly 100 provided in an embodiment of the present application, Fig.44 1 is a schematic diagram of the structure of the fifth cover plate assembly 100 provided in an embodiment of the present application. It can be understood that the conductive structure 10 may include a bottom plate 1019, such as Figure 40 to Figure 43 The conductive structure 10 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.44 shown.

[0432] In detail, along the thickness direction of the cover plate 110, the cover plate 110 has a first surface A and a second surface A opposite to each other. Fig.50 When the cover plate assembly 100 is mounted on the housing 1100 of the battery cell 1000, the first surface A is a side surface away from the housing 1100, and the second surface A is a side surface close to the housing 1100. Along the thickness direction of the cover plate 110, a mounting hole 114 is provided through the cover plate 110, and the conductive structure 10 is provided on the cover plate 110 through the mounting hole 114.

[0433] In some embodiments, the conductive structure 10 is a pole 101 or the conductive structure 10 is an integrated pole 101 and a terminal block 102; the cover assembly 100 further includes a current collector 120. The current collector 120 is a conductive component in the battery cell 1000 for connecting to the pole lug 1210 of the electrode assembly 1200. The current collector 120 is located on one side of the cover 110, specifically the side of the cover 110 away from the terminal block 102, that is, the current collector 120 is located on the second surface A of the cover 110. The current collector 120 is welded to the conductive structure 10. Specifically, the current collector 120 is welded to the second metal layer 2 in the conductive structure 10. Optionally, the material of the current collector 120 is the same as that of the second metal layer 2, that is, the material of the current collector 120 is the second metal, which can reduce the difficulty of welding the current collector 120 to the second metal layer 2 and improve the reliability of welding.

[0434] In some embodiments, the current collecting member 120 includes at least one of a current collecting plate and a connecting piece 1202 .

[0435] In some embodiments, see Fig. 9 The current collector 120 includes a current collector body 1201 and a connecting piece 1202 , the current collector body 1201 is connected to the connecting piece 1202 , wherein the current collector body 1201 is used to connect to the electrode tab 1210 of the electrode assembly 1200 , and the connecting piece 1202 is welded to the second metal layer 2 .

[0436] In some embodiments, the cover plate 110 includes a cover plate 110, a first insulating member 112 and a second insulating member 113, wherein the first insulating member 112 and the second insulating member 113 are respectively arranged on opposite sides of the cover plate 110. The first insulating member 112 is disposed between the conductive structure 10 and the cover plate 110, and the second insulating member 113 is disposed between the cover plate 110 and the current collecting member 120. Optionally, in the case where the first metal column 1 in the conductive structure 10 has a boss 13, the first insulating member 112 is disposed between the boss 13 and the cover plate 110. The cover plate 110 is provided with a mounting hole 114, which passes through the cover plate 110, the first insulating member 112 and the second insulating member 113. As an example, the cover plate 110 is a bare aluminum sheet, and the first insulating member 112 and the second insulating member 113 are both plastic parts.

[0437] 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.

[0438] In some embodiments, the cover plate assembly 100 further includes a sealing member 130, which is disposed on one side of the cover plate 110 close to the first insulating member 112, for example. Fig.42 and Fig.43 As shown, the sealing member 130 is located between the cover plate 110 and the conductive structure 10 to seal the gap between the conductive structure 10 and the mounting hole to prevent the electrolyte from leaking therefrom. As an example, the sealing member 130 is located between the cover plate 110 and the second insulating member 113 .

[0439] In another embodiment, the seal 130 may also be disposed on a side of the cover plate 110 close to the second insulating member 113. For example, the seal 130 may be located between the bottom plate 1019 and the cover plate 110. The bottom plate 1019 is connected to an end of the cylinder 27 away from the second section 15. Fig.40 and Fig.41 shown.

[0440] The specific location of the seal 130 is selected according to the application scenario.

[0441] See also Fig.45 , Fig.451 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 away from the cover plate 110. Both 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.

[0442] 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.

[0443] Exemplarily, the terminal has a rectangular cross section, and four corners are provided with bevel chamfers.

[0444] In an embodiment of the present application, the seal 130 may be disposed between the cover plate 110 and the flange 28. Fig.43 As shown, the seal 130 may also be disposed between the bottom plate 1019 and the cover plate 110, as shown in FIG. Fig.40 and Fig.41 As 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.38 and Fig.39 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.38 and Fig.41 The bottom of the cylinder 27 may also be a plane, such as Fig.29 , Fig.40 and Fig.43 The conductive structure may include a bottom plate, such as Fig.40 Character Fig.43 As shown, the bottom plate 1019 may not be provided at the bottom of the conductive structure 10. Fig.44 The above-mentioned configuration modes and their combinations are set according to actual application scenarios, and this embodiment does not limit this.

[0445] See also Fig.36 or Fig.37In one embodiment, the first metal column 1 includes a first section 14 and a second section 15 connected to each other, and the outer diameter of the first section 14 is smaller than the outer diameter of the second section 15. The end of the first section 14 away from the second section 15 is the first end, and the end of the second section away from the first section is the second end. The second metal layer 2 includes a cylinder 27 and a flange 28. The cylinder 27 covers the first section 14, and the flange 28 is connected to the end of the cylinder 27 close to the second section 15. The flange 28 extends along the radial direction of the conductive structure 10 and is embedded in the end surface of the second section 15 facing the first section 14. The second section 15 and the flange 28 are located on the side of the first insulating member 112 away from the cover plate 110. And when the second section 15 and the flange 28 are configured to be located outside the battery cell, the second section 15 has a first surface 1013 close to the first section 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 away from the second section 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 to the first insulating member 112.

[0446] It can be understood that one of the first region 1015 and the second region 1016 is protruded outward along the axial direction of the conductive structure 10 to form a height difference.

[0447] Exemplarily, along the axial direction of the first metal pillar 1 , the first region 1015 is protruded outward from the first surface 1013 . Alternatively, along the axial direction of the first metal pillar 1 , the second region 1016 is protruded outward from the plane where the first surface 1013 is located.

[0448] It can be understood that the cross section of the second section 15 can be cylindrical, polygonal or irregular.

[0449] 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 conductive structure 10 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.

[0450] 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 conductive structure 10 on the first insulating member 112 can be partially increased, thereby improving the sealing between the conductive structure 10 and the first insulating member 112 while controlling the material usage of the conductive structure 10, so as to improve the reliability of the battery cell 1000.

[0451] In addition, when the first zone 1015 protrudes outward along the axial direction of the conductive structure 10, the sealing of the outer periphery of the crimping surface between the conductive structure 10 and the first insulating member 112 can be improved, thereby effectively preventing external debris and impurities from entering between the conductive structure 10 and the first insulating member 112, thereby facilitating the stability of the sealing structure between the conductive structure 10 and the first insulating member 112.

[0452] At the same time, when the second zone 1016 protrudes outward along the axial direction of the conductive structure 10, 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 lifted toward the end face of the second section 15, so as to improve the sealing between the conductive structure 10 and the first insulating member 112 at the periphery.

[0453] See also Fig.36 In one embodiment, along the axial direction of the first metal column 1, the first region 1015 protrudes outward along the axial direction of the conductive structure 10, and the thickness dimension of the first region 1015 protruding relative to the second region 1016 is Ha1, and the second segment 15 has a thickness dimension Da in the axial direction of the conductive structure 10, satisfying 0<Ha1≤15%Da.

[0454] 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.

[0455] Exemplarily, the thickness dimension Da of the conductive structure 10 is 2 mm, Ha1=10%Da=0.2 mm.

[0456] 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 conductive structure 10; on the other hand, it can avoid the thickness dimension Ha1 protruding from the first zone 1015 being too large, which would cause greater difficulty in matching between the conductive structure 10 and the first insulating member 112 and a more complex dimensional chain.

[0457] When the exhaust groove 1121 is provided on the surface of the first insulating member 112 away from the cover plate 110, the first area 1015 is convex outwardly along the axial direction of the first metal column 1. In this way, the flow of gas between the first insulating member 112 and the second area 1016 can be improved, thereby improving the exhaust effect.

[0458] 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 protrusion of the first region 1015 can improve the sealing between the conductive structure 10 and the first insulating member 112 more significantly.

[0459] See also Fig.37 In one embodiment, along the axial direction of the first metal pillar 1, the second region 1016 is protruded outward along the axial direction of the conductive structure 10. The thickness dimension of the second region 1016 protruding relative to the first region 1015 is Ha2. The second segment 15 has a thickness dimension Da in the axial direction of the conductive structure 10, satisfying 0<Ha2≤15%Da.

[0460] 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.

[0461] Exemplarily, the dimension Da of the second segment 15 in the circumferential direction of the conductive structure 10 is 2 mm, and Ha2=10%Da=0.2 mm.

[0462] 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 conductive structure 10; 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 conductive structure 10 and the first insulating member 112 and a more complex dimensional chain.

[0463] 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 protrusion of the second area 1016 can improve the sealing between the conductive structure 10 and the first insulating member 112 more significantly.

[0464] In one embodiment, the first zone 1015 protrudes outward along the axial direction of the conductive structure 10 to form a first protruding portion 1017, and the first protruding portion 1017 extends in a ring shape along the circumferential direction of the conductive structure 10; or, the second zone 1016 protrudes outward along the axial direction of the conductive structure 10 to form a second protruding portion 1018, and the second protruding portion 1018 extends in a ring shape along the circumferential direction of the conductive structure 10.

[0465] In this embodiment, by extending the first protruding portion 1017 into a ring shape along the circumference of the conductive structure 10 , the force uniformity of the conductive structure 10 and the first insulating member 112 can be improved, thereby improving the force state of the battery cell 1000 and avoiding stress concentration.

[0466] In addition, by extending the second protruding portion 1018 into a ring shape along the circumference of the conductive structure 10 , the force uniformity of the conductive structure 10 and the first insulating member 112 can be improved, thereby improving the force state of the battery cell 1000 and avoiding stress concentration.

[0467] In some embodiments, the assembly process of the cover assembly 100 includes: stacking the second insulating member 113, the sealing member 130, the cover plate 110 and the first insulating member 112 together from bottom to top in sequence with the holes aligned, passing the conductive structure 10 through the mounting hole 114 from top to bottom, abutting the larger end of the conductive structure 10 (e.g., the boss 13) against the first insulating member 112, installing the current collecting member 120 on the side of the second insulating member 113 away from the sealing member 130, and welding the current collecting member 120 to the conductive structure 10, such as the second metal layer 2 in the conductive structure 10, by laser welding.

[0468] In some embodiments, the cover plate assembly 100 further includes an explosion-proof valve 140 , which is disposed on the cover plate 110 .

[0469] In some embodiments, the cover plate 110 is further provided with a liquid injection hole 115 and a sealing structure (not shown) for sealing the liquid injection hole.

[0470] See also Fig.39 , Fig.39 1 is a schematic diagram of the structure of the fourteenth conductive structure 10 provided in an embodiment of the present application. In one embodiment, the conductive structure 10 further includes a bottom plate 1019. The second metal layer 2 includes a cylinder 27. The cylinder 27 covers the first end and extends toward the second end. The bottom plate 1019 is connected to an end of the cylinder 27 away from the second end.

[0471] Specifically, the bottom plate 1019 and the cylinder 27 are welded, or the conductive structure 10 and the bottom plate 1019 are riveted.

[0472] 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 conductive structure 10 and the cover plate 110 .

[0473] See also Fig.39 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 end. The aperture of the pre-punched hole 273 gradually increases in the direction away from the second end. In this way, when the conductive structure 10 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 conductive structure 10 and the bottom plate 1019, so as to facilitate the riveting of the conductive structure 10 to the bottom plate 1019.

[0474] It can be understood that when a matching groove 271 is provided at the end of the cylinder 27 away from the second end, the pre-punched hole 273 is provided at the opening of the matching groove 271 .

[0475] In one embodiment, a step groove b272 is provided at one end of the cylinder 27 away from the second end. 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.

[0476] 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.

[0477] It can be understood that when welding the conductive structure 10 to the bottom plate 1019, the pre-punching holes 273 can be firstly formed by tooling extrusion, so that the second metal layer 2 can be radially expanded outward, thereby reducing the matching gap a29 between the conductive structure 10 and the bottom plate 1019, so as to rivet the conductive structure 10 to the bottom plate 1019. Then, the conductive structure 10 is welded to the bottom plate 1019. In this way, the riveting action before welding is conducive to improving the welding superiority of the conductive structure 10 and the bottom plate 1019, and improving the welding quality between the conductive structure 10 and the bottom plate 1019.

[0478] See also Fig.29 or Fig.33 or Fig.38 In one embodiment, 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 end of the first section 14 away from the second section 15 is the first end. The end of the second section 15 away from the first section is the second end. The second metal layer 2 includes a cylinder 27, and the cylinder 27 covers the first section 14. Among them, the second section 15 is configured to be located outside the battery cell 1000. The end of the cylinder 27 away from the second section 15 is configured to be connected to the current collector 120, so that the conductive structure 10 is clamped on the cover plate 110 of the battery cell 1000 through the current collector 120 and the second section 15.

[0479] 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 .

[0480] It can be understood that in a cylindrical battery cell, the current collecting member 120 may be a current collecting plate, and in a square shell battery cell, the current collecting member 120 may be a current collecting sheet or a current collecting foot.

[0481] 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.

[0482] For the fourth aspect, please see Fig.50 or Fig.51 The embodiment of the present application further provides a battery cell 1000, which is also called a battery cell. The battery cell 1000 refers to a basic unit for realizing mutual conversion between chemical energy and electrical energy.

[0483] Specifically, see Fig.50 The battery cell 1000 includes a housing 1100, an electrode assembly 1200 and the aforementioned cap assembly 100. Specifically, the housing 1100 has a receiving cavity 1110, the electrode assembly 1200 is disposed in the receiving cavity 1110, and the cap assembly 100 is connected to the housing 1100 and closes the opening of the receiving cavity 1110. The electrode assembly 1200 includes a tab 1210, and the conductive structure 10 is connected to the tab 1210.

[0484] Specifically, the electrode assembly 1200 further includes an electrode sheet and a separator, the tab 1210 is connected to the electrode sheet, the electrode sheet includes a positive electrode sheet and a negative electrode sheet, and the separator is located between the positive electrode sheet and the negative electrode sheet. It can be understood that the tab 1210 also includes a positive electrode tab and a negative electrode tab, wherein the positive electrode tab is connected to the positive electrode sheet, and the negative electrode tab is connected to the negative electrode sheet.

[0485] In addition, the battery cell 1000 further includes an electrolyte, which is located in the receiving cavity 1110 , and the electrode assembly 1200 is immersed in the electrolyte.

[0486] It can be understood that the battery cell 1000 can specifically be a cylindrical battery cell 1000, a square-shell battery cell 1000, a soft-pack battery cell 1000, a blade battery cell 1000, etc.

[0487] 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 conductive structure, characterized in that: include: a first metal post having opposing first and second ends; A second metal layer is bonded to a surface of the first metal column, and the second metal layer covers the first end and extends toward the second end.

2. The conductive structure according to claim 1, characterized in that: The second metal layer is inlaid and matched with the first metal column.

3. The conductive structure according to claim 2, characterized in that: An end of the second metal layer is embedded in the first metal column.

4. The conductive structure according to claim 3, characterized in that: A gap is formed between an end of the second metal layer and the first metal column.

5. The conductive structure according to claim 4, characterized in that: An end face and a transition face connected in sequence are formed at the end of the second metal layer, and the gap is formed only between the end face and the transition face and the first metal column, wherein the side of the end face away from the transition face is connected to the outer surface of the second metal layer, and the transition face is bent and transitioned from the end face to the first metal column; and / or the average spacing of the gap is less than 0.1 mm.

6. The conductive structure according to claim 1, characterized in that: The end of the second metal layer includes a first extension segment and / or a second extension segment, the first extension segment extends along a first direction, the second extension segment extends along a second direction, and the first direction intersects with the second direction.

7. The conductive structure according to claim 1, characterized in that: The conductive structure is a pole, and a support surface is formed on the end of the second metal layer, and the support surface is used to support the terminal pressing block.

8. The conductive structure according to claim 7, characterized in that: The supporting surface is an inclined surface, and along a direction away from the first end, the inclined surface gradually approaches the outer side surface of the first metal column from the outer side surface of the second metal layer.

9. The conductive structure according to claim 8, characterized in that: The inclined surface is an inclined straight surface, and the angle between the inclined straight surface and the outer side surface of the second metal layer is 110° to 130°.

10. The conductive structure according to claim 7, characterized in that: The support surface is a step surface, and the step surface includes a first sub-step surface and a second sub-step surface connected in sequence. The number of the first sub-step surfaces is greater than or equal to 1, and the number of the second sub-step surfaces is greater than or equal to 1.

11. The conductive structure according to claim 10, characterized in that: Along the axial direction of the pole, the height of the second sub-step surface is greater than or equal to 0.2 mm, and / or, along the radial direction of the pole, the width of the first sub-step surface is greater than or equal to 0.2 mm.

12. The conductive structure according to claim 7, characterized in that: Along the radial direction of the pole, the width of the supporting surface is greater than or equal to 0.3 mm and less than or equal to the thickness of the second metal layer.

13. The conductive structure according to claim 1, characterized in that: The first metal column protrudes radially to form a boss, and the second metal layer at least extends to the boss.

14. The conductive structure according to claim 13, characterized in that: The boss is located at the first end, and the boss is completely covered in the second metal layer.

15. The conductive structure according to claim 14, characterized in that: The conductive structure is an integrated pole and a current collecting member, wherein the boss is the current collecting member, and the current collecting member is used to be connected to the pole lug.

16. The conductive structure according to claim 13, characterized in that: The boss is far away from the first end, and a radial dimension of the boss is greater than a radial dimension of the first end.

17. The conductive structure according to claim 16, characterized in that: The boss is located at the second end, and a portion of the boss is exposed outside the second metal layer.

18. The conductive structure according to claim 17, characterized in that: The conductive structure is an integrated pole and a terminal pressing block, wherein the boss is the terminal pressing block.

19. The conductive structure according to claim 16, characterized in that: The second metal layer includes a first section, a second section and a third section, the first section corresponds to the end face of the first end, the second section corresponds to the side face of the first end, the third section corresponds to a side surface of the boss close to the first end, and the second section connects the first section and the third section.

20. The conductive structure according to claim 19, characterized in that The third section is formed as an end portion of the second metal layer, and the third section is embedded in the boss.

21. The conductive structure according to claim 19, characterized in that: The average thickness of the first section is greater than the average thickness of the second section, and the average thickness of the second section is greater than the average thickness of the third section.

22. The conductive structure according to claim 21, characterized in that: The average thickness of the second section is greater than half of the average thickness of the first section, and / or the average thickness of the third section is greater than half of the average thickness of the second section.

23. The conductive structure according to claim 21, characterized in that: The thickness of the second section at a portion close to the third section is greater than the thickness of the second section at a portion close to the first section.

24. The conductive structure according to claim 19, characterized in that: The end surface of the first end is partially concave to form a groove, and the first section includes a first sub-segment, a second sub-segment and a third sub-segment connected in sequence, the first sub-segment is located outside the groove, the second sub-segment is located on the side wall of the groove, and the third sub-segment is located on the bottom wall of the groove.

25. The conductive structure according to claim 24, characterized in that: A vertical distance between an outer surface of the first subsegment and an outer surface of the third subsegment is less than or equal to 2.5 mm.

26. The conductive structure according to claim 24, characterized in that The average thickness of the first subsection is greater than or equal to 0.5 mm, and / or the average thickness of the second section is greater than or equal to 0.5 mm.

27. The conductive structure according to claim 24, characterized in that: The second subsegment extends obliquely from the first subsegment toward the third subsegment, and an inclination angle of the second subsegment is greater than or equal to 15° and less than or equal to 60°.

28. The conductive structure according to claim 19, characterized in that The boss is located between the first end and the second end, and a radial dimension of the boss is larger than a radial dimension of the second end.

29. The conductive structure according to claim 28, characterized in that: The second metal layer further includes a fourth section, the fourth section corresponds to a side surface of the boss, and the fourth section is connected to the third section.

30. The conductive structure according to claim 29, characterized in that Along the axial direction of the first metal column, the distance between the outer surface of the third section and the end of the fourth section away from the first end is a, and along the radial direction of the first metal column, the distance between the outer surface and the inner surface of the fourth section is e, where a>e>0.5mm.

31. The conductive structure according to claim 29, characterized in that The second metal layer further includes a fifth section, the fifth section corresponds to a side surface of the boss away from the first end, and the fourth section connects the fifth section and the third section.

32. The conductive structure according to claim 31, characterized in that Along the axial direction of the first metal column, the distance between the inner surface of the fifth section and the inner surface of the third section is b, and b>0.5 mm.

33. The conductive structure according to claim 31, characterized in that Along the axial direction of the first metal column, the distance between the outer surface of the third segment and the outer surface of the fifth segment is h2; along the radial direction of the first metal column, the distance between the outer surface of the fourth segment and the root of the boss on the side close to the second end is c, and the distance between the outer surface of the fourth segment and the end of the fifth segment close to the central axis of the first metal column is d; wherein, c>h2 and d≥2 / 3c, or, c≤h2 and d>0.5mm.

34. The conductive structure according to claim 31, characterized in that The fourth section and the fifth section are formed as an inverted layer wrapping the free end of the boss. Along the axial direction of the first metal column, the distance between the outer surface of the third section and the outer surface of the inverted layer is K1, and the thickness of the inverted layer is K2, f=K2 / K1, where f is greater than or equal to 0.3 and less than 1.

35. The conductive structure according to claim 19, characterized in that The edge of the end surface of the first end is concave to form a first step portion, and the second metal layer also includes a second step portion, which matches the first step portion, is connected between the first section and the second section, and is used to connect to the pole ear.

36. The conductive structure according to claim 35, characterized in that The second step portion has a first step surface and a second step surface connected, the width of the first step surface in the radial direction of the first metal column is greater than or equal to 0.5 mm, and the height of the second step surface in the axial direction of the first metal column is greater than or equal to 0.4 mm.

37. The conductive structure according to any one of claims 1 to 36, characterized in that: The first metal column is an aluminum column, and the second metal layer is a copper layer.

38. The conductive structure according to claim 37, characterized in that The average thickness of the second metal layer is 0.1 mm-3 mm.

39. The conductive structure according to any one of claims 1 to 36, characterized in that: The bonding interface between the second metal layer and the first metal column has an uneven microstructure.

40. The conductive structure according to any one of claims 1 to 36, characterized in that: The diameter of the conductive structure is less than or equal to 30 mm.

41. The conductive structure according to claim 1, characterized in that The first metal column comprises 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, an end of the first section away from the second section is the first end, and an end of the second section away from the first section is the second end; The second metal layer includes a cylinder and a flange, the cylinder covers the first section, the flange is connected to the end of the cylinder close to the second section, and the flange extends along the radial direction of the conductive structure and is embedded in the end surface of the second section facing the first section; Wherein, in the axial direction of the conductive structure, 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 conductive structure.

42. The conductive structure according to claim 41, characterized in that In a longitudinal section of the conductive structure passing through the flange, along an axial direction close to the conductive structure, a 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; 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.

43. The conductive structure according to claim 42, characterized in that The curvature of the third line segment is greater than the curvature of the first line segment.

44. The conductive structure according to claim 43, 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 .

45. The conductive structure according to claim 42, characterized in that The curvature of the second line segment is less than or equal to 1×10 -4 mm -1 .

46. ​​The conductive structure according to claim 42, characterized in that In the longitudinal section, along the axial direction of the conductive structure, a bonding interface formed between a surface of the second metal layer close to the axis of the conductive structure and an outer peripheral surface of the first metal column comprises a fourth line segment and a fifth line segment, and two ends of the fourth line segment are connected to the third line segment and the fifth line segment respectively; 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.

47. The conductive structure according to claim 46, characterized in that The curvature of the first line segment is smaller than the curvature of the fifth line segment.

48. The conductive structure according to claim 47, 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 .

49. The conductive structure according to claim 46, characterized in that The curvature of the fourth line segment is less than or equal to 1×10 -4 mm -1 .

50. The conductive structure according to any one of claims 46 to 49, characterized in that: In a longitudinal section of the conductive structure, the first metal column has a plurality of forging flow lines, and a contact 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.

51. The conductive structure according to any one of claims 42 to 49, characterized in that: The two endpoints of the second line segment are point U and point V respectively; the straight line UV forms an angle W with the radial direction of the conductive structure on the side away from the flange, satisfying: 0<W≤20°.

52. The conductive structure according to any one of claims 41 to 49, 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.

53. The conductive structure according to any one of claims 41 to 49, characterized in that: There are a plurality of flanges, and the plurality of flanges are sequentially arranged along the circumferential direction of the conductive structure, and at least two flanges are arranged opposite to each other along the radial direction of the conductive structure.

54. The conductive structure according to any one of claims 41 to 49, characterized in that: In the axial cross section of the conductive structure, the length of the bonding interface formed by the first metal column and the second metal layer contacting each other is Lb, and the outer diameter of the cylinder is φb0, which satisfies: 1φb0≤Lb≤5φb0.

55. The conductive structure according to claim 54, characterized in that φb0≤4mm, and 3.6φb0≤Lb≤5φb0; 4mm<φb0<8mm, and 3φb0≤Lb≤3.6φb0; φb0≥8mm, and 1φb0≤Lb≤3φb0.

56. The conductive structure according to any one of claims 41 to 49, characterized in that: The second metal layer further includes a transition portion, and the transition portion is connected to the end surface of the cylinder close to the second section; The transition portion is embedded in the end surface of the second section facing the first section, and a part of the bonding interface between the transition portion and the second section is located on the circumferential surface of the second section.

57. The conductive structure according to claim 56, 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.

58. The conductive structure according to claim 57, characterized in that An end surface of the transition portion away from the axis of the conductive structure is coplanar with a side wall where the long side of the second section is located.

59. The conductive structure according to any one of claims 41 to 49, characterized in that: The contact portion between the first metal column and the second metal layer forms a bonding interface; the conductive structure 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 mixed with each other; The thickness of the metal mixed layer is Dc, and the thickness of the metal mixed layer is uneven.

60. The conductive structure according to claim 59, characterized in that The thickness dimension Dc satisfies: 1 μm≤Dc≤8 μm.

61. The conductive structure according to claim 59, 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.

62. The conductive structure according to claim 59, 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.

63. The conductive structure according to any one of claims 41 to 49, characterized in that: The flange extends in a ring shape along the circumference of the first section.

64. The conductive structure according to any one of claims 41 to 49, 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.

65. The conductive structure according to any one of claims 41 to 49, 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.

66. The conductive structure according to claim 65, characterized in that The gap a is located between an end of the flange away from the axis of the conductive structure and a groove wall of the fitting groove.

67. The conductive structure according to claim 66, characterized in that The second section has a thickness dimension Da in the axial direction of the conductive structure; The dimension of the gap a in the radial direction of the conductive structure is La, which satisfies: 0<La≤10%Da; And / or, the dimension of the gap a in the axial direction of the conductive structure is Ha3, satisfying: 0<Ha3≤40%Da.

68. The conductive structure according to any one of claims 41 to 49, characterized in that: A matching groove is arranged at one end of the cylinder away from the second section.

69. The conductive structure according to claim 68, 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.

70. The conductive structure according to claim 68, 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 so as to be embedded in the bottom wall of the cylinder.

71. The conductive structure according to any one of claims 41 to 49, 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.

72. The conductive structure according to claim 71, 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.

73. The conductive structure according to any one of claims 41 to 49, characterized in that: In the longitudinal section of the first metal column, a portion of the side lines of the second section are oblique lines that are arranged at an acute angle to the axis of the first metal column.

74. The conductive structure according to claim 73, characterized in that In the longitudinal section of the first metal column, the side line corresponding to the circumferential surface of the second section is the oblique line; And / or, the second section has a second surface facing away from the second metal layer, and in the longitudinal section of the first metal column, the sideline corresponding to the portion of the second surface close to the edge is the oblique line.

75. The conductive structure according to any one of claims 41 to 49, characterized in that: An inner shrinkage hole is provided on the end surface of the second section facing away from the first section, and the inner shrinkage hole extends along the axis of the first metal column, and the inner shrinkage hole is arranged adjacent to the axis of the first metal column; Wherein, as approaching the first section, the aperture of the inner shrinkage hole decreases.

76. The conductive structure according to any one of claims 41 to 49, characterized in that: The conductive structure further includes a second metal strip, which is disposed on the circumference of the second segment and away from the first segment, and extends in a ring shape along the circumference of the second segment.

77. The conductive structure according to any one of claims 41 to 49, characterized in that: The conductive structure is a pole of a battery cell, and at least the end of the flange is configured to be located on a side of the cover plate of the battery cell that is away from the electrode assembly of the battery cell.

78. The conductive structure according to claim 1, characterized in that The second end of the first metal column is provided with an extension portion extending toward the first end, and the extension portion at least covers a portion of the end portion of the second metal layer.

79. The conductive structure according to claim 78, characterized in that At least two sides of the second metal layer are covered by the extension parts, and the two extension parts have different thicknesses.

80. The conductive structure according to claim 78, characterized in that The first metal column comprises a first section and a second section connected in sequence, the outer diameter of the first section is smaller than the outer diameter of the second section, the second section has a first surface close to the first section, an end of the first section away from the second section is the first end, and an end of the second section away from the first section is the second end; One end of the extension portion is connected to the circumferential surface of the second section, and the other end extends toward the first end.

81. The conductive structure according to claim 80, characterized in that The diameter of the second section is φd, and along the radial direction of the first metal column, the extension portion has a thickness dimension Dd, which satisfies: 0<Dd≤0.3φd.

82. A method for preparing a conductive structure, characterized in that: include: Providing a blank, the blank comprising a first layer and a second layer, the first layer comprising a first metal, the second layer comprising a second metal; Placing the blank in a cavity of a first cold heading die, and maintaining the first layer and the second layer stacked in sequence along the direction from outside to inside of the cavity; The blank is subjected to a first cold heading treatment, and by means of a strong beam of the first cold heading die, when the first layer squeezes the second layer, the first layer is deformed and invades the second layer, and the second layer is thinned and extends toward the peripheral side of the first layer.

83. The method for preparing a conductive structure according to claim 82, characterized in that: In the blank, the first layer and the second layer are stacked together.

84. The method for preparing a conductive structure according to claim 83, characterized in that: The provision of blanks comprises: Providing a composite board, the composite board comprising a first layer and a second layer that are laminated and bonded; The composite board is punched to obtain a blank.

85. The method for preparing a conductive structure according to claim 83, characterized in that: The method for preparing the conductive structure further comprises: Before placing the blank into the mold cavity, the blank is screened so that when the blank is loaded into the mold cavity, the second layer faces the bottom wall of the mold cavity.

86. The method for preparing a conductive structure according to any one of claims 82 to 85, characterized in that: The method for preparing the conductive structure further includes: after the blank is subjected to a first cold heading treatment, the blank is placed in a second cold heading die, and a surface of the first layer facing away from the second layer is extruded.

87. A cover plate assembly, characterized in that: include: Cover plate; and a conductive structure, the conductive structure comprising a first metal column and a second metal layer, the first metal column having a first end and a second end opposite to each other; the second metal layer is bonded to a surface of the first metal column, the second metal layer covers the first end and extends to the second end; Wherein, the conductive structure is disposed on the cover plate.

88. The cover plate assembly according to claim 87, characterized in that The conductive structure is a pole or the conductive structure is an integrated pole and a terminal block; The cover plate assembly further includes a current collecting member, which is located at one side of the cover plate and welded to the conductive structure.

89. The cover plate assembly according to claim 88, characterized in that The cover plate assembly also includes: A first insulating member is disposed between the conductive structure and the cover plate, A second insulating member is disposed between the cover plate and the current collecting member; and / or, The cover plate assembly further includes a seal disposed between the cover plate and the conductive structure.

90. The cover plate assembly according to claim 89, characterized in that The sealing member is located on a side of the cover plate close to the first insulating member; Alternatively, the sealing member is located on a side of the cover plate close to the second insulating member.

91. The cover plate assembly according to claim 89, characterized in that An exhaust groove is provided on a surface of the first insulating member facing away from the cover plate, and two ends of the exhaust groove extend to the inner circumference and the outer circumference of the first insulating member respectively.

92. The cover plate assembly according to claim 89, characterized in that The first metal column comprises 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 end of the first section away from the second section is the first end, and the end of the second section away from the first section is the second end; the second metal layer comprises a cylinder and a flange, the cylinder covers the first section, the flange is connected to the end of the cylinder close to the second section, and the flange extends along the radial direction of the conductive structure and is embedded in the end surface of the second section facing the first section; The second section and the flange are located on a side of the first insulating member facing away from the cover plate; 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.

93. The cover plate assembly according to claim 92, characterized in that Along the axial direction of the first metal column, the first region protrudes outward along the axial direction of the conductive structure to form the height difference, and the thickness dimension of the first region protruding relative to the second region is Ha1, and the second segment has a thickness dimension Da in the axial direction of the conductive structure, satisfying 0<Ha1≤15%Da.

94. The cover plate assembly according to claim 93, characterized in that 2%Da≤Ha1≤15%Da.

95. The cover plate assembly according to claim 94, characterized in that Along the axial direction of the first metal column, the second region protrudes outward along the axial direction of the conductive structure to form the height difference, and the thickness dimension of the second region protruding relative to the first region is Ha2, and the second segment has a thickness dimension Da in the axial direction of the conductive structure, satisfying 0<Ha2≤15%Da.

96. The cover plate assembly according to claim 95, characterized in that 2%Da≤Ha2≤15%Da.

97. The cover plate assembly according to claim 94, characterized in that The first region is convexly arranged outwardly along the axial direction of the conductive structure to form a first convex portion, and the first convex portion extends in a ring shape along the circumferential direction of the conductive structure; or, The second region protrudes outwardly along the axial direction of the conductive structure to form a second protruding portion, and the second protruding portion extends in a ring shape along the circumferential direction of the conductive structure.

98. The cover plate assembly according to any one of claims 87 to 97, characterized in that: The conductive structure also includes a bottom plate; The second metal layer includes a cylinder, the cylinder covers the first end and extends to the second end; The bottom plate is connected to an end of the cylinder away from the second end.

99. The cover plate assembly according to claim 98, 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 end, and the aperture of the pre-punched hole gradually increases in a direction away from the second end.

100. The cover plate assembly according to claim 98, characterized in that A step groove b is provided at one end of the cylinder away from the second end. The step groove b extends in a ring shape around the circumference of the cylinder. The bottom plate is sleeved in the step groove b.

101. The cover plate assembly according to claim 99 or 100, characterized in that: The bottom plate is welded to the cylinder.

102. The cover plate assembly according to any one of claims 87-97, characterized in that: The first metal column comprises 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, an end of the first section away from the second section is the first end, and an end of the second section away from the first section is the second end; The second metal layer includes a cylinder, and the cylinder covers the first section; 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 conductive structure is clamped on the cover plate of the battery cell through the current collector and the second section.

103. 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; The cover plate assembly as described in any one of claims 87 to 102, wherein the cover plate assembly is connected to the shell and closes the opening of the accommodating cavity, and the conductive structure is connected to the pole ear.

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