Conductive structure, cover plate assembly and battery cell

Abstract

The utility model provides a conductive structure, 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, the second metal layer wraps the first end and extends towards the second end, the second metal layer is used for being connected with a tab, and the ratio of the volume of the second metal layer to the total volume of the conductive structure is 5 vol%-70 vol%. 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 over-current capability of the conductive structure is ensured, the size of the second metal layer can be reduced on the basis, and therefore the cost of the conductive structure is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a conductive structure, a cover assembly, and a battery cell. Background Art

[0002] 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 the module bar, and the other end of the pole is connected to the internal circuit of the battery cell, such as the pole ear in the electrode assembly through a current collector. At present, most poles are made of a single metal material. For example, the positive pole is made of aluminum and the negative pole is made of copper. 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 terminal block is generally made of aluminum. Due to the different melting points between copper and aluminum, laser welding can easily fail, resulting in cracking.

[0003] To reduce the difficulty of welding, a composite pole has been designed in related art. This pole consists of two stacked metal layers made of different materials, joined together by friction welding or stamping. Taking the negative pole as an example, the composite pole includes aluminum and copper layers. The copper layer typically accounts for a large volume in this type of pole, which increases the cost of the pole. However, reducing the volume of the copper layer reduces the current carrying capacity of the pole. Utility Model Content

[0004] The embodiments of the present application provide a conductive structure, a cover plate assembly, and a battery cell, which can improve the technical problem of high cost of composite poles.

[0005] In a first aspect, an embodiment of the present application provides a conductive structure, including:

[0006] a first metal post having opposing first and second ends;

[0007] A second metal layer is bonded to the surface of the first metal column, the second metal layer covers the first end and extends to the second end, the second metal layer is used to connect to the tab, and the ratio of the volume of the second metal layer to the total volume of the conductive structure is 5 vol% to 70 vol%.

[0008] In one embodiment, the second metal layer is inlaid with the first metal pillar.

[0009] In one embodiment, an end portion of the second metal layer is embedded in the first metal pillar.

[0010] In one embodiment, a gap is formed between an end portion of the second metal layer and the first metal pillar.

[0011] In one embodiment, an end face and a transition face connected in sequence are formed on 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.

[0012] In one embodiment, the average spacing of the gaps is less than 0.1 mm.

[0013] In one embodiment, the end portion 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.

[0014] In one embodiment, the conductive structure is a pole, and a support surface is formed on an end portion of the second metal layer, and the support surface is used to support the terminal pressing block.

[0015] In one embodiment, the supporting surface is an inclined surface, and in 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.

[0016] 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°.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] In one embodiment, the first metal column protrudes radially to form a boss, and the second metal layer extends at least to the boss.

[0021] In one embodiment, the boss is located at the first end, and the boss is completely covered in the second metal layer.

[0022] In one embodiment, 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 tab.

[0023] In one embodiment, the boss is away from the first end, and a radial dimension of the boss is greater than a radial dimension of the first end.

[0024] In one embodiment, the boss is located at the second end, and a portion of the boss is exposed outside the second metal layer.

[0025] In one embodiment, the conductive structure is an integrated pole and a terminal pressing block, wherein the boss is the terminal pressing block.

[0026] In one embodiment, the second metal layer includes a first segment, a second segment and a third segment, the first segment corresponds to the end face of the first end, the second segment corresponds to the side face of the first end, the third segment corresponds to a side surface of the boss close to the first end, and the second segment connects the first segment and the third segment.

[0027] 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.

[0028] In one embodiment, the average thickness of the first segment is greater than the average thickness of the second segment, and the average thickness of the second segment is greater than the average thickness of the third segment.

[0029] In one embodiment, the average thickness of the second segment is greater than half of the average thickness of the first segment, and / or the average thickness of the third segment is greater than half of the average thickness of the second segment.

[0030] In one embodiment, a thickness of a portion of the second section close to the third section is greater than a thickness of a portion of the second section close to the first section.

[0031] 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.

[0032] 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.

[0033] In one embodiment, the average thickness of the first sub-segment is greater than or equal to 0.5 mm, and / or the average thickness of the second sub-segment is greater than or equal to 0.5 mm.

[0034] In one embodiment, 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°.

[0035] In one embodiment, 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.

[0036] 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.

[0037] In one embodiment, along the axial direction of the first metal column, the distance between the outer surface of the third segment and the fourth segment 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 segment is e, where a>e>0.5mm.

[0038] 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.

[0039] In one embodiment, along the axial direction of the first metal column, a distance between the inner surface of the fifth section and the inner surface of the third section is b, and b>0.5 mm.

[0040] 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.

[0041] In one embodiment, the fourth section and the fifth section are formed as an inverted layer wrapping the free end of the boss, 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 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.

[0042] 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, the second step portion matches the first step portion, the second step portion is connected between the first section and the second section, and the second step portion is used to connect to the tab.

[0043] 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.

[0044] In one embodiment, the first metal pillar is an aluminum pillar, and the second metal layer is a copper layer.

[0045] In one embodiment, the average thickness of the second metal layer is 0.1 mm-3 mm.

[0046] In one embodiment, a bonding interface between the second metal layer and the first metal pillar has an uneven microstructure.

[0047] In one embodiment, the diameter of the conductive structure is less than or equal to 30 mm.

[0048] In one embodiment, the volume ratio of the second metal layer to the total volume of the conductive structure is 5 vol% to 40 vol%. In one embodiment, the volume ratio of the second metal layer to the first metal pillar is 0.1 to 0.65.

[0049] In a second aspect, an embodiment of the present application further provides a cover plate assembly, comprising:

[0050] Cover plate; the aforementioned conductive structure, wherein the conductive structure is arranged on the cover plate.

[0051] In one embodiment, the conductive structure is a pole or the conductive structure is an integrated pole and a terminal block;

[0052] The cover plate assembly further includes a current collecting member, which is located on one side of the cover plate and welded to the conductive structure.

[0053] In one embodiment, the cover plate comprises:

[0054] Cover body,

[0055] A first insulating member is provided between the conductive structure and the cover body,

[0056] A second insulating member is provided between the cover body and the current collecting member; and / or,

[0057] The cover plate assembly further includes a seal disposed between the cover plate and the conductive structure.

[0058] In a third aspect, an embodiment of the present application further provides a battery cell, comprising:

[0059] A housing having a receiving cavity;

[0060] An electrode assembly is disposed in the accommodating cavity, wherein the electrode assembly includes an electrode tab;

[0061] 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 tab.

[0062] Beneficial effects of the embodiments of the present application:

[0063] 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 arranging 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 to ensure the current flow capacity of the conductive structure. On this basis, the volume of the second metal layer can be reduced, and the volume proportion of the second metal layer in the conductive structure can be controlled within 70 vol%, thereby reducing the cost of the conductive structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. 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.

[0065] Figure 1 1 is a schematic diagram of the main structure of the first conductive structure provided in an embodiment of the present application;

[0066] Figure 2 yes Figure 1 A schematic cross-sectional view of the conductive structure in FIG.

[0067] Figure 3 yes Figure 2 Enlarged view of part A in the middle;

[0068] Figure 4 is a schematic diagram of the main structure of the second conductive structure provided in an embodiment of the present application;

[0069] Figure 5 yes Figure 4 A schematic cross-sectional view of the conductive structure in FIG.

[0070] Figure 6 is a schematic diagram of the three-dimensional structure of the third conductive structure provided in an embodiment of the present application;

[0071] Figure 7 yes Figure 6 A schematic cross-sectional view of the conductive structure in FIG.

[0072] Figure 8 yes Figure 6 A schematic cross-sectional structural diagram of a cover plate assembly formed by assembling the conductive structure in FIG.

[0073] Figure 9 yes Figure 8 Exploded view of the cover assembly in ;

[0074] Figure 10 is a schematic cross-sectional view of a fourth conductive structure provided in an embodiment of the present application;

[0075] Figure 11 yes Figure 10 Enlarged view of middle part B;

[0076] Figure 12 is a schematic cross-sectional view of a fifth conductive structure provided in an embodiment of the present application;

[0077] Figure 13 yes Figure 12 Enlarged view of the middle C section;

[0078] Figure 14 yes Figure 12 A schematic cross-sectional view of a conductive module formed by assembling the conductive structure in FIG.

[0079] Figure 15 yes Figure 14 Schematic diagram of the cross-sectional structure of the middle terminal block;

[0080] Figure 16 is a schematic diagram of the three-dimensional structure of the sixth conductive structure provided by an embodiment of the present application;

[0081] Figure 17 yes Figure 16 A schematic cross-sectional view of the conductive structure in FIG.

[0082] Figure 18 yes Figure 16 An exploded view of a cover plate assembly formed by assembling the conductive structure on the cover plate;

[0083] Figure 19 is a schematic cross-sectional view of a seventh conductive structure provided by an embodiment of the present application;

[0084] Figure 20 yes Figure 19 Enlarged view of the middle D part;

[0085] Figure 21 is a schematic cross-sectional view of an eighth conductive structure provided by an embodiment of the present application;

[0086] Figure 22 yes Figure 21 Enlarged view of the middle E part;

[0087] Figure 23 is a schematic cross-sectional view of a ninth conductive structure provided in an embodiment of the present application;

[0088] Figure 24 yes Figure 23 Enlarged view of the middle F part;

[0089] Figure 25 is a schematic diagram of a three-dimensional structure of a tenth conductive structure provided by an embodiment of the present application at one viewing angle;

[0090] Figure 26 yes Figure 25 A schematic diagram of the three-dimensional structure of the conductive structure in another perspective;

[0091] Figure 27 yes Figure 25 A schematic cross-sectional view of the conductive structure in FIG.

[0092] Figure 28 yes Figure 27 Enlarged view of the middle G section;

[0093] Figures 29 and 30 is a flow chart of the preparation of the conductive structure provided in the embodiment of the present application, wherein Figure 29 Schematic diagram showing the three-dimensional structure of the sample at different preparation stages, Figure 30 Schematic diagram showing the cross-sectional structure of the sample at different preparation stages;

[0094] Figure 31 It is a schematic diagram of the cross-sectional structure of a battery cell provided in an embodiment of the present application.

[0095] The reference numerals are as follows:

[0096] 10. Conductive structure; 101. Pole; 102. Terminal block;

[0097] 1. The first metal pillar;

[0098] 11, first end; 11a, first step portion; 11b, groove;

[0099] 12. Second end;

[0100] 13. Boss;

[0101] 2. Second metal layer;

[0102] 20, end; 201, first extension; 202, second extension; 20a, gap; 20b, end surface; 20c, transition surface;

[0103] 203, support surface;

[0104] 2031, inclined surface;

[0105] 2032, step surface; 20321, first sub-step surface; 20322, second sub-step surface;

[0106] 21, first section; 211, first subsection; 212, second subsection; 213, third subsection;

[0107] 22. Second section;

[0108] 23. The third section;

[0109] 24. Section 4;

[0110] 25. Section 5;

[0111] 251, reverse buckle layer;

[0112] 26, second step portion; 261, first step surface; 262, second step surface;

[0113] 3. Blank; 31. First layer; 32. Second layer;

[0114] 4. Semi-finished products;

[0115] 5. Composite board;

[0116] 100. Cover plate assembly;

[0117] 110, cover plate; 111, cover plate body; 112, first insulating member; 113, second insulating member; 114, mounting hole; 115, injection hole;

[0118] 120, current collecting parts;

[0119] 130. Seals;

[0120] 140. Explosion-proof valve;

[0121] 1000, battery cell;

[0122] 1100, housing; 1110, accommodating chamber;

[0123] 1200. Electrode assembly; 1210. Tab. DETAILED DESCRIPTION

[0124] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0125] Furthermore, it should be understood that the specific embodiments described herein are intended only to illustrate and explain the present application and are not intended to limit the present application. In this application, unless otherwise indicated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the directions of the drawings in the accompanying drawings; whereas "inner" and "outer" refer to the outline of the device.

[0126] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0127] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0128] The terms "comprises," "includes," or any other variations thereof are intended to encompass 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 "comprising a..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0129] In the description of the embodiments of this application, words such as "example" or "for example" are used to indicate an example, illustration, or description. Any embodiment or design described as "for example" or "for example" in the embodiments of this application is not to be construed as being preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to clearly present relative concepts.

[0130] To facilitate understanding of the solution 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.

[0131] Embodiments of the present application provide a conductive structure, a method for preparing the conductive structure, a cover plate assembly, and a battery cell.

[0132] In a first aspect, embodiments of the present application provide a conductive structure for connecting the internal circuit of a battery cell to a circuit external to the battery cell (referred to as the external circuit), thereby enabling communication between the battery cell and the external circuit, enabling the external circuit to power the battery cell (i.e., charging the battery cell), or the battery cell to power the external circuit (i.e., discharging the battery cell). Specifically, the conductive structure can be assembled onto a cover plate of a battery cell.

[0133] Specifically, see Figures 1 to 28 The conductive structure 10 includes a first metal pillar 1 and a second metal layer 2. The second metal layer 2 is bonded to the surface of the first metal pillar 1. The first metal pillar 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. The second metal layer 2 is used to connect to the tab.

[0134] The conductive structure 10 includes a first metal pillar 1 and a second metal layer 2. It is understood that the first metal pillar 1 is a columnar structure, and the material of the first metal pillar 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. Optionally, the electrical conductivity of the second metal is greater than the electrical conductivity of the first metal, that is, the conductivity of the second metal is better than the 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.

[0135] The second metal layer 2 is bonded to the surface of the first metal pillar 1, meaning that the second metal layer 2 is located on the outer surface of the first metal pillar 1 and is also bonded to the first metal pillar 1. Bonding here means that the second metal layer 2 and the first metal pillar 1 cannot be separated simply under the action of gravity. For example, the second metal layer 2 and the first metal pillar 1 are physically bonded together. As an example, the second metal layer 2 and the first metal pillar 1 can be bonded together by cold heading.

[0136] 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. The end 20 of the second metal layer 2 may extend to the second end 12, or the end 20 of the second metal layer 2 may extend 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 can be 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 tab. The second metal layer 2 may be directly connected to the tab, or the second metal layer 2 may be connected to the tab through other intermediate components (such as the current collector 120). As an example, the second metal layer 2 is welded to the current collector 120, which is in turn welded to the tabs. Tabs refer to the metal conductors that lead the positive and negative electrodes from the battery cells (i.e., battery cells). As an example, the current collector 120 includes at least one of a collecting plate and a connecting piece.

[0137] 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 outside 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.

[0138] 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%. As an example, the volume ratio of the second metal layer 2 is 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%.

[0139] 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 pillar 1 is extended from the surface of the first end 11 of the first metal pillar 1 to the second end 12. That is, the end surface of the first end 11 of the first metal pillar 1 and at least part of the side surface of the first metal pillar 1 are covered by the second metal layer 2. Compared with the form of only setting the second metal layer 2 on the end surface of one end of the first metal pillar 1, the bonding area between the second metal layer 2 and the first metal pillar 1 can be effectively increased to ensure the overcurrent capability (referred to as overcurrent capability) of the conductive structure 10. On this basis, the volume of the second metal layer 2 can be reduced, and the volume proportion of the second metal layer 2 in the conductive structure 10 can be controlled within 70 vol%, thereby reducing the cost of the conductive structure 10.

[0140] 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 to the second end 12 of the first metal column 1, shortening the distance between the second metal layer 2 and the second end 12, thereby shortening the current flow path and improving the current carrying capacity of the conductive structure 10.

[0141] In addition, increasing the bonding area between the second metal layer 2 and the first metal column 1 can also enhance the bonding strength between the second metal layer 2 and the first metal column 1 and reduce the risk of the second metal layer 2 falling off.

[0142] In some embodiments, see Figure 2 、 Figure 5 、 Figure 7 、 Figure 10 、 Figure 15 、 Figure 17 、 Figure 19 、 Figure 21 、 Figure 23 and Figure 27 The second metal layer 2 is embedded in the first metal pillar 1. The second metal layer 2 can be partially embedded in the first metal pillar 1, or the first metal pillar 1 can be partially embedded in the second metal layer 2. By embedding the second metal layer 2 and the first metal pillar 1 together, the bonding area between the second metal layer 2 and the first metal pillar 1 can be increased to a certain extent, improving the overcurrent capacity of the conductive structure 10 and reducing the risk of separation between the second metal layer 2 and the first metal pillar 1.

[0143] In some embodiments, see Figure 2 、 Figure 5 、 Figure 7 、 Figure 10 、 Figure 15 、 Figure 17 and Figure 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 into the first metal column 1, the area of ​​the combination of the end 20 of the second metal layer 2 and the first metal column 1 is increased, the flow 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, thereby reducing the risk of peeling of 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.

[0144] In some embodiments, see Figure 2 and Figure 3 A gap 20a is provided between the end 20 of the second metal layer 2 and the first metal pillar 1. Because the first metal pillar 1 is made of the first metal and the second metal layer 2 is made of the second metal, and the first and second metals are different, and the coefficients of thermal expansion differ between different metals, at high temperatures, this gap 20a provides a buffer for the larger volume expansion of either the first metal pillar 1 or the second metal layer 2. This allows the first metal pillar 1 to be tightly pressed against the end 20 of the second metal layer 2, reducing the risk of the second metal layer 2 separating from the first metal pillar 1 due to volume expansion.

[0145] 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 pillar 1 is less than 0.1 mm. The average spacing W1 refers to the average spacing distance between the end 20 of the second metal layer 2 and the first metal pillar 1. The average spacing W1 should not be too large, otherwise it will affect the bonding effect between the first metal pillar 1 and the second metal layer 2, and it will also be difficult to achieve tight contact between the first metal pillar 1 and the end 20 of the second metal layer 2 at high temperatures. As an example, W1 is 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm or 0.1 mm.

[0146] In some embodiments, see Figure 3The end 20 of the second metal layer 2 is formed with an end face 20b and a transition face 20c, which are connected in sequence. A gap 20a is formed between the second metal layer 2 and the first metal pillar 1 only between the end face 20b and the transition face 20c and the first metal pillar 1. The end face 20b is connected to the outer surface of the second metal layer 2 on the side away from the transition face 20c, and the transition face 20c is curved and transitioned from the end face 20b to the first metal pillar 1. The outer surface of the second metal layer 2 refers to the surface of the second metal layer 2 that is exposed to the outside. Typically, the outer surface of the second metal layer 2 faces away from the first metal pillar 1. For example, the transition face 20c is a circular curved surface, and the distance between the transition face 20c and the first metal pillar 1 decreases as it approaches the first metal pillar 1. By forming the gap 20a only between the end face 20b and the transition face 20c and the first metal pillar 1, the bonding area between the second metal layer 2 and the first metal pillar 1 is ensured.

[0147] 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 pillar 1 .

[0148] 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 on the end 20 of the second metal layer 2 extending along the first direction, and the second extension segment 202 refers to the portion on 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.

[0149] 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 performed in the gap between the pole 101 and the terminal block 102, the support surface 203 can form the bottom surface of the gap and block the laser during welding, thereby reducing the risk of laser penetration.

[0150] 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 here the inclined arc surface can be an arc surface that arches in the direction away from the second metal layer 2, or 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 block 102 is supported on the inclined surface 2031, the terminal block 102 will generate a radially 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 fitted with the first metal column 1, reducing the risk of the second metal layer 2 detaching.

[0151] In some embodiments, see Figure 13The inclined surface 2031 is an inclined straight surface, and the angle α between the inclined straight surface and the outer surface of the second metal layer 2 is 110° to 130°. Angle α within this range allows the second metal layer 2 and the first metal pillar 1 to form a deformable interlocking bonding interface under the radially inward partial pressure applied by the terminal block 102, thereby improving the bonding effect between the second metal layer 2 and the first metal pillar 1. As an example, angle α is 110°, 115°, 120°, 125°, or 130°.

[0152] In some embodiments, see Figures 6 to 11 The support surface 203 is a stepped surface 2032, which 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 a first direction, and the second sub-step surface 20322 refers to a surface extending along a 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 pillar 1, and the second direction is the axial direction of the first metal pillar 1. Optionally, both the second sub-step surface 20322 and the first sub-step surface 20321 are straight surfaces. The number of second sub-step surfaces 20322 is greater than or equal to 1, and the number of first sub-step surfaces 20321 is greater than or equal to 1. In other words, the number of second sub-step surfaces 20322 can be one or more, and the number of 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 resulting 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 multiple, the resulting 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 and the first sub-step surface 20321 are connected in sequence. In a multi-step surface, the second sub-step surface 20322 and the first sub-step surface 20321 are connected 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.

[0153] In some embodiments, see Figure 11Along 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 will be difficult to form and 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.

[0154] In some embodiments, see Figure 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 will be difficult to form and 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.

[0155] In some embodiments, see Figure 13 Along the radial direction of the terminal 101, the width W2 of the support surface 203 is greater than or equal to 0.3 mm and less than or equal to the thickness of the second metal layer 2. In the radial direction of the terminal 101, the maximum width W2 of the support surface 203 is subject to the thickness of the second metal layer 2, but the minimum width W2 of the support surface 203 is related to the design of the support surface 203 and should not be too small, otherwise it will affect the support effect of the support surface 203 on the terminal block 102, and further affect the effect of the second metal layer 2 on blocking the laser during laser welding. As an example, the width W2 of the support surface 203 is 0.3 mm, 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.

[0156] In some embodiments, see Figure 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. The end 20 of the second metal layer 2 is sandwiched between the first metal pole 1 and the terminal block 102. The end 20 is formed as a clamping portion 2a, which is sandwiched between the first metal pole 1 and the terminal block 102. In other words, part of the second metal layer 2 is sandwiched between the first metal pole 1 and the terminal block 102.

[0157] 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 bonded. The dual effects jointly reduce the risk of the second metal layer 2 separating from the first metal column 1.

[0158] In some embodiments, see Figure 15 The terminal pressing block 102 is provided with a through-hole 1021, through which the terminal pressing block 102 is sleeved onto the pole 101. In other words, the pole 101 is inserted into 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 onto one end of the pole 101. By sleeved the terminal pressing block 102 onto the pole 101, the height of the conductive module 10a can be appropriately reduced, and the terminal pressing block 102 can also limit the position of the pole 101.

[0159] In some embodiments, the terminal pressing block 102 is sleeved onto the first metal pillar 1 through the through hole 1021. The hole walls 1022 of some or all of the through holes 1021 may be in direct contact with the first metal pillar 1, that is, there is no second metal layer 2 between the hole walls 1022 of the through hole 1021 and the first metal pillar 1. Sleeving the terminal pressing block 102 onto the first metal pillar 1 through the through hole 1021 facilitates welding the terminal pressing block 102 to the first metal pillar 1, for example, by laser welding.

[0160] In some embodiments, through-hole 1021 forms an interference fit with terminal post 101. This allows for a tight fit between terminal block 102 and terminal post 101, improving the terminal post 101's resistance to thrust and torsion. Furthermore, the interference fit eliminates the need for additional connecting components, resulting in a simple structure and highly reliable connection.

[0161] In some embodiments, the terminal 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 block 102, at which time the pole 101 and the through hole 1021 may be a clearance fit, and then riveting the pole 101 and the through hole 1021 together through a pressure riveting process. In detail, during the riveting process, a riveting machine can be used to squeeze the pole 101 along the axial direction of the pole 101. The pole 101 will deform during the compression process, and the pole 101 will shrink in the axial direction, but the pole 101 will expand in the radial direction. 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 riveting process, the terminal pressing block 102 is fixed by a clamp and the terminal pressing block 102 cannot move.

[0162] In some embodiments, see Figure 15 , a mating surface 1023 that matches 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 that matches the inclined surface 2031. When the support surface 203 is a step surface 2032, the mating surface 1023 is a step mating surface 1023 that matches 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 configured as a ring, and the clamping portion 2a is connected to the periphery of the first metal column 1. By configuring the clamping portion 2a in a ring shape, the contact area between the clamping portion 2a and the circumference of the first metal post 1 can be increased, thereby increasing the bonding area between the second metal layer 2 and the first metal post 1, improving the current carrying capacity of the conductive structure 10, and reducing the risk of the second metal layer 2 falling off. This can also effectively reduce the manufacturing difficulty of the terminal 101. Of course, in other embodiments, the clamping portion 2a can also be configured to include multiple tabs, which are spaced apart around the circumference of the first metal post 1 and are clamped between the first metal post 1 and the terminal block 102.

[0163] 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 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 may be located only on the surface of the boss 13.

[0164] As an example, see Figure 2 The boss 13 is 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 .

[0165] As an example, see Figure 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 .

[0166] 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, thereby increasing the bonding area between the second metal layer 2 and the first metal column 1, enhancing the bonding force, reducing the risk of the second metal layer 2 detaching from the first metal column 1, and at the same time improving the current carrying capacity of the conductive structure 10.

[0167] 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.

[0168] 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 generally shaped like an inverted T. When assembling the conductive structure 10 onto the cover 110, the smaller end of the conductive structure 10 can be passed through the mounting hole 114 on the cover 110 from bottom to top until the boss 13 abuts the cover 110. The second metal layer 2 on the upper surface of the boss 13 is clamped between the boss 13 and the cover 110 to prevent the second metal layer 2 from falling off.

[0169] 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 covers at least the side surface of the boss 13 and the side surface of the boss 13 close to the second end 12, that is, the boss 13 is completely enclosed in the second metal layer 2.

[0170] 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. By simply reusing the current collector 120, the bonding area of ​​the second metal layer 2 can be greatly increased, reducing the risk of the second metal layer 2 falling off, and improving the current carrying capacity of the conductive structure 10 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 terminal-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 tabs of the electrode assembly.

[0171] In some embodiments, see Figures 1 to 3 、 Figures 16 to 28 , the boss 13 is away from the first end 11, and the radial dimension of the boss 13 is larger 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 conductive structure 10 has a generally upright T-shape. When assembling the conductive structure 10 onto the cover 110, the smaller end of the conductive structure 10 can be passed through the mounting hole in the cover 110 from top to bottom until the boss 13 abuts the cover 110. The second metal layer 2 on the lower surface of the boss 13 is clamped between the boss 13 and the cover 110 to prevent the second metal layer 2 from falling off.

[0172] 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. When the conductive structure 10 and the cover plate 110 are assembled, the boss 13 is generally located outside the cover plate 110. By arranging 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 the module bar).

[0173] In some embodiments, the conductive structure 10 is an integrated pole-terminal pressing block structure, that is, the conductive structure 10 is an integrated pole 101 and terminal pressing block 102, wherein the boss 13 is the terminal pressing block 102. By integrating the pole 101 and the terminal pressing block 102, the process of assembling the pole 101 and the terminal pressing 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 pressing block 102, there is no need to increase the volume of the pole 101. By simply reusing the terminal pressing block 102, the bonding area of ​​the second metal layer 2 can be greatly increased, reducing the risk of the second metal layer 2 falling off, and improving the current carrying capacity of the conductive structure 10 without bringing about the burden of volume and weight. When the pole-terminal pressing block integrated structure is assembled on a battery cell, such as on the cover plate 110 of the battery cell, the boss 13 is located outside the battery cell.

[0174] In some embodiments, see Figure 2 、 Figures 16 to 28The second metal layer 2 includes a first segment 21, a second segment 22, and a third segment 23, wherein the first segment 21 corresponds to the end face of the first end 11, the second segment 22 corresponds to the side face of the first end 11, the third segment 23 corresponds to the side surface of the boss 13 close to the first end 11, and the second segment 22 connects the first segment 21 and the third segment 23. Here, the first segment 21, the second segment 22, and the third segment 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 segment 23 or not. When the end 20 of the second metal layer 2 is not located in the third segment 23, it means that the second metal layer 2 also includes other segments, i.e., other parts. Optionally, the number of segments of the second metal layer 2 is less than or equal to five, because the more segments there are, the greater the manufacturing difficulty and the higher the cost.

[0175] 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.

[0176] In some embodiments, see Figure 2 、 Figure 17 and Figure 19 , the third section 23 forms the end 20 of the second metal layer 2, and the third section 23 is embedded in the boss 13. By configuring 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, which serves as the end 20 of the second metal layer 2, is also embedded in the boss 13, increasing the bonding area, improving the current carrying capacity of the conductive structure 10, and ensuring the bonding strength of the second metal layer 2, thereby making the conductive structure 10 more cost-effective. In addition, in this way, under high temperature conditions, when the third section 23 expands, the first metal pillar 1 can limit the third section 23 from both ends of the third section 23, so that the third section 23 can better achieve a tight fit with the first metal pillar 1, thereby improving the bonding strength of the second metal layer 2.

[0177] In some embodiments, see Figure 2The average thickness d1 of the first segment 21 is greater than the average thickness d2 of the second segment 22, and the average thickness d2 of the second segment 22 is greater than the average thickness d3 of the third segment 23. That is, the first segment 21, the second segment 22, and the third segment 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 pillar 1 is oriented toward the interior of the battery cell 1000. With respect to the probability of contact with the electrolyte, the first segment 21 is more likely to contact the second segment 22, which in turn is more likely to contact the third segment 23. By arranging the average thicknesses of the first segment 21, the second segment 22, and the third segment 23 to decrease in sequence, the risk of corrosion of the first end 11 by the electrolyte can be reduced while also controlling costs.

[0178] In some embodiments, see Figure 2 The average thickness d2 of the second section 22 is greater than half 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.

[0179] In some embodiments, see Figure 2 The average thickness d3 of the third segment 23 is greater than half the average thickness d2 of the second segment 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.

[0180] 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. Thus, the portion of the second section 22 near the third section 23 can function as a buckle, improving the bonding strength between the second metal layer 2 and the first metal pillar 1 at this location.

[0181] In some embodiments, see Figure 17 、 Figures 21 to 28The end surface of the first end 11 is partially concave to form a groove 11b. 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 being 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 the second metal layer 2 being attached 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, the current carrying capacity of the conductive structure 10 is improved, and the bonding strength is enhanced.

[0182] In some embodiments, see Figure 28 The average thickness d2 of the second segment 22 is greater than or equal to 0.5 mm. Generally, the greater the average thickness d2 of the second segment 22, the higher the mechanical strength of the second segment 22, and the better the corrosion and fracture resistance. As an example, the average thickness d2 of the second segment 22 is 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, or 2.5 mm.

[0183] In some embodiments, see Figure 28 The average thickness d11 of the first subsegment 211 is greater than or equal to 0.5 mm. Generally, a greater average thickness of the first subsegment 211 indicates higher mechanical strength, corrosion resistance, and fracture resistance. For example, the average thickness d11 of the first subsegment 211 is 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, or 2.5 mm.

[0184] In some embodiments, see Figure 17 、 Figure 21 、 Figure 23 and Figure 27 The vertical distance H2 between the outer surface of the first subsegment 211 and the outer surface of the third subsegment 213 is ≤ 2.5 mm. As an example, H2 is 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, or 2.5 mm. Within the above range, the vertical distance H2 between the outer surface of the first subsegment 211 and the outer surface of the third subsegment 213 can ensure good bonding strength between the first metal pillar 1 and the second metal layer 2, and reduce the manufacturing difficulty of the conductive structure 10.

[0185] In some embodiments, see Figure 21 and Figure 23 , the second subsegment 212 extends obliquely from the first subsegment 211 to the third subsegment 213, and the inclination angle σ of the second subsegment 212 satisfies the following condition: 15°≤σ≤60°. Here, the inclination angle σ refers to the inclination angle of the second subsegment 212 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 subsegment 212, the second subsegment 212 can be made to smoothly transition from the first subsegment 211 to the third subsegment 213, thereby alleviating the stress concentration at the connection between the second subsegment 212 and the first subsegment 211 and the connection between the second subsegment 212 and the third subsegment 213, resulting in the phenomenon of the second metal layer 2 being broken.

[0186] 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 Figure 21 and Figure 23 When the boss 13 is located between the first end 11 and the second end 12, the conductive structure 10 has a roughly "Z"-shaped appearance. For this type of conductive structure 10, when the boss 13 serves as a stop, it can be clamped from both sides, achieving a more stable fixation of the second metal layer 2. To prevent the conductive structure 10 from being too tall, the boss 13 is typically made thinner, while the second end 12 is used for electrical connection to other components.

[0187] In some embodiments, see Figures 21 to 28 The second metal layer 2 further includes a fourth section 24, which corresponds to the side surface of the boss 13 and is connected to the third section 23. The provision of the fourth section 24 can further increase the bonding area between the second metal layer 2 and the first metal pillar 1. Here, the side surface of the boss 13 can be completely covered by the fourth section 24, or can be partially covered by the fourth section 24.

[0188] In some embodiments, see Figure 22Along the axial direction of the first metal pillar 1, the distance between the outer surface of the third segment 23 and the end of the fourth segment 24 facing away from the first end 11 is a. Along the radial direction of the first metal pillar 1, the distance between the outer surface and the inner surface of the fourth segment 24 is e, where a>e>0.5mm. Within this range, the bonding area between the fourth segment 24 and the boss 13 is large, and the fourth segment 24 itself is also strong, which not only improves the current carrying capacity of the conductive structure 10 but also enhances the bonding strength between the second metal layer 2 and the first metal pillar 1. Along the axial direction of the first metal pillar 1, the distance between the outer surface of the third segment 23 and the outer surface of the boss 13 is h1.

[0189] In some embodiments, see Figures 23 to 28 The second metal layer 2 further includes a fifth section 25, which corresponds to a surface of the boss 13 that is distal from the first end 11. The fourth section 24 connects the fifth section 25 and the third section 23. The provision of the fifth section 25 can further increase the bonding area between the second metal layer 2 and the first metal pillar 1. Optionally, the end 20 of the second metal layer 2 is located in the fifth section 25.

[0190] In some embodiments, see Figure 24 Along the axial direction of the first metal pillar 1, the distance b between the inner surface of the fifth section 25 and the inner surface of the third section 23 is greater than 0.5 mm. Because the boss 13 is at least partially located between the inner surfaces of the fifth section 25 and the third section 23, setting b greater than 0.5 mm helps ensure the mechanical strength of the boss 13. This reduces the risk of boss 13 breakage, especially when the boss 13 serves as a stop.

[0191] In some embodiments, see Figure 24 Along the axial direction of the first metal pillar 1, the distance between the outer surface of the third segment 23 and the outer surface of the fifth segment 25 is h2. Along the radial direction of the first metal pillar 1, the distance between the outer surface of the fourth segment 24 and the root of the boss 13 near the second end 12 is c, and the distance between the outer surface of the fourth segment 24 and the end of the fifth segment 25 near the central axis of the first metal pillar 1 is d. Where c>h2 and d≥2 / 3c, or c≤h2 and d>0.5mm. Within these ranges, the bonding strength between the second metal layer 2 and the first metal pillar 1 can be effectively improved.

[0192] In some embodiments, see Figure 28 The fourth and fifth sections 24 and 25 are formed such that a buckle layer 251 wraps around the free end of the boss 13. Along the axial direction of the first metal pillar 1, the distance between the outer surface of the third section 23 and the outer surface of the buckle layer 251 is K1. The thickness of the buckle layer 251 is K2, where f = K2 / K1, where f is greater than or equal to 0.3 and less than 1. The buckle layer 251 can enhance the mounting strength of the conductive structure 10.

[0193] In some embodiments, see Figure 19 、 Figure 20 、 Figures 25 to 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. The second step portion 26 matches the first step portion 11a and is connected between the first section 21 and the second section 22. The second step portion 26 is used to connect to the tab 1210. It can be foreseen that there will also be a step on one end of the conductive structure 10. The step 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 simultaneously. The advantage of this arrangement is that it changes the strong correlation between the area of ​​the second step portion 26 and the thickness of the second metal layer 2. 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 to the tab. Optionally, the first step portion 11a is a sink located at the edge of the end face of the first end 11. 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 26, and the second section 22 are connected in sequence. Optionally, the second step 26 is used to weld to the current collector 120 connected to the tab. As an example, when welding the second step 26 to the current collector 120, the current collector 120 can be first placed on the conductive structure 10, and the current collector 120 and the second step 26 cooperate with each other, and the current collector 120 is welded to the second step 26 by laser welding. The larger the surface area of ​​the second step 26, the larger the surface that can be welded between the second step 26 and the current collector 120, and the larger the welding surface, the higher the reliability of the welding.

[0194] In some embodiments, see Figure 19 、 Figure 20 and Figure 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, the second step portion 26 can have a sufficient contact surface, thereby improving the flow capacity and connection strength.

[0195] In some embodiments, the first metal is aluminum, i.e., the first metal pillar 1 is an aluminum pillar, and the second metal is copper, i.e., the second metal layer 2 is a copper layer. Aluminum is cheaper than copper, and by configuring the conductive structure 10 as a structure including the aluminum pillar and the copper layer, the cost of the conductive structure 10 can be effectively reduced. For example, the conductive structure 10 is a negative electrode pillar.

[0196] 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 pillar 1 is an aluminum pillar and the second metal layer 2 is a copper layer. This reduces the use of more expensive copper, effectively reducing the cost of the conductive structure 10 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.

[0197] In some embodiments, the average thickness D1 of the second metal layer 2 is 0.2 mm to 1.5 mm. Generally, as the average thickness D1 of the second metal layer 2 decreases, 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.

[0198] 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.

[0199] 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, as this increases the weight and cost of the battery cell. Alternatively, 5 mm ≤ φ ≤ 30 mm. Within this range, the conductive structure 10 has both good current carrying capacity and cost advantages. As examples, the diameter φ of the conductive structure 10 is 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mm.

[0200] 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.

[0201] 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 good bonding strength, current carrying capacity, and cost advantages. As an example, the volume ratio of the second metal layer 2 is 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, or 40 vol%.

[0202] 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.

[0203] In some embodiments, the bonding area between the second metal layer 2 and the first metal pillar 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. The surface where the second metal layer 2 and the first metal column 1 contact 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 contact each other. For 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.

[0204] In some embodiments, the bonding area between the second metal layer 2 and the first metal pillar 1 is greater than or equal to 80 mm 2 As an example, the bonding area is 80mm 2 , 90mm 2 , 100mm 2 , 120mm 2 , 130mm 2 , 140mm 2 , 150mm 2 , 200mm 2 , 250mm 2 , 300mm 2 , 400mm 2 or 500mm 2 .

[0205] In some embodiments, the volume ratio of the second metal layer 2 to the first metal pillar 1 is 0.1 to 0.65. That is, the volume of the first metal pillar 1 is 1.54 to 10 times the volume of the second metal layer 2, that is, the volume content of the first metal pillar 1 in the conductive structure 10 is much greater than the volume content of the second metal layer 2. When the bonding area between the second metal layer 2 and the first metal pillar 1 is increased, the conductive structure 10 still has sufficient current capacity. By reducing the content of the second metal layer 2 in the conductive structure 10, the cost of the conductive structure 10 can be reduced, especially when the first metal pillar 1 is an aluminum pillar 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 pillar 1 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.65. Generally, the volume ratio of the second metal layer 2 to the first metal pillar 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 pillar 1.

[0206] In some embodiments, see Figure 2 On the exterior 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 pillar 1 is greater than or equal to 0.25. Since the second metal layer 2 is bonded to the surface of the first metal pillar 1, the exposed surface of the second metal layer 2 forms the exterior surface of the conductive structure 10; when the first metal pillar 1 is not completely covered by the second metal layer 2, the exposed surface of the first metal pillar 1 also forms the exterior surface of the conductive structure 10. It can be understood that on the exterior surface of the conductive structure 10, the surface area of ​​the second metal layer 2 is the area of ​​the exposed surface of the second metal layer 2, and the surface area of ​​the first metal pillar 1 is the area of ​​the exposed surface of the first metal pillar 1. Increasing the surface area of ​​the second metal layer 2 on the exterior surface of the conductive structure 10 is equivalent to increasing the area of ​​the second metal layer 2 covering the first metal pillar 1, that is, increasing the bonding area between the second metal layer 2 and the first metal pillar 1. As an example, on the exterior 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 pillar 1 is 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5 or 3.

[0207] 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 pillar 1 is greater than or equal to 0.25 and less than or equal to 0.6. In order to facilitate direct connection of the second end 12 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 sufficient connection surface to connect with other components, and the bonding area is large enough, thereby ensuring the current flow 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.

[0208] 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 also leads to an increase in the cost of the conductive structure 10 and brings a volume and mass burden. In the case of 10 mm < φ ≤ 30 mm, 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. A portion of the second end 12 is retained to be exposed outside the second metal layer 2, and the other areas can be covered with the second metal layer 2 to increase the bonding area. In the case of 10 mm < φ ≤ 30 mm, 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.

[0209] In a second aspect, the present invention also provides a method for preparing a conductive structure 10. Figure 29 and Figure 30 The method for preparing the conductive structure 10 comprises:

[0210] S10, providing a blank 3, the blank 3 comprising a first layer 31 and a second layer 32, the first layer 31 comprising a first metal, and the second layer 32 comprising a second metal;

[0211] S20, placing the blank 3 in the cavity of the first cold heading die, and keeping the first layer 31 and the second layer 32 stacked in sequence from the outside to the inside of the cavity;

[0212] S30, performing a first cold heading treatment on the blank 3, whereby, by means of a strong beam of the first cold heading die, when the first layer 31 squeezes the second layer 32, the first layer 31 deforms and invades the second layer 32, and the second layer 32 becomes thinner and extends toward the circumference of the first layer 31, thereby obtaining a semi-finished product 4;

[0213] S40 , performing a first shaping process on the semi-finished product 4 to obtain a conductive structure 10 .

[0214] The blank 3 includes a first layer 31 and a second layer 32. The first layer 31 includes a first metal, that is, the first layer 31 is a metal layer, and the material of the first layer 31 is the first metal; the second layer 32 includes a second metal, that is, the second layer 32 is also a metal layer, and the material of the second layer 32 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 31 and the second layer 32 in the blank 3 are stacked and bonded together. Of course, in some cases, the first layer 31 and the second layer 32 in the blank 3 can also be separable, because the subsequent first cold heading treatment can also bond the first layer 31 and the second layer 32 together. Therefore, the first layer 31 and the second layer 32 in the blank 3 are not necessarily required to be bonded together.

[0215] The first cold heading die has a cavity, and the blank 3 is placed in the cavity of the first cold heading die. Specifically, the first layer 31 and the second layer 32 are kept stacked in sequence from the outside to the inside of the cavity, that is, the second layer 32 is closer to the bottom wall of the cavity than the first layer 31, and the first layer 31 is closer to the opening of the cavity than the second layer 32. When the blank 3 is placed in the cavity, the blank 3 can be completely contained in the cavity, or one end of the blank 3 can extend into the cavity. The part of the blank 3 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 4. As an example, when the cavity includes a first cavity segment and a second cavity segment that are 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, then the obtained semi-finished product 4 appears to be Figure 29 Figure (c) and Figure 30 The mushroom head shape shown in Figure (c) in the figure.

[0216] The first cold heading process refers to performing an upsetting process on the blank 3. For example, the blank 3 is punched using a cold heading device. Since the second layer 32 of the blank 3 is kept facing the inside of the cavity and the first layer 31 of the blank 3 is facing the outside of the cavity when the blank 3 is placed in the cavity of the first cold heading die, the punch of the cold heading device acts directly on the first layer 31, that is, the blank 3 is squeezed from the side of the first layer 31 facing away from the second layer 32. Since the first layer 31 and the second layer 32 are both metal layers, and metal has ductility, the first layer 31 and the second layer 32 will deform and extend during the upsetting of the blank 3. For example, when the blank 3 is upset along the axial direction of the blank 3, the first layer 31 and the second layer 32 will extend in the radial direction of the blank 3.

[0217] Because the blank 3 is placed in the cavity of the first cold heading die, the first cold heading die, specifically the sidewalls of the cavity, exerts a strong constraint on the blank 3, referred to as strong constraint, which regulates the direction in which the first layer 31 and the second layer 32 will deform and extend. Therefore, the first cold heading process can also be called strong constraint processing or cold heading forming. Typically, the thickness of the sidewalls of the cavity in the first cold heading die, the material of the first cold heading die, etc., will affect the strong constraint effect of the first cold heading die. As an example, the first cold heading die is a stainless steel die.

[0218] See Figure 29 Figure (c) and Figure 30 In Figure (c), when the blank 3 is upset, since the first layer 31 and the second layer 32 are stacked, the first layer 31 will squeeze the second layer 32. However, due to the strong force of the first cold upsetting die, the first layer 31 is deformed by pressure and invades the second layer 32. The second layer 32 is deformed and thinned by pressure and extends to the circumference of the first layer 31, that is, it extends along the tiny gap between the first layer 31 and the side wall of the cavity, thereby obtaining a semi-finished product 4.

[0219] In order to improve the dimensional accuracy, shape or surface roughness of the semi-finished product 4 and remove excess material, the semi-finished product 4 is further subjected to the first shaping process, thereby obtaining a conductive structure 10 that meets the requirements. Figure 29 Figure (e) and Figure 30 Here, the first shaping process includes but is not limited to at least one of punching, polishing and grinding.

[0220] Optionally, the preparation method of the conductive structure 10 is used to prepare the conductive structure 10 provided in the first aspect, wherein the first layer 31 can be deformed by upsetting to obtain the first metal column 1, and the second layer 32 can be deformed by upsetting to obtain the second metal layer 2.

[0221] The method for preparing the conductive structure 10 provided in the embodiment of the present application utilizes cold forging to bond the first layer 31 and the second layer 32 together. During the cold forging process, the deformation, extension, and intrusion of the first layer 31 and the second layer 32 can transform the bonding interface between the two into a microscopically uneven surface, thereby increasing the bonding surface area and enhancing the bonding strength. Furthermore, during the cold forging process, the second layer 32 extends toward the circumference of the first layer 31, meaning that the second layer 32 bonds not only to the bottom surface of the first layer 31 but also to the side surfaces of the first layer 31, further increasing the bonding area and enhancing the bonding strength.

[0222] In some embodiments, see Figure 29 Figure (b) and Figure 30 In Figure (b), in the blank 3, the first layer 31 and the second layer 32 are stacked and bonded together. It can be understood that in the blank 3, the first layer 31 is located on one side of the second layer 32, and the first layer 31 and the second layer 32 are bonded together. By first stacking the first layer 31 and the second layer 32 together, it is easier to load the first layer 31 and the second layer 32 together and place them in the mold cavity, simplifying the manufacturing process of the conductive structure 10.

[0223] In some embodiments, in the blank 3, the ratio of the average thickness of the second layer 32 to the average thickness of the blank 3 is 0.1 to 0.2. That is, the average thickness of the first layer 31 is much greater than the average thickness of the second layer 32. Generally, the second layer 32 should not be too large, otherwise the second layer 32 will not be easily ductile, especially when the hardness of the second metal is greater than the hardness of the first metal, which will increase the manufacturing difficulty of the first cold heading process. The second layer 32 should not be too thin, otherwise the second layer 32 will easily tear during the cold heading process. As an example, the ratio of the average thickness of the second layer 32 to the average thickness of the blank 3 is 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.2.

[0224] In some embodiments, see Figure 29 Figure (b) and Figure 30 In Figure (b), in the blank 3, the edge of the second layer 32 protrudes beyond the edge of the first layer 31. The edge of the second layer 32 protrudes slightly beyond the edge of the first layer 31. This allows a certain gap to be maintained between the side surface of the first layer 31 and the inner wall of the cavity when the blank 3 is placed in the cavity of the first cold heading mold. During the first cold heading process, the presence of this gap promotes extension toward the circumference of the first layer 31, reducing manufacturing difficulty.

[0225] In some embodiments, see Figure 29 Figure (a) and Figure 30In FIG. (a), a blank 3 is provided, including preparing the blank 3. The preparation process of the blank 3 includes:

[0226] S11, providing a composite plate 5, the composite plate 5 including a first layer 31 and a second layer 32 stacked together;

[0227] S12, punching the composite plate 5 to obtain a blank 3.

[0228] Optionally, the blank 3 is columnar. For example, when the first metal is aluminum and the second metal is copper, the composite plate 5 is a copper-aluminum composite plate, which includes a laminated copper layer and an aluminum layer. A copper-aluminum composite column, i.e., the blank 3, can be obtained by punching the copper-aluminum composite plate using a punching device.

[0229] The blank 3 is obtained by adopting the composite plate 5 , which simplifies the process and facilitates manufacturing.

[0230] In some embodiments, the method for preparing the conductive structure 10 further includes:

[0231] S13: Before placing the blank 3 in the mold cavity, perform a second shaping process on the blank 3.

[0232] The original blank 3 may have defects such as burrs, deformation, and dimensional deviations, which may prevent the blank 3 from being placed in the mold cavity and, in turn, prevent subsequent processing. In addition, the conductive structure 10 is produced in batches during the preparation process, and there will be differences between different blanks 3. These differences will ultimately lead to differences in the conductive structure 10. The purpose of the second shaping process is to improve the consistency of the blank 3 and to ensure that the blank 3 can be placed in the mold cavity.

[0233] As an example, the second shaping process includes: placing the originally provided blank 3 into a shaping jig for shaping, and using the shaping jig to improve the consistency of the size of the blank 3.

[0234] As an example, the second shaping process includes, but is not limited to, at least one of a punching process, a cutting process, and a grinding process.

[0235] As an example, the blank 3 is a copper-aluminum composite column, which is subjected to a cutting process to remove a small amount of copper material attached to the top surface of the aluminum layer.

[0236] In some embodiments, the method for preparing the conductive structure 10 further includes:

[0237] S14. Before placing the blank 3 into the cavity, screen the blank 3 so that the second layer 32 of the blank 3 faces the bottom wall of the cavity when the blank 3 is loaded into the cavity.

[0238] The conductive structure 10 is produced in batches during the production process. During the production process, the blank 3 may fall over or turn upside down, which will affect loading, especially automatic loading. Therefore, the blank 3 is screened before loading, and the blanks 3 that meet the requirements are selected for loading. Here, the reverse direction refers to the first layer 31 and the second layer 32 of the blank 3 facing the opposite direction to the requirements. For example, when loading, the first layer 31 of the blank 3 is required to face up and the second layer 32 is required to face down. If the first layer 31 of the blank 3 faces down and the second layer 32 faces up, it is considered reversed.

[0239] As an example, the columnar blank 3 can be placed in a screening tray, and the screening tray can be used to screen the blank 3 so that the orientation of the first layer 31 in the screened blank 3 is consistent and meets the requirements.

[0240] In some embodiments, see Figure 29 Figure (d) and Figure 30 In FIG. (d), the method for preparing the conductive structure 10 further includes:

[0241] S31 , placing the semi-finished product 4 in a second cold heading die, and extruding the surface of the first layer 31 facing away from the second layer 32 .

[0242] Here, the semi-finished product 4 is subjected to a second cold heading process, and a second cold heading die can be used to further adjust the size and shape of the semi-finished product 4. If a different second cold heading die is used, the shape of the conductive structure 10 obtained will also be different.

[0243] 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.

[0244] 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.

[0245] Specifically, see Figure 8 、 Figure 9 and Figure 18 The cover plate assembly 100 includes a cover plate 110 and the aforementioned conductive structure 10 (which can 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.

[0246] In detail, along the thickness direction of the cover plate 110, the cover plate 110 has a first surface and a second surface that are opposite to each other. Figure 31 When the cover plate assembly 100 is mounted on the housing 1100 of the battery cell 1000, the first surface is the side surface away from the housing 1100, and the second surface is the side surface close to the housing 1100. A mounting hole 114 is provided through the cover plate 110 along its thickness, and the conductive structure 10 is mounted on the cover plate 110 through the mounting hole 114.

[0247] 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 plate 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 tab 1210 of the electrode assembly 1200. The current collector 120 is located on one side of the cover plate 110, specifically on the side of the cover plate 110 away from the terminal block 102, that is, the current collector 120 is located on the second surface of the cover plate 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 the welding.

[0248] In some embodiments, the current collecting member 120 includes at least one of a current collecting plate and a connecting piece 1202 .

[0249] In some embodiments, see Figure 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 tab 1210 of the electrode assembly 1200 , and the connecting piece 1202 is welded to the second metal layer 2 .

[0250] In some embodiments, the cover plate 110 includes a cover plate body 111, 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 body 111. The first insulating member 112 is disposed between the conductive structure 10 and the cover plate body 111, and the second insulating member 113 is disposed between the cover plate body 111 and the current collecting member 120. Optionally, when the first metal pillar 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 body 111. The cover plate 110 is provided with a mounting hole 114, which passes through the cover plate body 111, the first insulating member 112, and the second insulating member 113. As an example, the cover plate body 111 is a plain aluminum sheet, and the first insulating member 112 and the second insulating member 113 are both plastic parts.

[0251] In some embodiments, the cover assembly 100 further includes a seal 130 disposed between the cover 110 and the conductive structure 10 to seal the gap between the conductive structure 10 and the mounting hole to prevent electrolyte leakage therefrom. For example, the seal 130 is located between the cover body 111 and the second insulating member 113.

[0252] In some embodiments, the assembly process of the cover assembly 100 includes: stacking the second insulating member 113, the sealing member 130, the cover body 111 and the first insulating member 112 in sequence from bottom to top 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 (for example, the boss 13) on 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, for example, the second metal layer 2 in the conductive structure 10, by laser welding.

[0253] In some embodiments, the cover plate assembly 100 further includes an explosion-proof valve 140 , which is disposed on the cover plate 110 .

[0254] 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.

[0255] For the fourth aspect, please see Figure 31 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 the mutual conversion between chemical energy and electrical energy.

[0256] Specifically, see Figure 31 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, in which the electrode assembly 1200 is disposed. The cap assembly 100 is connected to the housing 1100 and seals the opening of the receiving cavity 1110. The electrode assembly 1200 includes a tab 1210, to which the conductive structure 10 is connected.

[0257] Specifically, the electrode assembly 1200 further includes an electrode sheet and a separator, and 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.

[0258] 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.

[0259] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein 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 those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods 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 the surface of the first metal column, the second metal layer covers the first end and extends to the second end, and the second metal layer is used to connect to the tab. The ratio of the volume of the second metal layer to the total volume of the conductive structure is 5 vol% to 70 vol%.

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

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

4. The conductive structure according to claim 3, wherein: A gap is formed between an end portion of the second metal layer and the first metal pillar.

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. The conductive structure according to claim 1 , wherein: The end portion of the second metal layer includes a first extending segment and / or a second extending segment, the first extending segment extends along a first direction, the second extending segment extends along a second direction, and the first direction intersects with the second direction.

7. The conductive structure according to claim 1, wherein: 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, wherein: The supporting surface is an inclined surface, and in 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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 tab.

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

17. The conductive structure according to claim 16, wherein: 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, wherein: 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, wherein: 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 the 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, wherein: 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, wherein: The average thickness of the first segment is greater than the average thickness of the second segment, and the average thickness of the second segment is greater than the average thickness of the third segment.

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

23. The conductive structure according to claim 21, wherein: 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, wherein: 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 sub-segment is greater than or equal to 0.5 mm, and / or the average thickness of the second sub-segment is greater than or equal to 0.5 mm.

27. The conductive structure according to claim 24, wherein: 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, wherein: 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, wherein: Along the axial direction of the first metal column, the distance between the outer surface of the third segment and the end of the fourth segment 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 segment is e, where a>e>0.5mm.

31. The conductive structure according to claim 29, wherein: The second metal layer further includes a fifth section corresponding 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, wherein: Along the axial direction of the first metal column, a distance b is between the inner surface of the fifth section and the inner surface of the third section, where 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, wherein: 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, wherein: 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 tab.

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 0.1mm-3mm; and / or the ratio of the volume of the second metal layer to the total volume of the conductive structure is 5vol%~40vol%; and / or the volume ratio of the second metal layer to the first metal column is 0.1~0.

65.

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. A cover plate assembly, characterized in that: include: cover; The conductive structure according to any one of claims 1 to 40, wherein the conductive structure is provided through the cover plate.

42. The cover plate assembly according to claim 41, wherein: The conductive structure is a pole or an integrated pole and terminal block; The cover plate assembly further includes a current collecting member, which is located on one side of the cover plate and welded to the conductive structure.

43. The cover plate assembly according to claim 42, wherein: The cover plate comprises: Cover body, A first insulating member is provided between the conductive structure and the cover body, A second insulating member is provided between the cover body and the current collecting member; and / or, The cover plate assembly further includes a seal disposed between the cover plate and the conductive structure.

44. A battery cell, characterized in that: include: A housing having a receiving cavity; An electrode assembly is disposed in the accommodating cavity, wherein the electrode assembly includes an electrode tab; The cover plate assembly according to any one of claims 41 to 43, 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 tab.

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