A composite terminal post, battery cover and battery

Abstract

This invention relates to the field of battery technology, specifically disclosing a composite electrode post, a battery cover, and a battery. The composite electrode post includes a copper portion and an aluminum portion. A first end face of the copper portion has a flange, and the inner wall of the flange and the first end face of the copper portion form a receiving groove. The end face of the aluminum portion located within the receiving groove is a second end face. The second end face and the first end face are formed by friction welding to create a copper-aluminum bonding surface. The aluminum portion has a cylindrical first cutting layer circumferentially, with the circumferential surface of the first cutting layer spaced apart from the inner wall of the flange. The outer diameter φF and the inner diameter φE of the first cutting layer satisfy the following condition: 1.25 ≤ φF / φE ≤ 3. Therefore, when machining the integral structure formed by friction welding of the copper and aluminum portions, a material layer with lower circumferential bonding strength at the copper-aluminum bonding surface can be removed, ensuring higher bonding strength at the copper-aluminum bonding surface in the finished composite electrode post. This invention also provides a battery cover and a battery, including the aforementioned composite electrode post.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a composite terminal, a battery cover, and a battery. Background Technology

[0002] As an accessory in lithium-ion batteries, the battery cover's main function is to seal the internal and external environments by welding it to the aluminum casing. Secondly, it connects the internal and external circuits, allowing the current inside the lithium-ion battery to be transported to the outside through the terminals on the top cover, thus serving as a current guide.

[0003] Traditionally, battery terminals are fixed to the top cover by riveting. These terminals include positive and negative terminals. To improve lithium-ion battery performance, the negative terminal is often made of a copper-aluminum composite material, reducing internal resistance and increasing power and energy density. However, due to the low bonding strength at the copper-aluminum interface, the composite terminal is prone to detachment after assembly with the top cover, leading to terminal failure. Summary of the Invention

[0004] The purpose of this invention is to provide a composite electrode post, a battery cover plate, and a battery, which defines important parameters for the friction welding of the composite electrode post, thereby improving the connection strength between the copper and aluminum parts, preventing the composite electrode post from separating at the copper-aluminum interface, and ensuring high reliability and safety.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a composite electrode post, comprising:

[0007] The copper material part has a flange on its first end face, and the inner wall surface of the flange forms a receiving groove with the first end face;

[0008] The aluminum part has one end located in the receiving groove. The second end face of the aluminum part facing the copper part is friction-welded with the first end face to form a copper-aluminum bonding surface. The aluminum part is provided with a cylindrical first cutting layer in the circumferential direction. The circumferential side of the first cutting layer is spaced apart from the inner wall surface of the flange.

[0009] Wherein, the outer diameter of the first cutting layer is φF, the inner diameter of the first cutting layer is φE, and φF and φE satisfy the following condition: 1.25≤φF / φE≤3;

[0010] The value range of φF is: 5mm≤φF≤70mm;

[0011] The value range of φE is: 4mm≤φE≤Φ50mm.

[0012] Optionally, the thickness of the flange along the first direction is A, and the height of the flange along the second direction is B. A and B satisfy the condition: 1.5≤B / A≤3, and A and φF satisfy the condition: 0.1≤A / φF≤1.

[0013] The range of values ​​for A is: 2mm ≤ A ≤ 10mm;

[0014] The value of B is in the range of 3mm≤B≤30mm.

[0015] Optionally, the aluminum material portion is further provided with a second cutting layer in the circumferential direction. After the first cutting layer and the second cutting layer are peeled off from the aluminum material portion, the remaining portion of the aluminum material portion includes a first column and a second column, and the end face of the second column facing away from the first column is the second end face.

[0016] The copper material portion is provided with a third cutting layer in the circumference. After the third cutting layer is peeled off from the copper material portion, the remaining part of the copper material portion includes a plate and a third column. The end face of the third column facing away from the plate is the first end face.

[0017] Optionally, the copper-aluminum bonding surface is an arc surface, and the copper-aluminum bonding surface protrudes along the second direction to the side where the plate is located. The intersection of the copper-aluminum bonding surface with the peripheral side surface of the second column and the third column forms an annular intersection line.

[0018] Along the second direction, the distance between the annular intersecting line and the end face of the plate facing the third column is k, and the value of k is in the range of 0.2mm≤k≤10mm.

[0019] Optionally, along the second direction, the height difference between the vertex of the protrusion on the side where the copper-aluminum bonding surface faces the plate and the annular intersection line is a, and the value of a ranges from 0.2mm to 0.5mm.

[0020] Optionally, along the second direction, the distance between the vertex of the protrusion on the side of the copper-aluminum bonding surface facing the plate and the end face of the plate facing away from the third column is h;

[0021] The value range of h is: 1.5mm≤h≤10mm.

[0022] Optionally, the roughness of the first end face is γ1, and the range of values ​​for γ1 is:

[0023] Ra3.2≤γ1≤Ra12.5;

[0024] The roughness of the second end face is γ2, and the value range of γ2 is: Ra3.2≤γ2≤Ra12.5.

[0025] Optionally, the bonding pressure during friction welding between the second end face of the aluminum material and the first end face of the copper material is P, and the value range of P is: 100Mpa≤P≤200Mpa.

[0026] Secondly, the present invention provides a battery cover plate, including a cover plate body and a composite terminal post as described in any of the above embodiments, wherein the composite terminal post is integrated on the cover plate body.

[0027] Thirdly, the present invention provides a battery including the battery cover described above.

[0028] The beneficial effects of this invention are as follows:

[0029] This invention provides a composite electrode post, comprising a copper portion and an aluminum portion. The first end face of the copper portion has a flange, and the inner wall of the flange and the first end face of the copper portion form a receiving groove. The end face of the aluminum portion located within the receiving groove is a second end face. The second end face and the first end face are formed by friction welding to create a copper-aluminum bonding surface, thus connecting the copper and aluminum portions into a single structure. The aluminum portion is columnar, and a cylindrical first cutting layer is provided circumferentially. The circumferential surface of the first cutting layer is spaced apart from the inner wall of the flange. The outer diameter φF and the inner diameter φE of the first cutting layer satisfy the following condition: 1.25 ≤ φF / φE ≤ 3. Therefore, when machining the integrated structure formed by friction welding of the copper and aluminum portions, the material layer with lower bonding strength on the outer circumference of the copper-aluminum bonding surface can be removed, ensuring higher bonding strength between the copper and aluminum portions in the finished composite electrode post. Simultaneously, material consumption is minimized, resulting in lower costs.

[0030] The present invention also provides a battery cover, including a cover body and the aforementioned composite terminal, wherein the composite terminal is integrated on the cover body. By using this composite terminal, after the composite terminal is assembled with the cover body, the composite terminal is less likely to separate at the copper-aluminum interface when the cover body is subjected to impact, thus ensuring high reliability of the battery cover and reducing the likelihood of failure.

[0031] The present invention also provides a battery including the aforementioned battery cover. By using the aforementioned battery cover, the reliability of the battery can be ensured to be high, and the battery cover is not prone to failure. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0033] Figure 1This is a top view of the composite pole (before cutting) provided in an embodiment of the present invention;

[0034] Figure 2 for Figure 1 Cross-sectional view of section I-I;

[0035] Figure 3 This is a cross-sectional view of the composite pole (after cutting) provided in an embodiment of the present invention;

[0036] Figure 4 This is a cross-sectional view of the composite pole (after cutting and riveting) provided in an embodiment of the present invention;

[0037] Figure 5 This is an exploded view of the battery cover provided in an embodiment of the present invention.

[0038] In the picture:

[0039] 100. Composite pole; 110. Copper part; 111. Flanged edge; 1101. Receiving groove; 112. Third cutting layer; 113. Third column; 114. Plate; 120. Aluminum part; 121. First cutting layer; 122. Second cutting layer; 123. First column; 1231. Protrusion; 124. Second column; 130. Copper-aluminum mating surface; 200. Cover plate body; 201. First mounting hole; 300. First plastic part; 301. Second mounting hole; 400. Second plastic part; 401. Third mounting hole; 500. Connecting block; 501. Fourth mounting hole; 600. Sealing element; 700. Positive pole. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0044] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0047] like Figure 1 and Figure 2 As shown, this embodiment provides a composite electrode post 100, which includes a copper portion 110 and an aluminum portion 120. The copper portion 110 and the aluminum portion 120 are connected by friction welding to form an integral structure. To facilitate material flow and diffusion during friction welding, the aluminum portion 120 can be made of Al1060 H112, and the copper portion 110 can be made of CUTP2.

[0048] Specifically, the first end face of the copper part 110 is provided with a flange 111, and the inner wall surface of the flange 111 and the first end face of the copper part 110 form a receiving groove 1101. The receiving groove 1101 is a groove with a circular cross-section. The aluminum part 120 is columnar, with one end of the aluminum part 120 located in the receiving groove 1101. The aluminum part 120 is provided with a cylindrical first cutting layer 121 around its circumference, and the circumferential side surface of the first cutting layer 121 is spaced apart from the inner wall surface of the flange 111. By providing a gap between the circumferential side surface of the first cutting layer 121 and the inner wall surface of the flange 111, it is convenient to rotate the aluminum part 120 so that the second end face of the aluminum part 120 facing the copper part 110 and the first end face of the copper part 110 are fused together under the high temperature generated by friction. Thus, the second end face and the first end face form a copper-aluminum bonding surface 130 through friction welding, and the copper part 110 and the aluminum part 120 are connected into an integral structure.

[0049] It should be noted that when the copper part 110 and the aluminum part 120 are friction welded, the aluminum material of the aluminum part 120 will flow outward along the gap between the peripheral side of the first cutting layer 121 and the inner wall of the flange 111, resulting in a low circumferential outer ring bonding strength at the copper-aluminum bonding surface 130 of the copper part 110 and the aluminum part 120. Therefore, after the copper part 110 and the aluminum part 120 are formed into an integral structure through friction welding, the copper part 110 and the aluminum part 120 are machined to remove the material layer at the circumferential outer ring of the copper-aluminum bonding surface 130, ultimately forming the finished composite pole 100. In this embodiment, the first cutting layer 121 of the aluminum part 120 is removed, and the area on the copper part 110 connected to the first cutting layer 121 is also cut off (the removed portion is...). Figure 2 (The dotted line portion in the image). Therefore, the portion of the copper-aluminum bonding surface 130 located on its outer circumferential ring will be cut off to ensure a high connection strength between the copper portion 110 and the aluminum portion 120 in the finished composite pole 100.

[0050] The outer diameter of the first cutting layer 121 is φF, and the inner diameter is φE. φF and φE satisfy the condition: 1.25 ≤ φF / φE ≤ 3. For example, the value of φF / φE can be 1.25, 1.50, 2.00, 2.50, or 3.00, etc. By limiting the value of φF / φE to the above range, it can be ensured that the weaker parts of the copper-aluminum bonding surface 130 can be removed, leaving a portion with higher bonding strength, while saving material consumption and reducing costs. Otherwise, if the value of φF / φE is too small, the outermost material layers removed from the copper portion 110 and the aluminum portion 120 will be thin, affecting the bonding strength of the copper-aluminum bonding surface 130. Under tensile force, the copper-aluminum bonding surface 130 is prone to detachment from the periphery towards the center, failing to guarantee that the bonding strength of the copper-aluminum bonding surface 130 meets the requirements, and posing a risk of separation. When the value of φF / φE is too large, it will result in a large amount of material being used in the first cutting layer 121, causing a large amount of aluminum material to be wasted and increasing costs.

[0051] It is important to note that the inner diameter φE of the first cutting layer 121 is the diameter of the end where the aluminum part 120 and the copper part 110 are connected after material removal, which is also the diameter of the copper-aluminum bonding surface 130 in the finished composite pole 100. By limiting the value of φE within the above range, it can be ensured that the aluminum part 120 has high mechanical strength after material removal, and can resist large push-pull stress (>1000N) without breaking. At the same time, the bonding strength at the copper-aluminum bonding surface 130 of the copper part 110 and the aluminum part 120 is also high, and the copper part 110 and the aluminum part 120 are not easy to separate. This ensures that the assembly structure of the composite pole 100 on the cover plate body 200 is stable and highly reliable.

[0052] Optionally, in this embodiment, the value range of φE is: 4mm≤φE≤Φ50mm. For example, the value of φE can be 4mm, 10mm, 20mm, 30mm, 40mm, or 50mm, etc.

[0053] The value range of φF is: 5mm ≤ φF ≤ 70mm. For example, when the value of φE is 4mm, the value of φF can be 5mm, 8mm, 10mm, or 12mm. When the value of φE is 20mm, the value of φF can be 25mm, 30mm, 40mm, or 50mm, etc. When the value of φE is 50mm, the value of φF can be 62.5mm, 65mm, or 70mm, etc.

[0054] See also Figure 2 In this embodiment, the thickness of the flange 111 along the first direction is A, and the height of the flange 111 along the second direction is B. Wherein, the first direction is... Figure 2 The Y-axis direction shown is the second direction. Figure 2The Z-axis direction is shown in the figure. The relationship between A and B satisfies: 1.5 ≤ B / A ≤ 3. For example, the value of B / A can be 1.50, 2.00, 2.50, or 3.00, etc. And the relationship between A and φF satisfies: 0.1 ≤ A / φF ≤ 1. For example, the value of A / φF can be 0.1, 0.3, 0.5, 0.8, or 1.0, etc. By limiting the values ​​of B / A and A / φF within the above ranges, the mechanical strength of the flange 111 can be guaranteed to be high. When the aluminum part 120 is subjected to pressure and friction welding with the copper part 110, the flange 111 can suppress the aluminum material of the aluminum part 120 from overflowing outward from the gap between the peripheral side surface of the first cutting layer 121 and the inner wall surface of the flange 111, thereby reducing aluminum material loss. It also ensures that the bonding pressure between the aluminum part 120 and the copper part 110 meets the requirements, thus ensuring high connection strength of the copper-aluminum bonding surface 130 and preventing separation.

[0055] Optionally, the value range of A is: 2mm ≤ A ≤ 10mm. The value range of B is: 3mm ≤ B ≤ 30mm. For example, when the value of A is 2mm, the value of B can be 3mm, 4mm, 5mm, or 6mm, and the value of φF can be 2mm, 5mm, 10mm, 15mm, or 20mm, etc. When the value of A is 10mm, the value of B can be 15mm, 20mm, 25mm, or 30mm, and the value of φF can be 10mm, 30mm, 50mm, or 70mm, etc.

[0056] Furthermore, to ensure a high connection strength between the copper part 110 and the aluminum part 120 during friction welding, the roughness of the first end face in this embodiment is γ1, and the value range of γ1 is: Ra3.2≤γ1≤Ra12.5. The roughness of the second end face is γ2, and the value range of γ2 is: Ra3.2≤γ2≤Ra12.5. By limiting the roughness of the first end face γ1 and the roughness of the second end face γ2 to both within the range of Ra3.2-Ra12.5, a high bonding strength can be ensured during friction welding of the first and second end faces. Otherwise, if the values ​​of γ1 and γ2 are too small, the roughness of the first and second end faces will be small, making it difficult to bond the copper part 110 and the aluminum part 120 during friction welding. When the values ​​of γ1 and γ2 are too large, the roughness of the first end face and the second end face is large, the temperature rise during friction between the copper part 110 and the aluminum part 120 is too fast, the metal grains at the copper-aluminum bonding surface 130 are rapidly damaged, and the bonding strength between the copper part 110 and the aluminum part 120 will also be affected.

[0057] In addition, to prevent the temperature from rising too quickly during friction between the copper part 110 and the aluminum part 120, the rotation speed of the aluminum part 120 or the copper part 110 can be adjusted so that the temperature T of the contact surface between the copper part 110 and the aluminum part 120 during friction welding is between 400℃ and 1000℃, i.e., 400℃≤T≤1000℃, so as to improve the bonding strength between the copper part 110 and the aluminum part 120.

[0058] Optionally, the bonding pressure during friction welding between the second end face of the aluminum part 120 and the first end face of the copper part 110 is P, and the value of P ranges from 100 MPa ≤ P ≤ 200 MPa. For example, the value of P can be 100 MPa, 150 MPa, or 200 MPa. By limiting the value of P to the above range, it is beneficial to improve the bonding strength between the copper part 110 and the aluminum part 120, while ensuring that the deformation of the copper part 110 and the aluminum part 120 is small, which facilitates the subsequent machining process. Otherwise, if the value of P is too small, the connection strength between the copper part 110 and the aluminum part 120 at the copper-aluminum bonding surface 130 will be small; if the value of P is too large, it will easily lead to deformation of the copper part 110 or the aluminum part 120, which is not conducive to the subsequent machining process.

[0059] See also Figure 2 and Figure 3 After the copper part 110 and the aluminum part 120 are joined into a single structure by friction welding, they need to be machined to finally form a composite pole 100. Specifically, the parts to be removed during machining include the first cutting layer 121 and the second cutting layer 122 of the aluminum part 120, and the third cutting layer 112 of the copper part 110. The second cutting layer 122 of the aluminum part 120 is also located circumferentially, and is located inside the first cutting layer 121.

[0060] It should be noted that the first cutting layer 121 and the third cutting layer 112 can be processed in one machining step, and then the second cutting layer 122 is peeled off from the aluminum part 120 by machining. Finally, after the first cutting layer 121 and the second cutting layer 122 are peeled off from the aluminum part 120, the remaining part of the aluminum part 120 forms the first pillar 123 and the second pillar 124, and the diameter of the first pillar 123 is smaller than the diameter of the second pillar 124. The remaining part of the copper part 110 forms the plate 114 and the third pillar 113, and the third pillar 113 and the second pillar 124 are connected at the end opposite to the first pillar 123. That is, the end face of the second column 124 facing away from the first column 123 is the second end face, and the end face of the third column 113 facing away from the plate 114 is the first end face. The end face of the second column 124 facing away from the first column 123 and the end face of the third column 113 facing away from the plate 114 are combined to form a copper-aluminum bonding surface 130. Afterwards, the composite pole 100 is processed into a finished product, which can be assembled with the cover plate body 200.

[0061] See Figure 4 and Figure 5 In some embodiments, the first column 123 of the composite pole 100 can be riveted to the connecting block 500 provided on one side of the cover plate body 200 after passing through the cover plate body 200. The first column 123 expands along its radial direction and forms a protrusion 1231. Thus, the composite pole 100 can be fixed on the cover plate body 200 through the protrusion 1231 and the plate body 114.

[0062] See also Figure 3 In this embodiment, after the composite pole 100 is formed, its copper-aluminum bonding surface 130 is an arc surface, and along the second direction, the copper-aluminum bonding surface 130 protrudes towards the side of the plate 114. The intersection of the copper-aluminum bonding surface 130 with the peripheral surfaces of the second pole 124 and the third pole 113 forms an annular intersection line. Along the second direction, the distance between the annular intersection line and the end face of the plate 114 facing the third pole 113 is k, and the value of k is in the range of 0.2mm≤k≤10mm. For example, the value of k can be 0.2mm, 0.5mm, 1.0mm, 2.0mm, 5.0mm, 8.0mm, or 10.0mm, etc. By adopting the above configuration, the copper-aluminum bonding surface 130 is offset from the position of the most stress concentration in the composite pole 100 (the connection between the plate 114 and the third pole 113), thereby providing a certain degree of protection for the copper-aluminum bonding surface 130 and reducing the risk of separation between the copper part 110 and the aluminum part 120.

[0063] Along the second direction, the height difference between the apex of the copper-aluminum bonding surface 130 protruding towards the side of the plate 114 and the annular intersection line is 'a', and the value of 'a' ranges from 0.2mm to 0.5mm. For example, the value of 'a' can be 0.2mm, 0.3mm, 0.4mm, or 0.5mm, etc. By limiting the value of 'a' to the above range, it can be ensured that the copper-aluminum bonding surface 130 does not protrude excessively towards the side of the plate 114, thereby maximizing the connection strength between the copper part 110 and the aluminum part 120.

[0064] Furthermore, the plate 114 of the composite electrode 100 needs to be welded to the battery tab. In this embodiment, the distance between the apex of the copper-aluminum bonding surface 130 protruding towards the side of the plate 114 along the second direction and the end face of the plate 114 on the side away from the third column 113 is h, and the value of h is in the range of 1.5mm ≤ h ≤ 10mm. For example, the value of h can be 1.5mm, 2.0mm, 5.0mm, 8.0mm, or 10.0mm, etc. By limiting the value of h to the above range, the copper-aluminum bonding surface 130 is protected from the heat generated during welding, thereby ensuring a high bonding strength between the second column 124 and the third column 113, making separation less likely.

[0065] The parameter limitations in the above processing procedure are verified using composite poles 100 in some specific embodiments, and the results are shown in Table 1.

[0066] Table 1

[0067]

[0068] The results above show that in Example 1, the values ​​of parameters φF / φE are close to the upper limit of their size constraints, the value of A / φF is at the lower limit of their size constraints, and the other parameters are all within normal ranges. At this point, the connection strength at the copper-aluminum interface 130 in the finished composite electrode 100 is high, making separation less likely. The composite electrode 100 exhibits high reliability, and the product is of good quality.

[0069] In Example 2, the values ​​of parameters φF / φE are at the lower limit of their size constraints, the value of A / φF is at the upper limit of their size constraints, and the other parameters are all within normal ranges. At this point, the connection strength at the copper-aluminum interface 130 in the finished composite electrode 100 is high, making separation less likely. The composite electrode 100 has high reliability, and the product is of good quality.

[0070] In Example 3, the values ​​of parameters φF / φE are at the lower limit of their size constraints, the value of h is close to the lower limit of its size constraints, and the other parameters are all within normal ranges. At this point, the connection strength at the copper-aluminum interface 130 in the finished composite electrode 100 is high, making separation less likely. The composite electrode 100 has high reliability, and the product is of good quality.

[0071] In Example 4, the value of parameter B / A is at the upper limit of its size limitation, while the other parameters are all within normal ranges. At this point, the connection strength at the copper-aluminum interface 130 in the finished composite electrode 100 is high, making separation less likely. The composite electrode 100 exhibits high reliability, resulting in a good product.

[0072] In Example 5, the value of parameter B / A is at the lower limit of its size constraint, while the other parameters are all within normal ranges. At this point, the connection strength at the copper-aluminum interface 130 in the finished composite electrode 100 is high, making separation less likely. The composite electrode 100 exhibits high reliability, resulting in a good product.

[0073] In Example 6, the value of parameter a is close to the lower limit of its size constraint, while the other parameters are all within normal ranges. At this time, the connection strength at the copper-aluminum interface 130 in the finished composite electrode 100 is high, and separation is not easy to occur. The composite electrode 100 has high reliability and the product is of good quality.

[0074] Referring to Comparative Example 1, the value of parameter A / φF exceeds the lower limit of 0.1≤A / φF≤1, while the other parameters are within normal ranges. At this time, before machining the composite electrode 100, during friction welding of the copper part 110 and the aluminum part 120, the mechanical strength of the flange 111 of the copper part 110 is insufficient, and the aluminum part 120 experiences significant overflow. The machined composite electrode 100 can withstand a pull-out force of less than 1000N, and the composite electrode 100 is prone to separation at the copper-aluminum interface 130. This results in low reliability and defective products.

[0075] Referring to Comparative Example 2, the value of parameter φF / φE exceeds the lower limit of 1.25≤φF / φE≤3, while the other parameters are within normal ranges. In this case, the portion with lower connection strength in the copper-aluminum interface 130 is not completely removed, resulting in the composite electrode 100 being unable to withstand a pull-out force of less than 1000N after machining. Consequently, the composite electrode 100 separates at the copper-aluminum interface 130, leading to low reliability and product defects.

[0076] Referring to Comparative Example 3, the value of parameter h exceeds the lower limit of 1.5mm ≤ h ≤ 10mm, while the other parameters are within normal ranges. At this point, the distance between the copper-aluminum bonding surface 130 and the end face of the plate 114 facing away from the third column 113 is too close. The copper-aluminum bonding surface 130 is easily affected by the heat generated during welding of the plate 114 and the electrode tab, resulting in decreased connection strength. The composite electrode 100 is prone to separation at the copper-aluminum bonding surface 130, leading to low reliability and product defects.

[0077] Referring to Comparative Example 4, the value of parameter A exceeds the lower limit of 2mm≤A≤10mm, while the other parameters are within normal ranges. At this time, before machining the composite electrode 100, during friction welding of the copper part 110 and the aluminum part 120, the mechanical strength of the flange 111 of the copper part 110 is insufficient, and the aluminum part 120 experiences significant overflow. When the composite electrode 100 after machining can withstand a pull-out force of less than 1000N, the composite electrode 100 separates at the copper-aluminum interface 130. This results in low reliability of the composite electrode 100 and defective products.

[0078] Referring to Comparative Example 5, the value of parameter B / A exceeds the lower limit of 1.5 ≤ B / A ≤ 3, while the other parameters are within normal ranges. At this time, before machining the composite electrode 100, during friction welding of the copper part 110 and the aluminum part 120, the mechanical strength of the flange 111 of the copper part 110 is insufficient, and the aluminum part 120 experiences significant overflow. When the composite electrode 100 after machining can withstand a pull-out force of less than 1000N, the composite electrode 100 separates at the copper-aluminum interface 130. This results in low reliability of the composite electrode 100 and defective products.

[0079] Referring to Comparative Example 6, the value of parameter 'a' exceeds the lower limit of 0.2mm ≤ a ≤ 0.5mm, while the other parameters are within normal ranges. In this case, the copper-aluminum bonding surface 130 protrudes excessively towards the side where the plate 114 is located, reducing the connection strength at the copper-aluminum bonding surface 130. The composite pole 100 is prone to separation at the copper-aluminum bonding surface 130, resulting in low reliability and product defects.

[0080] In summary, this invention defines important parameters for the composite electrode 100 during friction welding and machining. It can be seen that when the above parameters φE, φF, φF / φE, A, B / A, A / φF, a, and h are within their respective dimensional limits, the connection strength at the copper-aluminum interface 130 of the machined composite electrode 100 can be guaranteed to be high, the pull-out force can be greater than 1000N, the composite electrode 100 is not easy to separate at the copper-aluminum interface 130, and the composite electrode 100 has high reliability.

[0081] See Figure 5 This embodiment also provides a battery cover, including a cover body 200 and the aforementioned composite terminal 100, which is integrated onto the cover body 200. By employing the composite terminal 100 in this embodiment, after the composite terminal 100 is assembled with the cover body 200, when the cover body 200 is subjected to impact, the composite terminal 100 is less likely to separate at the copper-aluminum bonding surface 130. The composite terminal 100 is well fixed to the cover body 200, ensuring high reliability of the battery cover and reducing the likelihood of failure.

[0082] Specifically, the battery cover in this embodiment further includes a first plastic part 300, a second plastic part 400, and a connecting block 500. The first plastic part 300 and the second plastic part 400 are respectively disposed on both sides of the cover body 200, and the connecting block 500 is disposed on the side of the first plastic part 300 facing away from the cover body 200. The cover body 200 has a first mounting hole 201, the first plastic part 300 has a second mounting hole 301, and the second plastic part 400 has a third mounting hole 401. The connecting block 500 has a fourth mounting hole 501. The first column 123 of the composite electrode 100 passes through the third mounting hole 401, the first mounting hole 201, the second mounting hole 301, and the fourth mounting hole 501 in sequence. The first column 123 is then riveted to the connecting block 500 to form a protrusion 1231. The protrusion 1231 is welded to the connecting block 500. The plate 114 of the composite electrode 100 is welded to the electrode lug of the electrode assembly, thereby realizing the installation of the composite electrode 100 on the cover plate body 200. The battery cover plate also includes a sealing element 600. The sealing element 600 is sleeved on the second column 124 and the third column 113 of the composite electrode 100 and is sandwiched between the composite electrode 100 and the cover plate body 200, thereby achieving the sealing of the battery cover plate.

[0083] Furthermore, the battery cover also integrates a positive terminal 700, which is also integrated on the cover body 200. The mounting structure of the positive terminal 700 is the same as that of the composite terminal 100.

[0084] This embodiment also provides a battery, including a casing, an electrode assembly, and the aforementioned battery cover. The electrode assembly is disposed within the casing, and the battery cover seals the opening in the casing, thus encapsulating the electrode assembly through the battery cover and the casing. The electrode assembly includes a positive tab and a negative tab. The positive tab is electrically connected to the positive terminal 700, and the negative tab is electrically connected to the plate 114 of the composite terminal 100. By employing the aforementioned battery cover, the battery's reliability can be ensured to be high, and the battery cover is less prone to failure.

[0085] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A composite electrode, characterized in that, The composite pole includes: The copper material part has a flange on its first end face, and the inner wall surface of the flange forms a receiving groove with the first end face; The aluminum part has one end located in the receiving groove. The second end face of the aluminum part facing the copper part is friction-welded with the first end face to form a copper-aluminum bonding surface. The aluminum part is provided with a cylindrical first cutting layer in the circumferential direction. The circumferential side of the first cutting layer is spaced apart from the inner wall surface of the flange. Wherein, the outer diameter of the first cutting layer is φF, the inner diameter of the first cutting layer is φE, and φF and φE satisfy the following condition: 1.25≤φF / φE≤3; The value range of φF is: 5mm≤φF≤50mm; The value range of φE is: 4mm≤φE≤Φ50mm; The thickness of the flange along the first direction is A, and the height of the flange along the second direction is B; The relationship between A and B satisfies: 1.5 ≤ B / A ≤ 3; The relationship between A and φF satisfies: 0.1 ≤ A / φF ≤ 1; The range of values ​​for A is: 2mm ≤ A ≤ 10mm; The value of B is in the range of 3mm≤B≤30mm.

2. The composite electrode according to claim 1, characterized in that, The aluminum material portion is further provided with a second cutting layer in the circumferential direction. After the first cutting layer and the second cutting layer are peeled off from the aluminum material portion, the remaining part of the aluminum material portion includes a first column and a second column. The end face of the second column facing away from the first column is the second end face. The copper material portion is provided with a third cutting layer in the circumference. After the third cutting layer is peeled off from the copper material portion, the remaining part of the copper material portion includes a plate and a third column. The end face of the third column facing away from the plate is the first end face.

3. The composite electrode according to claim 2, characterized in that, The copper-aluminum bonding surface is an arc surface, and the copper-aluminum bonding surface protrudes along the second direction to the side where the plate is located. The intersection of the copper-aluminum bonding surface with the peripheral side surface of the second column and the third column forms an annular intersection line. Along the second direction, the distance between the annular intersecting line and the end face of the plate facing the third column is k, and the value of k is in the range of 0.2mm≤k≤10mm.

4. The composite electrode according to claim 3, characterized in that, Along the second direction, the height difference between the vertex of the protrusion on the side of the copper-aluminum bonding surface facing the plate and the annular intersection line is a; The range of values ​​for 'a' is: 0.2mm ≤ a ≤ 0.5mm.

5. The composite electrode according to claim 3, characterized in that, Along the second direction, the distance between the vertex of the protrusion on the side of the copper-aluminum bonding surface facing the plate and the end face of the plate facing away from the third column is h, and the value of h is in the range of 1.5mm≤h≤10mm.

6. The composite electrode according to claim 1, characterized in that, The roughness of the first end face is γ1, and the value range of γ1 is: Ra3.2≤γ1≤Ra12.5; The roughness of the second end face is γ2, and the value range of γ2 is: Ra3.2≤γ2≤Ra12.

5.

7. The composite electrode according to claim 1, characterized in that, The bonding pressure during friction welding between the second end face of the aluminum material and the first end face of the copper material is P; The range of values ​​for P is: 100 MPa ≤ P ≤ 200 MPa.

8. A battery cover, characterized in that, It includes a cover plate body and a composite pole as described in any one of claims 1-7, wherein the composite pole is integrated on the cover plate body.

9. A battery, characterized in that, Includes the battery cover as described in claim 8.

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