Special-shaped copper strip for preparing embedded groove copper-aluminum composite strip

Abstract

The utility model provides a special-shaped copper strip for preparing an embedded groove copper-aluminum composite strip, and relates to the field of copper-aluminum composite materials. When the special-shaped copper strip is observed from the section direction, the upper plate surface is a convex arc surface, and the lower plate surface is a plane or a concave arc surface; a plurality of caulking grooves are formed in the lower plate face side by side, the groove bottom face of each caulking groove is a concave arc face, and at least one of the two groove edge faces of each caulking groove inclines outwards. After the special-shaped copper strip is cast and rolled, the groove bottom angle and the groove top angle of the caulking groove can be obtuse angles, so that the stress generated in a corner area when molten aluminum is solidified is reduced, and the anti-stripping performance of the copper-aluminum composite strip is effectively improved. The upper plate surface of the special-shaped copper strip is the convex cambered surface, and when the special-shaped copper strip is subjected to cast-rolling compounding with molten aluminum, firstly, a casting roller can generate larger rolling force at the caulking groove part, so that the compounding strength of the molten aluminum at the caulking groove part is favorably improved; and secondly, a rolling deformation part firstly appears at a part with a higher convex cambered surface and then extends towards two sides, so that the composite strength of the lower plate surface, the caulking groove and molten aluminum is improved.

Description

Technical Field

[0001] This utility model is specifically a shaped copper strip for preparing grooved copper-aluminum composite strips, and relates to the field of copper-aluminum composite material technology. Background Technology

[0002] Copper-aluminum composite materials combine the advantages of both copper and aluminum, featuring high electrical and thermal conductivity, lightweight, corrosion resistance, and low overall cost. They are widely used in fields such as power, semiconductors, electronic devices, and new energy vehicles.

[0003] Copper-aluminum composite materials come in a variety of forms, requiring processing into different shapes and structures according to customer requirements, such as copper-aluminum composite strips with grooved structures. (See attached document.) Figure 1 A certain type of copper-aluminum composite strip with a grooved structure is described. This copper-aluminum composite strip uses a copper strip with a grooved structure as the base material, and a layer of aluminum material is laminated onto the copper strip using a copper-aluminum solid-liquid composite process. The copper-aluminum solid-liquid composite process is a composite process in which copper strip is coated onto semi-molten aluminum and then cast and rolled. Compared to mechanical pressing-in interlocking processes, the copper-aluminum solid-liquid composite process has advantages such as higher interfacial bonding strength, lower production costs, and suitability for continuous production.

[0004] See attached document Figure 2 The grooved structure increases the contact area and heat dissipation of copper and aluminum. However, actual testing revealed defects at the four corners of the grooved structure in the copper-aluminum composite strip. The defect was largest at corner A, while the defect at corner B was smaller than that at corner A. After applying a test force, peeling first occurred at corner A of the grooved structure. Furthermore, further testing showed that the smaller the corner, the larger the defect and the more prone it was to copper-aluminum peeling. Utility Model Content

[0005] In order to overcome the shortcomings of the prior art, this utility model discloses a special-shaped copper strip for preparing grooved copper-aluminum composite strip. Its purpose is to solve the problem that the grooved part has defects and copper-aluminum peeling is easy to occur in the prior art.

[0006] The present invention adopts the following technical solution:

[0007] A profiled copper strip for preparing grooved copper-aluminum composite strip, when viewed from the cross-sectional direction, has an upper plate surface that is a convex arc surface and a lower plate surface that is a flat or concave arc surface; multiple grooves are arranged side by side on the lower plate surface, the bottom surface of the groove is a concave arc surface, and at least one of the two groove sides of the groove is inclined outward.

[0008] Further improve the technical solution: the width of the upper plate is greater than the width of the lower plate.

[0009] Further technical improvement: A rounded corner is provided between the bottom plate and the side plate.

[0010] Further improve the technical solution: the included angle between the bottom plate and the side plate is 110-150°.

[0011] Further improve the technical solution: the angle of outward inclination of the groove side is 105-130°.

[0012] Further improve the technical solution: The groove is set along the length direction of the shaped copper strip.

[0013] Further improve the technical solution: take the center line of the irregular copper strip as the reference line, and the grooves on both sides of the reference line have the groove edge surface on the side closer to the reference line at a right angle to the bottom plate surface, and the groove edge surface on the side farther from the reference line at an obtuse angle to the bottom plate surface.

[0014] Further improve the technical solution: take the center line of the irregular copper strip as the reference line, and the grooves on both sides of the reference line have two groove edges that are obtuse angles with the lower plate surface, and the obtuse angle closer to the reference line is smaller than the obtuse angle farther away from the reference line.

[0015] After implementing the above technical solution, the beneficial effects of this utility model compared to the prior art are:

[0016] 1. A disadvantage of copper-aluminum casting-rolling composites is that stress is generated in the corner areas after the aluminum liquid solidifies, especially at acute or right angles, where the stress increases with the smaller the angle. The shaped copper strip of this invention, after casting and rolling, makes both the bottom and top angles of the groove obtuse, reducing the stress generated in the corner areas during aluminum solidification and effectively improving the anti-peeling performance of the copper-aluminum composite strip.

[0017] 2. The upper surface of this special-shaped copper strip is a convex arc surface, which makes the thickness of the middle part of the special-shaped copper strip greater than that of the two sides. When it is cast and rolled together with aluminum liquid, on the one hand, the casting and rolling roll can generate greater rolling force at the groove, which is conducive to improving the composite strength of aluminum liquid at the groove; on the other hand, the rolling deformation part first appears at the higher part of the convex arc surface, and then extends to both sides, which is conducive to improving the composite strength of the lower plate surface, the groove and the aluminum liquid. Attached Figure Description

[0018] Appendix Figure 1 The diagram shown is a schematic representation of the overall structure of the copper-aluminum composite strip.

[0019] Appendix Figure 2 The attached image shows the attached image. Figure 1 A partial structural diagram.

[0020] Appendix Figure 3 The diagram shown is a schematic of the irregularly shaped copper strip in Example 1.

[0021] Appendix Figure 4 The diagram shown is a schematic of the copper-aluminum casting-rolling composite process.

[0022] Appendix Figure 5 The image shown is a front view of the shaped copper strip entering the roll gap.

[0023] Appendix Figure 6 The image shown is a side view of the shaped copper strip entering the roll gap.

[0024] Appendix Figure 7 The diagram shows the structure of the copper-aluminum composite strip after casting and rolling.

[0025] Appendix Figure 8 The diagram shown illustrates the milling process for a copper-aluminum composite strip.

[0026] Appendix Figure 9 The diagram shown is a schematic of the irregularly shaped copper strip in Example 2.

[0027] Appendix Figure 10 The diagram shown is a schematic diagram of the copper-aluminum composite strip after casting and rolling in Example 2.

[0028] Appendix Figure 11 The diagram shown is a structural schematic of a high-voltage connector in Embodiment 3.

[0029] Appendix Figure 12 The diagram shown is a schematic of the irregularly shaped copper strip in Example 3.

[0030] Appendix Figure 13 The diagram shown is a schematic diagram of the copper-aluminum composite strip after casting and rolling in Example 3.

[0031] Appendix Figure 14 The diagram shown is a schematic of milling a copper-aluminum composite strip.

[0032] Appendix Figure 15 The diagram shown illustrates the slitting of copper-aluminum composite strip.

[0033] In the attached diagram: 1. Copper-aluminum composite strip; 1.1 Copper-clad surface; 1.2 Aluminum-clad surface; 1.3 Copper strip; 1.4 Aluminum insert; 2. Shaped copper strip; 2.1 Upper plate surface; 2.2 Lower plate surface; 2.3 Side plate surface; 2.4 Groove bottom surface; 2.5 Groove edge surface; 2.6 Rounded corner; 3. Furnace; 4. Casting nozzle; 5. Molten aluminum; 6. Casting roll. Detailed Implementation

[0034] The preferred embodiments of this utility model are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of this utility model and are not intended to limit the scope of protection of this utility model. It should be noted that in the description of this utility model, terms such as "front," "rear," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or element must have a specific orientation and positional relationship, and therefore should not be construed as a limitation of this utility model. It should also be noted that in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] Example 1: Refer again to the appendix Figure 1 and attached Figure 2 In this embodiment, the copper-aluminum composite strip is used for heat dissipation of electronic devices. This composite strip uses copper strip as the base material and aluminum as the composite material, with the copper-coated side being the conductive side and the aluminum-coated side being the heat dissipation side. Although aluminum's electrical and thermal conductivity are not as good as copper's, aluminum heats up faster and has a greater temperature difference with the environment. Under the same airflow, aluminum's heat dissipation is actually better than copper's. Multiple grooves are provided in the copper strip to increase the contact area between the copper and aluminum, thereby improving the heat dissipation of the copper-aluminum composite strip.

[0036] This copper-aluminum composite strip is produced using a copper-aluminum solid-liquid composite process. Due to defects at the corner of the groove, copper-aluminum peeling is prone to occur. Therefore, this invention improves the shape of the copper strip by processing it into a special-shaped copper strip.

[0037] See attached document Figure 3 The shaped copper strip can be prepared using continuous extrusion or rolling processes. Viewed from the cross-section, the upper surface 2.1 of the shaped copper strip 2 is a convex arc surface, and the lower surface 2.2 is a flat surface. Multiple grooves are provided on the lower surface 2.2 (see attached image for details). Figure 3 Only five slots are shown in the image. The bottom surface 2.4 of the slot is a concave arc surface. The slot in the middle has two slot edge surfaces 2.5 that are inclined outwards. The slots on both sides have the slot edge surface 2.5 near the inner side that is perpendicular to the bottom plate surface 2.2, and the slot edge surface 2.5 near the outer side that is inclined outwards and forms an obtuse angle with the bottom plate surface 2.2.

[0038] See attached document Figure 4 , attached Figure 4 The diagram shown illustrates the copper-aluminum casting-rolling composite process. (See attached diagram.) Figure 4 As can be seen, the casting and rolling equipment includes a furnace 3, a casting nozzle 4, and a pair of casting and rolling rolls 6. The shaped copper strip 2 is set on one side of the roll gap entrance. During the casting and rolling process, the lower plate surface 2.2 of the shaped copper strip 2 with the groove is placed on the aluminum liquid 5, and the shaped copper strip 2 is inclined along the length direction of the groove to enter the roll gap and be cast and rolled together with the aluminum liquid 5.

[0039] See attached document Figure 5 and attached Figure 6 The shaped copper strip 2 enters the roll gap at an angle along the length of the groove, which helps to completely expel the air between the shaped copper strip 2 and the molten aluminum 5, improving the bonding strength and conductivity of the copper-aluminum composite. Secondly, since the upper plate surface 2.1 is a convex arc surface and the bottom surface 2.4 of the groove is a concave arc surface, the thickness of the middle part of the shaped copper strip 2 is greater than that of the two sides. When it is cast and rolled together with the molten aluminum 5, the casting roll 6 can generate a greater rolling force at the groove part, which is beneficial to improving the composite strength of the molten aluminum 5 at the groove part. More importantly, the rolling of the shaped copper strip 2 by the casting roll 6 is not only a thinning in the thickness direction, but also an extension in the width and length directions. The rolling deformation first appears at the higher part of the convex arc surface (upper plate surface), and then extends to both sides (width direction).

[0040] See attached document Figure 7 , attached Figure 7 The diagram shown is a structural schematic of the copper-aluminum composite strip after casting and rolling. (See attached diagram.) Figure 7 It can be seen that after the shaped copper strip 2 is rolled by the casting roll 6, the upper plate surface 2.1 is rolled from a convex arc surface to a flat surface, and the bottom surface 2.4 of the groove is also rolled from a concave arc surface to a flat surface. Since the casting roll 6 has an extending effect on the shaped copper strip 2 in the width direction, the inclination angle of the two groove side surfaces 2.5 of the groove located in the middle remains basically unchanged. For the grooves on both sides, the groove side surfaces 2.5 near the inner side incline outward from their original vertical state, while the outward inclination angle of the groove side surfaces 2.5 near the outer side decreases. Thus, the two groove side surfaces 2.5 of all grooves are open and incline outward, with both the bottom and top angles being obtuse angles. It is also worth noting that, since the upper plate surface 2.1 is a convex arc surface and the lower plate surface 2.2 is a flat surface, the extension length of the upper plate surface 2.1 after casting and rolling is greater than the extension length of the lower plate surface 2.2, forming an obtuse angle structure between the lower plate surface 2.2 and the side plate surface 2.3.

[0041] After molten aluminum solidifies, stress is generated at corners, especially at acute or right angles; the smaller the angle, the greater the stress. Areas of stress concentration are weak points, much like tearing open a package where the tautest edges are the easiest to rip. This shaped copper strip, after casting and rolling, allows both sides of the groove to slope outwards, with obtuse angles at the bottom and top corners, effectively reducing the stress generated at the corners of the groove during aluminum solidification.

[0042] After casting and rolling, the lower plate surface 2.2 and the side plate surface 2.3 form an obtuse angle, and the upper plate surface 2.1 and the side plate surface 2.3 form an acute angle. This is equivalent to transferring the weak stress point from the obtuse angle to the acute angle. Therefore, the defect at the corner of point D is greater than the defect at the corner of point C. The corner of point D is the largest defect in this area and is most prone to copper-aluminum peeling.

[0043] Please refer to the appendix again. Figure 2 Appendix Figure 2 The reason why the two groove edges of the central slot are tilted to one side is that the extension of the shaped copper strip by the casting roll in the width direction was not taken into account, resulting in an acute angle at point A and an obtuse angle at point B. After applying the test force, peeling first appears at point A corner of the slot structure, and then extends to other parts.

[0044] See attached document Figure 8 The corners at points C and D have defects, and the corner at point D is the weakest point in the area. Therefore, the part most prone to copper-aluminum peeling can be milled off by milling the edges.

[0045] Example 2: Refer to Appendix Figure 9 and attached Figure 10 The shaped copper strip in this embodiment differs from that in Embodiment 1 in that:

[0046] 1. The width of the upper plate 2.1 is greater than the width of the lower plate 2.2, forming an obtuse angle structure between the lower plate 2.2 and the side plate 2.3, and an acute angle structure between the upper plate 2.1 and the side plate 2.3. After casting and rolling, the acute angle will become smaller and the obtuse angle will become larger, thereby transferring the stress weakness point from the obtuse angle to the acute angle, ensuring the composite strength of the shaped copper strip and aluminum.

[0047] 2. The included angle between the lower plate surface 2.2 and the side plate surface 2.3 is 110-150°. The larger the included angle, the lower the stress, but an excessively large included angle will cause material waste. The included angle of 110-150° combines the composite strength and economy of the copper-aluminum composite strip.

[0048] 3. A fillet 2.6 is provided between the lower plate surface 2.2 and the side plate surface 2.3. After the fillet is provided, the molten aluminum will generate less stress after solidification at the fillet 2.6.

[0049] 4. The lower plate surface 2.2 is a concave arc surface. Compared with the flat surface, the concave arc surface of the lower plate surface partially offsets the extension of the shaped copper strip by the casting roll in the width direction.

[0050] 5. The grooves located on both sides have two groove edge faces 2.5 that slope inwards, and the angle of inward slope of the groove edge face closer to the center line is smaller than the angle of inward slope of the groove edge face farther from the center line. After casting and rolling, the angle of inward slope of the groove edge face 2.5 closer to the center line will increase, and the angle of inward slope of the groove edge face 2.5 farther from the center line will decrease. This ensures that the grooves have a better symmetrical structure after casting and cold rolling.

[0051] Example 3: Refer to Appendix Figure 11 In this embodiment, the copper-aluminum composite strip is used to process a high-voltage connector, which is used for connecting lithium batteries in new energy vehicles. This high-voltage connector uses a copper strip 1.3 as the conductive substrate, with a groove 1mm deep and 12mm wide machined on the copper strip 1.3. An aluminum insert 1.4 is then embedded within the groove. After the copper and aluminum are combined, good conductivity and bonding strength are required between the aluminum insert 1.4 and the copper strip 1.3. The reason for embedding the aluminum insert 1.4 into the copper strip 1.3 is that copper has poor weldability, necessitating the use of aluminum as the welding material.

[0052] See attached document Figure 12 The shaped copper strip in this embodiment differs from that in Embodiment 1 in that the bottom surface 2.4 of the groove has an inner arc surface with a larger curvature.

[0053] See attached document Figure 13 From the appendix Figure 13 It can be seen that the curvature of the inner arc surface will decrease after casting and rolling, but the bottom surface 2.4 of the groove will still be arc-shaped, so that the bottom angle of the groove is greater than the top angle of the groove, which indirectly transfers the stress weak point from the bottom angle of the groove to the top angle of the groove.

[0054] See attached document Figure 14 The casting and rolling process leaves machining allowance, and the copper-aluminum composite strip still needs to be machined to the dimensions required for high-pressure connectors. First, the copper-clad surface 1.1 is milled using the aluminum-clad surface 1.2 of the copper-aluminum composite strip 1 as a reference, ensuring the distance from the bottom surface 2.4 of the groove to the copper-clad surface 1.1. Then, the aluminum-clad surface 1.2 is milled using the copper-clad surface 1.1 as a reference, ensuring the final thickness of the copper-aluminum composite strip 1 while removing the weak area located at the top corner of the groove.

[0055] See attached document Figure 15 A precision cutting machine is used to slit the copper-aluminum composite strip, ensuring that the cut strips meet the design requirements of high-voltage connectors.

[0056] It should be understood that the groove of this utility model is not limited to the above shape, and may also be other shapes such as T-shaped groove and dovetail groove.

[0057] It is worth noting that the content not described in detail in the above embodiments is prior art. It is also worth noting that any additions, subtractions, substitutions, and improvements made by those skilled in the art based on the structure and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A profiled copper strip for preparing a grooved copper-aluminum composite strip, characterized in that: The upper plate surface of the profiled copper strip is a convex arc surface, and the lower plate surface is a flat surface or a concave arc surface when viewed from the cross-sectional direction; a plurality of embedding grooves are arranged side by side on the lower plate surface, the groove bottom surface of the embedding groove is a concave arc surface, and at least one of the two groove side surfaces of the embedding groove is outwardly inclined.

2. A profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 1, characterized in that: The width of the upper plate surface is greater than the width of the lower plate surface.

3. A profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 1 or 2, characterized in that: A round corner is arranged between the lower plate surface and the side plate surface.

4. The profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 2, characterized in that: The included angle between the lower plate surface and the side plate surface is 110-150°.

5. The profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 1, characterized in that: The angle of the outwardly inclined groove side surface is 105-130°.

6. A profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 1, characterized in that: The embedding grooves are arranged along the length direction of the profiled copper strip.

7. The profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 1, characterized in that: With the center line of the profiled copper strip as a reference line, the groove side surface of the embedding groove located on the two sides of the reference line and close to the reference line is at a right angle to the lower plate surface, and the groove side surface of the embedding groove located on the two sides of the reference line and away from the reference line is at an obtuse angle to the lower plate surface.

8. The profiled copper strip for preparing a grooved copper-aluminum composite strip according to claim 1, characterized in that: With the center line of the profiled copper strip as a reference line, the two groove side surfaces of the embedding groove located on the two sides of the reference line are both at an obtuse angle to the lower plate surface, and the obtuse angle close to the reference line is smaller than the obtuse angle away from the reference line.

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