Special-shaped copper strip for copper-aluminum solid-liquid compounding

Abstract

The utility model provides a kind of copper-aluminum solid-liquid composite special-shaped copper strip, it is related to copper-aluminum composite strip technical field, mainly for solving the problem of copper surface width easy to be out of tolerance in prior art.The special-shaped copper strip is observed from cross section direction, and the special-shaped copper strip has bottom edge, top edge and a pair of side edges, wherein the length of bottom edge is greater than the length of top edge;The side edge of special-shaped copper strip is at least composed of a straight line and an arc, and the straight line intersects with top edge, and the inclination angle of the straight line is A, 65 ° ≤ A ≤ 87 °.Since the straight line intersecting with top edge has a large inclination angle, even if the milling depth appears a large deviation, copper surface width will not appear out of tolerance.The utility model can further increase the area of copper-aluminum interface, and under the condition of ensuring the bonding strength of copper-aluminum interface, the problem of copper surface width easy to be out of tolerance is solved.

Description

Technical Field

[0001] This utility model specifically relates to a special-shaped copper strip for copper-aluminum solid-liquid composite, and pertains to the technical field of copper-aluminum composite strips. Background Technology

[0002] Copper-aluminum composite strips combine the advantages of copper and aluminum materials, featuring high electrical conductivity, 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] According to the customer's requirements, a batch of products as shown in the attached document needs to be produced using a solid-liquid composite process. Figure 1 The copper-aluminum composite product 1 shown has a copper surface 1.1 in the middle and aluminum surfaces 1.2 on both sides. The width of the copper surface 1.1 is required to be W ± 0.5 mm, and the thickness is required to be D ± 0.5 mm. The copper-aluminum solid-liquid composite process is a composite process in which a trapezoidal copper strip 2 is cast and rolled onto a semi-molten aluminum liquid 3. After composite processing, the aluminum layer needs to be milled off to expose the copper surface 1.1, while ensuring the tolerance requirements of dimensions W and D, as shown in the attached figure. Figure 2 and attached Figure 3 As shown, the copper strip's cross-sectional shape is designed as a trapezoid because the trapezoidal slope increases the area of ​​the copper-aluminum interface and the peel strength of the copper and aluminum. However, precisely because it is a slope, even a slight deviation in the milling depth can cause the copper surface width to exceed tolerances significantly. Therefore, it is necessary to improve the cross-sectional shape of the copper strip while ensuring the bonding strength of the copper-aluminum interface. Utility Model Content

[0004] In order to overcome the shortcomings of the prior art, this utility model discloses a special-shaped copper strip for copper-aluminum solid-liquid composite, the purpose of which is to solve the problem of copper surface width easily exceeding tolerance while ensuring the bonding strength of the copper-aluminum interface.

[0005] The present invention adopts the following technical solution: A special-shaped copper strip for copper-aluminum solid-liquid composite has, when viewed from the cross-sectional direction, a bottom edge, a top edge, and a pair of side edges, wherein the length of the bottom edge is greater than the length of the top edge; the side edges of the special-shaped copper strip consist of at least a straight line and an arc, and the straight line intersecting the top edge has an inclination angle of A, where 65°≤A≤87°.

[0006] Further improve the technical solution: the irregular copper strip has a left-right symmetrical structure.

[0007] Further improvement to the technical solution: the top edge is a straight line or a convex arc, and the bottom edge is a straight line.

[0008] Further improve the technical solution: Let the height of the top edge to the bottom edge be H, and let the height of the straight line intersecting the top edge be h, h / H=1 / 5-1 / 2.

[0009] Further improvement of the technical solution: The arc includes convex arc and concave arc.

[0010] Further improve the technical solution: the irregular copper strip has an asymmetrical structure.

[0011] After implementing the above technical solution, the beneficial effects of this utility model compared to the prior art are: The side of this irregularly shaped copper strip consists of at least a straight line and an arc. Because the straight line intersecting the top edge has a large angle of inclination, even with significant deviations in milling depth, the copper surface width will not exceed tolerances. Furthermore, this invention further increases the area of ​​the copper-aluminum interface, which helps to further improve the peel strength of copper-aluminum composite products.

[0012] This invention solves the problem of copper surface width easily exceeding tolerance while ensuring the bonding strength of the copper-aluminum interface. Attached Figure Description

[0013] Appendix Figure 1 The diagram shown is a three-dimensional structural schematic of a copper-aluminum composite product.

[0014] Appendix Figure 2 The diagram shows a solid-liquid composite of a trapezoidal copper strip and molten aluminum.

[0015] Appendix Figure 3 The diagram shown illustrates the milling process of a copper-aluminum composite strip.

[0016] Appendix Figure 4 The diagram shown is a cross-sectional view of the irregular copper strip in Example 1.

[0017] Appendix Figure 5 The diagram shown is a milling schematic of the copper-aluminum composite strip in Example 1.

[0018] Appendix Figure 6 The diagram shown is a cross-sectional comparison of the irregular copper strip and the trapezoidal copper strip in Example 1.

[0019] Appendix Figure 7 The diagram shown is a cross-sectional view of the irregular copper strip in Example 2.

[0020] Appendix Figure 8 The diagram shown is a milling schematic of the copper-aluminum composite strip in Example 2.

[0021] Appendix Figure 9 The diagram shown is a cross-sectional view of the irregular copper strip in Example 3.

[0022] Appendix Figure 10 The diagram shown is a cross-sectional view of the irregular copper strip in Example 4.

[0023] In the attached diagram: 1. Copper-aluminum composite product; 1.1 Copper surface; 1.2 Aluminum surface; 2. Trapezoidal copper strip; 3. Molten aluminum; 4. Roller; 5. Shaped copper strip; 5.1 Top edge; 5.2 Bottom edge; 5.3 Side edge; 5.31 Top corner straight line; 5.32 Curve. Detailed Implementation

[0024] 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.

[0025] A special-shaped copper strip for copper-aluminum solid-liquid composite is disclosed, relating to the field of copper-aluminum composite strip technology, and is mainly used to solve the problem that the width of the copper surface is prone to exceed the tolerance in the prior art.

[0026] Example 1: Refer to Appendix Figure 4 The irregular copper strip 5 in this embodiment has the following characteristics: viewed from the cross-sectional direction, the irregular copper strip 5 has a left-right symmetrical structure, consisting of a bottom edge 5.2, a top edge 5.1, and a pair of side edges 5.3. Among them, the top edge 5.1 and the bottom edge 5.2 are both straight lines, and the length of the straight line of the bottom edge 5.2 is greater than the length of the straight line of the top edge 5.1.

[0027] To address the issue of the copper surface width W easily exceeding tolerances, the side 5.3 of the irregularly shaped copper strip 5 consists of a straight line and an arc 5.32, intersecting the top edge 5.1 with the apex angle straight line 5.31. Let the inclination angle of the apex angle straight line 5.31 be A, then 65° ≤ A ≤ 87°. Typically, the inclination angle A should not exceed 90°, otherwise gas accumulation may occur when the copper strip undergoes solid-liquid bonding with the molten aluminum. Let the height from the top edge 5.1 to the bottom edge 5.2 be H, and the height of the straight line intersecting the top edge 5.1 be h, where h / H = 1 / 5 - 1 / 2. In this embodiment, A = 78°, and h / H = 2 / 7.

[0028] See attached document Figure 5 According to the processing technology of copper-aluminum composite product 1, after the shaped copper strip 5 is solid-liquid bonded with molten aluminum, it still needs to undergo cold rolling, annealing, and milling processes. During cold rolling, the shaped copper strip 5 will be flattened, and the tilt angle A of the apex straight line 5.31 will become larger. This is the main reason why the tilt angle A is not recommended to exceed 87°. According to product requirements, when milling the aluminum layer, the bottom surface of the copper-aluminum composite strip needs to be used as a reference to ensure that the thickness dimension is D±0.5mm and the width dimension of the copper surface 1.1 is W±0.5mm. Because the apex straight line 5.31 has a large tilt angle, even if there is a large deviation in the milling depth, it will not cause the copper surface width W to exceed the tolerance. For example, after cold rolling, the tilt angle of the apex straight line 5.31 increases from 78° to 82°. When the milling depth has a unidirectional limit deviation of 0.5mm, the copper surface width W will only have a deviation of about 0.14mm (2tg8°). To give another extreme example, if the tilt angle A of the top angle line 5.31 is 65°, and the tilt angle of the top angle line 5.31 increases to 68° after cold rolling, when the milling depth has a unidirectional limit deviation of 0.5mm, the copper surface width W will have a maximum deviation of 0.404mm (2tg22°), which is still within the acceptable tolerance range.

[0029] See attached document Figure 6 Compared to the trapezoidal copper strip 2, with the top edge 5.1 and bottom edge 5.2 unchanged, the total length of the side edge 5.3, which is composed of the top angle straight line 5.31 and the arc 5.32, is greater than the length of the waist of the trapezoid (shown by the dotted line in the figure). Therefore, this invention can further increase the area of ​​the copper-aluminum interface and the peel strength of copper and aluminum.

[0030] It is worth noting that the arc 5.32 is not limited to circular arcs; it can also be other types of arcs, such as hyperbolas or parabolas.

[0031] Example 2: Refer to Appendix Figure 7 and attached Figure 8 Compared to Example 1, this example differs in the following ways: 1. The top edge 5.1 of the shaped copper strip 5 is a convex arc. Designing the top edge 5.1 as a convex arc creates a convex arc-shaped top surface for the shaped copper strip 5. This has two beneficial effects: First, during solid-liquid bonding, the top surface of the shaped copper strip 5 comes into contact with the molten aluminum first, and the convex arc-shaped top surface facilitates air expulsion, improving the bonding strength of the copper-aluminum interface. Second, during cold rolling, the shaped copper strip 5 is flattened; ideally, the convex arc-shaped top surface will essentially become a flat surface, and the inclination angle A of the apex angle line 5.31 will approach 90°. At this point, the width W of the copper surface is no longer affected by the milling depth.

[0032] 2. The side 5.3 of the irregular copper strip 5 consists of three straight lines and two curved lines 5.32. The more straight lines and curved lines 5.32 there are, the greater the area of ​​the copper-aluminum interface and the greater the peel strength of the copper and aluminum. It is known that the arc length of the curved line between two points is greater than the distance between the two points (the length of the straight line). Therefore, curved lines 5.32 should be set first. Under the same distance, the more curved lines 5.32 are set, the larger the area of ​​the copper-aluminum interface.

[0033] Example 3: Refer to Appendix Figure 9 Compared to Example 2, this example differs in the following ways: 1. The side 5.3 of the irregular copper strip 5 is composed of two straight lines and two arcs 5.32. One arc 5.32 is a convex arc and the other arc 5.32 is a concave arc.

[0034] 2. The irregular copper strip 5 has an anchor-hook-shaped structure that is wider in the middle and narrower at the top and bottom. Obviously, the anchor-hook-shaped structure embedded in the aluminum is more conducive to improving the peel strength between copper and aluminum.

[0035] Example 4: Refer to Appendix Figure 10 The irregularly shaped copper strip 5 in Examples 1-3 uses a symmetrical structure, while the irregularly shaped copper strip 5 in this example uses an asymmetrical structure. The left side consists of four straight lines and a concave arc 5.32, and the right side consists of four straight lines and a convex arc 5.32. The left and right sides are asymmetrical. Obviously, while ensuring the bonding strength of the copper-aluminum interface, the asymmetrical structure can also solve the problem of the copper surface width W easily exceeding the tolerance.

[0036] 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 special-shaped copper strip for copper-aluminum solid-liquid composite, characterized in that: Viewed from the cross-sectional direction, the irregular copper strip has a bottom edge, a top edge, and a pair of side edges, wherein the length of the bottom edge is greater than the length of the top edge; the side edge of the irregular copper strip consists of at least a straight line and an arc, and the straight line intersecting the top edge has an inclination angle of A, 65°≤A≤87°.

2. The shaped copper strip for copper-aluminum solid-liquid composite as described in claim 1, characterized in that: The irregularly shaped copper strip has a symmetrical structure.

3. The shaped copper strip for copper-aluminum solid-liquid composite as described in claim 1, characterized in that: The top edge is a straight line or a convex arc, and the bottom edge is a straight line.

4. The shaped copper strip for copper-aluminum solid-liquid composite as described in claim 1, characterized in that: Let H be the height of the top edge to the bottom edge, and let h be the height of the line intersecting the top edge. h / H = 1 / 5 - 1 / 2.

5. The shaped copper strip for copper-aluminum solid-liquid composite as described in claim 1, characterized in that: The arc includes convex arcs and concave arcs.

6. The shaped copper strip for copper-aluminum solid-liquid composite as described in claim 1, characterized in that: The irregularly shaped copper strip has an asymmetrical structure.

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