Copper-aluminum composite pole and battery cover plate

Abstract

The invention belongs to the technical field of batteries, and discloses a copper-aluminum composite pole and a battery cover plate, the copper-aluminum composite pole comprises a first pole body and a second pole body, one of the first pole body and the second pole body is made of an aluminum material, the other of the first pole body and the second pole body is made of a copper material, the second pole body is provided with a mounting through hole, and the mounting through hole is communicated with the first pole body and the second pole body. The first pole body is connected into the mounting through hole, a copper-aluminum interface is formed on the peripheral side of the first pole body, and a first welding printing area is arranged on the first pole body. Compared with a traditional pole prepared from a pure copper material, the use amount of copper is reduced, so that the cost is reduced, the weight is reduced, the distance A1 and the distance A2 between the first welding printing area on the first pole body prepared from different materials and the copper-aluminum interface are limited, the situation that the distance is too close during welding operation, and the welding quality is affected is avoided. A copper-aluminum interface is damaged by high temperature generated by welding, so that cracks are caused near the copper-aluminum interface, and the risk of fracture is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a copper-aluminum composite pole and a battery cover. Background Art

[0002] Lithium-ion batteries are currently widely used in various fields such as transportation power supply, electric energy storage power supply, new energy storage power supply, aerospace and military industry due to their large capacity, high operating voltage, strong charge retention ability and long cycle life. The structure of a single lithium battery generally includes a pole group, electrolyte, cover plate, shell, internal and external insulation structure, etc. The cover plate and shell are usually fixed by laser welding to form a closed space with a certain structural strength to protect the pole group. The cover plate is generally integrated with functional areas such as pole column, explosion-proof valve, and injection hole. The pole group is fixed by laser welding the pole ear and the pole column base of the cover plate to achieve electrical connection, thereby leading the internal current of the battery cell to the outside of the shell.

[0003] The positive electrode column connected to the positive electrode ear is generally made of pure aluminum, and the negative electrode column connected to the negative electrode ear is generally made of pure copper. However, since the cost and weight of copper are greater than those of aluminum, using pure copper as the electrode column not only increases the production cost, but also increases the overall weight of the lithium-ion battery, which does not conform to the principle of lightweight structural design. Summary of the invention

[0004] The object of the present invention is to provide a copper-aluminum composite pole and a battery cover plate, which have low production cost and light weight and conform to the principle of lightweight structure design.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] On the one hand, a copper-aluminum composite pole is provided, the copper-aluminum composite pole comprising a first pole body and a second pole body, one of the first pole body and the second pole body is made of aluminum, the other of the first pole body and the second pole body is made of copper, a mounting through hole is provided on the second pole body, the first pole body is connected to the mounting through hole, and a copper-aluminum interface is formed on the peripheral side of the first pole body, and a first welding print area is provided on the first pole body;

[0007] When the first pole body is made of aluminum, the first weld print area is located on the side of the first pole body facing the busbar and is used for welding the first pole body to the busbar. The spacing dimension between the first weld print area and the copper-aluminum interface along the first direction is A1, and A1≥0.5mm is satisfied;

[0008] Or, when the first pole column is made of copper, the first weld mark area is located on the side of the first pole column facing the pole ear and is used for welding the first pole column and the pole ear. The spacing dimension between the first weld mark area and the copper-aluminum interface along the first direction is A2, and A2≥0.8mm is satisfied.

[0009] Optionally, when the first pole body is made of aluminum, a spacing dimension between the first weld print area and the copper-aluminum interface along the second direction is B1, and B1≥0.5 mm;

[0010] Alternatively, when the first pole body is made of copper, a spacing dimension between the first weld print area and the copper-aluminum interface along the second direction is B2, and B2≥0.8 mm.

[0011] Optionally, a plurality of second weld print areas are provided on the second pole body, and the plurality of second weld print areas surround the circumference of the first pole body;

[0012] When the second pole body is made of aluminum, the second weld print area is located on the side of the second pole body facing the busbar and is used for welding the second pole body to the busbar. The spacing between the boundary of the second weld print area facing the copper-aluminum interface and the boundary of the copper-aluminum interface along the first direction is C1, and C1≥0.5mm is satisfied;

[0013] Or, when the second pole column is made of copper, the second weld mark area is located on the side of the second pole column facing the pole ear, and is used for welding the second pole column and the pole ear, and the spacing dimension between the boundary of the second weld mark area facing the copper-aluminum interface and the boundary of the copper-aluminum interface along the first direction is C2, and satisfies C2≥0.7mm.

[0014] Optionally, when the second pole body is made of aluminum, a distance between a boundary of the second weld mark area facing the copper-aluminum interface and a boundary of the copper-aluminum interface along the second direction is D1, and D1≥0.5 mm is satisfied;

[0015] Alternatively, when the second pole body is made of copper, a spacing dimension between a boundary of the second weld mark area facing the copper-aluminum interface and a boundary of the copper-aluminum interface along the second direction is D2, and D2≥0.7 mm.

[0016] Optionally, the second pole body includes a base and a connecting boss, the base protrudes in a direction close to the busbar to form the connecting boss, the mounting through hole is opened on the connecting boss, and the second weld print area is arranged on the connecting boss.

[0017] Optionally, when the second pole body is made of aluminum, a distance between a boundary of the second weld mark area away from the copper-aluminum interface and a boundary of the connecting boss along the first direction is E1, and E1≥1mm is satisfied;

[0018] Or, when the second pole body is made of copper, a spacing dimension E2 between a boundary of the second weld mark area away from the copper-aluminum interface and a boundary of the connecting boss along the first direction satisfies E2≥1.3 mm.

[0019] Optionally, when the second pole body is made of aluminum, a distance between a boundary of the second weld mark area away from the copper-aluminum interface and a boundary of the connecting boss along the second direction is F1, and F1≥1mm;

[0020] Alternatively, when the second pole body is made of copper, a spacing dimension between a boundary of the second weld mark area away from the copper-aluminum interface and a boundary of the connecting boss along the second direction is F2, and F2≥1.3 mm.

[0021] Optionally, the widths of the plurality of second weld print areas are the same or different.

[0022] Optionally, a plurality of the second weld print areas are symmetrically distributed on both sides of the first pole body along the first direction and / or the second direction.

[0023] On the other hand, a battery cover is provided, the battery cover comprising the copper-aluminum composite pole as described in any one of the above items.

[0024] Beneficial effects of the present invention:

[0025] The present invention provides a copper-aluminum composite pole. By adopting a combination of a first pole body and a second pole body, one of the first pole body and the second pole body is made of aluminum material, and the other of the first pole body and the second pole body is made of copper material, compared with a pole made of a traditional pure copper material, the use amount of copper material is reduced, thereby reducing cost and weight. In addition, by limiting the distance dimension A1 and the distance dimension A2 between a first weld print area on a first pole body made of different materials and a copper-aluminum interface, it is ensured that there is a sufficient interval between the first weld print area and the copper-aluminum interface in the first direction, so as to avoid the high temperature generated by welding when the distance is too close, thereby damaging the copper-aluminum interface, thereby inducing cracks near the copper-aluminum interface, reducing mechanical properties, and increasing the risk of fracture.

[0026] The present invention also provides a battery cover plate, which effectively controls the production cost and the weight of the finished product after assembly by applying the above-mentioned copper-aluminum composite connecting sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a front plan view of a copper-aluminum composite pole provided by the present invention, in which the first pole body is made of aluminum, the second pole body is made of copper, and a first weld print area is provided in the first pole body;

[0028] Figure 2 It is a front plan view of a copper-aluminum composite pole provided by the present invention, in which the first pole body is made of copper, the second pole body is made of aluminum, and a second weld print area is provided around the first pole body;

[0029] Figure 3 It is a back top view of the copper-aluminum composite pole provided by the present invention, in which the first pole body is aluminum, the second pole body is copper, and second weld print areas are provided on both sides of the first pole body in the first direction;

[0030] Figure 4 It is a back top view of the copper-aluminum composite pole provided by the present invention, in which the first pole body is aluminum, the second pole body is copper, and second weld print areas of equal width are provided on both sides of the first pole body in the second direction;

[0031] Figure 5 It is a back top view of the copper-aluminum composite pole provided by the present invention, in which the first pole body is aluminum, the second pole body is copper, and second weld print areas of unequal width are provided on both sides of the first pole body in the second direction;

[0032] Figure 6 It is a structural cross-sectional view of the copper-aluminum composite pole, busbar and pole ear after welding provided by the invention;

[0033] Figure 7 It is a back top view of the copper-aluminum composite pole provided by the present invention, in which the first pole body is made of copper, the second pole body is made of aluminum, and a first weld print area is provided in the first pole body;

[0034] Figure 8 It is a back top view of the copper-aluminum composite pole provided by the present invention, in which the first pole body is made of aluminum, the second pole body is made of copper, and a second weld print area is arranged around the first pole body.

[0035] In the figure:

[0036] 100, busbar; 200, tab;

[0037] 1. First pole column; 11. First welding area;

[0038] 2. Second pole column; 21. Second welding area; 22. Base body; 23. Connecting boss;

[0039] 3. Copper-aluminum interface. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0041] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0044] In the battery, since the negative electrode is copper, the pole connected to it is generally made of pure copper. The pole made of pure copper is not only heavy and does not conform to the design principle of lightweight structure, but also has high material cost, which leads to high production cost.

[0045] Therefore, in order to reduce the weight of the pole, meet the design principle of lightweight structure, reduce production costs, and improve product competitiveness, this embodiment provides a copper-aluminum composite pole.

[0046] like Figures 1 to 8As shown, the copper-aluminum composite pole comprises a first pole body 1 and a second pole body 2, one of the first pole body 1 and the second pole body 2 is made of aluminum, and the other of the first pole body 1 and the second pole body 2 is made of copper. A mounting through hole is provided on the second pole body 2, the first pole body 1 is connected to the mounting through hole, and a copper-aluminum interface 3 is formed on the peripheral side of the first pole body 1, and a first weld print area 11 is provided on the first pole body 1;

[0047] When the first pole body 1 is made of aluminum, the first weld print area 11 is located on the side of the first pole body 1 facing the busbar 100 and is used for welding the first pole body 1 to the busbar 100. The spacing dimension between the first weld print area 11 and the copper-aluminum interface 3 along the first direction is A1, and A1≥0.5mm is satisfied;

[0048] Or, when the first pole body 1 is made of copper, the first weld mark area 11 is located on the side of the first pole body 1 facing the pole lug 200 and is used for welding the first pole body 1 and the pole lug 200. The spacing dimension between the first weld mark area 11 and the copper-aluminum interface 3 along the first direction is A2, and A2≥0.8mm is satisfied.

[0049] By combining the first pole body 1 and the second pole body 2, and making one of the first pole body 1 and the second pole body 2 into aluminum material and the other of the first pole body 1 and the second pole body 2 into copper material, the use amount of copper material is reduced compared with the pole made of traditional pure copper material, thereby reducing the cost and weight, and by limiting the distance dimension A1 and the distance dimension A2 between the first weld print area 11 and the copper-aluminum interface 3 on the first pole body 1 made of different materials, it is ensured that there is a sufficient interval between the first weld print area 11 and the copper-aluminum interface 3 in the first direction, avoiding the high temperature generated by welding when the distance is too close, thereby damaging the copper-aluminum interface 3, thereby causing cracks near the copper-aluminum interface, reducing the mechanical properties, and increasing the risk of fracture.

[0050] Among them, the shape of the first pole body 1 is adapted to the shape of the mounting through hole. In the present embodiment, the mounting through hole is a rectangular hole, so the first pole body 1 is adapted thereto and is also rectangular, and the first weld print area 11 arranged on the first pole body 1 is in the shape of a "one", and the shape of the second pole body 2 can be the same as that of the first pole body 1 or different.

[0051] Alternatively, if Figure 1 , Figure 6 , Figure 7 As shown, when the first pole body 1 is made of aluminum, the spacing dimension between the first weld print area 11 and the copper-aluminum interface 3 along the second direction is B1, and B1≥0.5mm;

[0052] Alternatively, when the first pole body 1 is made of copper, the spacing dimension between the first weld mark area 11 and the copper-aluminum interface 3 along the second direction is B2, and B2≥0.8 mm.

[0053] By limiting the distance dimension B1 and the distance dimension B2 between the first weld print area 11 on the first pole body 1 made of different materials and the copper-aluminum interface 3, it is ensured that there is a sufficient interval between the first weld print area 11 and the copper-aluminum interface 3 in the second direction, so as to avoid the high temperature generated by welding when the distance is too close, thereby avoiding the destruction of the copper-aluminum interface 3, thereby causing cracks near the copper-aluminum interface 3, reducing the mechanical properties, and increasing the risk of fracture.

[0054] Alternatively, if Figure 2 , Figure 6 , Figure 8 As shown, a plurality of second weld print areas 21 are provided on the second pole body 2, and the plurality of second weld print areas 21 surround the circumference of the first pole body 1;

[0055] When the second pole body 2 is made of aluminum, the second weld mark area 21 is located on the side of the second pole body 2 facing the busbar 100 and is used for welding the second pole body 2 and the busbar 100. The distance between the boundary of the second weld mark area 21 facing the copper-aluminum interface 3 and the boundary of the copper-aluminum interface 3 along the first direction is C1, and C1≥0.5mm is satisfied.

[0056] Or, when the second pole body 2 is made of copper, the second weld mark area 21 is located on the side of the second pole body 2 facing the pole lug 200, and is used for welding the second pole body 2 and the pole lug 200, and the spacing dimension between the boundary of the second weld mark area 21 facing the copper-aluminum interface 3 and the boundary of the copper-aluminum interface 3 along the first direction is C2, and satisfies C2≥0.7mm.

[0057] By limiting the distance dimension C1 and the distance dimension C2 between the second weld print area 21 on the second pole body 2 made of different materials and the copper-aluminum interface 3, it is ensured that there is a sufficient interval between the second weld print area 21 and the copper-aluminum interface 3 in the first direction, so as to avoid the high temperature generated by welding when the distance is too close, thereby avoiding the destruction of the copper-aluminum interface 3, thereby causing cracks near the copper-aluminum interface 3, reducing the mechanical properties, and increasing the risk of fracture.

[0058] In this embodiment, a plurality of second weld print areas 21 are symmetrically distributed on both sides of the first pole body 1 along the first direction and / or the second direction. The distribution of the second weld print areas 21 can be freely set according to the requirements, for example, Figure 3 As shown, a second welding area 21 in the shape of a straight line is symmetrically distributed on both sides of the first pole body 1 along the first direction, or as shown in FIG. Figure 4 As shown in FIG. 1 , a second welding area 21 in the shape of a straight line is symmetrically distributed on both sides of the first pole body 1 along the second direction. Figure 2, Figure 8 As shown, a straight-line second weld print area 21 is arranged on both sides of the first pole body 1 along the first direction and the second direction, so that four straight-line second weld print areas 21 are distributed in a ring-like shape.

[0059] In addition, the widths of the plurality of second weld print areas 21 may be the same or different. The width of one of the second weld print areas 21 may be increased according to the welding strength requirement to improve the welding strength of the weak side. Figure 5 As shown, second weld print areas 21 of unequal width are arranged on both sides of the first pole body 1 along the second direction.

[0060] Alternatively, if Figure 2 , Figure 6 , Figure 8 As shown, when the second pole body 2 is made of aluminum, the distance between the boundary of the second weld mark area 21 facing the copper-aluminum interface 3 and the boundary of the copper-aluminum interface 3 along the second direction is D1, and D1≥0.5mm is satisfied;

[0061] Alternatively, when the second pole body 2 is made of copper, the distance between the boundary of the second weld mark area 21 facing the copper-aluminum interface 3 and the boundary of the copper-aluminum interface 3 along the second direction is D2, and D2≥0.7 mm.

[0062] By limiting the distance dimension D1 and the distance dimension D2 between the second weld print area 21 on the second pole body 2 made of different materials and the copper-aluminum interface 3, it is ensured that there is a sufficient interval between the second weld print area 21 and the copper-aluminum interface 3 in the second direction, so as to avoid the high temperature generated by welding when the distance is too close, thereby avoiding the destruction of the copper-aluminum interface 3, thereby causing cracks near the copper-aluminum interface 3, reducing the mechanical properties, and increasing the risk of fracture.

[0063] Alternatively, if Figure 2 , Figure 6 , Figure 8 As shown, the second pole body 2 includes a base 22 and a connection boss 23, the base 22 protrudes in the direction close to the busbar 100 to form the connection boss 23, the mounting through hole is opened on the connection boss 23, and the second weld print area 21 is arranged on the connection boss 23. By arranging the connection boss 23 on the second pole body 2, on the one hand, it is convenient to shorten the distance with the busbar 100 and connect with the busbar 100, and on the other hand, a groove structure for accommodating the pole lug 200 is formed in the second pole body 2, so that there is a spatial overlap between the second pole body 2 and the pole lug 200, saving space.

[0064] Alternatively, if Figure 2 , Figure 6 , Figure 8As shown, when the second pole body 2 is made of aluminum, the distance between the boundary of the second weld mark area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 along the first direction is E1, and E1≥1mm is satisfied;

[0065] Or, when the second pole body 2 is made of copper, the distance between the boundary of the second weld mark area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 along the first direction is E2, and E2≥1.3 mm.

[0066] In order to avoid the second pole body 2 from contacting with other metal parts and causing a short circuit, the outer side of the second pole body 2 is usually coated with an insulating component. By limiting the distance dimension E1 and the distance dimension E2 between the boundary of the second weld mark area 21 on the second pole body 2 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23, it is ensured that there is a sufficient distance in the first direction between the boundary of the second weld mark area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23, so as to avoid the high temperature generated by welding when the distance is too close, which will melt the insulating component coated on the outer side of the second pole body 2.

[0067] Alternatively, if Figure 2 , Figure 6 , Figure 8 As shown, when the second pole body 2 is made of aluminum, the distance between the boundary of the second weld mark area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 along the second direction is F1, and F1≥1mm;

[0068] Or, when the second pole body 2 is made of copper, the spacing dimension between the boundary of the second weld mark area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 along the second direction is F2, and F2≥1.3 mm.

[0069] In order to avoid the second pole body 2 from contacting with other metal parts and causing a short circuit, the outer side of the second pole body 2 is usually coated with an insulating component. By limiting the distance dimension F1 and the distance dimension F2 between the boundary of the second weld mark area 21 on the second pole body 2 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23, it is ensured that there is a sufficient distance between the boundary of the second weld mark area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 in the first direction, so as to avoid the high temperature generated by welding when the distance is too close, which will melt the insulating component coated on the outer side of the second pole body 2.

[0070] In this embodiment, in order to verify the above-mentioned size limitation on the first weld print area 11 and the second weld print area 21, and the influence on the welding of the copper-aluminum composite pole with the busbar 100 and the pole ear 200, as shown in Table 1, six groups of embodiments and six groups of comparative examples are provided for verification, wherein the first pole body 1 is set to be aluminum and welded to the busbar 100, and the second pole body 2 is set to be copper and welded to the pole ear 200. In this test, the copper-aluminum composite pole composed of the first pole body 1 and the second pole body 2 is first assembled with other components of the battery cover, and then the copper-aluminum composite pole is welded to the pole ear 200 and the busbar 100 respectively. After the welding is completed, first observe whether cracks are generated at the copper-aluminum interface 3, and whether the insulating component covering the outside of the second pole body 2 is melted due to welding. Secondly, a helium test is performed to perform an airtightness test to determine whether the sealing is qualified.

[0071] Table 1

[0072]

[0073] From the comparison between Example 1 and Comparative Example 1 in Table 1, it can be seen that the spacing dimension A1 between the first weld print area 11 and the copper-aluminum interface 3 along the first direction in Comparative Example 1 is 0.3 mm, which is less than the minimum value in the range of A1 ≥ 0.5 mm, resulting in the first weld print area 11 and the copper-aluminum interface 3 in Comparative Example 1 being too close to each other along the first direction, resulting in the high temperature generated when the busbar 100 and the first pole body 1 are connected through the first weld print area 11. The copper-aluminum interface 3 on both sides of the first weld print area 11 along the first direction has a thermal impact, resulting in cracks in the copper-aluminum interface 3 adjacent to the first weld print area 11 along the first direction, which leads to failure of the airtightness test during the helium test.

[0074] From the comparison between Example 2 and Comparative Example 2 in Table 1, it can be seen that the spacing dimension B1 between the first weld print area 11 and the copper-aluminum interface 3 along the second direction in Comparative Example 2 is 0.4 mm, which is less than the minimum value in the range of B1 ≥ 0.5 mm, resulting in the first weld print area 11 and the copper-aluminum interface 3 in Comparative Example 2 being too close in the second direction. As a result, when the busbar 100 and the first pole body 1 are connected through the first weld print area 11, the high temperature generated has a thermal impact on the copper-aluminum interface 3 on both sides of the first weld print area 11 along the second direction, resulting in cracks in the copper-aluminum interface 3 adjacent to the first weld print area 11 along the second direction, which leads to failure of the airtightness test during the helium test.

[0075] From the comparison between Example 3 and Comparative Example 3 in Table 1, it can be seen that the spacing dimension C1 between the second weld print area 21 and the copper-aluminum interface 3 along the first direction in Comparative Example 3 is 0.35 mm, which is less than the minimum value in the range of C1 ≥ 0.5 mm, resulting in the second weld print area 21 and the copper-aluminum interface 3 in Comparative Example 3 being too close along the first direction. As a result, when the pole ear 200 and the second pole body 2 are connected through the second weld print area 21, the high temperature generated has a thermal impact on the copper-aluminum interface 3 on both sides of the first pole body 1 along the first direction, resulting in cracks in the copper-aluminum interface 3 adjacent to the first pole body 1 along the first direction, which leads to failure of the airtightness test during the helium test.

[0076] From the comparison between Example 4 and Comparative Example 4 in Table 1, it can be seen that the spacing dimension D1 between the second weld print area 21 and the copper-aluminum interface 3 along the second direction in Comparative Example 4 is 0.45 mm, which is less than the minimum value in the range of D1 ≥ 0.5 mm, resulting in the second weld print area 21 in Comparative Example 4. The distance between the copper-aluminum interface 3 along the second direction is too close, resulting in the high temperature generated when the pole ear 200 and the second pole body 2 are connected through the second weld print area 21. The copper-aluminum interface 3 on both sides of the first pole body 1 along the second direction has a thermal impact, resulting in cracks in the copper-aluminum interface 3 adjacent to the first pole body 1 along the second direction, which leads to failure of the airtightness test during the helium test.

[0077] From the comparison between Example 5 and Comparative Example 5 in Table 1, it can be seen that the spacing dimension E1 along the first direction between the boundary of the second weld print area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 in Comparative Example 5 is 0.6 mm, which is less than the minimum value in the range of E1 ≥ 1 mm, resulting in the second weld print area 21 in Comparative Example 5. The distance between the boundary of the copper-aluminum interface 3 and the boundary of the connecting boss 23 along the first direction is too close, resulting in the high temperature generated when the pole ear 200 and the second pole column 2 are connected through the second weld print area 21. The insulating component coated on the second pole column 2 has a thermal impact, thereby causing the insulating component coated on the outside of the second pole column 2 to melt and deform on both sides along the first direction, resulting in a decrease in insulation performance, and failing to meet product safety requirements.

[0078] From the comparison between Example 6 and Comparative Example 6 in Table 1, it can be seen that the spacing dimension F1 along the second direction between the boundary of the second weld print area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 in Comparative Example 6 is 0.8 mm, which is less than the minimum value in the range of F1 ≥ 1 mm, resulting in the second direction The distance between the boundary of the second weld print area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 is too close, resulting in that when the pole ear 200 and the second pole column 2 are connected through the second weld print area 21, the high temperature generated has a thermal effect on the insulating component coated on the second pole column 2, thereby causing the insulating component coated on the outside of the second pole column 2 to melt and deform on both sides along the second direction, resulting in a decrease in insulation performance, and failing to meet product safety requirements.

[0079] In this embodiment, in order to verify the above-mentioned size limitation on the first weld print area 11 and the second weld print area 21, and the influence of the copper-aluminum composite pole after welding with the busbar 100 and the pole ear 200, as shown in Table 2, six groups of embodiments and six groups of comparative examples are provided for verification, wherein the first pole body 1 is set to be copper and welded with the pole ear 200, and the second pole body 2 is set to be aluminum and welded with the busbar 100. In this test, the copper-aluminum composite pole composed of the first pole body 1 and the second pole body 2 is first assembled with other components of the battery cover, and then the copper-aluminum composite pole is welded with the pole ear 200 and the busbar 100 respectively. After the welding is completed, first observe whether cracks are generated at the copper-aluminum interface 3, and whether the insulating component covering the outside of the second pole body 2 is melted due to welding. Secondly, a helium test is performed to perform an airtightness test to determine whether the sealing is qualified.

[0080] Table 2

[0081]

[0082] From the comparison between Example 7 and Comparative Example 7 in Table 2, it can be seen that the spacing dimension A2 between the first weld print area 11 and the copper-aluminum interface 3 along the first direction in Comparative Example 7 is 0.6 mm, which is less than the minimum value in the range of A2 ≥ 0.8 mm, resulting in the first weld print area 11 and the copper-aluminum interface 3 in Comparative Example 7. The distance along the first direction between the copper-aluminum interface 3 is too close, resulting in the high temperature generated when the pole ear 200 and the first pole body 1 are connected through the first weld print area 11. The copper-aluminum interface 3 on both sides of the first weld print area 11 along the first direction has a thermal impact, resulting in cracks in the copper-aluminum interface 3 adjacent to the first weld print area 11 along the first direction, which leads to failure of the airtightness test during the helium test.

[0083] From the comparison between Example 8 and Comparative Example 8 in Table 2, it can be seen that the spacing dimension B2 between the first weld print area 11 and the copper-aluminum interface 3 along the second direction in Comparative Example 8 is 0.7 mm, which is less than the minimum value in the range of B2 ≥ 0.8 mm, resulting in the first weld print area 11 and the copper-aluminum interface 3 in Comparative Example 8. The distance along the second direction is too close, resulting in the high temperature generated when the pole ear 200 and the first pole body 1 are connected through the first weld print area 11. The copper-aluminum interface 3 on both sides of the first weld print area 11 along the second direction has a thermal impact, resulting in cracks in the copper-aluminum interface 3 adjacent to the first weld print area 11 along the second direction, which leads to failure of the airtightness test during the helium test.

[0084] From the comparison between Example 9 and Comparative Example 9 in Table 2, it can be seen that the spacing dimension C2 between the second weld print area 21 and the copper-aluminum interface 3 along the first direction in Comparative Example 9 is 0.5 mm, which is less than the minimum value in the range of C2 ≥ 0.7 mm, resulting in the second weld print area 21 in Comparative Example 9. The distance between the copper-aluminum interface 3 along the first direction is too close, resulting in the high temperature generated when the busbar 100 and the second pole body 2 are connected through the second weld print area 21. The copper-aluminum interface 3 on both sides of the first pole body 1 along the first direction has a thermal impact, resulting in cracks in the copper-aluminum interface 3 adjacent to the first pole body 1 along the first direction, which leads to failure of the airtightness test during the helium test.

[0085] From the comparison between Example 10 and Comparative Example 10 in Table 2, it can be seen that the spacing dimension D2 between the second weld print area 21 and the copper-aluminum interface 3 along the second direction in Comparative Example 10 is 0.6 mm, which is less than the minimum value in the range of D2 ≥ 0.7 mm, resulting in the second weld print area 21 in Comparative Example 10. The distance between the copper-aluminum interface 3 along the second direction is too close, resulting in the high temperature generated when the busbar 100 and the second pole body 2 are connected through the second weld print area 21. The copper-aluminum interface 3 on both sides of the first pole body 1 along the second direction has a thermal impact, resulting in cracks in the copper-aluminum interface 3 adjacent to the first pole body 1 along the second direction, which leads to failure of the airtightness test during the helium test.

[0086] From the comparison between Example 11 and Comparative Example 11 in Table 2, it can be seen that the spacing dimension E2 along the first direction between the boundary of the second weld print area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 in Comparative Example 11 is 1 mm, which is less than the minimum value in the range of E2 ≥ 1.3 mm, resulting in the second weld print area 21 in Comparative Example 11. The distance between the boundary of the copper-aluminum interface 3 and the boundary of the connecting boss 23 along the first direction is too close, resulting in that when the busbar 100 and the second pole body 2 are connected through the second weld print area 21, the high temperature generated has a thermal effect on the insulating component coated on the second pole body 2, thereby causing the insulating component coated on the outside of the second pole body 2 to melt and deform on both sides along the first direction, resulting in a decrease in insulation performance, and failing to meet product safety requirements.

[0087] From the comparison between Example 12 and Comparative Example 12 in Table 2, it can be seen that the spacing dimension F2 along the second direction between the boundary of the second weld print area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 in Comparative Example 12 is 1.2 mm, which is less than the minimum value in the range of F2 ≥ 1.3 mm, resulting in the second direction The distance between the boundary of the second weld print area 21 away from the copper-aluminum interface 3 and the boundary of the connecting boss 23 is too close, resulting in that when the busbar 100 and the second pole body 2 are connected through the second weld print area 21, the high temperature generated has a thermal effect on the insulating component coated on the second pole body 2, thereby causing the insulating component coated on the outside of the second pole body 2 to melt and deform on both sides along the second direction, resulting in a decrease in insulation performance, and failing to meet product safety requirements.

[0088] In this embodiment, a battery cover is also provided, which includes the copper-aluminum composite pole. The battery cover uses the copper-aluminum composite connecting sheet, thereby effectively controlling the production cost and the weight of the finished product after assembly.

[0089] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Copper-aluminum composite pole, characterized in that: The copper-aluminum composite pole comprises a first pole body and a second pole body, one of the first pole body and the second pole body is made of aluminum, the other of the first pole body and the second pole body is made of copper, a mounting through hole is provided on the second pole body, the first pole body is connected to the mounting through hole, and a copper-aluminum interface is formed on the peripheral side of the first pole body, and a first welding print area is provided on the first pole body; When the first pole body is made of aluminum, the first weld print area is located on the side of the first pole body facing the busbar and is used for welding the first pole body to the busbar. The spacing dimension between the first weld print area and the copper-aluminum interface along the first direction is A1, and A1≥0.5mm is satisfied; Or, when the first pole column is made of copper, the first weld mark area is located on the side of the first pole column facing the pole ear and is used for welding the first pole column and the pole ear. The spacing dimension between the first weld mark area and the copper-aluminum interface along the first direction is A2, and A2≥0.8mm is satisfied.

2. The copper-aluminum composite pole according to claim 1, characterized in that: When the first pole body is made of aluminum, the spacing dimension between the first weld print area and the copper-aluminum interface along the second direction is B1, and B1≥0.5mm; Alternatively, when the first pole body is made of copper, a spacing dimension between the first weld print area and the copper-aluminum interface along the second direction is B2, and B2≥0.8 mm.

3. The copper-aluminum composite pole according to claim 1, characterized in that: The second pole body is provided with a plurality of second weld print areas, and the plurality of second weld print areas surround the circumference of the first pole body; When the second pole body is made of aluminum, the second weld print area is located on the side of the second pole body facing the busbar and is used for welding the second pole body to the busbar. The spacing between the boundary of the second weld print area facing the copper-aluminum interface and the boundary of the copper-aluminum interface along the first direction is C1, and C1≥0.5mm is satisfied; Or, when the second pole column is made of copper, the second weld mark area is located on the side of the second pole column facing the pole ear, and is used for welding the second pole column and the pole ear, and the spacing dimension between the boundary of the second weld mark area facing the copper-aluminum interface and the boundary of the copper-aluminum interface along the first direction is C2, and satisfies C2≥0.7mm.

4. The copper-aluminum composite pole according to claim 3, characterized in that: When the second pole body is made of aluminum, the distance between the boundary of the second weld mark area facing the copper-aluminum interface and the boundary of the copper-aluminum interface along the second direction is D1, and D1≥0.5mm; Alternatively, when the second pole body is made of copper, a spacing dimension between a boundary of the second weld mark area facing the copper-aluminum interface and a boundary of the copper-aluminum interface along the second direction is D2, and D2≥0.7 mm.

5. The copper-aluminum composite pole according to claim 3, characterized in that: The second pole body includes a base and a connecting boss, the base protrudes in a direction close to the busbar to form the connecting boss, the mounting through hole is opened on the connecting boss, and the second weld print area is arranged on the connecting boss.

6. The copper-aluminum composite pole according to claim 5, characterized in that: When the second pole body is made of aluminum, the distance between the boundary of the second weld mark area away from the copper-aluminum interface and the boundary of the connecting boss along the first direction is E1, and E1≥1mm; Or, when the second pole body is made of copper, a spacing dimension E2 between a boundary of the second weld mark area away from the copper-aluminum interface and a boundary of the connecting boss along the first direction satisfies E2≥1.3 mm.

7. The copper-aluminum composite pole according to claim 5, characterized in that: When the second pole body is made of aluminum, the distance between the boundary of the second weld mark area away from the copper-aluminum interface and the boundary of the connecting boss along the second direction is F1, and F1≥1mm; Alternatively, when the second pole body is made of copper, a spacing dimension between a boundary of the second weld mark area away from the copper-aluminum interface and a boundary of the connecting boss along the second direction is F2, and F2≥1.3 mm.

8. The copper-aluminum composite pole according to claim 3, characterized in that: The widths of the plurality of second weld print areas are the same or different.

9. The copper-aluminum composite pole according to claim 3, characterized in that: The plurality of second weld print areas are symmetrically distributed on both sides of the first pole body along the first direction and / or the second direction.

10. A battery cover, characterized in that: The battery cover plate includes the copper-aluminum composite pole as described in any one of claims 1-9.

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