Tab structure and welding tool

Abstract

Provided in the present application are a tab structure and a welding tool. The tab structure comprises a plurality of tab units stacked and pre-welded together. The tab structure comprises a first end face and a second end face arranged opposite each other, wherein the first end face is configured to be connected to a welding head; the second end face is connected to a welding platform; the difference value between the highest point and the lowest point of a metallographic section of the first end face in a first direction is H1; and the difference value between the highest point and the lowest point of a metallographic section of the second end face in the first direction is H2, where H1≤H2.

Description

Electrode structure and welding fixture

[0001] This application claims priority to Chinese Patent Application No. 202421871584.5, filed with the Chinese Patent Office on August 2, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of electrode structure technology, specifically to an electrode structure and welding fixture. Background Technology

[0003] In battery manufacturing, the welding of multi-layer tabs is a crucial step, and the welding process itself is particularly important. Traditional welding methods involve pre-welding the multi-layer tabs using ultrasonic welding. Invention Overview

[0004] However, during the pre-welding process, the welding head of ultrasonic welding is usually a toothed structure, which will damage the surface of the welded tab structure, resulting in poor flatness of the tab structure surface. This makes it difficult to weld the tab to other components in the future and fails to meet the welding requirements of the tab.

[0005] This application provides a tab structure. The tab structure includes multiple tab units pre-welded together in a stacked manner. The tab structure includes a first end face and a second end face disposed opposite to each other. The difference between the highest and lowest points of the metallographic cross-section of the first end face in a first direction is H1, and the difference between the highest and lowest points of the metallographic cross-section of the second end face in the first direction is H2, where H1 ≤ H2.

[0006] This application also provides a welding fixture. The welding fixture is used to stack and weld multiple tab units into a tab structure as described above, wherein a first end face of the tab structure is used to abut against a welding head, and a second end face of the tab structure is used to abut against a welding station. Beneficial effects

[0007] The electrode structure provided in this application ensures the flatness of the first end face of the electrode structure by making the difference H1 between the highest and lowest points of the metallographic section of the first end face in the first direction less than or equal to the difference H2 between the highest and lowest points of the metallographic section of the second end face in the first direction, so as to meet the requirements for subsequent welding of the electrode structure with other components.

[0008] The welding fixture provided in this application connects the first end face of the electrode structure to the welding head and the second end face of the electrode structure to the welding station. After welding, due to the high flatness of the welding station and the smaller difference between the highest and lowest points of the metallographic section of the first end face in the first direction than the difference between the highest and lowest points of the metallographic section of the second end face in the first direction, the flatness of the first end face of the electrode structure can be guaranteed as much as possible, which is conducive to welding the electrode structure to other components to meet the welding requirements of the electrode. Attached Figure Description

[0009] Figure 1 is a metallographic cross-sectional schematic diagram of the tab structure provided in an embodiment of this application;

[0010] Figure 2 is a three-dimensional structural schematic diagram of the welding fixture provided in an embodiment of this application;

[0011] Figure 3 is a top view of the welding fixture provided in an embodiment of this application;

[0012] Figure 4 is a side view of the tab structure provided in an embodiment of this application;

[0013] Figure 5 is an enlarged view of point A in Figure 4.

[0014] Explanation of reference numerals in the attached figures:

[0015] 1. Electrode structure; 11. First end face; 12. Second end face;

[0016] 20. Welding head; 21. Welding teeth;

[0017] X, the first direction. Embodiments of the present invention

[0018] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0019] In this application, unless otherwise expressly 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 being directly above or diagonally above the second feature, where the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, where the first feature is at a lower horizontal level than the second feature.

[0020] In the description of this embodiment, the terms "upper," "lower," "left," "right," "front," and "rear," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used for ease of description and simplification of operation, 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 this application. Furthermore, the terms "first" and "second" are used for distinction in description and have no special meaning.

[0021] As shown in Figures 1 to 5, in a first aspect, embodiments of this application provide a tab structure 1, which is formed by stacking and pre-welding multiple tab units. The tab structure 1 includes a first end face 11 and a second end face 12 disposed opposite to each other. The first end face 11 is used to connect with the welding head 20, and the second end face 12 is used to connect with the welding station. The difference between the highest point and the lowest point of the metallographic section of the first end face 11 in a first direction is H1, and the difference between the highest point and the lowest point of the metallographic section of the second end face 12 in the first direction is H2, where H1≤H2.

[0022] When H1 > H2, the difference between the highest and lowest points of the metallographic section of the first end face 11 in the first direction is greater than the difference between the highest and lowest points of the metallographic section of the second end face 12 in the first direction. This makes it impossible to guarantee the flatness of the first end face 11, thus failing to meet the requirements for subsequent welding of the tab structure 1 to other components. In this application, subsequent welding includes final welding, which is the direct welding of the electrode structure to the electrode post.

[0023] Furthermore, the final welding specifically involves laser welding. In laser welding, it is necessary to select an appropriate material so that there are more electrons at the high (sub)energy level than at the low energy level, i.e., population inversion. This ensures that stimulated emission exceeds absorption, thereby generating laser light. After electrons are excited to the high energy level, they must remain there for a sufficiently long time to generate powerful laser energy. Simultaneously, the operating temperature of the precision laser welding equipment needs to be maintained within a certain range to ensure its stability and lifespan. Also, to prevent thermal deformation of the electrode structure 1 and its impact on welding quality, the indoor temperature needs to be kept stable. Excessive humidity can cause condensation inside the equipment, affecting its normal operation. Therefore, relative humidity needs to be controlled at a low level. Furthermore, during laser welding, dust, fumes, and other impurities can affect beam transmission and focusing, thus impacting welding quality. Therefore, the workplace should be kept clean, with regular dust removal and cleaning. Additionally, to prevent external dust from entering, windows should be closed or dustproof curtains should be installed. Moreover, laser welding equipment is sensitive to vibration; therefore, the workplace needs to have good anti-vibration measures to ensure the stability and precision of the welding process.

[0024] Furthermore, gas pressure control is crucial in laser welding. Gas pressure is a key parameter in laser welding, affecting multiple factors such as weld quality, molten pool morphology, porosity formation, and welding speed. The gas pressure control standard needs to be determined based on the specific welding material and thickness, generally controlled within the range of 0.1-1 MPa.

[0025] In this application, the surface flatness of the tab structure 1 is relatively good, so it is relatively friendly to the laser beam and there will be no phenomenon of laser reflection burning through the tab due to excessive gap between the tab units, thus ensuring the stability during final welding.

[0026] By applying the technical solution of this application, the first end face 11 of the electrode structure 1 is connected to the welding head 20, and the second end face 12 of the electrode structure 1 is connected to the welding station. After welding, due to the high flatness of the welding station, after metallographic section analysis and comparison, the difference between the highest and lowest points of the metallographic section of the first end face 11 in the first direction is less than the difference between the highest and lowest points of the metallographic section of the second end face 12 in the first direction. This can ensure the flatness of the first end face 11 of the electrode structure 1 as much as possible, which is beneficial for welding the electrode structure 1 with other components to meet the welding requirements of the electrode.

[0027] In one embodiment, H1 ≤ 0.11 mm. When H1 > 0.11 mm, the difference between the highest and lowest points of the metallographic section of the first end face 11 in the first direction is too large, resulting in poor flatness of the first end face 11. Consequently, during subsequent welding, there will be no phenomenon of laser reflection burning through the electrode due to excessive gaps between the electrode units, thus failing to improve the stability at the final welding stage. Therefore, setting 0 ≤ H1 ≤ 0.11 mm not only ensures better flatness of the first end face 11, but also prevents laser reflection burning through the electrode due to excessive gaps between the electrode units during subsequent welding, thereby improving the stability at the final welding stage. Optionally, H1 can be set to values ​​such as 0.05 mm, 0.08 mm, or 0.11 mm. The specific setting should be selected according to the usage environment of the electrode structure 1, and no specific limitation is made here.

[0028] In one embodiment, 0.05mm ≤ H2 ≤ 0.3mm. When H2 > 0.3mm, the difference between the highest and lowest points of the metallographic cross-section of the second end face 12 in the first direction is too large. This causes the welding station to damage the structure of the second end face 12 of the electrode structure 1 after it comes into contact with the welding station, thus affecting the flatness of the second end face 12 of the electrode structure 1, making it difficult to weld with other components. When H2 < 0.05mm, the difference between the highest and lowest points of the metallographic cross-section of the second end face 12 in the first direction is too small. This places higher demands on the flatness of the welding station, thereby increasing welding costs and hindering the mass production of the electrode structure 1. Therefore, setting H2 to 0.05mm ≤ H2 ≤ 0.3mm ensures that the welding station will not damage the structure of the second end face 12 of the electrode structure 1 after it comes into contact with the welding station. This prevents the flatness of the second end face 12 of the electrode structure 1 from being affected, facilitating subsequent welding with other components without increasing welding costs, and promoting mass production of the electrode structure 1. Optionally, H2 can be set to values ​​such as 0.05mm, 0.08mm, or 0.3mm. The specific setting should be selected according to the operating environment of the valve body 10, and no specific restrictions are imposed here.

[0029] In one embodiment, the tab structure 1 includes a plurality of tab units stacked along a first direction. The side of the tab unit located at the highest point away from the tab unit located at the lowest point forms a first end face 11, and the side of the tab unit located at the lowest point away from the tab unit located at the highest point forms a second end face 12. This arrangement allows for the stacking and connection of multiple tab units, thereby reducing the overall volume of the multiple tab units and achieving miniaturization of the tab structure 1.

[0030] Secondly, embodiments of this application provide a welding fixture for stacking and welding multiple tab units into a tab structure 1 as described above. The first end face 11 of the tab structure 1 is used to abut against the welding head 20, and the second end face 12 of the tab structure 1 is used to abut against the welding station.

[0031] In one embodiment, the welding fixture includes: a welding head 20 with welding teeth 21 for connecting to the first end face 11 of the electrode structure 1; and a welding station (not shown in this application) for connecting to the second end face 12 of the electrode structure 1. The welding teeth 21 are flat teeth with a surface roughness of Sa, where 10 μm ≤ Sa ≤ 85 μm. When Sa > 85 μm, the surface roughness of the welding teeth 21 is too large. This large surface roughness reduces the effective contact area between the welding head 20 and the workpiece to be welded, leading to increased pressure at the contact point and accelerating wear on the workpiece. This is because microscopic protrusions on a rough surface are more prone to stress concentration during friction, resulting in increased wear. When Sa < 10 μm, the surface roughness is too small, requiring higher precision in processing equipment and processes, necessitating more precise machine tools, cutting tools, and stricter processing parameters, which increases processing costs and time. Therefore, setting Sa to 10μm≤Sa≤85μm not only increases the effective contact area between the welding head 20 and the workpiece to be welded, but also reduces the pressure at the contact point, thus preventing accelerated wear of the workpiece. Furthermore, it avoids placing excessive demands on processing equipment and processes, thereby not increasing processing costs or time. Optionally, Sa can be set to values ​​such as 10μm, 50μm, or 85μm. The specific setting should be selected based on the usage environment of the welding tooth 21, and no specific restrictions are imposed here.

[0032] In one embodiment, the height of the welding tooth 21 in the first direction is H3, where H3 ≤ 100 μm. When H3 > 100 μm, the height of the welding tooth 21 in the first direction is too large, which increases the production cost of the welding tooth 21. Therefore, setting H3 ≤ 100 μm does not reduce the processing cost of the welding tooth 21. Optionally, H3 can be set to values ​​such as 50 μm, 80 μm, or 100 μm. The specific setting should be selected according to the usage environment of the welding tooth 21, and no specific limitation is made here.

[0033] In this application, the welding teeth 21 are processed by chemical etching or electrical discharge machining.

[0034] In one embodiment, the area of ​​the welding head 20 is S1, and the area of ​​the welding tooth 21 is S2, where 60% ≤ S2 ∶ S1 ≤ 90%. When S2 ∶ S1 > 90%, the ratio of the area of ​​the welding head 20 to the area of ​​the welding tooth 21 is too large, indicating that the area of ​​the welding tooth 21 is too large. Since the area of ​​the welding head 20 is a fixed value, and there is a pressing edge around the welding tooth 21, the area of ​​the pressing edge will be reduced. This will reduce the contact area between the pressing edge and the non-welded area of ​​the electrode tab structure 1, thus failing to ensure effective pressing of the pressing edge against the non-welded area of ​​the electrode tab. When S2 ∶ S1 < 60%, the ratio of the area of ​​the welding head 20 to the area of ​​the welding tooth 21 is too large, indicating that the area of ​​the welding tooth 21 is too small. Since the area of ​​the welding head 20 is a fixed value, the area of ​​the welding tooth 21 is reduced, thus reducing welding efficiency. Therefore, setting 60%≤S2∶S1≤90% not only helps ensure effective clamping of the pressing part against the non-welded area of ​​the electrode structure 1, but also ensures the area of ​​the welding teeth 21, thus improving welding efficiency. Optionally, S2∶S1 can be set to values ​​such as 60%, 80%, or 90%. The specific setting should be selected according to the usage environment of the ultrasonic welding head 20, and no specific restrictions are imposed here.

[0035] In one embodiment, 15mm 2 ≤S2≤600mm 2 When S2 > 600mm 2 When the area of ​​the welding tooth 21 is too large, and since the area of ​​the welding head 20 is a fixed value, and there is a pressing part around the welding tooth 21, the area of ​​the pressing part will be reduced. This will reduce the contact area between the pressing part and the non-welded area of ​​the electrode tab structure 1, thus failing to ensure effective clamping of the pressing part against the non-welded area of ​​the electrode tab. When S2 < 15mm 2 At that time, the area of ​​the welding tooth 21 was too small. Since the area of ​​the welding head 20 is a fixed value, this reduced the area of ​​the welding tooth 21, thus decreasing welding efficiency. Therefore, the 15mm area was... 2 ≤S2≤600mm 2 This not only helps ensure effective clamping of the pressing edge to the non-welded area of ​​the electrode lug structure 1, but also ensures the area of ​​the welding teeth 21, thus improving welding efficiency. Optionally, S2 can be set to 15mm. 2 100mm 2 Or 600mm 2 The specific settings should be selected according to the usage environment of the first pressing part 31, and no specific restrictions are made here.

[0036] In one embodiment, 24mm 2 ≤S1≤780mm 2 When S1 > 780mm2 When the area of ​​the welding head 20 is too large, it is not convenient to accurately align the welding head 20 with the workpiece to be welded, thus reducing welding efficiency and increasing the production cost of the welding head 20, which is not conducive to the mass production of the welding head 20. When S1 < 24mm 2 At that time, the area of ​​the welding head 20 was too small to meet the welding requirements of larger parts. Therefore, the 24mm area was... 2 ≤S1≤780mm 2 This not only facilitates precise alignment between the welding head 20 and the workpiece to be welded, thereby improving welding efficiency, but also avoids increasing the production cost of the welding head 20. This facilitates mass production of the welding head 20 and can also meet the welding needs of larger workpieces. Optionally, S1 can be set to 24mm. 2 200mm 2 Or 780mm 2 The specific settings should be selected based on the usage environment of the welding head 20, and no specific restrictions are imposed here.

[0037] By applying the technical solution of this application, the first end face 11 of the electrode structure 1 is connected to the welding head 20, and the second end face 12 of the electrode structure 1 is connected to the welding station. After welding, through metallographic section analysis and comparison, due to the high flatness of the welding station, the difference between the highest and lowest points of the metallographic section of the first end face 11 in the first direction is smaller than the difference between the highest and lowest points of the metallographic section of the second end face 12 in the first direction. This can ensure the flatness of the first end face 11 of the electrode structure 1 as much as possible, which is beneficial for welding the electrode structure 1 to other components to meet the welding requirements of the electrode.

Claims

1. A tab structure comprising a plurality of tab units stacked and pre-welded together, the tab structure comprising oppositely arranged first and second end faces, a difference between a highest point and a lowest point of a metallographic section of the first end face in a first direction being H1, a difference between a highest point and a lowest point of a metallographic section of the second end face in the first direction being H2, H1≤H2.

2. The tab structure of claim 1, wherein, H1≤0.11mm.

3. The tab structure of claim 1, wherein, 0.05mm≤H2≤0.3mm.

4. A welding fixture, wherein, The welding tool is used for stacking and welding a plurality of tab units into the tab structure as claimed in any one of claims 1-3, a first end face of the tab structure being used for abutting against a welding head, and a second end face of the tab structure being used for abutting against a welding table.

5. The welding fixture of claim 4, wherein, The welding tool comprises: a welding head having a welding tooth used for connecting with the first end face of the tab structure; a welding table used for connecting with the second end face of the tab structure; wherein the welding tooth is a flat-tooth structure.

6. The welding fixture of claim 5, wherein, A surface roughness of the welding tooth is Sa, 10μm≤Sa≤85μm.

7. The welding fixture of claim 5, wherein, A height of the welding tooth in the first direction is H3, H3≤100μm.

8. The welding fixture of claim 5, wherein, An area of the welding head is S1, and an area of the welding tooth is S2, 60%≤S2∶S1≤90%.

9. The welding fixture of any of claims 5-8, wherein, 15 mm 2 ≤ S2≤ 600 mm 2 .

10. The welding fixture of any one of claims 5-8, wherein, 24 mm 2 ≤ S1≤ 780 mm 2 .

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