Busbar single-side welding method

Abstract

The invention relates to a busbar single-face welding method. The busbar single-face welding method comprises the following steps that firstly, a welding area is set; and then welding in sequence. On one hand, on the basis that the busbar and the copper column are connected in an inserted mode and form the lap joint state, the assembling seam cavity is shrunk section by section in the one-by-one welding process so that internal gas can be exhausted from the exhaust hole, the splashing problem caused by the too high internal air temperature can be effectively solved, the number of bubbles and cracks in the fusion area of the copper column and the busbar is reduced, and the welding efficiency is improved; therefore, the welding quality is obviously improved; on the other hand, one-time welding forming of the busbar and the copper column is achieved, operation is easy and convenient, welding efficiency is high, and energy consumption is low.

Description

[0001] This application is a divisional application with the application date of October 21, 2024, application number 2024114638098, and the name of a single-sided segmented exhaust plug welding process. Technical Field

[0002] The invention belongs to the technical field of welding, and in particular relates to a busbar single-sided welding method. Background Art

[0003] Plugs are widely used in power devices, and are generally welded together by a busbar and a copper column.

[0004] At present, the existing plug welding process is generally to first process a through hole on the busbar; then insert the copper column into the through hole so that one end of the copper column is aligned with one end of the through hole (that is, the end face of the copper column is flush with the surface of the corresponding side of the busbar), and the other end extends out of the through hole; then use a laser welding device to perform splicing welding between the end face of the copper column and the surface of the corresponding side of the busbar, and perform fillet welding between the part of the copper column extending out of the through hole and the surface of the corresponding side of the busbar; finally, the completed welded plug product is subjected to a hot and cold shock test to inspect the product welding quality.

[0005] However, in the actual welding process, the prior art is prone to the following defects:

[0006] 1. Due to the large gap between the copper column and the inner wall of the through hole, cracks and pores are easily generated during fillet welding or splicing welding, and the welding spatter problem is serious, which can easily damage the laser welding equipment. In addition, during the subsequent hot and cold shock test, the weld is very likely to break, resulting in a low product yield;

[0007] 2. It is necessary to carry out splicing welding and fillet welding in two processes respectively. Therefore, it is necessary to change the clamping positioning of the product and adjust the welding position and angle of the laser welding equipment. The operation is cumbersome and the welding efficiency is low, which cannot meet the production needs. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a new busbar single-sided welding method.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] A single-sided welding method for a busbar, wherein a plug hole and an exhaust hole are formed on the assembly surface and welding surface of both sides of the busbar respectively; a copper column is inserted into the plug hole from one end and forms an overlap state with the portion of the busbar from the welding surface to the plug hole, and an assembly seam cavity connected to the exhaust hole is formed between one end of the copper column and the inner wall of the plug hole, and the welding method comprises the following steps:

[0011] First, the welding area is set, with the projection of the plug hole on the welding surface as the reference, and including multiple welds distributed along the chord length direction of the projection parallel to any radial direction, wherein both ends of any weld are located outside the projection, and the length of the middle connection line of the multiple welds is greater than or equal to the diameter of the projection; the welding surface of the busbar is divided into multiple welding areas, and the multiple welds correspond to the multiple welding areas one by one, and in the positive projection on the welding surface of the busbar, the multiple welds are distributed side by side along the center connection direction of the exhaust hole and the plug hole, and the multiple welds are defined as the 1st, 2nd, 3rd...Nth welds in the arrangement direction;

[0012] Secondly, weld in sequence, taking the first weld as the reference, and weld one by one from the first weld to the adjacent welds. During each welding, the assembly seam cavity is reduced section by section to discharge the internal gas from the exhaust hole, and the exhaust hole is covered from the Nth weld.

[0013] Preferably, during welding, the 1st weld to the N-1th weld are welded from any end to the other end, and the Nth weld is welded from both ends to the middle. Here, welding is performed in steps, so that the gas in the assembly seam cavity can be discharged while effectively preventing the gas from flowing back into the overlapped portion and the end of the copper column to form bubbles.

[0014] Specifically, from the 1st weld to the N-1th weld, the welding directions of adjacent welds are opposite and remain connected end to end, or the welding directions of adjacent welds remain the same.

[0015] Preferably, the extension direction of each weld is perpendicular to the arrangement direction of the multiple welds.

[0016] Preferably, every two adjacent welds are spliced ​​with each other or partially overlapped.

[0017] Preferably, the exhaust hole is located in the middle of the Nth weld.

[0018] Preferably, laser welding is used during welding. The laser starts from a position of the welding surface of the busbar away from the exhaust hole and gradually approaches the exhaust hole to form each weld seam, and the exhaust hole is sealed during the formation of the last weld seam.

[0019] Preferably, the welding method also includes inspection of welding quality, including hot and cold shock tests and tensile tests, wherein in the tensile test, the busbar and the copper column are pulled in opposite directions by a tensile testing machine, and the maximum load that the plug can withstand is recorded.

[0020] Specifically, when the tensile machine pulls the busbar and the copper column, the tensile end of the tensile machine maintains a lateral deflection, and the deflection amplitude is 1.5 to 2 mm. The purpose of this test is, first, to test the connection strength between the busbar and the copper column by stretching; second, compared with the traditional static tensile test, this application uses the deflection of the tensile force to test whether the matching relationship between the busbar and the copper column is stable, ensuring the accuracy and credibility of the test results.

[0021] In addition, the deflection directions of the two tension ends on the tensile testing machine corresponding to the busbar and the copper column are the same or opposite.

[0022] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0023] There is a large gap between the existing copper column and the inner wall of the through hole. During the process of corner welding or splicing welding, cracks and pores are easily generated, and the welding spatter problem is serious, which can easily cause damage to the laser welding equipment. In addition, during the subsequent hot and cold shock tests, the weld is very likely to break, resulting in a low product yield. Moreover, splicing welding and corner welding need to be performed in two separate processes, so it is necessary to change the clamping positioning of the product and adjust the welding position and angle of the laser welding equipment. The operation is cumbersome, the welding efficiency is low, and it cannot meet production needs. The present application makes an overall design for the single-sided welding method of the busbar, which ingeniously solves the deficiencies and defects of the prior art. After adopting the welding method, the welding area is first set, wherein the projection of the plug hole on the welding surface is used as a reference, and includes a plurality of welds distributed along the chord length direction of the projection parallel to any radial direction, wherein both ends of any weld are located outside the projection, and the length of the middle connecting line of the plurality of welds is greater than or equal to the diameter of the projection; secondly, welding is performed in sequence, and the welding surface of the busbar is divided into a plurality of welding areas, and the plurality of welds correspond to the plurality of welding areas one by one, and the welding area of ​​the busbar is In the orthographic projection on the joint surface, the multiple welds are distributed side by side along the direction of the center line connecting the exhaust hole and the plug hole; the multiple welds are defined as the 1st, 2nd, 3rd...Nth welds in the arrangement direction, and during welding, the 1st weld is taken as a reference, and welded one by one from the 1st weld to the adjacent welds, and the assembly seam cavity is gradually reduced during the welding to discharge the internal gas from the exhaust hole, and the exhaust hole is covered from the Nth weld, wherein the 1st weld to the N-1th weld are all welded from any end to the other end, and welding is performed from both ends of the Nth weld to the middle. Therefore, compared with the prior art, the present invention is based on the busbar and the copper column being plugged in and overlapped, and the assembly seam cavity is gradually reduced during welding to discharge the internal gas from the exhaust hole, effectively reducing the spattering problem caused by excessive internal air temperature, and reducing the number of bubbles and cracks in the fusion area of ​​the copper column and the busbar, thereby significantly improving the welding quality; on the other hand, the busbar and the copper column are welded and formed in one step, which is simple and convenient to operate, with high welding efficiency and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the plug of Example 1;

[0026] Figure 2 is a schematic top view of the plug of Example 1;

[0027] Figure 3 for Figure 2 AA section view;

[0028] Figure 4 for Figure 3 A magnified schematic diagram of the structure at B in the middle;

[0029] Figure 5 This is the metallographic structure diagram (I) of the weld position of the plug sample of Example 1;

[0030] Figure 6 This is the metallographic structure diagram (II) of the weld position of the plug sample of Example 1;

[0031] Figure 7 This is the metallographic structure diagram (III) of the weld position of the plug sample of Example 1;

[0032] Figure 8 This is the metallographic structure diagram (IV) of the weld position of the plug sample of Example 1;

[0033] Fig. 9 It is a schematic diagram of the three-dimensional structure of the plug of comparative example 1;

[0034] Fig.10 A half-section schematic diagram of the plug of Comparative Example 1;

[0035] Fig.11 This is a metallographic structure diagram of the fillet weld position on one side of the plug sample of Comparative Example 1;

[0036] Fig.12 This is the metallographic structure diagram of the fillet weld position on the other side of the plug sample of Comparative Example 1;

[0037] Fig.13 This is a metallographic structure diagram of the weld seam on one side of the plug sample of Comparative Example 1;

[0038] Fig.14 This is the metallographic structure diagram of the welding seam on the other side of the plug sample of Comparative Example 1;

[0039] Among them: T, plug; T0, busbar; k1, plug hole; k2, exhaust hole; k3, through hole; b, overlapping part; T1, copper column; m, chamfered surface; q0, assembly seam cavity; f, weld; q1, welding area. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0041] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] In the present application, unless otherwise expressly specified and limited, the first feature "above" or "below" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature may be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. It should be noted that when an element is referred to as "fixed to" or "set on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0045] Example 1

[0046] like Figures 1 to 4 As shown, the single-sided segmented exhaust plug welding process involved in this embodiment includes S1, assembly of busbar and copper column; S2, welding of busbar and copper column; S3, inspection of welding quality. The plug T involved in this embodiment includes busbar T0 and copper column T1, wherein the busbar T0 and copper column T1 are made of the same material, both copper.

[0047] Specifically, step S1 includes: a) forming a plug hole k1 from the assembly surface of the busbar T0 inwardly, which is an interference fit with the assembly end of the copper column T1, wherein the depth of the plug hole k1 is at least 0.8 times the thickness of the busbar T0, and the portion between the welding surface of the busbar T0 and the plug hole k1 constitutes a lap portion b; and forming a vent hole k2 connected to the plug hole k1 from the welding surface of the busbar T0; b) using a copper column T1 with a chamfered assembly end to insert the self-assembly end into the plug hole k1, and forming an assembly cavity q0 by the assembly end surface of the chamfered end of the copper column T1 and the inner wall of the plug hole k1, and the vent hole k2 is connected to the assembly cavity q0.

[0048] In some specific embodiments, in step a) of S1, the depth of the plug hole k1 is 0.85 to 0.95 times the thickness of the busbar T0. In this embodiment, preferably, the depth of the plug hole k1 is 0.93 times the thickness of the busbar T0. Under this layout, the welding fusion rate of the busbar and the copper column is accelerated, and the welding quality can be ensured simultaneously; at the same time, by controlling the depth of the plug hole and the thickness of the busbar, the connection strength requirements after welding of the copper column and the busbar are met.

[0049] Meanwhile, the diameter of the plug hole k1 is d1, and the diameter of the exhaust hole k2 is d2, wherein 0.12d1≤d2≤0.17d1, and in this embodiment, d2=0.167d1. Under this layout, the exhaust requirement is met while the melting and splashing of the copper column end can be effectively prevented.

[0050] The exhaust hole k2 extends along the thickness direction of the busbar T0, and in the projection on the welding surface of the busbar T0, the exhaust hole k2 is arranged to overlap with the plug hole k1. For the convenience of implementation, the exhaust hole k2 is tangent to the plug hole k1, and the difference between the diameter of the exhaust hole k2 and the radius of the plug hole k1 is smaller than the radius of the assembly end face of the copper column T1, that is, the edge of the assembly end face of the copper column T1 extends into the inner side of the exhaust hole k2. Here, it is convenient for the gas to be quickly discharged after being heated during welding, and at the same time, the flow path of the gas in the exhaust hole is shortened to reduce the deformation caused by uneven force on the busbar; at the same time, under this layout, in the early stage of the welding process, it can avoid the melt flow blocking the exhaust hole in advance and affecting the exhaust effect.

[0051] In step b) of S1, the assembly end of the copper column T1 fits with the inner end surface of the plug hole k1, that is, the assembly end of the copper column T1 and the overlapping portion b form an overlapping state, and an assembly cavity q0 is formed between the chamfered surface m of the copper column T1 and the inner end surface and side wall of the plug hole k1.

[0052] In this example, step S2 includes: a) setting the welding area, wherein the projection of the plug hole k1 on the welding surface of the busbar T0 is used as a reference, and includes multiple welds f distributed along the chord length direction of the projection parallel to any radial direction, wherein both ends of any weld f are located outside the projection, and the length of the middle connecting line of the multiple welds f is greater than or equal to the diameter of the projection; b) welding in sequence, wherein any weld f is used as a reference, and the adjacent welds f are welded one by one, and the assembly seam cavity q0 is gradually reduced during the welding to discharge the internal gas from the exhaust hole k2.

[0053] In some specific embodiments, the welding area of ​​the welding surface of the busbar T0 is divided into multiple welding areas q1, and multiple welds f correspond to the multiple welding areas q1 one by one, and in the orthographic projection on the welding surface of the busbar T0, multiple welds f are arranged side by side along the central connecting line direction of the exhaust hole k2 and the plug hole k1; the extension direction of each weld f is arranged perpendicular to the arrangement direction of the multiple welds f; and each two adjacent welds f are spliced ​​or partially overlapped. Here, by partitioning and implementing welding in steps, it is convenient to exhaust the gas in the assembly seam cavity, and it can also effectively prevent the gas from flowing back into the overlap part and the end of the copper column to form bubbles.

[0054] At the same time, multiple welds f are defined as the 1st, 2nd, 3rd...Nth welds in the arrangement direction. When welding, welding starts from the 1st weld and covers the exhaust hole k2 from the Nth weld. The exhaust hole k2 is located in the middle of the Nth weld. When welding, the 1st weld to the N-1th weld are welded from any end to the other end (adjacent welds can be welded in opposite directions to achieve end-to-end connection, or the welding direction can be kept the same), and welding is performed from both ends of the Nth weld to the middle. This embodiment adopts laser welding. The laser starts from the position of the welding surface of the busbar T0 away from the exhaust hole k2 and gradually approaches the exhaust hole k2 to form each weld, and the exhaust hole k2 is sealed in the formation of the last weld. In this embodiment, N=4.

[0055] In this example, the inspection method of step S3 includes a hot and cold shock test and a pull-off test, wherein the hot and cold shock test is a conventional inspection method and will not be described in detail here; in the pull-off test, the busbar T0 and the copper column T1 are pulled in opposite directions by a tensile testing machine, and the maximum load that the plug can withstand is recorded. When the tensile testing machine pulls the busbar T0 and the copper column T1, the tensile end of the tensile testing machine maintains a lateral deflection, and the deflection amplitude is 1.5 to 2 mm. The deflection directions of the two tensile ends can be the same or opposite. The purpose of this inspection is, first, to inspect the connection strength between the busbar and the copper column by stretching; second, compared with the traditional static pull-off test, the deflection of the tensile force is used to inspect whether the matching relationship between the busbar and the copper column is stable, so as to ensure the accuracy and reliability of the inspection results.

[0056] Therefore, in this embodiment, four plug samples were selected and welded using the welding process of this embodiment. When the tensile test was performed, the maximum load values ​​obtained were shown in Table 1.

[0057] Table 1

[0058] sample 1 2 3 4 Maximum load (N) 3943 3941 3983 4021

[0059] In addition, a plug sample welded by the welding process of this embodiment is selected. After the processing, the metallographic microstructures at four locations on the plug sample are as follows: Figures 5 to 8 As shown, it is obvious that the grain boundaries of the structure are clear, and bubbles and cracks are almost invisible.

[0060] Comparative Example 1

[0061] like Fig. 9 and Fig.10As shown, the plug T involved in this comparative example is different from that in Example 1 in that a through hole k3 is provided on the busbar T0 of this comparative example, and the copper pillar T1 is inserted into the through hole k3 to form a clearance fit, wherein one end of the copper pillar T1 is flush with the back of the busbar T0. Therefore, when welding the plug of this comparative example, first, the corresponding end face of the copper pillar T1 and the back of the busbar T0 are spliced ​​and welded; secondly, the clamping direction of the plug T is changed, and a fillet weld is performed between the side wall of the copper pillar T1 and the front of the busbar T0, thereby completing the welding of the plug T of this comparative example.

[0062] When testing, the testing steps of this comparative example are the same as those of Example 1. Four plug samples welded by the welding process of this comparative example are selected. When performing a tensile test (test parameters are the same as those of Example 1), the maximum load values ​​obtained are shown in Table 2.

[0063] Table 2

[0064] sample 1 2 3 4 Maximum load (N) 2382 2347 2325 2247

[0065] Obviously, the maximum load that the plug sample using the comparative welding process can withstand is much lower than that of Example 1.

[0066] In addition, a plug sample welded by the welding process of this comparative example is selected. After treatment, the metallographic microstructure of the fillet welds and the joint welds on both sides of the plug sample is as follows: Figures 11 to 14 As shown, compared with Example 1, it can be clearly observed in the metallographic structure diagram of the plug product completed in this comparative example that there are more bubbles and cracks. Therefore, the welding process of the present application can effectively reduce the number of bubbles and cracks and significantly improve the welding quality.

[0067] In summary, after adopting this welding process, first, a plug-in hole that is interference fit with the assembly end of the copper column is formed inward from the assembly surface of the busbar, and an exhaust hole connected to the plug-in hole is formed from the welding surface of the busbar; then the copper column with a chamfered assembly end is inserted into the plug-in hole from the assembly end, and an assembly seam cavity is formed by the assembly end surface of the chamfered end of the copper column and the inner wall of the plug-in hole, and the exhaust hole is connected to the assembly seam cavity; then, taking the projection of the plug-in hole on the welding surface as a reference, including a plurality of welds distributed along the chord length direction of the projection parallel to any radial direction, wherein the two ends of any weld are located outside the projection, and the length of the middle connecting line of the plurality of welds is greater than or equal to the diameter of the projection, finally, taking any weld as a reference, welding is performed to the adjacent welds one by one, and the assembly seam cavity is gradually reduced during the welding to discharge the internal gas from the exhaust hole, thereby completing the vertical welding of the busbar and the copper column. Therefore, compared with the prior art, the present invention, on the one hand, is based on the interference fit between the copper column and the busbar, so that the assembly seam cavity formed by the assembly end of the copper column and the inner wall of the plug hole and the exhaust hole formed by the busbar welding surface are connected, and the assembly seam cavity is gradually reduced during welding to discharge the internal gas from the exhaust hole, effectively reducing the spatter problem caused by excessive internal air temperature, and reducing the number of bubbles and cracks in the fusion area of ​​the copper column and the busbar, thereby significantly improving the welding quality; on the other hand, the busbar and the copper column are welded and formed in one time, which is simple and convenient to operate, with high welding efficiency and low energy consumption; thirdly, the welding fusion rate of the busbar and the copper column is accelerated, and the welding quality can be ensured simultaneously; at the same time, by controlling the depth of the plug interface and the thickness of the busbar, the connection between the copper column and the busbar after welding can be met Strength requirements; fourthly, while meeting the exhaust requirements, it can also effectively prevent the melting and splashing of the copper column end; fifthly, it is convenient for the gas to be quickly discharged after being heated during welding, and at the same time shorten the flow path of the gas in the exhaust hole to reduce the deformation of the busbar caused by uneven force; sixthly, by partitioning and implementing welding in steps, so as to facilitate the exhaust of gas in the assembly seam cavity, it can also effectively prevent the gas from flowing back and merging into the overlap and the end of the copper column to form bubbles; seventhly, the inspection method of this embodiment is adopted, first, the connection strength between the busbar and the copper column is tested by stretching; secondly, compared with the traditional static tensile test, the deflection of the tensile force is used to test whether the matching relationship between the busbar and the copper column is stable, so as to ensure the accuracy and reliability of the inspection results.

[0068] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A busbar single-sided welding method, characterized in that: The busbar is provided with a plug-in hole and an exhaust hole formed on the assembly surface and the welding surface on both sides respectively; the copper column is inserted into the plug-in hole from one end and overlaps with the portion of the busbar from the welding surface to the plug-in hole, and an assembly seam cavity connected to the exhaust hole is formed between one end of the copper column and the inner wall of the plug-in hole. The welding method comprises the following steps: First, a welding area is set, with the projection of the plug hole on the welding surface as a reference, and including a plurality of welds distributed along the chord length direction of the projection parallel to any radial direction, wherein both ends of any weld are located outside the projection, and the length of the middle connecting line of the plurality of welds is greater than or equal to the diameter of the projection; the welding surface of the busbar is divided into a plurality of welding areas, and the plurality of welds correspond to the plurality of welding areas one by one, and in the orthographic projection on the welding surface of the busbar, the plurality of welds are distributed side by side along the center connecting line direction of the exhaust hole and the plug hole, and the plurality of welds are defined as the 1st, 2nd, 3rd ... Nth welds in the arrangement direction; Secondly, welding is performed in sequence, taking the first weld as a reference, and welding is performed line by line from the first weld to adjacent welds. During welding, the assembly seam cavity is gradually reduced to discharge the internal gas from the exhaust hole, and the exhaust hole is covered from the Nth weld.

2. The busbar single-sided welding method according to claim 1, characterized in that: During welding, the 1st weld to the N-1th weld are welded from any end to the other end, and the Nth weld is welded from both ends to the middle.

3. The busbar single-sided welding method according to claim 2, characterized in that: From the 1st weld to the N-1th weld, the welding directions of adjacent welds are opposite and they are kept connected end to end, or the welding directions of adjacent welds are kept the same.

4. The busbar single-sided welding method according to claim 1, characterized in that: The extending direction of each weld is perpendicular to the arrangement direction of the multiple welds.

5. The busbar single-sided welding method according to claim 1, characterized in that: Every two adjacent welds are spliced ​​with each other or partially overlapped.

6. The busbar single-sided welding method according to claim 1, characterized in that: The exhaust hole is located in the middle of the Nth weld.

7. The busbar single-sided welding method according to claim 1, characterized in that: During welding, laser welding is used.

8. The busbar single-sided welding method according to claim 1, characterized in that: The welding method also includes welding quality inspection, which includes hot and cold shock tests and tensile tests. In the tensile test, the busbar and the copper column are pulled in opposite directions by a tensile testing machine, and the maximum load that the plug can withstand is recorded.

9. The busbar single-sided welding method according to claim 7, characterized in that: When the tensile machine pulls the busbar and the copper column, the tensile end of the tensile machine maintains a lateral deflection with a deflection amplitude of 1.5 to 2 mm.

10. The busbar single-sided welding method according to claim 8, characterized in that: The deflection directions of the two tension ends on the tensile machine corresponding to the busbar and the copper column are the same or opposite.

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