Battery components and welding tooling

Abstract

The present application discloses a battery assembly and welding tooling, which belongs to the field of battery production technology. The battery assembly includes: a busbar and a winding core. Since the welding trajectory lines in the busbar are continuously distributed around the first non-welding area, the busbar can form a circle of evenly distributed and closely connected welding contact areas with the end face of the winding core over its entire circumference, thereby improving the welding strength between the busbar and the end face of the winding core, and further improving the reliability of the battery. In addition, a first boundary line is set between the welding area and the first non-welding area, and a second boundary line is set between the welding area and the second non-welding area. The welding trajectory line has a plurality of first contact points distributed on the first boundary line, and a plurality of second contact points distributed on the second boundary line. In this way, the total length of the welding trajectory line can be increased, thereby further enhancing the welding strength between the busbar and the end face of the winding core, so that the reliability of the battery is higher.

Description

Technical Field

[0001] The present application relates to the technical field of battery production, and in particular to a battery assembly and welding tooling. Background Art

[0002] With the rapid development of battery technology, batteries have become an indispensable component of many electronic devices. Batteries can provide reliable energy support for mobile phones, laptops, smart wearable devices, and many other electronic devices.

[0003] Generally, a battery consists of a metal shell, a winding core, a busbar, and a cap. The connection quality between the busbar and the exposed part of the winding core (i.e., the tab) is crucial to the overall performance and reliability of the battery. In the prior art, laser welding technology is used to achieve the connection between the busbar and the tab.

[0004] However, in the existing welding method, the welding track between the busbar and the corresponding tab is discontinuous, which leads to insufficient strength of the welding point between the busbar and the tab, and further leads to poor battery reliability. Summary of the invention

[0005] The embodiment of the present application provides a battery assembly and welding tooling, which can solve the problem of poor reliability of batteries in the prior art. The technical solution is as follows:

[0006] In one aspect, a battery assembly is provided, comprising:

[0007] Busbars and reels;

[0008] The busbar and the end of the winding core are connected by welding;

[0009] The busbar comprises: a first non-welding area and a second non-welding area, and a welding area between the first non-welding area and the second non-welding area, the welding area and the second non-welding area are both distributed around the first non-welding area, and the welding area has a welding track line, which is a track continuously distributed around the first non-welding area;

[0010] There is a first boundary line between the first non-welding area and the welding area, there is a second boundary line between the second non-welding area and the welding area, and the welding trajectory line has a plurality of first contact points distributed on the first boundary line and a plurality of second contact points distributed on the second boundary line.

[0011] Optionally, the welding trajectory line includes: a plurality of welding segments connected end to end in sequence, the plurality of welding segments are distributed around the first non-welding area, each welding segment has a first contact point in the middle, and each welding segment has two second contact points at both ends.

[0012] Optionally, two adjacent welding segments have an intersection, the intersection is located between the first boundary line and the second boundary line, and the distance between the intersection and the first boundary line is smaller than the distance between the intersection and the second boundary line.

[0013] Optionally, the plurality of intersections correspond to the plurality of second contact points one by one, and each of the intersections and the corresponding second contact point, as well as the center of the busbar, are located on the same straight line.

[0014] Optionally, the area enclosed by each intersection and the corresponding second contact point, and the two welding segments located on both sides of the intersection is a first area D; the area enclosed by each welding segment and the second boundary line is a second area S;

[0015] The first area D and the second area S satisfy the relationship: S / 4≤D≤3S / 4.

[0016] Optionally, each of the welding segments is a trajectory extending in an arc shape, and each of the welding segments is tangent to the first boundary line.

[0017] Optionally, the welding trajectory line further includes: a plurality of transition segments, two ends of each transition segment are respectively connected to two adjacent welding segments, and a second contact point is provided in the middle of each transition segment;

[0018] Wherein, each of the transition sections is a trajectory extending in an arc shape, and each of the transition sections is tangent to the second boundary line.

[0019] On the other hand, a welding tool is provided, which is used to position the busbar during the welding process of the busbar and the winding core, so that any of the above-mentioned battery assemblies can be obtained after the busbar and the winding core are welded.

[0020] Optionally, the welding tool comprises: a positioning seat, and an electromagnetic generator electrically connected to the positioning seat;

[0021] The electromagnetic generator is configured to generate a magnetic field around the positioning seat so that the busbar is adsorbed on the positioning seat.

[0022] Optionally, the positioning seat includes: a first avoidance hole and a second avoidance hole that are connected to each other, the second avoidance hole is used for a welding laser to pass through so as to weld the busbar and the end of the winding core; the inner diameter of the first avoidance hole is larger than the inner diameter of the second avoidance hole, so that an annular limiting surface can be formed between the first avoidance hole and the second avoidance hole;

[0023] The second non-welding area in the busbar contacts the annular limiting surface, and the welding area in the busbar and the first non-welding area are both exposed through the second avoidance hole.

[0024] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0025] Since the welding track line in the busbar is continuously distributed around the first non-welding area, the busbar can form a circle of uniformly distributed and closely connected welding contact areas with the end face of the winding core in its entire circumference, thereby improving the welding strength between the busbar and the end face of the winding core, and further improving the reliability of the battery. In addition, a first boundary line is set between the welding area and the first non-welding area, and a second boundary line is set between the welding area and the second non-welding area. The welding track line has multiple first contact points distributed on the first boundary line, and multiple second contact points distributed on the second boundary line. In this way, the total length of the welding track line can be increased, effectively reducing the risk of disconnection between the busbar and the end face of the winding core due to mechanical stress, thereby further enhancing the welding strength between the busbar and the end face of the winding core, making the battery more reliable. At the same time, by extending the length of the welding track line, the transmission path of the current between the busbar and the winding core is optimized, the obstacles in the current transmission process are reduced, the internal resistance of the entire battery is reduced, and the heat generation phenomenon is reduced, thereby significantly improving the overall performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 is an exploded view of a battery assembly provided in an embodiment of the present application;

[0028] Figure 2 It is a structural schematic diagram of a busbar provided in an embodiment of the present application;

[0029] Figure 3 is a schematic structural diagram of another busbar provided in an embodiment of the present application;

[0030] Figure 4 It is a structural schematic diagram of another busbar provided in an embodiment of the present application;

[0031] Figure 5 is a structural schematic diagram of another busbar provided in an embodiment of the present application;

[0032] Figure 6 is a structural schematic diagram of a busbar provided by another embodiment of the present application;

[0033] Figure 7 It is a structural schematic diagram of a welding tool provided in an embodiment of the present application;

[0034] Figure 8 is a structural schematic diagram of a welding tool provided in an embodiment of the present application from another perspective;

[0035] Fig. 9 It is a structural schematic diagram of a welding tool provided in an embodiment of the present application from another perspective. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0037] Please refer to Figure 1 and Figure 2 , Figure 1 is an exploded view of a battery assembly provided in an embodiment of the present application, Figure 2 1 is a schematic diagram of the structure of a busbar provided in an embodiment of the present application. A battery assembly 000 may include: a busbar 100 and a winding core 200 .

[0038] The busbar 100 in the battery assembly 000 may be connected to the end of the winding core 200 by welding.

[0039] The busbar 100 in the battery assembly 000 may include: a first non-welding area A1 and a second non-welding area A2, and a welding area A3 located between the first non-welding area A1 and the second non-welding area A2. The welding area A3 and the second non-welding area A2 are both distributed around the first non-welding area A1, and the welding area A3 may have a welding track line 101, which may be a track continuously distributed around the first non-welding area A1.

[0040] There is a first boundary line U1 between the first non-welding area A1 and the welding area A3, there is a second boundary line U2 between the second non-welding area A2 and the welding area A3, and the welding trajectory line 101 has a plurality of first contact points V1 distributed on the first boundary line U1, and a plurality of second contact points V2 distributed on the second boundary line U2.

[0041] Generally, laser welding technology can be used to achieve the connection between the busbar and the end face of the core. However, in the traditional welding method, the welding track between the busbar and the end face of the core is often discontinuous along the circumference of the busbar, resulting in insufficient strength of the welding point between the busbar and the end face of the core, which in turn leads to poor battery reliability.

[0042] In the embodiment of the present application, since the welding track line 101 in the busbar 100 is continuously distributed around the first non-welding area A1, the busbar 100 can form a circle of continuously distributed and closely connected welding contact areas with the end face of the winding core 200 in its entire circumference, thereby improving the welding strength between the busbar 100 and the end face of the winding core 200, and further improving the reliability of the battery. In addition, a first intersection line U1 is set between the welding area A3 and the first non-welding area A1, and a second intersection line U2 is set between the welding area A3 and the second non-welding area A2. The welding track line 101 has a plurality of first contact points V1 distributed on the first intersection line U1, and a plurality of second contact points V2 distributed on the second intersection line U2. In this way, the total length of the welding track line 101 can be increased, and the risk of disconnection between the busbar 100 and the end face of the winding core 200 due to mechanical stress is effectively reduced, thereby further enhancing the welding strength between the busbar 100 and the end face of the winding core 200, so that the reliability of the battery is higher. At the same time, by extending the length of the welding track line 101, the current transmission path between the busbar 100 and the winding core 200 is optimized, the obstacles in the current transmission process are reduced, the internal resistance of the entire battery assembly 000 is reduced, and the heat generation phenomenon is reduced, thereby significantly improving the overall performance of the battery assembly 000.

[0043] In summary, an embodiment of the present application provides a battery assembly, including: a busbar and a winding core. Since the welding track line in the busbar is continuously distributed around the first non-welding area, the busbar can form a circle of continuously distributed and closely connected welding contact areas with the end face of the winding core in its entire circumference, thereby improving the welding strength between the busbar and the end face of the winding core, and further improving the reliability of the battery. In addition, a first boundary line is set between the welding area and the first non-welding area, and a second boundary line is set between the welding area and the second non-welding area. The welding track line has a plurality of first contact points distributed on the first boundary line, and a plurality of second contact points distributed on the second boundary line. In this way, the total length of the welding track line can be increased, effectively reducing the risk of disconnection between the busbar and the end face of the winding core due to mechanical stress, thereby further enhancing the welding strength between the busbar and the end face of the winding core, so that the reliability of the battery is higher. At the same time, by extending the length of the welding track line, the current transmission path between the busbar and the winding core is optimized, the obstacles in the current transmission process are reduced, the internal resistance of the entire battery assembly is reduced, and the heat generation phenomenon is reduced, thereby significantly improving the overall performance of the battery assembly.

[0044] In the examples of this application, please refer to Figure 3 , Figure 31 is a schematic diagram of the structure of another busbar provided in an embodiment of the present application. The welding track line 101 in the busbar 100 may include: a plurality of welding segments 1011 connected in sequence end to end. The plurality of welding segments 1011 may be distributed around the first non-welding area A1, and the middle position of each welding segment 1011 may have a first contact point V1, and the two ends of each welding segment 1011 may respectively have two second contact points V2.

[0045] In this case, the multiple welding segments 1011 are connected end to end in sequence to ensure the overall continuity of the welding track line 101. This allows the busbar 100 to form a circle of continuously distributed and closely connected welding contact areas with the end surface of the winding core 200 in its entire circumference, thereby enhancing the welding strength between the busbar 100 and the end surface of the winding core 200, and effectively improving the reliability of the battery.

[0046] Optional, please refer to Figure 4 , Figure 4 It is a structural schematic diagram of another busbar provided in an embodiment of the present application. Two adjacent welding segments 1011 in the welding trajectory line 101 may have an intersection point V3, and the intersection point V3 may be located between the first intersection line U1 and the second intersection line U2, and the distance between the intersection point V3 and the first intersection line U1 is smaller than the distance between the intersection point V3 and the second intersection line U2.

[0047] In this case, through these intersections V3, the layout of the welding trajectory line 101 on the busbar 100 can be made more complex and tortuous. In this way, not only the total length of the welding trajectory line 101 is increased, but also the contact area between the welding point and the end surface of the busbar 100 and the core 200 is made wider. This not only enhances the mechanical strength of the welding point between the end surface of the busbar 100 and the core 200, but also reduces the risk of fracture of the end surface of the busbar 100 and the core 200 caused by external force or vibration, thereby improving the reliability of the battery. In addition, a longer welding path helps to optimize the current transmission efficiency, reduce obstacles in the current transmission process, reduce the internal resistance of the entire battery, and reduce heat generation, thereby improving the overall performance of the battery.

[0048] In the embodiment of the present application, the plurality of intersection points V3 may correspond one-to-one to the plurality of second contact points V2 , and each intersection point V3 may be located on the same straight line as the corresponding second contact point V2 and the center of the busbar 100 .

[0049] In this case, the welding track line 101 becomes more neat and regular because the intersection point V3 and the second contact point V2, as well as the center of the busbar 100, are located on the same straight line. This not only ensures the uniformity of heat distribution during welding, effectively reduces quality problems caused by uneven welding, thereby extending the service life of the battery assembly 000; at the same time, it also makes the welding track line 101 visually present a neat and regular geometric pattern, enhancing the visual beauty of the product, reducing the sense of clutter, and making the overall look more neat and orderly.

[0050] Optional, please refer to Figure 5 , Figure 5 : This is a schematic diagram of the structure of another busbar provided in an embodiment of the present application. The area enclosed by each intersection point V3 and the corresponding second contact point V2, and the two welding segments 1011 located on both sides of the intersection point V3 is the first area D; the area enclosed by each welding segment 1011 and the second boundary line U2 is the second area S.

[0051] The first area D and the second area S satisfy the relationship: S / 4≤D≤3S / 4. For example, the second area S is three times the first area D.

[0052] In this case, it can not only ensure that any two adjacent welding sections 1011 will not generate heat concentration and stress concentration problems due to being too close, thereby effectively avoiding the risk of reduced welding quality and reduced welding point strength. At the same time, it also ensures that the welding track line 101 can be extended as much as possible while maintaining a neat and regular layout. And the longer welding track line not only enhances the welding strength between the busbar 100 and the end face of the winding core 200, improves the reliability of the battery, but also optimizes the current transmission path between the busbar 100 and the winding core 200, reduces obstacles in the current transmission process, reduces the internal resistance of the battery, and reduces the heat generation phenomenon, thereby significantly improving the overall performance of the battery.

[0053] In the embodiments of the present application, Figure 3 As shown, each welding segment 1011 in the welding trajectory line 101 may be a trajectory extending in an arc shape, and each welding segment 1011 is tangent to the first intersection line U1. For example, the point where the welding segment 1011 is tangent to the first intersection line U1 is the first contact point V1.

[0054] In this case, the arc-shaped welding segment 1011 can ensure the smoothness and continuity of the welding trajectory 101, effectively avoiding the pause or deceleration caused by the sharp change of the path during welding, thereby increasing the welding speed, shortening the welding time, and significantly enhancing the efficiency of the welding operation. In addition, the welding trajectory 101 formed by connecting multiple arc-shaped welding segments 1011 presents a smooth and regular shape, which greatly improves the appearance competitiveness of the product.

[0055] Optional, such as Figure 3 As shown, the welding track line 101 in the busbar 100 can be a spiral curve track that is continuously distributed around the first non-welding area A1.

[0056] In this case, the continuity of the spiral curve reduces the number of starts and stops during the welding process, reduces welding defects such as pores and cracks caused by welding interruptions, and helps improve the overall quality of welding, thereby making the connection strength between the busbar 100 and the end surface of the winding core 200 higher. At the same time, the spiral welding trajectory can guide the laser beam to evenly distribute heat on the busbar 100, avoiding the problem of local overheating, helping to reduce welding deformation, and improving the stability of the battery assembly 000.

[0057] Optional, please refer to Figure 6 , Figure 6 1 is a schematic diagram of the structure of a busbar provided in another embodiment of the present application. The welding track line 101 in the busbar 100 may also include: a plurality of transition sections 1012, each transition section 1012 having two ends connected to two adjacent welding sections 1011, and each transition section 1012 may have a second contact point V2 in the middle.

[0058] Each transition segment 1012 is an arc-shaped extending track, and each transition segment 1012 is tangent to the second boundary line U2. For example, the point where the transition segment 1012 is tangent to the second boundary line U2 is the second contact point V2.

[0059] Normally, in the end face welding operation of busbars and coils, the sudden change of welding trajectory often leads to the appearance of sharp inflection points. These inflection points cause heat and stress to concentrate in this area during welding due to the sharp change in shape. This concentration effect increases the risk of deformation and cracking in this area. Once the accumulated stress exceeds the material's tolerance limit, it will trigger the phenomenon of blowout welding. When blowout welding occurs, the welding arc is out of control, accompanied by violent sparks and spatter, and even accompanied by an explosive sound, which seriously affects the welding quality, such as poor weld shape, improper penetration, etc., and also poses a major hidden danger to the safety of welding equipment and operators.

[0060] In the embodiment of the present application, a plurality of arc-shaped transition sections 1012 are designed, each transition section 1012 is tangent to the second boundary line U2, and a second contact point V2 is formed in the middle position which is smoothly tangent to the second boundary line U2. In this way, the entire welding trajectory can be made smoother, and the existence of sharp inflection points is eliminated. Due to the arc-shaped design of the transition section 1012, the heat and stress generated during welding can be distributed more evenly, reducing the concentration effect at the inflection point. In this way, not only the deformation and cracking risks in this area are reduced, but also the welding quality is significantly improved. At the same time, since sharp inflection points are avoided, the probability of explosion welding is also greatly reduced, thereby ensuring the safety of welding equipment and operators.

[0061] In summary, an embodiment of the present application provides a battery assembly, including: a busbar and a winding core. Since the welding track line in the busbar is continuously distributed around the first non-welding area, the busbar can form a circle of uniformly distributed and closely connected welding contact areas with the end face of the winding core in its entire circumference, thereby improving the welding strength between the busbar and the end face of the winding core, and further improving the reliability of the battery. In addition, a first boundary line is set between the welding area and the first non-welding area, and a second boundary line is set between the welding area and the second non-welding area. The welding track line has a plurality of first contact points distributed on the first boundary line, and a plurality of second contact points distributed on the second boundary line. In this way, the total length of the welding track line can be increased, effectively reducing the risk of disconnection between the busbar and the end face of the winding core due to mechanical stress, thereby further enhancing the welding strength between the busbar and the end face of the winding core, so that the reliability of the battery is higher. At the same time, by extending the length of the welding track line, the current transmission path between the busbar and the winding core is optimized, the obstacles in the current transmission process are reduced, the internal resistance of the entire battery is reduced, and the heat generation is reduced, thereby significantly improving the overall performance of the battery.

[0062] The present application also provides a welding tool, please refer to Figure 7 , Figure 8 and Fig. 9 , Figure 7 is a structural schematic diagram of a welding tool provided in an embodiment of the present application, Figure 8 is a structural schematic diagram of a welding tool provided in an embodiment of the present application from another perspective, Fig. 9 001 is a structural schematic diagram of a welding tool provided in an embodiment of the present application from another perspective. The welding tool 001 can be used to position the busbar 100 during the welding process of the busbar 100 and the winding core 200, so that any of the above-mentioned battery assemblies 000 can be obtained after the busbar 100 and the winding core 200 are welded.

[0063] In this case, the busbar 100 is positioned by the welding jig 001, ensuring that the relative position of the busbar 100 and the end face of the winding core 200 is accurate during the welding process, thereby improving the welding quality and making the battery assembly 000 more reliable. And by fixing and positioning the busbar 100 by the welding jig 001, the preparation work before welding can be greatly simplified, and the time and error of manual adjustment can be reduced, thereby improving the welding efficiency. In addition, the use of the welding jig 001 can also reduce the safety risks in the welding operation. By fixing the busbar 100, accidental injuries caused by improper operation or movement of the workpiece during welding can be reduced.

[0064] In the embodiments of the present application, Figure 7 , Figure 8 and Fig. 9 As shown, the welding tool 001 may include: a positioning seat 010 , and an electromagnetic generator 020 electrically connected to the positioning seat 010 .

[0065] The electromagnetic generator 020 in the welding tool 001 may be configured to generate a magnetic field around the positioning seat 010 so that the busbar 100 is adsorbed on the positioning seat 010 .

[0066] Typically, the electromagnetic generator 020 is designed with a precision coil inside. When current is applied to it, a magnetic field is excited around the coil according to the principles of electromagnetism. The direction and strength of the magnetic field are directly related to the direction and magnitude of the current.

[0067] In the embodiment of the present application, since the electromagnetic generator 020 is electrically connected to the positioning seat 010 , after the electromagnetic generator 020 is powered on, current will pass through the positioning seat 010 to form a stable and adjustable magnetic field around the positioning seat 010 .

[0068] In addition, the busbar 100 is made of metal material, and this magnetic field can attract and firmly fix the busbar 100 on the positioning seat 010, ensuring accurate positioning and stable support before welding. At the same time, by accurately controlling the current in the electromagnetic generator 020, fine adjustment of the magnetic field can be achieved to meet the positioning requirements of busbars 100 of different shapes, materials or weights, so that the welding tool 001 can efficiently and accurately complete the production and manufacturing tasks of the battery assembly 000.

[0069] Optional, such as Figure 7 , Figure 8 and Fig. 9As shown, the positioning seat 010 in the welding tool 001 may include: a first avoidance hole K1 and a second avoidance hole K2 that are connected, and the second avoidance hole K2 can be used for the welding laser to pass through to weld the ends of the busbar 100 and the winding core 200; and the inner diameter of the first avoidance hole K1 is larger than the inner diameter of the second avoidance hole K2, so that an annular limiting surface L can be formed between the first avoidance hole K1 and the second avoidance hole K2.

[0070] The second non-welding area A2 in the busbar 100 can contact the annular limiting surface L, and the welding area A3 and the first non-welding area A1 in the busbar 100 can be exposed through the second avoidance hole K2. That is, the welding area A3 and the first non-welding area A1 in the busbar 100 are both located in the area surrounded by the boundary of the second avoidance hole K2.

[0071] In this case, when the electromagnetic generator 020 is electrically connected to the positioning base 010 and the electromagnetic generator 020 is powered on, current will pass through the positioning base 010 to form a stable and adjustable magnetic field around the positioning base 010 .

[0072] In addition, the busbar 100 is made of metal material, and this magnetic field can attract and firmly fix the busbar 100 on the limiting surface L, ensuring accurate positioning and stable support before welding. At the same time, since the welding area A3 and the first non-welding area A1 in the busbar 100 are exposed through the second avoidance hole K2, it can ensure that the welding laser can directly act on the welding area A3 without hindrance, and achieve accurate welding with the end of the winding core 200.

[0073] In this way, not only the accuracy and efficiency of welding are improved, but also potential damage to non-welding areas during welding is avoided, ensuring the overall quality and performance of the battery assembly 000. In addition, the annular limit surface L can provide a stable support surface for the busbar 100, further enhancing the stability of the busbar 100 during welding, so that the welding tool 001 can efficiently complete the production and manufacturing tasks of the battery assembly 000, and improve the automation level and production efficiency of the production line.

[0074] In the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0075] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A battery assembly, characterized in that: include: A busbar (100) and a winding core (200); The busbar (100) and the end of the winding core (200) are connected by welding; The busbar (100) comprises: a first non-welding area (A1) and a second non-welding area (A2), and a welding area (A3) located between the first non-welding area (A1) and the second non-welding area (A2), wherein the welding area (A3) and the second non-welding area (A2) are both distributed around the first non-welding area (A1), and the welding area (A3) has a welding track line (101), and the welding track line (101) is a track that is continuously distributed around the first non-welding area (A1); There is a first boundary line (U1) between the first non-welding area (A1) and the welding area (A3), there is a second boundary line (U2) between the second non-welding area (A2) and the welding area (A3), and the welding trajectory line (101) has a plurality of first contact points (V1) distributed on the first boundary line (U1), and a plurality of second contact points (V1) distributed on the second boundary line (U2).

2. The battery assembly according to claim 1, characterized in that: The welding trajectory line (101) comprises: a plurality of welding segments (1011) connected in sequence end to end, the plurality of welding segments (1011) are distributed around the first non-welding area (A1), each welding segment (1011) has a first contact point (V1) at the middle position, and each welding segment (1011) has two second contact points (V2) at both ends.

3. The battery assembly according to claim 2, characterized in that: Two adjacent welding sections (1011) have an intersection point (V3), and the intersection point (V3) is located between the first boundary line (U1) and the second boundary line (U2), and the distance between the intersection point (V3) and the first boundary line (U1) is smaller than the distance between the intersection point (V3) and the second boundary line (U2).

4. The battery assembly according to claim 3, characterized in that: The plurality of intersection points (V3) correspond one-to-one to the plurality of second contact points (V2), and each of the intersection points (V3) and the corresponding second contact point (V2), as well as the center of the busbar (100) are located on the same straight line.

5. The battery assembly according to claim 4, characterized in that: The area enclosed by each intersection (V3) and the corresponding second contact point (V2), and the two welding segments (1011) located on both sides of the intersection (V3) is a first area D; the area enclosed by each welding segment (1011) and the second boundary line (U2) is a second area S; The first area D and the second area S satisfy the relationship: S / 4≤D≤3S / 4.

6. The battery assembly according to any one of claims 2 to 5, characterized in that: Each of the welding sections (1011) is a trajectory extending in a circular arc shape, and each of the welding sections (1011) is tangent to the first boundary line (U1).

7. The battery assembly according to any one of claims 2 to 5, characterized in that: The welding trajectory line (101) further comprises: a plurality of transition sections (1012), the two ends of each transition section (1012) being respectively connected to two adjacent welding sections (1011), and the middle position of each transition section (1012) having a second contact point (V2); Wherein, each of the transition sections (1012) is a trajectory extending in an arc shape, and each of the transition sections (1012) is tangent to the second boundary line (U2).

8. A welding tool, characterized in that: The welding tool is used to position the busbar (100) during the welding process of the busbar (100) and the winding core (200), so that after the busbar (100) and the winding core (200) are welded, a battery assembly according to any one of claims 1 to 7 can be obtained.

9. The welding tool according to claim 8, characterized in that: The welding tool comprises: a positioning seat (010), and an electromagnetic generator (020) electrically connected to the positioning seat (010); The electromagnetic generator (020) is configured to generate a magnetic field around the positioning seat (010) so that the busbar (100) is adsorbed on the positioning seat (010).

10. The welding tool according to claim 9, characterized in that: The positioning seat (010) comprises: a first avoidance hole (K1) and a second avoidance hole (K2) which are connected to each other; the second avoidance hole (K2) is used for a welding laser to pass through so as to weld the ends of the busbar (100) and the winding core (200); the inner diameter of the first avoidance hole (K1) is greater than the inner diameter of the second avoidance hole (K2), so that an annular limiting surface (L) can be formed between the first avoidance hole (K1) and the second avoidance hole (K2); The second non-welding area (A2) in the busbar (100) contacts the annular limiting surface (L), and the welding area (A3) in the busbar (100) and the first non-welding area (A1) are both exposed through the second avoidance hole (K2).

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