Battery assembly and welding tool

Abstract

The utility model discloses a battery assembly and a welding tool, and belongs to the technical field of battery production. The battery assembly comprises a confluence plate and a roll core. As the welding track lines in the confluence plate are continuously distributed around the first non-welding area, a circle of uniformly distributed and tightly connected welding contact areas can be formed between the confluence plate and the end surface of the roll core in the whole circumferential direction, so that the welding strength of the confluence plate and the end surface of the roll core can be improved, and the reliability of the battery can be improved. In addition, a first boundary line is arranged between the welding area and the first non-welding area, and a second boundary line is arranged between the welding area and the second non-welding area. A plurality of first contact points are distributed on the first boundary line of the welding track line, and a plurality of second contact points are distributed on the second boundary line of the welding track line. Therefore, the total length of the welding track line can be increased, so that the welding strength between the confluence plate and the end face of the roll core is further enhanced, and the reliability of the battery is relatively high.

Description

TECHNICAL FIELD

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

[0002] With the rapid development of battery technology, batteries have become an indispensable part 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 is composed of a metal shell, a winding core, a busbar, and a cap, etc. Among them, 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 realize the connection between the busbar and the tab.

[0004] However, the existing welding method is discontinuous in the welding track between the busbar and the corresponding tab, resulting in insufficient welding strength between the busbar and the tab, and further leading to poor battery reliability. UTILITY MODEL CONTENT

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

[0006] On the one hand, a battery assembly is provided, comprising:

[0007] a busbar and a winding core;

[0008] the end of the busbar and the winding core are welded and connected;

[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 distributed around the first non-welding area, and the welding area has a welding track line, which is a continuous track around the first non-welding area;

[0010] wherein the first non-welding area and the welding area have a first boundary line, the second non-welding area and the welding area have a second boundary line, 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.

[0011] Optionally, the welding track line comprises a plurality of welding segments connected in sequence, the plurality of welding segments are distributed around the first non-welding area, the middle position of each welding segment has a first contact point, and the two ends of each welding segment have two second contact points respectively.

[0012] Optionally, two adjacent welding sections have a cross point, the cross point is located between the first boundary line and the second boundary line, and the distance between the cross point and the first boundary line is less than the distance between the cross point and the second boundary line.

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

[0014] Optionally, each cross point and the corresponding second contact point, and the area surrounded by the two welding sections on both sides of the cross point are a first area D; the area surrounded by each welding section and the second boundary line is a second area S.

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

[0016] Optionally, each welding section is a circular arc-shaped trajectory, and each welding section is tangent to the first boundary line.

[0017] Optionally, the welding trajectory line further comprises a plurality of transition sections, two ends of each transition section are connected with two adjacent welding sections respectively, and the middle position of each transition section has a second contact point;

[0018] Wherein, each transition section is an arc-shaped trajectory, and each transition section is tangent to the second boundary line.

[0019] On the other hand, a welding tool is provided, which is used for positioning the busbar during welding of the busbar and the winding core, so that the busbar and the winding core can be welded to obtain any one of the above-mentioned battery assemblies.

[0020] Optionally, the welding tool comprises a positioning seat and an electromagnetic generator electrically connected with 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 comprises a first avoiding hole and a second avoiding hole in communication, the second avoiding hole is used for welding laser to pass through to weld the end of the busbar and the winding core; the inner diameter of the first avoiding hole is greater than the inner diameter of the second avoiding hole, so that an annular limiting surface can be formed between the first avoiding hole and the second avoiding hole.

[0023] The second non-welding area in the busbar is in contact with the annular limiting surface, and the welding area and the first non-welding area in the busbar are exposed through the second avoiding hole.

[0024] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects:

[0025] Since the welding track line in the busbar is continuously distributed around the first non-welding area, the busbar can form a uniformly distributed and closely connected welding contact area between the busbar and the end face of the winding core in the entire circumferential direction, thereby improving the welding strength of the busbar and the end face of the winding core, and further improving the reliability of the battery. In addition, the first interface line is arranged between the welding area and the first non-welding area, and the second interface line is arranged between the welding area and the second non-welding area. The welding track line is distributed with a plurality of first contact points on the first interface line and a plurality of second contact points on the second interface line. In this way, the total length of the welding track line can be increased, effectively reducing the risk of the busbar and the end face of the winding core being disconnected due to mechanical stress, thereby further enhancing the welding strength between the busbar and the end face of the winding core, and making the battery have high reliability. At the same time, by prolonging the length of the welding track line, the transmission path of the current between the busbar and the winding core is optimized, the obstruction in the current transmission process is reduced, the internal resistance of the entire battery is reduced, and the heating phenomenon is reduced, thereby significantly improving the overall performance of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

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

[0028] Figure 2 is a structural schematic view of a busbar provided by the embodiment of the present application;

[0029] Figure 3 is a structural schematic view of another busbar provided by the embodiment of the present application;

[0030] Figure 4 is a structural schematic view of still another busbar provided by the embodiment of the present application;

[0031] Figure 5 is a structural schematic view of still another busbar provided by the 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 is a structural schematic diagram of a welding tool provided by an embodiment of the present application;

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

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

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

[0037] Please refer to Figure 1 and Figure 2 , Figure 1 is an exploded view of a battery assembly provided by an embodiment of the present application, Figure 2 is a structural schematic diagram of a busbar provided by an embodiment of the present application. The battery assembly 000 can include a busbar 100 and a winding core 200.

[0038] The busbar 100 in the battery assembly 000 can be welded to the end of the winding core 200.

[0039] The busbar 100 in the battery assembly 000 can 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 both surround the first non-welding area A1, and the welding area A3 can have a welding track line 101, which can be a continuous track surrounding the first non-welding area A1.

[0040] Among them, the first non-welding area A1 has a first boundary line U1 with the welding area A3, the second non-welding area A2 has a second boundary line U2 with the welding area A3, the welding track 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 realize the connection between the busbar and the winding core end face. However, in the traditional welding method, the welding track of the busbar and the winding core end face along the circumferential direction of the busbar is often discontinuous, which leads to insufficient welding point strength between the busbar and the winding core end face, and further leads to poor battery reliability.

[0042] In the embodiment of the present application, since the welding track lines 101 in the busbar 100 are continuously distributed around the first non-welding area A1, a continuous and closely connected welding contact area can be formed between the busbar 100 and the end face of the winding core 200 in the entire circumference of the busbar 100, so as to improve the welding strength between the busbar 100 and the end face of the winding core 200, and further improve the reliability of the battery. In addition, the first boundary line U1 is arranged between the welding area A3 and the first non-welding area A1, and the second boundary line U2 is arranged between the welding area A3 and the second non-welding area A2. The welding track lines 101 are distributed with a plurality of first contact points V1 on the first boundary line U1 and a plurality of second contact points V2 on the second boundary line U2. In this way, the total length of the welding track lines 101 can be increased, the risk of the busbar 100 and the end face of the winding core 200 being disconnected due to mechanical stress can be effectively reduced, and the welding strength between the busbar 100 and the end face of the winding core 200 is further enhanced, so that the reliability of the battery is higher. At the same time, by prolonging the length of the welding track lines 101, the transmission path of the current between the busbar 100 and the winding core 200 is optimized, the obstruction in the current transmission process is reduced, the internal resistance of the entire battery assembly 000 is reduced, and the heating phenomenon is reduced, so as to significantly improve the overall performance of the battery assembly 000.

[0043] In summary, the embodiment of the present application provides a battery assembly, which comprises a busbar and a winding core. Since the welding track lines in the busbar are continuously distributed around the first non-welding area, a continuous and closely connected welding contact area can be formed between the busbar and the end face of the winding core in the entire circumference of the busbar, so as to improve the welding strength between the busbar and the end face of the winding core, and further improve the reliability of the battery. In addition, the first boundary line is arranged between the welding area and the first non-welding area, and the second boundary line is arranged between the welding area and the second non-welding area. The welding track lines are distributed with a plurality of first contact points on the first boundary line and a plurality of second contact points on the second boundary line. In this way, the total length of the welding track lines can be increased, the risk of the busbar and the end face of the winding core being disconnected due to mechanical stress can be effectively reduced, and the welding strength between the busbar and the end face of the winding core is further enhanced, so that the reliability of the battery is higher. At the same time, by prolonging the length of the welding track lines, the transmission path of the current between the busbar and the winding core is optimized, the obstruction in the current transmission process is reduced, the internal resistance of the entire battery assembly is reduced, and the heating phenomenon is reduced, so as to significantly improve the overall performance of the battery assembly.

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

[0045] In this case, the plurality of welding segments 1011 are connected in sequence, which ensures the overall continuity of the welding track line 101. This enables the busbar 100 to form a continuous and closely connected welding contact area with the end face of the core 200, thereby enhancing the welding strength between the busbar 100 and the end face of the core 200, and effectively improving the reliability of the battery.

[0046] Optionally, please refer to Figure 4 , Figure 4 is another structural schematic diagram of a busbar provided by an embodiment of the present application. The two adjacent welding segments 1011 in the welding track line 101 can have a cross point V3, which can be located between the first boundary line U1 and the second boundary line U2, and the distance between the cross point V3 and the first boundary line U1 is less than the distance between the cross point V3 and the second boundary line U2.

[0047] In this case, the cross points V3 can make the layout of the welding track line 101 on the busbar 100 more complex and tortuous. In this way, not only the total length of the welding track line 101 is increased, but also the contact area of the welding points with the busbar 100 and the end face of the core 200 is more extensive. This not only enhances the mechanical strength of the welding points between the busbar 100 and the end face of the core 200, but also reduces the risk of fracture of the busbar 100 and the end face of the core 200 caused by external force or vibration, thereby improving the reliability of the battery. In addition, the longer welding path helps to optimize the current transmission efficiency, reduce the obstacles in the current transmission process, reduce the internal resistance of the entire battery, and reduce the heating phenomenon, thereby improving the overall performance of the battery.

[0048] In the embodiment of the present application, the plurality of cross points V3 can correspond to the plurality of second contact points V2 one by one, and each cross point V3 can be located on the same straight line with 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 due to the intersection point V3 and the second contact point V2, and the center of the busbar 100 being located on the same straight line. This not only ensures the uniformity of heat distribution during welding, effectively reducing quality problems caused by uneven welding, thereby prolonging 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 aesthetics of the product, reducing the sense of disorder, and overall looking more neat and orderly.

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

[0051] Among them, 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, not only can it be ensured that any two adjacent welding segments 1011 will not cause 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 as long 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 core 200, improves the reliability of the battery, but also optimizes the transmission path of the current between the busbar 100 and the core 200, reduces the obstacles in the current transmission process, reduces the internal resistance of the battery, and reduces the heating phenomenon, thereby significantly improving the overall performance of the battery.

[0053] In the embodiments of the present application, as shown in Figure 3 each welding segment 1011 in the welding track line 101 can be an arc-shaped track, and each welding segment 1011 is tangent to the first boundary line U1. For example, the point where the welding segment 1011 is tangent to the first boundary line U1 is the first contact point V1.

[0054] In this case, the welding segment 1011 configured in a circular arc shape can ensure the smoothness and continuity of the welding track line 101, effectively avoiding the pause or deceleration phenomenon caused by the sharp change of the path during welding, thereby improving the welding speed, shortening the welding time, and significantly enhancing the efficiency of the welding operation. Moreover, the welding track line 101 connected by multiple circular arc-shaped welding segments 1011 presents a smooth and regular shape, greatly improving the appearance competitiveness of the product.

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

[0056] In this case, the continuity of the spiral curve reduces the number of start and stop during welding, reduces the welding defects such as pores and cracks caused by welding interruption, and helps to improve the overall quality of welding, so that the connection strength of the busbar 100 and the end face of the core 200 is higher. At the same time, the spiral welding track can guide the laser beam to uniformly distribute heat on the busbar 100, avoiding the problem of local overheating, which helps to reduce welding deformation and improves the stability of the battery assembly 000.

[0057] Optionally, please refer to Figure 6 , Figure 6 is a structural schematic diagram of a busbar provided by another embodiment of the application. The welding track line 101 in the busbar 100 can also include: a plurality of transition segments 1012, both ends of each transition segment 1012 are connected with two adjacent welding segments 1011, and the middle position of each transition segment 1012 can have a second contact point V2.

[0058] Each transition segment 1012 is an arc-shaped 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] Generally, in the welding operation of the busbar and the end face of the core, the sudden change of the welding track often leads to the appearance of sharp inflection points. These inflection points cause the heat and stress to concentrate in this area due to the sharp change in shape during welding. This concentration effect aggravates the deformation and cracking risk of this part. Once the accumulated stress exceeds the bearing limit of the material, the explosive welding phenomenon will be triggered. When explosive welding occurs, the welding arc is out of control, accompanied by violent sparks and splashes, and even accompanied by an explosion-like sound, which seriously affects the welding quality, such as poor weld shape, improper penetration, etc., and also poses a major safety hazard to the welding equipment and operators.

[0060] In the embodiment of the present application, by designing a plurality of arc-shaped transition sections 1012, each transition section 1012 is tangent to the second boundary line U2 and forms a second contact point V2 smoothly tangent to the second boundary line U2 at the middle position. In this way, the entire welding trajectory becomes 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 more evenly distributed, reducing the concentration effect at the inflection point. In this way, not only does it reduce the risk of deformation and cracking in this area, but it also significantly improves the welding quality. At the same time, due to the avoidance of sharp inflection points, the probability of explosive welding phenomenon is greatly reduced, thereby ensuring the safety of the welding equipment and operators.

[0061] In summary, the embodiment of the present application provides a battery assembly, which comprises a busbar and a winding core. Since the welding trajectory line in the busbar is continuously distributed around the first non-welding area, it can form a uniformly distributed and closely connected welding contact area between the busbar and the winding core end face in the entire circumferential direction of the busbar, thereby improving the welding strength between the busbar and the winding core end face, and further improving the reliability of the battery. In addition, a first boundary line is arranged between the welding area and the first non-welding area, and a second boundary line is arranged between the welding area and the second non-welding area. The welding trajectory line has a plurality of first contact points on the first boundary line and a plurality of second contact points on the second boundary line. In this way, the total length of the welding trajectory line can be increased, effectively reducing the risk of the busbar and the winding core end face being disconnected due to mechanical stress, thereby further enhancing the welding strength between the busbar and the winding core end face, and making the battery have high reliability. At the same time, by lengthening the length of the welding trajectory 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 heating phenomenon is reduced, thereby significantly improving the overall performance of the battery.

[0062] The embodiment of the present application also provides a welding tool, please refer to Figure 7 、 Figure 8 and Figure 9 , Figure 7 is a structural schematic diagram of a welding tool provided by the embodiment of the present application, Figure 8 is a structural schematic diagram of a welding tool provided by the embodiment of the present application from another perspective, Figure 9 is a structural schematic diagram of a welding tool provided by the 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 the busbar 100 and the winding core 200 can obtain any one of the above-mentioned battery assemblies 000 after welding.

[0063] In this case, the busbar 100 is positioned by the welding tool 001, ensuring the relative position between the busbar 100 and the end face of the winding core 200 during welding is accurate, thereby improving the welding quality and making the reliability of the battery assembly 000 higher. Moreover, the busbar 100 is fixed and positioned by the welding tool 001, which can greatly simplify the preparation work before welding, reduce the time and error of manual adjustment, and thereby improve the welding efficiency. In addition, the use of the welding tool 001 can also reduce the safety risk 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, as shown in Figure 7 , Figure 8 and Figure 9 , the welding tool 001 can 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 can be configured to generate a magnetic field around the positioning seat 010 to enable the busbar 100 to be adsorbed on the positioning seat 010.

[0066] Generally, the electromagnetic generator 020 is internally designed with a precision coil. When an electric current is applied thereto, a magnetic field will be excited around the coil according to the principle of electromagnetism. The direction and strength of the magnetic field are directly related to the direction and size of the electric current.

[0067] In the embodiments 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, the electric 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 operation. At the same time, by accurately regulating the electric current in the electromagnetic generator 020, fine adjustment of the magnetic field can be realized to adapt to 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] Optionally, as shown in Figure 7 , Figure 8 and Figure 9As shown, the positioning seat 010 in the welding tool 001 can include a first avoiding hole K1 and a second avoiding hole K2 in communication, the second avoiding hole K2 can be used for welding laser to pass through to weld the end of the busbar 100 and the winding core 200, and the inner diameter of the first avoiding hole K1 is larger than that of the second avoiding hole K2, so that an annular limiting surface L can be formed between the first avoiding hole K1 and the second avoiding hole K2.

[0070] The second non-welding area A2 in the busbar 100 can be in contact with 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 avoiding hole K2. That is, the welding area A3 and the first non-welding area A1 in the busbar 100 are located in the area surrounded by the boundary of the second avoiding hole K2.

[0071] In this case, the electromagnetic generator 020 is electrically connected with the positioning seat 010, and after the electromagnetic generator 020 is powered on, the current passes through the positioning seat 010 to form a stable and adjustable magnetic field around the positioning seat 010.

[0072] In addition, the busbar 100 is made of metal material, and the magnetic field can attract and firmly fix the busbar 100 on the limiting surface L, ensuring accurate positioning and stable support before welding operation. 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 avoiding hole K2, it can be ensured that the welding laser can directly act on the welding area A3 without obstruction, realizing 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 the non-welding area during welding is avoided, ensuring the overall quality and performance of the battery assembly 000. In addition, the annular limiting 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 task of the battery assembly 000, improving the automation level and production efficiency of the production line.

[0074] In the present application, the terms "first" and "second" are only for descriptive purposes, and cannot be understood or implied to indicate or suggest relative importance. The term "a plurality of" means two or more, unless otherwise explicitly limited.

[0075] The above description is only optional embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, 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: Busbar (100) and core (200); The ends of the manifold (100) and the core (200) are welded together; The busbar (100) includes: a first non-welded area (A1) and a second non-welded area (A2), and a welded area (A3) located between the first non-welded area (A1) and the second non-welded area (A2). The welded area (A3) and the second non-welded area (A2) are both distributed around the first non-welded area (A1), and the welded area (A3) has a welding trajectory line (101), which is a trajectory continuously distributed around the first non-welded area (A1). The first non-welded area (A1) and the welded area (A3) have a first boundary line (U1), the second non-welded area (A2) and the welded area (A3) have a second boundary line (U2), 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).

2. The battery assembly according to claim 1, characterized in that, The welding trajectory line (101) includes: multiple welding segments (1011) connected end to end, the multiple 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 each end.

3. The battery assembly according to claim 2, characterized in that, Two adjacent welding segments (1011) have an intersection point (V3), which 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 less 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 multiple intersection points (V3) correspond one-to-one with the multiple second contact points (V2), and the center of each intersection point (V3), the corresponding second contact point (V2), and 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 the first area D; the area enclosed by each welding segment (1011) and the second boundary line (U2) is the second area S. The first area D and the second area S satisfy the following 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 welded segments (1011) is an arc-shaped trajectory, and each of the welded segments (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 includes: multiple transition segments (1012), each of which is connected at both ends to two adjacent welding segments (1011), and each of which has a second contact point (V2) at the middle position. Each of the transition segments (1012) is an arc-shaped trajectory, and each of the transition segments (1012) is tangent to the second boundary line (U2).

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

9. The welding fixture according to claim 8, characterized in that, The welding fixture includes: 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 base (010) so that the busbar (100) is attracted to the positioning base (010).

10. The welding fixture according to claim 9, characterized in that, The positioning seat (010) includes: a first clearance hole (K1) and a second clearance hole (K2) that are connected to each other. The second clearance hole (K2) is used for welding laser to pass through in order to weld the ends of the manifold (100) and the core (200). The inner diameter of the first clearance hole (K1) is larger than the inner diameter of the second clearance hole (K2) so that an annular limiting surface (L) can be formed between the first clearance hole (K1) and the second clearance hole (K2). The second non-welded area (A2) in the manifold (100) is in contact with the annular limiting surface (L), and the welded area (A3) and the first non-welded area (A1) in the manifold (100) are both exposed through the second clearance hole (K2).

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