Cathode busbar for multi-tab cylindrical battery

Abstract

The utility model relates to the technical field of lithium batteries, in particular to a cathode busbar for a multi-tab cylindrical battery, which comprises a busbar body, a working surface is arranged on one surface of the busbar body, a contact boss is arranged on the working surface, and a welding area is arranged on the surface of the contact boss back to the working surface. The welding area is provided with raised pocks, and the busbar body and a shell of the battery are welded through the pocks. According to the utility model, the convex pits are arranged on the contact bosses of the cathode busbar, and the cathode busbar is welded with the shell of the battery through the convex pits, so that the surface contact welding between the contact bosses on the traditional cathode busbar and the shell of the battery is replaced by multi-point contact welding; pseudo soldering between the contact boss and the shell of the battery is avoided, the effectiveness of contact welding between the cathode busbar and the shell of the battery is ensured, and the firmness and reliability of welding between the cathode busbar and the shell of the battery are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and particularly to a negative busbar for a multi-tab cylindrical battery. Background Art

[0002] At present, a cylindrical lithium battery includes a housing, a negative busbar, and a wound core. The wound core is a battery core formed by winding electrode materials. The negative tab of the wound core needs to be welded to the negative busbar, and the negative busbar is connected to the housing by resistance welding (which refers to a method of using the resistance heat generated by the current passing through the welded parts and the contact points as the heat source to locally heat the welded parts and applying pressure for welding) to achieve negative conduction. Specifically, during welding, the welding needle passes through the central hole of the wound core and reaches the bottom of the negative of the wound core. The negative busbar is pressurized by the resistance heat generated by the welding needle to achieve the welding between the negative busbar and the housing.

[0003] In order to facilitate the welding between the negative busbar and the housing, contact bosses are usually designed on the bottom surface of the negative busbar. For example, a cylindrical lithium battery negative short-circuit safety blocking structure disclosed in a Chinese patent (publication number: CN217606996U) contacts and welds with the housing through the contact bosses on the negative busbar. However, since the contact between the contact bosses and the housing is a surface contact, virtual welding is likely to occur during their welding, and the firm reliability of the welding between the negative busbar and the housing cannot be ensured. Summary of the Utility Model

[0004] One of the main purposes of the utility model is to provide a negative busbar for a multi-tab cylindrical battery, aiming to solve the technical problem that the contact between the contact bosses on the negative busbar of the existing battery and the housing of the battery is a surface contact, resulting in virtual welding during their welding.

[0005] To achieve the above purpose, the utility model provides a negative busbar for a multi-tab cylindrical battery, including a busbar body. One surface of the busbar body is set as a working surface, and contact bosses are arranged on the working surface. The surface of the contact boss facing away from the working surface is set as a welding area, and raised pockmarks are arranged in the welding area. The busbar body is welded to the housing of the battery through the pockmarks.

[0006] Further, each contact point between the pockmarks and the housing is a spherical contact point.

[0007] Further, the busbar body is in a disc-shaped structure. A tab passing portion penetrating through the opposite surfaces of the busbar body is provided on the busbar body. The tab passing portion is located outside the contact boss. The busbar body is used to connect to the negative end of the battery core of the multi-tab cylindrical battery, and the tab passing portion allows multiple negative tabs of the battery core of the multi-tab cylindrical battery to pass through.

[0008] Further, the surface of the bus bar body facing away from the working surface is the inner surface, and a groove corresponding to the contact boss is formed on the inner surface, and the inner diameter of the groove is the same as the inner diameter of the contact boss.

[0009] Further, the contact boss is a protruding disc, and the groove is a concave circular groove.

[0010] Further, the tab passing-out portion includes a first arc-shaped hole, the outer shape of the first arc-shaped hole is the same as the outer shape of one of the negative tabs, the first arc-shaped hole is located on one side outside the contact boss, and a first tab welding area is formed by the distance between the first arc-shaped hole and the contact boss.

[0011] Further, the tab passing-out portion further includes a second arc-shaped hole, the shape of the second arc-shaped hole is the same as the shape of the other negative tab, the second arc-shaped hole is located on the other side outside the contact boss, and a second tab welding area is formed by the distance between the second arc-shaped hole and the contact boss.

[0012] Further, the tab passing-out portion further includes a third arc-shaped hole, the third arc-shaped hole and the second arc-shaped hole are arranged at intervals along the radial direction of the bus bar body, and a third tab welding area is formed by the distance between the third arc-shaped hole and the second arc-shaped hole.

[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0014] In the present utility model, raised pockmarks are provided on the contact boss of the negative bus bar, and the raised pockmarks are welded to the outer shell of the battery. The surface contact welding between the contact boss on the traditional negative bus bar and the outer shell of the battery is replaced by multiple point contact weldings, avoiding the occurrence of false welding between the contact boss and the outer shell of the battery, thereby ensuring the effectiveness of the contact welding between the negative bus bar and the outer shell of the battery, and further ensuring the firm and reliable welding between the negative bus bar and the outer shell of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic structural diagram of a negative bus bar involved in the embodiment;

[0016] Figure 2 is a schematic structural diagram of the negative bus bar involved in the embodiment from another angle;

[0017] Figure 3 is a schematic structural diagram of the inner surface of the bus bar involved in the embodiment;

[0018] Figure 4 is a schematic structural diagram of the core of a multi-tab cylindrical battery involved in the embodiment.

[0019] Reference numerals in the accompanying drawings:

[0020] 1. Bus bar body; 10. Working surface; 101. Contact boss; 102. Dimples; 11. Inner surface; 110. Groove; 12. First arc-shaped hole; 120. First tab welding area; 13. Second arc-shaped hole; 130. Second tab welding area; 14. Third arc-shaped hole; 140. Third tab welding area; 2. Core; 20. Central hole; 21. First negative tab; 22. Second negative tab; 23. Third negative tab. Detailed implementation manners

[0021] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "width", "upper", "lower", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0023] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "set" 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, a direct connection, or an indirect connection through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features that they contact. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature has a lower horizontal height than the second feature.

[0025] Please refer to Figure 1 - Figure 4, the present utility model provides a negative busbar for a multi-tab cylindrical battery, including a busbar body 1. One surface of the busbar body 1 is set as a working surface 10, and the surface of the busbar body 1 facing away from the working surface 10 is an inner surface 11. A contact boss 101 is arranged on the working surface 10. The contact boss 101 is integrally formed with the busbar body 1. The contact boss 101 is a convex disc. A groove 110 corresponding to the contact boss 101 is opened on the inner surface 11. The groove 110 is a concave circular groove, and the inner diameter of the groove 110 is the same as the inner diameter of the contact boss 101; the surface of the contact boss 101 facing away from the working surface 10 is set as a welding area, and raised pockmarks 102 are arranged on the welding area. The pockmarks 102 are integrally formed with the contact boss 101. The busbar body 1 is welded to the outer shell of the battery through the raised pockmarks 102.

[0026] In the actual application process, the negative busbar is connected to the negative electrode end of the core 2 (electrode core) of the multi-tab cylindrical battery. The groove 110 is aligned with the central hole 20 of the core 2, and the groove 110 is coaxial with the central hole 20 of the core 2. In this way, when welding the negative busbar to the outer shell of the battery, the welding needle passes through the central hole 20 of the core 2 and reaches the bottom of the negative electrode of the core 2, inserts the welding needle into the groove 110, and presses the negative busbar through the resistance heat generated by the welding needle, so that the raised pockmarks 102 can be welded to the outer shell of the battery, realizing the welding between the negative busbar and the outer shell.

[0027] In summary, the negative busbar of the present utility model sets raised pockmarks 102 on the contact boss 101 of the busbar body 1, and welds through the raised pockmarks 102 to the outer shell of the battery, replacing the surface contact welding between the contact boss 101 on the traditional negative busbar and the outer shell of the battery with multiple point contact welds, avoiding the occurrence of false welding between the contact boss 101 and the outer shell of the battery, thereby ensuring the effectiveness of the contact welding between the negative busbar and the outer shell of the battery, and further ensuring the firm and reliable welding between the negative busbar and the outer shell of the battery.

[0028] It should be noted that using the resistance welding method to realize the welding between the negative busbar and the outer shell of the battery is an existing technology, and the welding principle will not be described here.

[0029] In this embodiment, each contact point between the raised pockmarks 102 and the outer shell of the battery is a spherical contact point. The spherical contact point is beneficial to accelerating the welding between the raised pockmarks 102 and the outer shell of the battery, thereby further improving the welding effect between the pockmarks 102 and the outer shell of the battery.

[0030] In this embodiment, the negative busbar is a disc-shaped negative busbar made of nickel material or nickel-copper-nickel composite material. Since the negative busbar is applied to a multi-tab cylindrical battery, the disc-shaped negative busbar can be more conveniently used in cooperation with the core 2 of the multi-tab cylindrical battery.

[0031] Among them, the negative electrode end of the winding core 2 of the multi-tab cylindrical battery has a plurality of negative tabs. Exemplarily, there are three negative tabs at the negative electrode end of the winding core 2, namely, an arc-shaped first negative tab 21, an arc-shaped second negative tab 22, and an arc-shaped third negative tab 23. The first negative tab 21 is located on one side outside the central hole 20 of the winding core 2, and both the second negative tab 22 and the third negative tab 23 are located on the other side outside the central hole 20 of the winding core 2. The second negative tab 22 and the third negative tab are arranged at intervals along the radial direction of the winding core 2. Of course, in other embodiments, the number of negative tabs can also be set to four or six, etc., which is not limited here.

[0032] In this embodiment, a tab passing portion penetrating through the opposite surfaces of the bus bar body 1 is provided. The tab passing portion is located outside the contact boss 101. When the bus bar body 1 is connected to the negative electrode end of the battery core of the multi-tab cylindrical battery, the tab passing portion allows a plurality of negative tabs of the battery core of the multi-tab cylindrical battery to pass through.

[0033] Specifically, the tab passing portion includes a first arc-shaped hole 12, a second arc-shaped hole 13, and a third arc-shaped hole 14. The outer shape of the first arc-shaped hole 12 is the same as the outer shape of the first negative tab 21. The first arc-shaped hole 12 is located on one side outside the contact boss 101. A first tab welding area 120 is formed by the distance between the first arc-shaped hole 12 and the contact boss 101. The shape of the second arc-shaped hole 13 is the same as the shape of the second negative tab 22. The second arc-shaped hole 13 is located on the other side outside the contact boss 101. A second tab welding area 130 is formed by the distance between the second arc-shaped hole 13 and the contact boss 101. The third arc-shaped hole 14 and the second arc-shaped hole 13 are arranged at intervals along the radial direction of the bus bar body 1, and a third tab welding area 140 is formed by the distance between the third arc-shaped hole 14 and the second arc-shaped hole 13. During use, after the first negative tab 21 at the negative electrode end of the winding core 2 passes through the first arc-shaped hole 12, it is flattened and welded to the first tab welding area 120; after the second negative tab 22 passes through the second arc-shaped hole 13, it is flattened and welded to the second tab welding area 130; after the third negative tab 23 passes through the third arc-shaped hole 14, it is flattened and welded to the third tab welding area 140, achieving the purpose of welding the multi-tabs of the winding core 2 to the negative bus bar.

[0034] It should be noted that the welding of the plurality of negative tabs at the negative electrode end of the winding core 2 to the negative bus bar increases the current conduction area, reduces the internal resistance of the battery, and achieves the effect of extending the service life of the battery.

[0035] The above are only the preferred embodiments of the present utility model, and do not thus limit the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present utility model.

Claims

1. A negative electrode busbar for a multi-electrode cylindrical battery, comprising a busbar body, one surface of the busbar body being set as a working surface, and a contact boss being set on the working surface, characterized in that: The surface of the contact boss facing away from the working surface is set as a welding area, and the welding area is provided with raised pits, and the busbar body and the battery shell are welded through the pits.

2. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 1, characterized in that: Each contact point between the pits and the shell is a spherical contact point.

3. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 1, characterized in that: The busbar body is a disc-shaped structure, and is provided with a tab protrusion portion that passes through the relative surface of the busbar body. The tab protrusion portion is located on the outside of the contact boss. The busbar body is used to be connected to the negative terminal of the battery cell of the multi-pole tab cylindrical battery, and the tab protrusion portion is used for the multiple negative tabs of the battery cell of the multi-pole tab cylindrical battery to protrude.

4. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 1, characterized in that: The surface of the busbar body facing away from the working surface is an inner surface, and a groove corresponding to the contact boss is formed on the inner surface, and the inner diameter of the groove is the same as the inner diameter of the contact boss.

5. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 4, characterized in that: The contact boss is a raised disc, and the groove is a sunken circular groove.

6. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 3, characterized in that: The tab protrusion portion includes a first arc-shaped hole, the shape of the first arc-shaped hole is the same as that of a negative tab, the first arc-shaped hole is located on one side outside the contact boss, and the distance between the first arc-shaped hole and the contact boss forms a first tab welding area.

7. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 6, characterized in that: The tab protrusion also includes a second arc-shaped hole, the shape of the second arc-shaped hole is the same as the shape of the other negative tab, the second arc-shaped hole is located on the other side outside the contact boss, and the distance between the second arc-shaped hole and the contact boss forms a second tab welding area.

8. The negative electrode busbar for a multi-electrode cylindrical battery according to claim 7, characterized in that: The tab protrusion portion further includes a third arc-shaped hole, the third arc-shaped hole and the second arc-shaped hole are arranged at intervals along the radial direction of the busbar body, and the interval between the third arc-shaped hole and the second arc-shaped hole forms a third tab welding area.

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