Ultrasonic welding horn for secondary battery and ultrasonic welding apparatus for secondary battery comprising same

Abstract

The present invention provides an ultrasonic welding horn for a secondary battery, which is employed in an ultrasonic welding apparatus for a secondary battery, and has a certain length and is disposed vertically, has an upper end connected to an ultrasonic vibrator of the ultrasonic welding apparatus, is inserted into a can of a secondary battery to carry out welding by applying ultrasonic waves while pressing an object to be welded, and has an outer circumference at a lower end, to which a ring structure of a ring shape is detachably coupled.

Description

Ultrasonic welding horn for secondary batteries and ultrasonic welding device for secondary batteries including the same

[0001] The present invention relates to an ultrasonic welding horn for a secondary battery and an ultrasonic welding device for a secondary battery including the same.

[0002]

[0003] Unlike primary batteries, secondary batteries are rechargeable and are being extensively researched and developed recently due to their potential for miniaturization and high capacity.

[0004] As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing.

[0005] Secondary batteries are classified into coin batteries, cylindrical batteries, prismatic batteries, and pouch batteries according to the shape of the battery case.

[0006] The electrode assembly mounted inside the battery case of a secondary battery is a power generation device capable of charging and discharging, consisting of a stacked structure of electrodes and separators.

[0007] The electrode assembly can be roughly classified into a jelly roll type, which is wound with a separator interposed between a sheet-type positive electrode coated with an active material and a negative electrode; a stack type, which is formed by sequentially stacking unit cells, each having at least one electrode and at least one separator; and a stack / folding type, which is formed by winding unit cells into a long separating film.

[0008] In conventional secondary batteries, resistance welding is mainly applied to the negative or positive tabs of cylindrical secondary batteries.

[0009] Cylindrical secondary batteries come in various sizes, and since their diameters are small, such as 18mm, 21mm, and 46mm, and considering the condition of the electrodes inside the can, the area to be welded is a narrow, long region with a diameter of less than a few millimeters. Therefore, there are many restrictions on welding as it must be done without interference or damage.

[0010]

[0011] FIG. 1 is a drawing showing an ultrasonic welding device for a secondary battery according to the prior art.

[0012] An ultrasonic welding device (100) for a secondary battery according to the prior art is an ultrasonic welding device (100) for a secondary battery that ultrasonically welds an electrode tab of an electrode assembly accommodated inside a can (200) and a bottom surface of the can (200) or a current collector plate joined to the bottom surface of the can (200).

[0013] The ultrasonic welding device (100) for such a secondary battery includes a horn (110) that applies ultrasonic vibration to an electrode tab, and an ultrasonic vibration unit (S) that vibrates the horn (110).

[0014] The ultrasonic vibration unit (S) includes a torsional vibration unit (120) that torsionally vibrates the horn (110).

[0015] Additionally, the ultrasonic welding device (100) for a secondary battery further includes a support frame (170) and a fixing jig (160).

[0016]

[0017] Figure 2 is a drawing showing the horn and workpiece of an ultrasonic welding device for a secondary battery according to the prior art.

[0018] The horn (110) creates an uneven shape on the first member (S1).

[0019] Drawing symbol d is the thickness of the first member (S1).

[0020] The horn (110) applies a constant load while in contact with the first member (S1) and simultaneously applies ultrasonic waves to ultrasonically weld the first member (S1) and the second member (S2).

[0021] That is, the horn (110) presses the first member (S1) to ultrasonically weld the first member (S1) and the second member (S2).

[0022] The horn (110) includes a knurling portion (N) having a plurality of protrusions (T) configured to protrude toward the first member (S1).

[0023] The unexplained symbol h is the height of the projection (T).

[0024] Multiple protrusions (T) are pressed with a constant load while in contact with the first member (S1), and ultrasonically weld the first member (S1) and the second member (S2) by simultaneously applying ultrasonic waves.

[0025]

[0026] Figure 3 is a diagram showing the state in which a burr is generated on a workpiece by the horn of an ultrasonic welding device for a secondary battery according to the prior art.

[0027] When ultrasonic welding, the horn, which is the energy transfer medium, comes into contact with the workpiece, and as it vibrates at approximately 20,000 Hz during the welding process and penetrates the workpiece, the generation of burrs is inevitable.

[0028] Since burrs formed in such a sharp shape can damage the separator and cause internal short circuits, it is necessary to minimize the generation of burrs during the welding process.

[0029]

[0030] [Prior Art Literature]

[0031] (Patent Document 1) KR 10-2024-0101240 A

[0032] (Patent Document 2) KR 10-2024-0101500 A

[0033]

[0034] The present invention has been devised to solve the various conventional problems described above, and aims to provide an ultrasonic welding horn for a secondary battery and an ultrasonic welding device for a secondary battery including the same, which can suppress burr growth during ultrasonic welding and secure a uniform and clean weld surface.

[0035]

[0036] To achieve the above objectives, the present invention provides an ultrasonic welding horn for a secondary battery, which is employed in an ultrasonic welding device for a secondary battery, characterized in that it is formed to a predetermined length and arranged vertically, its upper end is connected to an ultrasonic vibrating part of the ultrasonic welding device, is inserted inside the can of the secondary battery to perform welding by applying ultrasonic waves while pressing the workpiece, and has a ring-shaped ring structure detachably coupled to the outer circumference of its lower end.

[0037] The above workpiece may be an electrode tab of an electrode assembly accommodated inside the can and a bottom surface of the can or a current collector plate joined to the bottom surface of the can.

[0038] The above ultrasonic welding horn is formed in the shape of a cylinder, and the diameter of the upper part may be formed larger than the diameter of the lower part.

[0039] The lower surface of the ultrasonic welding horn may include a knurling portion having a plurality of protrusions formed to protrude toward the workpiece to create an uneven shape on the workpiece.

[0040] The above protrusion may be formed so that its width narrows as it moves toward the workpiece.

[0041] The longitudinal section of the projection along the length direction of the ultrasonic welding horn may have a trapezoidal shape.

[0042] A first rounded portion in a rounded shape may be formed on the outermost edge of the knurling portion.

[0043] When the above ring structure is coupled to the above ultrasonic welding horn, the lower end of the ring structure is located lower than the lower end of the protrusion formed on the bottom surface of the ultrasonic welding horn with respect to the longitudinal direction of the ultrasonic welding horn, so that the protrusion can be received inside the ring structure.

[0044] A second rounded portion in a rounded shape may be formed at the bottom of the above ring structure.

[0045] Meanwhile, the present invention discloses an ultrasonic welding device for a secondary battery comprising an ultrasonic welding horn for a secondary battery.

[0046]

[0047] According to the means for solving the aforementioned problem, the present invention has the following effects.

[0048] The present invention combines a ring-shaped structure around the lower outer circumference of an ultrasonic welding horn, forms a first rounded portion at the outermost edge of the knurling portion, and forms a second rounded portion at the bottom of the ring structure, thereby reducing plastic deformation caused by the pressure applied to the workpiece during ultrasonic welding, suppressing burr growth, and ensuring a uniform and clean weld surface.

[0049] Accordingly, by suppressing burr growth and preventing foreign substances, it becomes possible to enhance the internal performance of the secondary battery and secure stable secondary battery performance.

[0050] In addition, since the present invention allows a ring structure to be detachably attached to an existing ultrasonic welding horn as needed, there is no need to manufacture an ultrasonic welding horn separately, which has the effect of significantly reducing manufacturing costs.

[0051]

[0052] FIG. 1 is a drawing showing an ultrasonic welding device for a secondary battery according to the prior art.

[0053] Figure 2 is a drawing showing the horn and workpiece of an ultrasonic welding device for a secondary battery according to the prior art.

[0054] Figure 3 is a diagram showing the state in which a burr is generated on a workpiece by the horn of an ultrasonic welding device for a secondary battery according to the prior art.

[0055] FIG. 4 is a drawing showing an ultrasonic welding horn for a secondary battery according to the present invention.

[0056] Figure 5 is a drawing showing an enlarged view of part A of Figure 4.

[0057] Figure 6 is a drawing showing the state in which the ring structure in Figure 5 has been removed.

[0058] FIG. 7 is a drawing showing a ring structure employed in an ultrasonic welding horn for a secondary battery according to the present invention.

[0059]

[0060] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques are not specifically described to avoid the present invention being interpreted ambiguously. Throughout the specification, like reference numerals refer to like components.

[0061] In drawings, thicknesses may be enlarged to clearly represent multiple layers and regions. Throughout the specification, the same reference numerals are used for similar parts. When a part such as a layer, film, region, or plate is described as being "above" another part, this includes not only cases where it is "immediately above" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately above" another part, it means that there is no other part in between. Furthermore, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only cases where it is "immediately below" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately below" another part, it means that there is no other part in between.

[0062] FIG. 4 is a drawing showing an ultrasonic welding horn for a secondary battery according to the present invention, and FIG. 5 is a drawing showing an enlarged view of part A of FIG. 4.

[0063] FIG. 6 is a drawing showing the state in which the ring structure is removed from FIG. 5, and FIG. 7 is a drawing showing the ring structure employed in the ultrasonic welding horn for a secondary battery according to the present invention.

[0064] The ultrasonic welding horn (10) for a secondary battery according to the present invention is formed with a predetermined length and arranged vertically, and its upper end is connected to the ultrasonic vibration part of the ultrasonic welding device, and is inserted into the can of the secondary battery to perform welding by applying ultrasonic waves while pressing the workpiece.

[0065] The ultrasonic welding horn (10) of this type is formed in the shape of a cylinder, and the diameter of the upper part can be formed larger than the diameter of the lower part.

[0066] The lower part of the ultrasonic welding horn (10) is inserted into the can of a secondary battery, and ultrasonic welding can be performed by applying ultrasonic waves to the contact area between the electrode tab of an electrode assembly accommodated inside the can, for example, the bottom surface of the can or the current collector plate joined to the bottom surface of the can, which is the workpiece to be welded, and simultaneously applying ultrasonic waves.

[0067] The lower surface of the ultrasonic welding horn (10) may include a knurling portion (12) having a plurality of protrusions (14) formed to protrude toward the workpiece to create an uneven shape on the workpiece.

[0068] A plurality of protrusions (14) can be pressed with a constant load while in contact with the workpiece, and at the same time, ultrasonic waves can be applied to the ultrasonic welding horn (10) to ultrasonically weld the workpiece.

[0069] These multiple protrusions (14) can be formed regularly at regular intervals on the bottom surface of the ultrasonic welding horn (10), and may also be formed irregularly as needed.

[0070] It is preferable that the protrusion (14) be formed so that its width narrows as it moves toward the workpiece, in order to minimize the contact area with the workpiece and prevent the formation of burrs and foreign matter on the workpiece.

[0071] For example, the longitudinal section of the projection (14) along the length direction of the ultrasonic welding horn (10) may have a trapezoidal shape.

[0072] Meanwhile, since ultrasonic welding horns are generally manufactured through profile processing using a diamond wheel that performs rotational and reciprocating motions, the outermost edge of the knurling section must inevitably be formed in an unfinished state.

[0073] When ultrasonic welding is performed by such an ultrasonic welding horn (10), plastic deformation occurs in the workpiece at the outermost edge of the knurling part (12) due to the applied pressure.

[0074] Accordingly, foreign substances such as burrs or metal particles may be generated.

[0075] If the workpiece corresponds to an internal component of a secondary battery, burrs or foreign matter remain inside the battery, and these residues are a major cause of significant impact on secondary battery performance due to potential risk factors such as short circuits.

[0076] In the ultrasonic welding horn (10) according to the present invention, a first rounded portion (12a) in a rounded shape is formed on the outermost edge portion of the knurling portion (12).

[0077] As a result, plastic deformation caused by the pressure applied to the workpiece during ultrasonic welding is reduced, thereby enabling the suppression of burr growth.

[0078] A ring-shaped ring structure (20) can be detachably attached to the lower outer circumference of the ultrasonic welding horn (10) according to the present invention.

[0079] For example, mutually corresponding screw threads are formed on the lower outer circumference (outer surface) of the ultrasonic welding horn (10) and the inner surface of the ring structure (20) so that screw connection can be made.

[0080] As another example, a press fit may be made so that the inner surface of the ring structure (20) contacts the lower outer circumference (outer surface) of the ultrasonic welding horn (10).

[0081] In addition to this, any configuration can be adopted as long as a ring-shaped ring structure (20) can be detachably attached to the lower outer circumference of the ultrasonic welding horn (10).

[0082] When such a ring structure (20) is coupled to an ultrasonic welding horn (10), the lower end of the ring structure (20) is located lower than the lower end of the protrusion (14) formed on the bottom surface of the ultrasonic welding horn (10) with respect to the longitudinal direction of the ultrasonic welding horn (10), so that the protrusion (14) can be received inside the ring structure.

[0083] A second rounded section (22) in a rounded shape may be formed at the bottom of the ring structure (20).

[0084] When welding is performed by joining the ring structure (20) to the ultrasonic welding horn (10) in this way, the stress on the second round portion (22) in contact with the workpiece can be minimized, and plastic deformation caused by the pressure applied to the workpiece can be reduced, thereby minimizing the generation of burrs and foreign matter.

[0085] As such, the present invention combines a ring-shaped ring structure (20) around the lower outer circumference of an ultrasonic welding horn (10), forms a rounded first rounded portion (12a) at the outermost edge of the knurling portion (12), and forms a rounded second rounded portion (22) at the bottom of the ring structure (20), thereby reducing plastic deformation caused by the pressure applied to the workpiece during ultrasonic welding, suppressing burr growth, and securing a uniform and clean weld surface.

[0086] Accordingly, there is an advantage in that internal performance of the secondary battery can be enhanced and stable secondary battery performance secured by inhibiting burr growth and preventing foreign substances.

[0087] In addition, since the present invention allows for the detachable attachment of a ring structure (20) to an existing ultrasonic welding horn (10), the ring structure (20) may be attached to the ultrasonic welding horn (10) and used according to the frictional force required for ultrasonic welding, or the ring structure (20) may be detached and used.

[0088] For example, if a lot of friction is required, ultrasonic welding can be performed with the ring structure (20) separated, and if a little friction is required, ultrasonic welding can be performed with the ring structure (20) joined.

[0089]

[0090] Meanwhile, the ultrasonic welding device for a secondary battery according to the present invention may include the aforementioned ultrasonic welding horn (10) for a secondary battery and an ultrasonic vibration unit (see FIG. 1, S).

[0091] The ultrasonic vibration unit (see FIG. 1, S) may be a linear vibration unit that vibrates the ultrasonic welding horn (10) in a horizontal direction, a torsional vibration unit (see FIG. 1, 120) that vibrates the ultrasonic welding horn (10) in a torsional direction, and may be configured with the linear vibration unit and the torsional vibration unit in parallel.

[0092] Such an ultrasonic vibrator is not a technical feature of the present invention and is a well-known conventional technology, so a detailed description is omitted.

[0093]

[0094] [Explanation of the symbol]

[0095] 10: Ultrasonic welding horn

[0096] 12: Knurling section

[0097] 12a: First round section

[0098] 14 : Protrusion

[0099] 20: Ring structure

[0100] 22: Round 2

Claims

1. As an ultrasonic welding horn employed in an ultrasonic welding device for secondary batteries, It is formed with a predetermined length and arranged vertically, the upper end is connected to the ultrasonic vibration part of the ultrasonic welding device, is inserted inside the can of a secondary battery to perform welding by applying ultrasound while the workpiece is under pressure, and a ring-shaped ring structure is detachably coupled to the outer circumference of the lower end. Ultrasonic welding horn for secondary batteries.

2. In Claim 1, The above workpiece is, The electrode tab of the electrode assembly accommodated inside the can and the bottom surface of the can or the current collector plate joined to the bottom surface of the can, Ultrasonic welding horn for secondary batteries.

3. In Claim 1, The above ultrasonic welding horn is formed in a cylindrical shape, wherein the diameter of the upper part is larger than the diameter of the lower part. Ultrasonic welding horn for secondary batteries.

4. In Claim 3, The lower surface of the above-mentioned ultrasonic welding horn includes a knurling portion having a plurality of protrusions formed to protrude toward the workpiece to create an uneven shape on the workpiece. Ultrasonic welding horn for secondary batteries.

5. In Claim 4, The above protrusion is formed such that its width narrows as it moves toward the workpiece. Ultrasonic welding horn for secondary batteries.

6. In Claim 5, The longitudinal cross-section of the projection along the longitudinal direction of the ultrasonic welding horn has a trapezoidal shape. Ultrasonic welding horn for secondary batteries.

7. In Claim 4, A first rounded portion is formed on the outermost edge of the knurling portion, Ultrasonic welding horn for secondary batteries.

8. In Claim 4, When the above ring structure is coupled to the above horn, Based on the longitudinal direction of the ultrasonic welding horn, the lower end of the ring structure is located lower than the lower end of the protrusion formed on the bottom surface of the ultrasonic welding horn so that the protrusion is received inside the ring structure. Ultrasonic welding horn for secondary batteries.

9. In Claim 8, A second rounded portion is formed at the bottom of the above ring structure, Ultrasonic welding horn for secondary batteries.

10. An ultrasonic welding device for a secondary battery comprising an ultrasonic welding horn for a secondary battery according to any one of claims 1 to 9.

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