Ultrasonic welding device and welding structure

Abstract

Provided are an ultrasonic welding device for ultrasonic welding of stacked materials to be welded such that burrs and / or residues are not generated, and a welding structure using same. The ultrasonic welding device includes a horn for pressing a first member for torsional ultrasonic welding of the first member and a second member in contact with the first member, wherein the horn includes: a horn body having a cylindrical shape to perform torsional rotation; a horn tip extending from one end of the horn body and facing the first member; and a knurling part protruding from the horn tip to form irregularities in the first member, and the knurling part includes a plurality of knurling parts spaced apart from each other to prevent the first member from being extruded to the outside of the horn tip by the torsional rotation of the horn and secure a space in which the first member is accommodated.

Description

Ultrasonic welding device and welded structure

[0001] The present invention relates to an ultrasonic welding device and a welded structure using the same, and in particular, to an ultrasonic welding device and a welded structure for ultrasonically welding stacked workpieces so as not to generate burrs and / or foreign matter.

[0002] The demand for secondary batteries is increasing as an energy source for electronic devices such as mobile phones, laptop computers, and wearable devices, or for electric vehicles. In particular, electric vehicles may be equipped with battery packs to supply power to the drive motor.

[0003] The battery pack consists of a plurality of battery modules and a pack case that encloses the plurality of battery modules, and each battery module may be composed of a plurality of battery cells.

[0004] Secondary batteries can be classified into nickel-cadmium, nickel-hydrogen, and lithium secondary batteries depending on the type of electrode; among these, research and development on lithium secondary batteries is actively underway due to their advantages of high operating voltage and high energy density per unit weight.

[0005] Lithium secondary batteries can be classified according to the shape of the battery case into prismatic secondary batteries and cylindrical secondary batteries in which the electrode assembly is embedded in a metal can, and pouch-type secondary batteries in which the electrode assembly is embedded in a pouch case made of an aluminum laminate sheet.

[0006] By inserting a cylindrical battery, the electrode terminals provided on the closed side of the battery can penetrate the closed side and come into contact with the current collector plate positioned on the inside of the battery can. Therefore, if ultrasonic welding is performed by contacting a welding horn onto the current collector plate on the inside of the battery can, the contact area between the current collector plate and the electrode terminals can be welded.

[0007] The contact plate and the electrode terminal can be connected by ultrasonic welding, and the ultrasonic welding device may include an anvil on which the electrode terminal is seated and a horn that presses the collector plate.

[0008] The horn may be provided with a knurling section, which is a plurality of protrusion structures, to increase friction and pressure. According to the structure of this knurling section, burrs and / or metallic foreign matter may be generated on the collector plate, which is the upper member, due to the applied pressure at the outermost point of the welding area; if used as is, the burrs and / or metallic foreign matter may remain inside the battery and affect the battery's performance.

[0009] The present invention aims to provide an ultrasonic welding device configured to prevent the generation of burrs and / or foreign matter on a workpiece during ultrasonic welding.

[0010] The present invention aims to provide a welded structure comprising a plurality of stacked workpieces in which burrs and / or foreign matter are not generated.

[0011] The present invention aims to provide a welded structure comprising a plurality of stacked workpieces in which burrs and / or foreign matter are generated in a specific size or a specific number or less.

[0012] The present invention aims to enhance internal battery performance and ensure stable battery performance by preventing the generation of burrs and / or foreign substances.

[0013] An ultrasonic welding device according to one aspect of the present invention includes a horn that presses the first member to torsionally ultrasonically weld a first member and a second member in contact with the first member, and the horn includes a horn body having a cylindrical shape to torsionally rotate, a horn tip extending from one end of the horn body and facing the first member, and a knurling portion protruding from the horn tip to form irregularities on the first member, and the knurling portion may include a plurality of knurling portions spaced apart from each other to prevent the first member from being extruded outward from the horn tip by the torsional rotation of the horn and to secure a space for the first member to be received.

[0014] In addition, the plurality of knurling portions may be arranged symmetrically from the center of the horn tip.

[0015] In addition, the distance between the aforementioned multiple knurling sections may differ.

[0016] Additionally, the plurality of knurling portions may include a first knurling portion adjacent to the edge of the horn tip, and a second knurling portion disposed near the center of the horn tip.

[0017] Additionally, the cross-section of the horn tip may include a circular shape, and the first knurling portion may include a plurality of first knurling portions that are orthogonal to each other with respect to the center of the horn tip.

[0018] In addition, the knurling portion may be configured such that its cross-sectional area decreases in the direction from the horn tip toward the first member.

[0019] In addition, the knurling portion may include a truncated cone shape in which the cross section of the knurling portion is circular and the longitudinal section of the knurling portion is trapezoidal, so that the flow of the first member due to the twisting rotation of the knurling portion is smooth.

[0020] Additionally, the knurling portion may include a knurling base having a circular cross-section that contacts the horn tip, a knurling tip having a circular cross-section with a diameter smaller than the diameter of the cross-section of the knurling base that can contact the first member, and a knurling body connecting the knurling base and the knurling tip.

[0021] In addition, the first knurling portion may be positioned to make point contact with the edge of the horn tip.

[0022] Additionally, the first knurling portion may be positioned so as to be spaced apart from the edge of the horn tip toward the center of the horn tip.

[0023] In addition, the shape of the first knurling portion may be configured to be different from the shape of the second knurling portion.

[0024] In addition, the plurality of knurling sections may have a trapezoidal cross-section, the first knurling section may have a truncated cone shape, and the second knurling section may have a truncated rectangle shape.

[0025] In addition, the plurality of knurling portions may include five knurling portions spaced apart from each other along the diameter of the horn tip.

[0026] An ultrasonic welding device according to another aspect of the present invention comprises a horn that presses the first member to perform torsional ultrasonic welding of a first member and a second member in contact with the first member, wherein the horn comprises a horn body configured to rotate torsionally, a horn tip extending from one end of the horn body and facing the first member, and a knurling portion protruding from the horn tip to form irregularities on the first member, wherein the horn tip may include a knurling surface on which the knurling portion is disposed, and a flat surface adjacent to the edge of the horn tip and surrounding the knurling surface to prevent the shape of the irregularities corresponding to the edge of the horn tip from being incompletely formed.

[0027] In addition, the knurling portion may include a truncated cone shape in which the longitudinal cross-section of the knurling portion forms a trapezoid.

[0028] A welded structure according to one aspect of the present invention comprises a first member and a second member torsionally ultrasonically welded with the first member, wherein the first member comprises a plurality of indentations formed on its surface spaced apart from each other by ultrasonically welding, and the plurality of indentations may form a circular shape.

[0029] In addition, the above-mentioned welded structure can form a cylindrical battery cell.

[0030] Additionally, the first member may include a current collector plate constituting the cylindrical battery cell, and the second member may include an electrode terminal provided in a battery case that constituting the cylindrical battery cell and accommodating the current collector plate.

[0031] The present invention can prevent the formation of burrs and / or foreign matter on the workpiece during ultrasonic welding.

[0032] The present invention can enhance internal battery performance and ensure stable battery performance by preventing the generation of burrs and / or foreign substances.

[0033] FIG. 1 is a drawing illustrating an ultrasonic welding device according to a first embodiment of the present invention, and a first member and a second member which are the workpieces to be welded.

[0034] FIG. 2 is a drawing illustrating the process of torsional ultrasonic welding of a first member and a second member in an ultrasonic welding device according to a first embodiment of the present invention.

[0035] FIG. 3 is a drawing showing a horn included in an ultrasonic welding device according to the first embodiment of the present invention.

[0036] FIG. 4 is a side view of a horn included in an ultrasonic welding device according to the first embodiment of the present invention.

[0037] FIG. 5 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to the first embodiment of the present invention.

[0038] FIG. 6 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to a second embodiment of the present invention.

[0039] FIG. 7 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to a third embodiment of the present invention.

[0040] FIG. 8 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to the fourth embodiment of the present invention.

[0041] FIG. 9 is a drawing illustrating a cylindrical battery cell including an ultrasonic welding structure according to a first embodiment of the present invention.

[0042] FIG. 10 is a drawing showing a current collector in a cylindrical battery cell including an ultrasonic welding structure according to a first embodiment of the present invention.

[0043] FIG. 11 is a drawing illustrating a battery pack comprising a cylindrical battery cell including an ultrasonic welding structure according to the present invention.

[0044] FIG. 12 is a drawing illustrating an electric vehicle equipped with a battery pack comprising a cylindrical battery cell including an ultrasonic welding structure according to the present invention.

[0045] The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and various modifications that may replace the embodiments and drawings of this specification may exist at the time of filing this application.

[0046] Additionally, the same reference numbers or symbols presented in each figure of this specification represent parts or components that perform substantially the same function. Furthermore, the terms used in this specification are for describing embodiments and are not intended to limit or / or restrict the disclosed invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0047] In this specification, terms such as “comprising” or “having” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0048] Additionally, terms including ordinal numbers, such as "first," "second," etc., used in this specification may be used to describe various components, but said components are not limited by said terms, and said terms are used solely for the purpose of distinguishing one component from another.

[0049] Meanwhile, terms such as “front,” “rear,” “upper,” and “lower” used in the following description are defined based on the drawings, and the shape and location of each component are not limited by these terms.

[0050] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0051] FIG. 1 is a drawing illustrating an ultrasonic welding device according to a first embodiment of the present invention, and a first member and a second member which are works to be welded. FIG. 2 is a drawing illustrating a process of torsional ultrasonic welding of the first member and the second member according to an ultrasonic welding device according to a first embodiment of the present invention. FIG. 3 is a drawing illustrating a horn included in an ultrasonic welding device according to a first embodiment of the present invention. FIG. 4 is a drawing illustrating a side view of a horn included in an ultrasonic welding device according to a first embodiment of the present invention. FIG. 5 is a drawing illustrating a bottom view of a horn included in an ultrasonic welding device according to a first embodiment of the present invention.

[0052] Referring to FIGS. 1 to 5, an ultrasonic welding device (10) according to a first embodiment of the present invention may include a horn (100) configured to weld a first member (S1) and a second member (S2) together, which are works to be welded.

[0053] The horn (100) can create an uneven shape on the first member (S1) placed on the upper part of the second member (S2) through ultrasonic welding. The horn (100) can press the first member (S1) with a constant load while in contact with the first member (S1), and at the same time, ultrasonic welding can be performed on the first member (S1) and the second member (S2).

[0054] The horn (100) can press the first member (S1) to ultrasonically weld the first member (S1) and the second member (S2). The horn (100) may include a horn body (110) and a horn tip (120) extending from one end of the horn body (110) and facing the first member (S1). The horn (100) may include a knurling portion (130) protruding from the horn tip (120) toward the first member (S1) so as to be able to ultrasonically weld while in contact with the first member (S1).

[0055] The knurling portion (130) can press the first member (S1) with a constant load while in contact with the first member (S1), and at the same time, ultrasonically weld the first member (S1) and the second member (S2) by applying ultrasonic waves.

[0056] However, the present invention is not limited to ultrasonically welding only the first member (S1) and the second member (S2). That is, the ultrasonically welding device (10) according to the first embodiment of the present invention can ultrasonically weld two or more various members in addition to the first member (S1) and the second member (S2).

[0057] The ultrasonic welding device (10) according to the first embodiment of the present invention can ultrasonically weld a first member (S1) and a second member (S2) through a composite vibration that rotates by simultaneously vibrating the horn (100) linearly and torsionally. However, it is not limited thereto.

[0058] The ultrasonic welding device (10) according to the first embodiment of the present invention can prevent cracks and burrs from occurring in the welded area and can provide uniform welding quality by applying a complex vibration ultrasonic that rotates by simultaneously vibrating the horn (100) linearly and torsionally.

[0059] An ultrasonic welding device (10) according to a first embodiment of the present invention may include a horn (100) that presses the first member (S1) to perform torsional ultrasonic welding of the first member (S1) and the second member (S2) in contact with the first member (S1).

[0060] The horn (100) may include a horn body (110) configured to rotate in a twisting motion, and a horn tip (120) configured to extend from one end of the horn body (110) and to face a first member (S1). The horn body (110) may have a cylindrical shape. The horn tip (120) may have a cylindrical shape. The cross-section of the horn body (110) may have a circular shape. The cross-section of the horn tip (120) may have a circular shape.

[0061] That is, unlike linear ultrasonic welding, the horn body (110) and horn tip (120) according to the first embodiment of the present invention may include a cylindrical shape to rotate for torsional ultrasonic welding.

[0062] One end of the horn tip (120) may extend from the horn body (110), and the other end of the horn tip (120) may be separably connected to the first member (S1) that is ultrasonically welded by the horn (100).

[0063] A horn (100) according to a first embodiment of the present invention may include a knurling portion (130) protruding from a horn tip (120) to form irregularities on a first member (S1). One end of the knurling portion (130) may extend from the horn tip (120), and the other end of the knurling portion (130) may detachably contact the first member (S1).

[0064] The knurling portion (130) may include a plurality of knurling portions (130) protruding from the horn tip (120). The plurality of knurling portions (130) may be configured to have the same shape as each other. However, it is not limited thereto.

[0065] A plurality of knurling portions (130) may be spaced apart from each other to prevent the first member (S1) from being extruded outward from the horn tip (120) by the twisting rotation of the horn tip (120) and to secure a space for the first member (S1) to be received.

[0066] That is, the plurality of knurling portions (130) according to the first embodiment of the present invention rotate and vibrate for torsional ultrasonic welding, unlike linear ultrasonic welding, so they can be spaced apart from each other to prevent the first member (S1) from being extruded to the outer edge of the horn tip (120). Through this, the first member (S1) being torsionally ultrasonic welded is prevented from being extruded to the outer edge of the horn tip (120) and can be accommodated between the plurality of spaced-apart knurling portions (130).

[0067] A plurality of knurling portions (130) may be arranged symmetrically from the center of the horn tip (120). The horn tip (120) may include a circular cross-section, and a plurality of knurling portions (130) may be arranged symmetrically from the center point of the horn tip (120) having a circular cross-section. However, it is not limited thereto.

[0068] Multiple knurling sections (130) may be spaced apart from each other at different distances.

[0069] A plurality of knurling portions (130) may include a first knurling portion (131) positioned adjacent to the edge of the horn tip (120), and a second knurling portion (132) positioned adjacent to the center of the horn tip (120). The second knurling portion (132) may be positioned spaced apart adjacent to the first knurling portion (131).

[0070] The first knurling portion (131) may include a plurality of first knurling portions (131) protruding from the horn tip (120). The second knurling portion (132) may include a plurality of second knurling portions (132) protruding from the horn tip (120).

[0071] The distance at which the plurality of first knurling sections (131) are spaced apart from each other may differ from the distance at which the plurality of second knurling sections (132) are spaced apart from each other. The distance at which the plurality of first knurling sections (131) are spaced apart from each other may differ. The distance at which the plurality of second knurling sections (132) are spaced apart from each other may differ. However, this is not limited thereto.

[0072] The knurling portion (130) may be positioned in contact with the edge of the horn tip (120) to prevent the shape of the knurling portion (130) from being incompletely positioned at the edge of the horn tip (120). One end of the knurling portion (130) may be in contact with the edge of the horn tip (120). The knurling portion (130) may be in line contact with the edge of the horn tip (120). The knurling portion (130) may meet the edge of the horn tip (120) at two points. However, it is not limited thereto.

[0073] The first knurling portion (131) may be positioned in contact with the edge of the horn tip (120) to prevent the shape of the first knurling portion (131) from being incompletely positioned at the edge of the horn tip (120). One end of the first knurling portion (131) may be in contact with the edge of the horn tip (120). The first knurling portion (131) may be in line contact with the edge of the horn tip (120). The first knurling portion (131) may meet the edge of the horn tip (120) at two points. However, it is not limited thereto.

[0074] By doing so, the ultrasonic welding device (10) according to the first embodiment of the present invention can remove the knurling portion (130) that is incompletely formed at the outermost edge of the horn tip (120) and prevent the shape of one end of the knurling portion (130) from being incompletely formed.

[0075] That is, it is possible to prevent the end surface of one end of the knurling portion (130) from being formed incompletely and sharply. Accordingly, the ultrasonic welding device (10) according to the first embodiment of the present invention can reduce the plastic deformation rate of the first member (S1) being ultrasonically welded by preventing the end of the knurling portion (130) from being formed incompletely and sharply.

[0076] As the plastic strain of the first member (S1) decreases, the ultrasonic welding device (10) according to the first embodiment of the present invention can reduce the generation of burrs or metallic foreign matter from the first member (S1) being ultrasonically welded.

[0077] The first knurling portion (131) may include a plurality of first knurling portions (131) that are orthogonal to each other. The plurality of first knurling portions (131) may include four first knurling portions (131) that are arranged to be in contact with the edge of the horn tip (120) and arranged orthogonally to each other at 90 degrees from the center of the horn tip (120).

[0078] Among the four mutually orthogonal first knurling sections (131), each of the two first knurling sections (131) may be arranged in series along the X-axis or Y-axis direction. The straight line connecting the two first knurling sections (131) arranged in series along the X-axis direction among the four first knurling sections (131) may be perpendicularly orthogonal to the straight line connecting the other two first knurling sections (131) arranged in series along the Y-axis direction. However, it is not limited thereto.

[0079] According to the first embodiment of the present invention, the knurling portion (130) may be configured such that the cross-sectional area decreases in the direction from the horn tip (120) toward the first member (S1). The end portion of the knurling portion (130) in contact with the horn tip (120) and the tangling portion of the knurling portion (130) in contact with the first member (S1) may include a flat surface. The flat surface area of ​​the end portion of the knurling portion (130) in contact with the horn tip (120) may be larger than the flat surface area of ​​the other end portion of the knurling portion (130) in contact with the first member (S1).

[0080] The knurling portion (130) may have a longitudinal section that is trapezoidal. The knurling portion (130) may include a truncated cone shape. The cross section of the knurling portion (130) may include a circular shape. However, it is not limited thereto.

[0081] That is, the knurling portion (130) according to the first embodiment of the present invention may include a truncated cone shape in which the cross section of the knurling portion (130) is circular and the longitudinal section of the knurling portion (130) is trapezoidal, so that the flow of the first member (S1) due to the twisting rotation of the knurling portion (130) is smooth. The knurling portion (130) may include a knurling base (133) having a circular cross section that contacts the horn tip (120), a knurling tip (135) provided to be able to contact the first member (S1), and a knurling body (134) connecting the knurling base (133) and the knurling tip (135).

[0082] The knurling base (133) and the knurling tip (135) may include a circular plane. The diameter of the circular cross-section of the knurling base (133) may be larger than the diameter of the circular cross-section of the knurling tip (135). However, it is not limited thereto.

[0083] The knurling portion (130) according to the first embodiment of the present invention includes a frustum of a cone shape rather than a truncated square shape, thereby preventing the concentration of stress occurring in the knurling portion (130), and in particular, preventing the concentration of stress at the knurling tip (135), which is the other end of the knurling portion (130) facing the first member (S1) being torsionally ultrasonic welded. Through this, the generation of burrs or metallic foreign matter from the first member (S1) being torsionally ultrasonic welded can be reduced.

[0084] The knurling portion (130) may include a plurality of knurling portions (130) spaced apart from each other. The plurality of knurling portions (130) may protrude from the horn tip (120) toward the Z-axis so as to be spaced apart from each other. In the first embodiment of the present invention, the plurality of knurling portions (130) are spaced apart from each other, thereby preventing contact between the plurality of knurling portions (130).

[0085] The other end of the horn tip (120) in contact with the plurality of knurling portions (130) may include a space formed between the plurality of knurling portions (130) that are spaced apart from each other. Accordingly, in the ultrasonic welding device (10) according to the first embodiment of the present invention, a space in which a part of the first member (S1) that is torsionally ultrasonically welded by the pressure and vibration of the horn (100) can be accommodated may be formed between the plurality of knurling portions (130) provided at the other end of the horn tip (120).

[0086] By doing so, the ultrasonic welding device (10) according to the first embodiment of the present invention can prevent the first member (S1) being ultrasonically welded from being pushed outward from the knurling portion (130), thereby reducing the generation of burrs or metallic foreign matter from the first member (S1) being ultrasonically welded.

[0087] A plurality of second knurling sections (132) may include nine second knurling sections (132) positioned at the center of the horn tip (120) and near the center. A plurality of second knurling sections (132) may be positioned to form a square at the center of the horn tip (120). A plurality of second knurling sections (132) may include nine second knurling sections (132) forming a square at the center of the horn tip (120). However, it is not limited thereto.

[0088] A plurality of knurling portions (130) may include five knurling portions (130) spaced apart from each other along the diameter of the horn tip (120). The five knurling portions (130) spaced apart from each other along the diameter of the horn tip (120) may be arranged perpendicularly to the other five knurling portions (130) spaced apart from each other along the diameter of the horn tip (120) with respect to the center of the horn tip (120).

[0089] Five knurling portions (130) arranged to be spaced apart from each other in the X-axis direction along the diameter of the horn tip (120) may be arranged perpendicularly to five other knurling portions (130) arranged to be spaced apart from each other in the Y-axis direction along the diameter of the horn tip (120) with respect to the center of the horn tip (120). However, this is not limited thereto.

[0090] The five knurling sections (130) spaced apart from each other along the diameter of the horn tip (120) may include two first knurling sections (131) placed at both ends and three second knurling sections (132) placed between the two first knurling sections (131). However, they are not limited thereto.

[0091] The diameter of the circular cross-section of the horn tip (120) may be 3 to 4 mm. Preferably, the diameter of the circular cross-section of the horn tip (120) may be 3.35 mm. However, it is not limited thereto.

[0092] The diameter of the circular cross-section of the knurling base (133) may be 0.6 to 0.8 mm. Preferably, the diameter of the circular cross-section of the knurling base (133) may be 0.6 mm. However, it is not limited thereto.

[0093] Accordingly, when five knurling sections (130) are arranged along the diameter of the circular cross-section of the horn tip (120), the diameter of the circular cross-section of the knurling base (133) is 0.6 to 0.8 mm, so the length of the five knurling sections (130) may be 3 to 4 mm. In this case, if the diameter of the circular cross-section of the horn tip (120) is 3 to 4 mm, the five knurling sections (130) may be arranged in contact with each other without being spaced apart.

[0094] Accordingly, so that the five knurling portions (130) can be spaced apart from each other, the diameter of the circular cross-section of the horn tip (120) may preferably be 3.35 mm, and the diameter of the circular cross-section of the knurling base (133) may be 0.6 mm. However, it is not limited thereto.

[0095] The diameter of the circular cross-section of the knurling tip (135) may be 0.1 to 0.2 mm. Preferably, the diameter of the circular cross-section of the knurling tip (135) may be 0.14 mm. However, it is not limited thereto.

[0096] The height of the knurling body (134) along the Z-axis direction from the horn tip (120) toward the first member (S1) may be 0.2 to 0.3 mm. Preferably, the length of the knurling body (134) along the Z-axis direction from the horn tip (120) toward the first member (S1) may be 0.23 mm. However, it is not limited thereto.

[0097] The distance between multiple knurling portions (130) along the X-axis or Y-axis direction may be 0.05 to 0.15 mm. Preferably, the distance between multiple knurling portions (130) along the X-axis or Y-axis direction may be 0.1 mm. However, it is not limited thereto.

[0098] The distance at which the knurling base (133) of one of the multiple knurling sections (130) is separated from the knurling base (133) of another of the multiple knurling sections (130) along the X-axis or Y-axis direction may be 0.05 to 0.15 mm.

[0099] Preferably, the distance between the knurling base (133) of one of the plurality of knurling parts (130) and the knurling base (133) of another of the plurality of knurling parts (130) along the X-axis or Y-axis direction may be 0.1 mm. However, it is not limited thereto.

[0100] The distance from the center of the knurling tip (135) of one of the knurling parts (130) of the plurality of knurling parts (130) along the X-axis or Y-axis direction to the center of the knurling tip (135) of another of the plurality of knurling parts (130) may be 0.6 to 0.8 mm.

[0101] Preferably, the distance from the center of the knurling tip (135) of one of the knurling parts (130) to the center of the knurling tip (135) of another of the knurling parts (130) along the X-axis or Y-axis direction may be 0.7 mm. However, it is not limited thereto.

[0102] Accordingly, the ultrasonic welding device (10) according to the present invention may include a plurality of knurling portions (130) spaced apart from each other.

[0103] FIG. 6 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to a second embodiment of the present invention. Referring to FIG. 6, the knurling portion (230) according to the second embodiment of the present invention may include a plurality of knurling portions (230).

[0104] A plurality of knurling portions (230) may include a first knurling portion (231) positioned adjacent to the edge of the horn tip (120), and a second knurling portion (232) positioned adjacent to the center of the horn tip (120).

[0105] The first knurling portion (231) may include a plurality of first knurling portions (231) protruding from the horn tip (120). The second knurling portion (232) may include a plurality of second knurling portions (232) protruding from the horn tip (120).

[0106] The knurling portion (230) may be positioned in contact with the edge of the horn tip (120) to prevent the shape of the knurling portion (230) from being incompletely positioned at the edge of the horn tip (120). One end of the knurling portion (230) may be in contact with the edge of the horn tip (120). The knurling portion (230) may be in point contact with the edge of the horn tip (120). The knurling portion (230) may meet the edge of the horn tip (120) at a single point. However, it is not limited thereto.

[0107] The first knurling portion (231) may be positioned in contact with the edge of the horn tip (120) to prevent the shape of the first knurling portion (231) from being incompletely positioned at the edge of the horn tip (120). One end of the first knurling portion (231) may be in contact with the edge of the horn tip (120). The first knurling portion (231) may be in point contact with the edge of the horn tip (120). The first knurling portion (231) may meet the edge of the horn tip (120) at a single point. However, it is not limited thereto.

[0108] By doing so, the knurling portion (230) according to the second embodiment of the present invention can be prevented from being incompletely formed at the outermost edge of the horn tip (120), and the shape of one end of the knurling portion (230) can be prevented from being incompletely formed.

[0109] That is, the end surface of the knurling portion (230) can be prevented from being formed sharply due to incompleteness. Therefore, by preventing the end surface of the knurling portion (230) from being formed sharply due to incompleteness, the plastic deformation rate of the first member (S1, see FIG. 2) being torsionally ultrasonically welded can be reduced.

[0110] As the plastic strain of the first member (S1, see FIG. 2) decreases, the generation of burrs or metallic foreign matter from the first member (S1) being torsionally ultrasonically welded can be reduced.

[0111] The knurling portion (230) may include a knurling base (233) having a circular cross-section that contacts the horn tip (120), a knurling tip (235) that is provided to be in contact with the first member (S1, see FIG. 2), and a knurling body (234) that connects the knurling base (233) and the knurling tip (235).

[0112] The diameter of the circular cross-section of the horn tip (120) may be 3 to 4 mm. Preferably, the diameter of the circular cross-section of the horn tip (120) may be 3.4 mm. The diameter of the circular cross-section of the knurling base (233) may be 0.6 to 0.8 mm. Preferably, the diameter of the circular cross-section of the knurling base (233) may be 0.6 mm.

[0113] Accordingly, when five knurling sections (230) are arranged along the diameter of the circular cross-section of the horn tip (120), preferably, since the diameter of the circular cross-section of the knurling base (233) is 0.6 mm, the length of the five knurling sections (230) may be 3 mm. Since the diameter of the circular cross-section of the horn tip (120) is 3.4 mm, the five knurling sections (130) may be arranged spaced 0.1 mm apart from each other.

[0114] FIG. 7 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to a third embodiment of the present invention. Referring to FIG. 7, the knurling portion (330) according to the third embodiment of the present invention may include a plurality of knurling portions (330).

[0115] A plurality of knurling portions (330) may include a first knurling portion (331) positioned adjacent to the edge of the horn tip (120) and a second knurling portion (332) positioned adjacent to the center of the horn tip (120).

[0116] The first knurling portion (331) may include a plurality of first knurling portions (331) protruding from the horn tip (120). The second knurling portion (332) may include a plurality of second knurling portions (332) protruding from the horn tip (120).

[0117] The knurling portion (330) may be positioned so as to be spaced apart from the edge of the horn tip (120) toward the center of the horn tip (120) to prevent the shape of the knurling portion (330) from being incompletely positioned at the edge of the horn tip (120). The first knurling portion (331) may be positioned so as to be spaced apart from the edge of the horn tip (120) toward the center of the horn tip (120) to prevent the shape of the first knurling portion (331) from being incompletely positioned at the edge of the horn tip (120).

[0118] That is, the horn tip (120) according to the third embodiment of the present invention may include a knurling surface (321) on which a knurling portion (330) is disposed, and a flat surface (322) surrounding the knurling surface (321) and adjacent to the edge of the horn tip (120).

[0119] The knurling portion (330) may be entirely located within the area of ​​the knurling surface (321), and the area within the flat surface (322) may be a flat area where the knurling portion (330) is not located.

[0120] By doing so, the knurling portion (330) according to the third embodiment of the present invention can be prevented from being incompletely formed at the outermost edge of the horn tip (120), and the shape of one end of the knurling portion (330) can be prevented from being incompletely formed.

[0121] That is, the end surface of the knurling portion (330) can be prevented from being formed sharply due to incompleteness. Therefore, by preventing the end surface of the knurling portion (330) from being formed sharply due to incompleteness, the plastic deformation rate of the first member (S1, see FIG. 2) being torsionally ultrasonically welded can be reduced.

[0122] As the plastic strain of the first member (S1, see FIG. 2) decreases, the generation of burrs or metallic foreign matter from the first member (S1, see FIG. 2) being torsionally ultrasonically welded can be reduced.

[0123] The knurling portion (330) may include a first knurling portion (331) positioned near the edge of the horn tip (120) and a second knurling portion (332) positioned near the center of the horn tip (120). The first knurling portion (331) may include a plurality of first knurling portions (331), and the second knurling portion (332) may include a plurality of second knurling portions (332).

[0124] A plurality of first knurling portions (331) may be spaced apart from the edge of the horn tip (120) and arranged to form a circle along the inner circumference of the horn tip (120). The spacing between the plurality of first knurling portions (331) may be the same. However, it is not limited thereto.

[0125] A plurality of second knurling portions (332) may be surrounded by a plurality of first knurling portions (331) and spaced apart from each other near the center of the horn tip (120). The spacing between the plurality of second knurling portions (332) may be the same. However, it is not limited thereto.

[0126] The distance between any one of the multiple first knurling sections (331) and any one of the multiple second knurling sections (332) that are adjacent to each other may be different from the distance between the multiple first knurling sections (331) or the distance between the multiple second knurling sections (332). However, it is not limited thereto.

[0127] Four knurling sections (330) may be arranged along the diameter along the X-axis direction of the knurling surface (321) of the horn tip (120). Two first knurling sections (331) may be arranged near the edge of the horn tip (120), and two second knurling sections (332) may be arranged near the center of the horn tip (120).

[0128] The knurling portion (330) may include a knurling base (333) having a circular cross-section that contacts the horn tip (120), a knurling tip (335) that is provided to be in contact with the first member (S1, see FIG. 2), and a knurling body (334) that connects the knurling base (333) and the knurling tip (335).

[0129] The diameter of the circular cross-section of the horn tip (120) may be 3 to 4 mm. Preferably, the diameter of the circular cross-section of the horn tip (120) may be 3.35 mm. The diameter of the circular cross-section of the knurling base (233) may be 0.6 to 0.8 mm. Preferably, the diameter of the circular cross-section of the knurling base (233) may be 0.6 mm.

[0130] The distance between adjacent first knurling portions (331) and second knurling portions (332) along the X-axis of the horn tip (120) can preferably be 0.1 mm.

[0131] FIG. 8 is a drawing showing the bottom surface of a horn included in an ultrasonic welding device according to a fourth embodiment of the present invention. Referring to FIG. 8, the knurling portion (430) according to the fourth embodiment of the present invention may be configured such that the cross-sectional area decreases in the direction from the horn tip (120) toward the first member (S1, see FIG. 2).

[0132] The one end of the knurling portion (430) in contact with the horn tip (120) and the tangling portion of the knurling portion (430) in contact with the first member (S1, see FIG. 2) may include a flat surface. The flat surface area of ​​the one end of the knurling portion (430) in contact with the horn tip (120) may be larger than the flat surface area of ​​the other end of the knurling portion (430) in contact with the first member (S1, see FIG. 2). The longitudinal cross-section of the knurling portion (430) may form a trapezoid.

[0133] The knurling portion (430) according to the fourth embodiment of the present invention may include a plurality of knurling portions (430). The plurality of knurling portions (430) may include a first knurling portion (431) disposed adjacent to the edge of the horn tip (120), and a second knurling portion (432) disposed adjacent to the center of the horn tip (120).

[0134] The shape of the first knurling portion (431) may be configured to be different from the shape of the second knurling portion (432). The first knurling portion (431) may include a truncated cone shape. The cross-section of the first knurling portion (431) may include a circular shape.

[0135] The knurling portion (430) may include a knurling base (433) in contact with the horn tip (120), a knurling tip (435) provided to be in contact with the first member (S1, see FIG. 2), and a knurling body (434) connecting the knurling base (433) and the knurling tip (435).

[0136] The knurling base (433) and knurling tip (435) of the first knurling section (431) may include a circular plane. The diameter of the circular cross-section of the knurling base (433) of the first knurling section (431) may be larger than the diameter of the circular cross-section of the knurling tip (435).

[0137] The second knurling portion (432) may include a truncated square shape. The second knurling portion (432) may include a truncated rectangular shape. The cross-section of the second knurling portion (432) may include a square.

[0138] The knurling base (433) and knurling tip (435) of the second knurling section (432) may include a rectangular plane. The diameter of the rectangular cross-section of the knurling base (433) of the second knurling section (432) may be larger than the diameter of the rectangular cross-section of the knurling tip (435).

[0139] FIG. 9 is a drawing illustrating a cylindrical battery cell including an ultrasonic welding structure according to a first embodiment of the present invention. FIG. 10 is a drawing illustrating a current collector in a cylindrical battery cell including an ultrasonic welding structure according to a first embodiment of the present invention.

[0140] Referring to FIGS. 2, 9, and 10, a welded structure (20) according to a first embodiment of the present invention may include a first member (S1) and a second member (S2) that is torsionally ultrasonically welded to the first member (S1). The first member (S1) may include a plurality of indentations (P) formed on its surface spaced apart from each other by torsional ultrasonically welding. The plurality of indentations (P) may form a circular shape. However, it is not limited thereto.

[0141] A welded structure (20) according to the first embodiment of the present invention may form a cylindrical battery cell (1). More specifically, among a plurality of stacked welded parts, a first member (S1) may include a current collector plate (30) that forms the cylindrical battery cell (1), and a second member (S2) may include an electrode terminal (40) provided in a battery case (2) that forms the cylindrical battery cell (1) and accommodates the current collector plate (30).

[0142] The electrode assembly (5) included in the cylindrical battery cell (1) formed by the welded structure (20) may include a first electrode (not shown) having a first polarity, a second electrode (not shown) having a second polarity, and a separator (not shown) interposed between the first electrode (not shown) and the second electrode (not shown). The first electrode (not shown) may be a negative electrode or a positive electrode, and the second electrode (not shown) may correspond to an electrode having a polarity opposite to that of the first electrode (not shown).

[0143] The electrode assembly (5) can be manufactured by winding a laminate formed by sequentially stacking a first electrode (not shown), a separator (not shown), a second electrode (not shown), and a separator (not shown) at least once. That is, the electrode assembly (5) applied to the present invention may be a jelly-roll type electrode assembly (5). The jelly-roll type electrode assembly (5) may have a center hole (C) formed approximately in the center and extending along the Z-axis direction.

[0144] The first electrode (not shown) may include a first current collector (not shown) and a first electrode active material layer (not shown) formed by coating a first electrode active material on at least one surface of the first current collector (not shown). The second electrode (not shown) may include a second current collector (not shown) and a second electrode active material layer (not shown) formed by coating a second electrode active material on at least one surface of the second current collector (not shown).

[0145] The first electrode (not shown) may include an uncoated portion (6) on the first current collector (not shown) where no positive active material or negative active material is applied. At least a portion of the uncoated portion (6) may function as an electrode tab.

[0146] At least a portion of the unwound portion (6) may include a plurality of segments divided along the winding direction of the electrode assembly (5). The plurality of segments of the unwound portion (6) may be bent along the radial direction of the electrode assembly (5).

[0147] Multiple segments of the bent non-bent portion (6) can be overlapped in multiple layers. The collector plate (30) can be attached to the area where multiple segments of the non-bent portion (6) are overlapped in multiple layers.

[0148] A current collector plate (30) may be coupled to one side of an electrode assembly (5). The current collector plate (30) may include an electrode coupling part (31) coupled to the electrode assembly (5) and a terminal coupling part (32) coupled to an electrode terminal (40).

[0149] The electrode coupling portion (31) may be disposed on one side of the electrode assembly (5). The electrode coupling portion (31) may be coupled with the non-electrode portion (6). The electrode coupling portion (31) may be coupled with the non-electrode portion (6) by laser welding.

[0150] The electrode coupling portion (31) may include a laser welding portion (L) that is laser welded to the non-reinforced portion (6). The electrode coupling portion (31) may include a plurality of electrode coupling portions (31).

[0151] The terminal coupling portion (32) can be coupled to the electrode terminal (40). The terminal coupling portion (32) can be coupled to the electrode terminal (40) by twist ultrasonic welding. The terminal coupling portion (32) may include an ultrasonic welding portion (U) coupled to the electrode terminal (40).

[0152] The entire terminal coupling portion (32) may form an ultrasonic welding portion (U), and a central part of the terminal coupling portion (32) may also form an ultrasonic welding portion (U). However, it is not limited thereto.

[0153] The terminal coupling portion (32) may be formed such that at least a portion is thinner than the thickness of the electrode coupling portion (31). The area of ​​the terminal coupling portion (32) having a thickness thinner than the thickness of the electrode coupling portion (31) may include an ultrasonic welding portion (U).

[0154] The electrode terminal (40) may include a terminal exposure portion (41) and a terminal insertion portion (42). The terminal exposure portion (41) may be exposed to the outside of the battery case (2). The terminal exposure portion (41) may be located at the center of the battery case (2).

[0155] The terminal insertion part (42) can be coupled with the terminal coupling part (32) of the current collector plate (30). The terminal insertion part (42) can be coupled with the current collector plate (30) by twist ultrasonic welding at a position corresponding to the center hole (C) of the electrode assembly (5).

[0156] The collector plate (30) and the electrode terminal (40) can be welded by torsional ultrasonic welding. Ultrasonic welding is cheaper than laser welding and may result in less thermal deformation. While laser welding can damage the separator of the electrode assembly (5) due to the heat generated, ultrasonic welding can prevent damage to the separator.

[0157] In the welding process, laser welding may require securing a center hole (C) of a certain size or larger to secure the laser focus, but ultrasonic welding can perform the welding process by inserting a horn (100) corresponding to the size of the center hole (C).

[0158] The horn (100) according to the first embodiment of the present invention includes a horn body (110) having a cylindrical shape, so that insertion and separation can be easily made in correspondence with a hollow center hole (C). In addition, the cylindrical horn body (110) rotating for torsional ultrasonic welding is prevented from colliding with the center hole (C) and can rotate smoothly.

[0159] The ultrasonic welding device (10) can perform torsional ultrasonic welding on a collector plate (30) and an electrode terminal (40). That is, the collector plate (30) may correspond to a first member (S1), and the electrode terminal (40) may correspond to a second member (S2).

[0160] Since the ultrasonic welding device (10) according to the first embodiment of the present invention performs torsional ultrasonic welding, unlike linear ultrasonic welding, a separate anvil (not shown) placed on one side of the second member (S2) with the first member (S1) and the second member (S2) placed between the knurling portion (130) may not be required.

[0161] The height of the knurling portion (130) provided in the horn (100) protruding toward the collector plate (30) may be equal to or greater than the thickness of the collector plate (30). Here, the thickness of the collector plate (30) may include the thickness of the portion where torsional ultrasonic welding occurs on the collector plate (30). That is, it may include the thickness of the ultrasonic welding portion (U) of the terminal coupling portion (32) of the collector plate (30).

[0162] The horn (100) of the ultrasonic welding device (10) is inserted into the center hole (C) of the electrode assembly (5) to perform torsional ultrasonic welding between the collector plate (30) and the electrode terminal (40).

[0163] According to torsional ultrasonic welding, the first member (S1) and the second member (S2) can be welded by recrystallization caused by plastic flow. Therefore, if the terminal joint (32) is excessively thick, plastic flow may not occur smoothly, so it may be desirable for the terminal joint (32) to be configured to a thickness of less than a predetermined thickness.

[0164] When torsional ultrasonic welding is performed by the horn (100), plastic deformation may occur in the first member (S1) corresponding to the edge of the knurling portion (130) due to the pressure of the horn (100). Due to the plastic deformation of the first member (S1), foreign matter such as burrs or metal particles may be generated in the first member (S1).

[0165] Accordingly, if the first member (S1) and the second member (S2) correspond to components forming a cylindrical battery cell (1), foreign matter including burrs or metal particles may remain inside the cylindrical battery cell (1).

[0166] Foreign matter remaining inside the cylindrical battery cell (1) can damage the separator (not shown) forming the cylindrical battery cell (1), and as a result, since it is a potential risk factor that can cause a short circuit, it can be a major cause that greatly affects the performance of the cylindrical battery cell (1).

[0167] The ultrasonic welding device (10) according to the first embodiment of the present invention can reduce plastic deformation caused by pressure at the outermost point of the knurling part (130) during welding, thereby preventing the formation of burrs and foreign matter.

[0168] Accordingly, when the first member (S1) and the second member (S2) correspond to components within the cylindrical battery cell (1), the internal performance of the cylindrical battery cell (1) can be enhanced and stable battery performance secured by preventing foreign matter.

[0169] FIG. 11 is a drawing illustrating a battery pack comprising a cylindrical battery cell including an ultrasonic welding structure according to the present invention. FIG. 12 is a drawing illustrating an electric vehicle equipped with a battery pack comprising a cylindrical battery cell including an ultrasonic welding structure according to the present invention.

[0170] Referring to FIGS. 11 and 12, a plurality of cylindrical battery cells (1) including an ultrasonic welding structure according to the present invention can be accommodated in a pack case (4) to form a battery pack (3).

[0171] The battery pack (3) may additionally include various control and protection systems such as a Battery Management System (BMS).

[0172] The battery pack (3) can be applied to various devices. Specifically, it can be applied to means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles, or to an Energy Storage System (ESS). However, it is not limited to these, and can be applied to various devices that can use secondary batteries.

[0173] The electric vehicle (V) can be driven by an electric motor that is powered by a battery pack (3).

[0174] Although the technical concept of the present invention has been explained above through specific embodiments, the scope of the present invention is not limited to these embodiments.

[0175] Various embodiments that can be modified or varied by a person skilled in the art, within the scope of not departing from the gist of the technical concept of the present invention as specified in the patent claims, shall also be deemed to fall within the scope of the rights of the present invention.

Claims

1. An ultrasonic welding device comprising a horn that presses the first member to torsionally ultrasonically weld the first member and the second member in contact with the first member, wherein The above horn has a horn body having a cylindrical shape to perform torsional rotation, A horn tip extending from one end of the horn body and facing the first member, and It includes a knurling portion protruding from the horn tip to form irregularities on the first member, and An ultrasonic welding device comprising a plurality of knurling portions spaced apart from each other to prevent the first member from being extruded to the outer edge of the horn tip by the twisting rotation of the horn and to secure a space for the first member to be received.

2. In Paragraph 1, The above plurality of knurling sections are arranged symmetrically from the center of the horn tip in an ultrasonic welding device.

3. In Paragraph 1, The above-mentioned plurality of knurling sections are ultrasonic welding devices with different spacing distances from each other.

4. In Paragraph 1, The above plurality of knurling parts are, A first knurling portion adjacent to the edge of the horn tip, and An ultrasonic welding device comprising a second knurling portion positioned near the center of the horn tip.

5. In Paragraph 4, The cross-section of the above horn tip includes a circular shape, An ultrasonic welding device comprising a plurality of first knurling sections that are orthogonal to each other with respect to the center of the horn tip.

6. In Paragraph 1, An ultrasonic welding device configured such that the knurling portion has a cross-sectional area that decreases in the direction from the horn tip toward the first member.

7. In Paragraph 6, An ultrasonic welding device comprising a knurling portion having a truncated cone shape in which the cross section of the knurling portion is circular and the longitudinal section of the knurling portion is trapezoidal, so as to facilitate the smooth flow of the first member by the twisting rotation of the knurling portion.

8. In Paragraph 1, The above knurling portion is, A knurled base in contact with the above horn tip and having a circular cross-section, A knurling tip capable of contacting the first member and having a circular cross-section with a diameter smaller than the diameter of the cross-section of the knurling base, and An ultrasonic welding device comprising a knurling body connecting the knurling base and the knurling tip.

9. In Paragraph 4, The above-mentioned first knurling portion is an ultrasonic welding device positioned to make point contact with the edge of the horn tip.

10. In Paragraph 4, An ultrasonic welding device in which the first knurling portion is positioned so as to be spaced apart from the edge of the horn tip toward the center of the horn tip.

11. In Paragraph 4, An ultrasonic welding device configured such that the shape of the first knurling portion is different from the shape of the second knurling portion.

12. In Paragraph 11, The above plurality of knurling sections have a cross-sectional shape that is trapezoidal, and The above-mentioned first knurling portion has a truncated cone shape, and The above second knurling section is an ultrasonic welding device having a truncated rectangular shape.

13. In Paragraph 1, An ultrasonic welding device comprising five knurling sections spaced apart from each other along the diameter of the horn tip.

14. An ultrasonic welding device comprising a horn that presses the first member to torsionally ultrasonically weld the first member and the second member in contact with the first member, wherein The above horn is a horn body configured to perform torsional rotation, A horn tip extending from one end of the horn body and facing the first member, and It includes a knurling portion protruding from the horn tip to form irregularities on the first member, and The above horn tip is, A knurling surface on which the above-mentioned knurling portion is disposed, and An ultrasonic welding device comprising a flat surface adjacent to the edge of the horn tip and surrounding the knurling surface to prevent the shape of the irregularities corresponding to the edge of the horn tip from being incompletely formed.

15. In Paragraph 14, The above knurling portion is an ultrasonic welding device comprising a truncated cone shape in which the longitudinal cross-section of the above knurling portion forms a trapezoid.

16. A welded structure comprising a first member and a second member ultrasonically welded to the first member, The first member includes a plurality of indentations formed on the surface spaced apart from each other by torsional ultrasonic welding, and The above plurality of indentations form a circular welded structure.

17. In Paragraph 16, The above welded structure is a welded structure constituting a cylindrical battery cell.

18. In Paragraph 17, The first member above includes a current collector plate constituting the cylindrical battery cell, and The above second member is a welded structure comprising an electrode terminal provided in a battery case that constitutes the cylindrical battery cell and accommodates the current collector plate.

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