Laser welding nozzle

Abstract

One embodiment of the present invention provides a laser welding nozzle that enables stable welding by ensuring a fluid balance for the weld pool formed during laser welding. The laser welding nozzle of one embodiment includes a beam guide member through which a laser beam passes and whose diameter decreases toward the bottom, forming a beam discharge port of minimum diameter at the bottom, and a housing coupled such that its inner surface faces the outer surface of the beam guide member to form a shielding gas line on the outer edge of the beam discharge port and a suction line connected to the beam discharge port. The shielding gas line includes a plurality of branch chambers that are divided along the circumferential direction near the beam discharge port and branch injection ports that extend radially from the branch chambers. The plurality of branch chambers are merged at the upper part of the region between the outer surface of the beam guide member and the inner surface of the housing and are connected to the shielding gas injection port. The plurality of branch injection ports may be spaced apart from each other along the circumference on the outer edge of the beam discharge port.

Description

Technology Field

[0001] The present invention relates to a laser welding nozzle, and more specifically, to a laser welding nozzle that ensures a balance of shielding gas input. Background Technology

[0002] Unlike primary batteries, rechargeable batteries are batteries that undergo repeated charging and discharging. Small-capacity rechargeable batteries are used in portable small electronic devices such as mobile phones, laptop computers, and camcorders. Large-capacity and high-density rechargeable batteries are used as power sources for driving motors in hybrid and electric vehicles, or for energy storage.

[0003] For example, a secondary battery includes an electrode assembly comprising a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes, a case housing the electrode assembly, and electrode terminals electrically connected to the electrode assembly. The secondary battery performs charging and discharging operations through the electrochemical reaction of the positive electrode, the negative electrode, and an electrolyte injected into the case. The case may be cylindrical or rectangular to suit the intended use.

[0004] Laser welding is used in the manufacturing process of secondary batteries. During laser welding of secondary batteries, efforts are being made to improve defects caused by porosity formation and metallic foreign matter, but a significant amount of laser spatter metallic foreign matter still occurs. This metallic foreign matter causes short circuit defects or voltage variation (dV) defects within the secondary battery. Furthermore, when keyhole welding of the Cu base material, a single beam was used to improve welding quality, but due to the increased thermal conductivity of the Cu base material, stable welding quality and control of spatter metallic foreign matter are required. The problem to be solved

[0005] One embodiment of the present invention provides a laser welding nozzle that enables stable welding by ensuring a fluid balance for the weld pool formed during laser welding.

[0006] One embodiment of the present invention provides a laser welding nozzle that removes spatter metal foreign matter by ensuring an input and output balance of shielding gas. means of solving the problem

[0007] A laser welding nozzle according to one embodiment of the present invention comprises a beam guide member through which a laser beam passes and whose diameter decreases toward the bottom, forming a beam discharge port of minimum diameter at the bottom, and a housing coupled such that its inner surface faces the outer surface of the beam guide member to form a shielding gas line on the outer edge of the beam discharge port and a suction line connected to the beam discharge port, wherein the shielding gas line comprises a plurality of branch chambers that are divided along the circumferential direction near the beam discharge port and branch injection ports that extend radially from the branch chambers, wherein the plurality of branch chambers are merged at the upper part of the region between the outer surface of the beam guide member and the inner surface of the housing and connected to the shielding gas injection port, and the plurality of branch injection ports are spaced apart from each other along the circumference on the outer edge of the beam discharge port.

[0008] The shielding gas line can be divided into multiple stages as it descends toward the beam discharge port.

[0009] The shielding gas line may include a first branch chamber connected to the inlet of the shielding gas and divided into two, two first branch inlets provided on both sides in the radial direction of the first branch chamber, four second branch chambers connected to the first branch inlets and divided into two, and four second branch inlets provided on four sides in the radial direction of the second branch chamber and arranged at equal intervals along the circumference.

[0010] Between the outer surface of the beam guide member and the inner surface of the housing, the first branch chamber and the second branch chamber are formed along the circumference, and the first branch injection port and the second branch injection port may be formed along an incline.

[0011] The shielding gas line may further include a circular inlet connecting the four second branch inlets into one on the outer surface of the beam discharge port.

[0012] The shielding gas line can be formed on the inner surface of the conical portion of the housing and set on the outer surface of the conical portion of the beam guide member coupled to the inner surface.

[0013] When considering the upper and lower portions of the beam guide member and the housing joined together, the shielding gas line and the suction line are provided in the conical portion, the shielding gas line is provided on the lower side, and the suction line can be provided on the upper side of the shielding gas line.

[0014] The beam guide member protrudes to the opposite side of the beam discharge port and further includes a partition wall, the partition wall divides the internal space into a central space and a peripheral space of a donut structure, and the main penetration port provided in the conical part can be connected to a suction discharge port through a suction chamber.

[0015] The above main penetration holes are provided in multiple numbers to connect the surrounding space and the suction chamber at equal intervals along the circumference.

[0016] The suction line may include a connection of the central space to the beam discharge port, a connection of the peripheral space to the central space to the top of the bulkhead, and a connection of the suction chamber and the suction outlet to the main penetration port in the peripheral space.

[0017] The above bulkhead may further be provided with an auxiliary penetration opening that directly connects the central space and the surrounding space.

[0018] The above auxiliary penetration holes are provided in multiple numbers and arranged at equal intervals along the circumference to connect the central space and the surrounding space.

[0019] The above suction line may further include an auxiliary suction line connecting the central space and the surrounding space through the auxiliary penetration hole.

[0020] The conical portion of the beam guide member may further be provided with an additional through hole that directly connects the central space and the suction outlet.

[0021] The above additional penetration holes may be provided in multiple numbers.

[0022] The above suction line may further include an additional suction line connecting the central space and the suction outlet through the additional penetration hole. Effects of the invention

[0023] One embodiment of the present invention divides the shielding gas line into a plurality of branch chambers as it extends from the shielding gas inlet to the beam discharge port, and arranges the branch inlets provided in the branch chambers at equal intervals along the circumference from the outer edge of the beam discharge port, thereby ensuring a balance of shielding gas injection and enabling the removal of spattered metal foreign matter.

[0024] In addition, one embodiment enables stable welding by ensuring a fluid balance for the weld pool formed during laser welding. Brief explanation of the drawing

[0025] FIG. 1 is a perspective view of a laser welding nozzle according to a first embodiment of the present invention. Figure 2 is an exploded perspective view of the laser welding nozzle illustrated in Figure 1. Figure 3 is a cross-sectional view taken along line III-III of Figure 1. Figure 4 is a cross-sectional view taken along line IV-IV of Figure 2. FIG. 5 is a perspective view showing a shielding gas line and a suction line set between the housing and the inner member in the laser welding nozzle of FIG. 1 in three dimensions. FIG. 6 is a perspective view of a laser welding nozzle according to a second embodiment of the present invention. Figure 7 is a cross-sectional view taken along the line Ⅶ-Ⅶ of Figure 6. FIG. 8 is a perspective view showing the bottom portion of a laser welding nozzle according to a third embodiment of the present invention. FIG. 9 is a perspective view showing the upper part of the laser welding nozzle of FIG. 8. FIG. 10 is a cross-sectional view taken along the line X-X of FIG. 9. Specific details for implementing the invention

[0026] Hereinafter, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts unrelated to the explanation have been omitted to clearly explain the present invention, and the same reference numerals have been used throughout the specification for identical or similar components.

[0027] FIG. 1 is a perspective view of a laser welding nozzle according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the laser welding nozzle shown in FIG. 1. Referring to FIG. 1 and FIG. 2, the laser welding nozzle (100) of the first embodiment includes a beam guide member (20) and a housing (30).

[0028] The beam guide member (20) has a conical section (21) that passes a laser beam and decreases in diameter as it goes downward, and forms a beam outlet (22) of minimum diameter at the bottom of the conical section (21).

[0029] The housing (30) is coupled to the outer surface of the beam guide member (20) so that its inner surface faces the outer surface to form a shielding gas line (40) on the outer edge of the beam discharge port (22), and a main suction line (50) is formed independently of the shielding gas line (40) and connected to the inside of the beam discharge port (22).

[0030] When viewed from a planar perspective, the main suction line (50) is formed at the center of the beam discharge port (22), and the shielding gas line (40) is formed at the outer edge of the beam discharge port (22). Thus, oxidation of the molten pool is prevented due to the shielding action of nitrogen used as the shielding gas, and welding vapor pressure, i.e., waste shielding gas used for shielding and spatter metal foreign matter, is discharged through the main suction line (50).

[0031] The shielding gas line (40) supplies shielding gas to the space set between the outer surface (23) of the beam guide member (20) and the inner surface (33) of the housing (30). The main suction line (50) suctions and discharges waste shielding gas and spattered metal foreign matter through the beam discharge port (22), and for this purpose, it is formed independently from the shielding gas line (40) so as not to interfere with each other.

[0032] FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2. Referring to FIG. 3 and FIG. 4, the shielding gas line (40) is merged into one at the upper part of the area between the outer surface (23) of the beam guide member (20) and the inner surface (33) of the housing (30) and connected to the inlet (43) of the shielding gas.

[0033] The shielding gas line (40) includes a plurality of branch chambers (411, 421) that are divided near the beam discharge port (22), and the branch chambers (411, 421) may again include a plurality of branch injection ports (412, 422). The plurality of branch injection ports (412, 422) may be arranged at equal intervals along the circumference from the outer edge of the beam discharge port (22).

[0034] FIG. 5 is a perspective view illustrating, in three dimensions, a shielding gas line and a suction line set between the housing and the inner member in the laser welding nozzle of FIG. 1. Referring to FIG. 3 to FIG. 5, the shielding gas line (40) can be divided into multiple stages as it descends toward the beam discharge port (22).

[0035] In one embodiment, the shielding gas line (40) is divided into two stages, so it includes a first branch chamber (411) and a first branch inlet (412), and a second branch chamber (421) and a second branch inlet (422). The more stages divided into two, the better the balance of shielding gas shielding the weld area at the beam discharge port (22) can be ensured.

[0036] The first branch chamber (411) is connected to the inlet (43) of the shielding gas and is divided into two along the circumference. The first branch inlets (412) are provided along the slope on each side in the diameter direction of the first branch chamber (411) divided into two, that is, are provided as two that are spaced at equal intervals along the circumference.

[0037] The second branch chamber (421) is connected to each of the two first branch inlets (412) and is divided into two along the circumference, forming a total of four. The second branch inlets (422) are provided along the incline on each of the four sides in the diameter direction of the four second branch chambers (421), that is, formed into four that are arranged at equal intervals along the circumference.

[0038] In the region between the outer surface (23) of the beam guide member (20) and the inner surface (33) of the housing (30), the lengths of the two branch paths constituting the first branch chamber (411) are equal along the circumference, and the lengths of the two branch paths constituting the second branch chamber (421) are equal along the circumference. The first branch inlet (412) and the second branch inlet (422) are formed with equal lengths along the slope.

[0039] Accordingly, the shielding gas injected from the shielding gas inlet (43) can be uniformly distributed into two first branch chambers (411) that branch in both directions and can be uniformly injected into two first branch inlets (412). Then, the shielding gas injected into the first branch inlets (412) can be uniformly distributed into two second branch chambers (421) that branch in both directions and can be uniformly injected into four second branch inlets (422).

[0040] The shielding gas line (40) further includes a circular inlet (44) provided on the inner surface (33) of the conical portion (31) of the housing (30) located outside the beam discharge port (22). The circular inlet (44) connects four second branch inlets (422) into one on the inner surface (33) of the conical portion (31) outside the beam discharge port (22), thereby ensuring that the shielding gas is discharged uniformly along the circumference from the outer edge of the beam discharge port (22).

[0041] Accordingly, in the first embodiment, the four second branch injection ports (422) and the circular injection port (44) stabilize the discharge balance of the shielding gas to the molten pool and the fluidity of the molten pool formed during laser welding.

[0042] For example, the shielding gas line (40) forms a groove, namely a first branch chamber (411), a first branch inlet (412), a second branch chamber (421), and a second branch inlet (422), on the inner surface (33) of the conical portion (31) of the housing (30), and is set on the outer surface (23) of the conical portion (21) of the beam guide member (20) coupled to this inner surface (33). Additionally, although not illustrated, the shielding gas line may form a groove on the outer surface of the conical portion of the beam guide member and be set on the inner surface of the conical portion of the housing coupled to this outer surface.

[0043] In addition, when considering the upper and lower portions of the beam guide member (20) and the housing (30) joined together, the shielding gas line (40) and the main suction line (50) are provided in the respective conical portions (21, 31). The shielding gas line (40) is provided on the lower side to stably supply shielding gas to the molten pool, and the main suction line (50) is provided on the upper side of the shielding gas line (40) to effectively discharge waste shielding gas and metal foreign matter spatter without hindering the supply of shielding gas.

[0044] Specifically, the beam guide member (20) further includes a partition wall (24) protruding to the opposite side of the beam discharge port (22). The partition wall (24) is formed as a cylinder extending from the top of the conical portion (21).

[0045] Accordingly, the partition (24) divides the internal space of the beam guide member (20) into a central space (241) and a peripheral space (242) of the donut structure. The main penetration port (51) provided in the conical portion (21) is connected to the suction outlet (52) through the suction chamber (55).

[0046] The suction chamber (55) is formed on the inner surface of the conical portion (31) of the housing (30) and is set on the outer surface of the conical portion (21) of the beam guide member (20) that is coupled to this inner surface. The suction chamber (55) is formed separately from the shielding gas line (40).

[0047] Additionally, the main penetration port (51) is provided in multiple numbers to connect the peripheral space (242) and the suction chamber (55) at equal intervals along the circumference. Accordingly, the main suction line (50) includes the connection of the central space (241) to the beam discharge port (22), the connection of the peripheral space (242) to the central space (241) at the top of the partition wall (24), and the connection of the suction chamber (55) and the suction discharge port (52) to the peripheral space (242) via the main penetration port (51).

[0048] To this end, the beam guide member (20) is provided with a laser beam transmission window (53) spaced apart from the top of the partition wall (24). The laser beam transmission window (53) transmits the laser beam and enables the discharge of waste shielding gas and spattered metal foreign matter through the main suction line (50).

[0049] A plurality of main penetration holes (51) arranged at equal intervals apply suction force acting as a suction discharge port (52) and a main suction line (50) uniformly along the circumference of the surrounding space (242) of the donut structure, thereby applying it uniformly along the circumference of the central space (242) connected to the top of the partition wall (24).

[0050] Therefore, the main suction line (50) can discharge waste shielding gas and spatter metal foreign matter without hindering uniform shielding of the welding pool by shielding gas that is discharged uniformly along the circumference from the outer edge of the beam discharge port (22).

[0051] Various embodiments of the present invention are described below. Compared to the first embodiment and the previously described embodiment, the description of identical configurations is omitted, and different configurations are described.

[0052] FIG. 6 is a perspective view of a laser welding nozzle according to a second embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6. Referring to FIG. 6 and FIG. 7, in the laser welding nozzle (200) of the second embodiment, the partition (224) of the beam guide member (220) further comprises an auxiliary through hole (243) that directly connects the central space (241) and the peripheral space (242).

[0053] Auxiliary penetration holes (243) are provided in multiple numbers and are provided at equal intervals along the circumference to connect the central space (241) and the peripheral space (242). Accordingly, the suction line (250) includes the connection of the central space (241) to the main suction line (50) through the top of the partition wall (224), that is, the connection of the peripheral space (242) to the central space (241) through the top of the partition wall (224), and the connection of the suction chamber (55) and the suction outlet (52) to the peripheral space (242) through the main penetration hole (51), and further includes an auxiliary suction line (251) through the auxiliary penetration holes (243).

[0054] This auxiliary suction line (251) can further enhance the suction capacity in addition to the suction action of the main suction line (50) through the top of the bulkhead (224) as a connection of the peripheral space (242) to the central space (241) through the auxiliary penetration hole (243).

[0055] The auxiliary suction line (251) and the suction line (250) including it can more effectively discharge waste shielding gas and spatter metal foreign matter without hindering the uniform shielding of the welding pool caused by the shielding gas discharged uniformly along the circumference from the outer edge of the beam discharge port (22).

[0056] FIG. 8 is a perspective view showing the bottom of a laser welding nozzle according to a third embodiment of the present invention, FIG. 9 is a perspective view showing the top of the laser welding nozzle of FIG. 8, and FIG. 10 is a cross-sectional view taken along the line X-X of FIG. 9.

[0057] Referring to FIGS. 8 to 10, in the laser welding nozzle (300) of the third embodiment, the conical portion (21) of the beam guide member (320) further comprises an additional through hole (244) that directly connects the central space (241) and the suction outlet (52). The additional through hole (244) is provided in multiple numbers, i.e., two on one side. Although not shown, the additional through holes (244) may be arranged at equal intervals in the conical portion (21).

[0058] Additional penetration holes (244) are provided in multiple numbers to connect the central space (241) with the extension suction chamber (255) connected to the suction chamber (55). Thus, the suction line (350) further includes a main suction line (50) through the top of the partition wall (324), an auxiliary suction line (251) through the auxiliary penetration hole (243), and an additional suction line (351) through the additional penetration hole (244).

[0059] This additional suction line (351) is connected to the central space (241) through the additional penetration hole (244) to the extension suction chamber (255), thereby further enhancing the suction capacity in addition to the suction action of the main suction line (50) through the top of the partition wall (324) and the suction action of the auxiliary suction line (251) through the auxiliary penetration hole (243).

[0060] The additional suction line (351), the auxiliary suction line (251), and the suction line (350) including them can more effectively discharge waste shielding gas and spatter metal foreign matter without hindering the uniform shielding of the welding pool caused by the shielding gas discharged uniformly along the circumference from the outer edge of the beam discharge port (22).

[0061] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and can be implemented with various modifications within the scope of the claims, the description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention. Explanation of the symbols

[0062] 20, 220, 320: Beam guide members 21, 31: Conical section 22: Beam outlet 23: Outer surface 24, 224, 324: Bulkhead 30: Housing 33: Inner 40: Shielding gas line 43: Inlet 44: Circular inlet 50: Main suction line 51: Main penetration 52: Suction outlet 53: Laser beam transmission window 55: Suction chamber 100, 200, 300: Welding nozzle 241: Central Space 242: Peripheral Space 243: Secondary penetration 244: Additional penetration 250: Suction line 251: Auxiliary suction line 255: Extension suction chamber 350: Suction line 351: Additional suction line 411, 421: 1st and 2nd branch chambers 412, 422: 1st and 2nd branch inlets

Claims

Claim 1 A beam guide member that passes a laser beam, with the diameter decreasing as it moves downward, and forms a beam discharge port of minimum diameter in the conical portion at the bottom; The apparatus includes a housing coupled to the outer surface of the beam guide member such that its inner surface faces the outer surface, thereby forming a shielding gas line on the outer edge of the beam discharge port and forming a suction line connected to the beam discharge port on the conical portion. The shielding gas line includes a plurality of branch chambers that are divided along the circumferential direction near the beam discharge port and branch injection ports that extend radially from the branch chambers. The plurality of branch chambers are merged at the upper part of the region between the outer surface of the beam guide member and the inner surface of the housing and connected to the shielding gas injection port. The plurality of branch injection ports are spaced apart from each other along the circumference at the outer edge of the beam discharge port. The shielding gas line is set to a groove formed on the inner surface of the conical portion of the housing and to the outer surface of the conical portion of the beam guide member coupled to the inner surface, and is connected to an injection port provided in the beam guide member. A suction chamber is set to a groove formed on the inner surface of the conical portion of the housing and to the outer surface of the conical portion of the beam guide member coupled to the inner surface. The suction chamber is formed through a main through hole provided in the conical portion of the beam guide member. A laser welding nozzle connected to a suction outlet provided in the beam guide member, wherein the injection port and the suction outlet are spaced apart from each other in the beam guide member. Claim 2 A laser welding nozzle according to claim 1, wherein the shielding gas line is divided into multiple stages as it descends toward the beam discharge port. Claim 3 A laser welding nozzle according to claim 1, wherein the shielding gas line comprises a first branch chamber connected to an inlet of the shielding gas and divided into two, two first branch inlets provided on both sides in the radial direction of the first branch chamber, four second branch chambers connected to the first branch inlets and divided into two, and four second branch inlets provided on four sides in the radial direction of the second branch chambers and arranged at equal intervals along the circumference. Claim 4 A laser welding nozzle according to claim 3, wherein between the outer surface of the beam guide member and the inner surface of the housing, the first branch chamber and the second branch chamber are formed along the circumference, and the first branch injection port and the second branch injection port are formed along the incline. Claim 5 A laser welding nozzle according to claim 4, wherein the shielding gas line further comprises a circular inlet connecting the four second branch inlets into one on the outer surface of the beam discharge port. Claim 6 delete Claim 7 A laser welding nozzle according to claim 1, wherein, when viewed from the upper and lower perspectives of the beam guide member and the housing joined together, the shielding gas line and the suction line are provided in the conical portion, the shielding gas line is provided on the lower side, and the suction line is provided on the upper side of the shielding gas line. Claim 8 A laser welding nozzle according to claim 1, wherein the beam guide member protrudes to the opposite side of the beam discharge port and further includes a partition wall, said partition wall dividing the internal space into a central space and a peripheral space of a donut structure. Claim 9 A laser welding nozzle according to claim 8, wherein the main penetration holes are provided in plurality and connect the surrounding space and the suction chamber at equal intervals along the circumference. Claim 10 A laser welding nozzle according to claim 9, wherein the suction line comprises a connection of the central space to the beam discharge port, a connection of the peripheral space to the central space to the top of the bulkhead, and a connection of the suction chamber and the suction discharge port to the main penetration port in the peripheral space. Claim 11 In claim 8, the laser welding nozzle further comprises an auxiliary penetration hole in which the bulkhead directly connects the central space and the peripheral space. Claim 12 A laser welding nozzle according to claim 11, wherein the auxiliary penetration holes are provided in plurality and spaced at equal intervals along the circumference to connect the central space and the peripheral space. Claim 13 A laser welding nozzle according to claim 11, wherein the suction line further comprises an auxiliary suction line connecting the central space and the peripheral space through the auxiliary penetration hole. Claim 14 A laser welding nozzle according to claim 11, wherein the conical portion of the beam guide member further comprises an additional through hole directly connecting the central space and the suction outlet. Claim 15 In claim 14, the laser welding nozzle is provided with a plurality of additional penetration holes. Claim 16 A laser welding nozzle according to claim 14, wherein the suction line further comprises an additional suction line connecting the central space and the suction outlet through the additional penetration hole.

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