Laser welding device and welding method using the same

Abstract

The present invention relates to a laser welding apparatus and a welding method using the same. The laser welding apparatus includes a lower jig, a laser welding unit that welds a metal arranged on an upper surface of a PCB arranged on the lower jig to another metal, and an upper jig that supports at least one of at least a part of the upper surface of the PCB, at least a part of the upper surface of the metal, and at least a part of the upper surface of the other metal. The upper jig may be fixed so that its vertical position is constant, or may be fixed at a specific position when the upper jig moves up and down. The present invention also relates to a laser welding apparatus that can weld a PCB while vibrating it, and a welding method using the same.

Description

[Technical Field]

[0001] The present invention relates to a laser welding apparatus and a welding method using the same, and more particularly to a laser welding apparatus and a welding method using the same that can reduce or suppress weak welding defects that may occur due to focal position deviation when laser welding thin metals. [Background technology]

[0002] Electric vehicles use battery modules, which are made up of a number of electrically connected battery cells, or battery packs, which are made up of a number of such battery modules. The battery cells housed in the battery modules or battery packs are connected in series and / or parallel. The battery cells are either directly welded to bus bars, or their electrode leads are welded to a PCB (Printed Circuit Board).

[0003] There are various welding methods, including electric resistance welding, ultrasonic welding, and laser welding. However, the use of laser welding is exploding due to its advantages of being able to precisely weld small areas, being fast, and causing little thermal distortion.

[0004] In the past, to weld an electrode lead to a PCB, a metal pad, typically 0.3 mm thick, was added to the PCB copper foil, and then the metal pad and the electrode lead were welded. After the PCB copper foil and the metal pad were electrically connected, the electrode lead was placed on the metal pad. The vertical position of the laser welding device was adjusted to focus the laser, and then the metal pad and the electrode lead were welded. Even if the focus of the laser welding device was not precisely positioned between the metal pad and the electrode lead, the metal pad melted and electrically connected to the electrode lead after a certain period of time due to the thickness of the metal pad.

[0005] Recently, various attempts have been made to reduce the internal space of a battery module or a battery pack in order to increase its capacity. When there is only one metal pad, its thickness is not a major issue, but when a multi-layer PCB is used, the thickness needs to be reduced.

[0006] When welding PCB copper foil and electrode leads without metal pads, the focal point of the laser welding device must be positioned very precisely. Because the thickness of the PCB copper foil and electrode lead is typically less than 0.1 mm, if the focal point of the laser welding device is not positioned accurately between them, the weld will not be formed, only a portion of the electrode lead surface will melt, or the PCB copper foil will be damaged. After adjusting the height and focusing, the laser welding device moves horizontally along the length or thickness of the electrode lead to perform the overall welding. Mechanical deviations that can occur during horizontal movement of the laser welding device can cause the focal point to fluctuate, reducing the accuracy of the welding position and resulting in poor welding. Even if the laser welding device moves horizontally at the same height without deviation, poor welding can also occur due to thickness variations between the PCB substrate, copper foil, and electrode lead.

[0007] Fig. 1 is a schematic cross-sectional view of a conventional laser welding apparatus 10. Unlike the laser welding apparatus 10 in Fig. 2, the laser welding apparatus 10 in Fig. 1 does not use a metal pad P. Referring to Fig. 1, the conventional laser welding apparatus 10 includes a lower jig 100 that supports a PCB 500, a metal 510 that is inserted and placed on the top surface of the PCB 500, a laser welding portion 200 that welds another metal M that is placed on the top surface of the metal 510, and an upper jig 300 that presses against a portion of the top surface of the PCB 500.

[0008] Here, the metal 510 can be a copper foil of a normal PCB, and the other metal M can be an electrode lead.

[0009] The conventional laser welding device 10 uses a laser L to weld a metal 510 to another metal M, thereby electrically connecting them together.

[0010] 1, the thin thickness of the metal 510 and the other metal M makes it easy for the laser focus to deviate from the boundary surface. High precision is required to adjust the focus position to the boundary surface of the thin metal. This can result in a weak weld between the metal 510 and the other metal M.

[0011] Fig. 2 is a cross-sectional schematic diagram of another prior art laser welding apparatus 20. The laser welding apparatus 20 of Fig. 2 shows a case where a separate metal pad P is used. Referring to Fig. 2, the prior art laser welding apparatus 20 includes a lower jig 100 that supports a PCB 600, a metal 610 that is implanted and disposed on the upper surface of the PCB 600, a laser welding portion 200 that welds the metal pad P located on the upper surface of the metal 610 to another metal M, and an upper jig 300 that presses a portion of these upper surfaces.

[0012] Here, the metal 610 may be a copper foil of a normal PCB, the metal pad P may be a separate copper foil to assist welding, and the other metal M may be an electrode lead.

[0013] In both Figures 1 and 2, the lower jig 100 is fixed in its vertical position.

[0014] The conventional laser welding device 20 uses a laser L to weld and electrically connect the metal 610 and the other metal M. Due to the thin thickness of the metal 610 and the other metal M, it is difficult to move the welding focus or accurately align the focus position. This can lead to a problem of weak welding defects between the metal 610 and the other metal M.

[0015] To solve this problem, a metal pad P is added between the metal 610 and the other metal M to prevent the occurrence of weak welding defects. The metal pad P acts as an intermediate medium to electrically connect the metal 610 and the other metal M. In this case, not only does the manufacturing cost increase, but the increased thickness due to welding makes it impossible to apply technologies for increasing capacity or reducing weight.

[0016] For the purpose of increasing capacity or reducing weight, the use of the conventional laser welding device 20 is not an adequate solution, so the problem of poor welding must be solved while using the conventional laser welding device 10.

[0017] Taking one of the actual application examples of FIG. 1 as an example, metal 510 is copper foil, and its thickness is 0.08 mm. In the case of PCB 500, the deviation due to thickness is ±0.15 mm, and the tolerance due to the position of laser weld 200 is ±0.2 mm. When the deviation due to the thickness of PCB 500 and the tolerance due to the position of laser weld 200 are accumulated, the focus deviation of laser weld 200 becomes ±0.35 mm. metal 510. In this case, the focus of the laser weld 200 is metal The boundary surface between 510 and other metal M does not match, resulting in poor welding.

[0018] Another conventional solution is to perform laser welding by "over-welding" rather than "weak welding." This means that the welding area or thickness is increased beyond the normal level, resulting in an excessive weld. metal Although 510 and other metals M can be welded together, excessive welding can damage the underlying layers of PCB 500.

[0019] FIG. 3 shows an example of a pattern formed by laser welding. It shows the movement of the laser welding unit 200 while performing welding. Even if normal welding is performed without overwelding, if welding is performed in a manner such as that shown in FIG. 3(a), overwelding may occur in overlapping welds. The applicant of the present invention has proposed a solution to the problem of overwelding due to overlapping patterns, as well as the problem of overwelding caused by overlapping patterns, as shown in FIG. 3(a), and has filed a patent application for this solution. However, this solution requires the preparation of a separate PCB with a metal protective layer.

[0020] Patent Document 1 discloses a laser welding jig that welds a PCB and a connecting member by bringing them into close contact with each other. Patent Document 1 aims to prevent welding defects caused by separation between the PCB and the connecting member. Patent Document 1 is a technology that simply presses the PCB and the connecting member to bring them into close contact, and does not take into consideration the positions of the closely contacted PCB and connecting member. Therefore, Patent Document 1 does not disclose a solution that can resolve laser welding focus deviation that occurs due to the thin thickness between the objects to be welded.

[0021] Patent Document 2 discloses a laser welding device for electrode terminals of a coin-type battery that includes an ultrasonic vibration control unit that vibrates in the left-right direction.

[0022] Patent Document 2 provides ultrasonic vibrations instead of simple vibrations, but these also move back and forth. The purpose of providing ultrasonic vibrations in Patent Document 2 is to improve the mechanical properties due to the growth morphology of the metal during welding. Patent Document 2 aims to improve the thermal effects and metal structure of the metal to be welded, while the welding itself is performed without any problems, and does not appear to have recognized the issue of the focal position itself. Patent Document 2 directly affects the metal to be welded using ultrasonic energy, but this does not eliminate focal deviation.

[0023] Patent Document 3 discloses a technology for vibrating materials by forming a magnetic field around a laser weld. This technology is intended to exhaust gases that may be generated during welding, and is applicable only to magnetic materials that must be vibrated by a magnetic field. It is applied to already molten metal, regardless of the welding focus. Patent Document 3 also varies the spacing between materials, which may exacerbate the focus deviation problem of the present invention.

[0024] As such, no reliable solution has been presented that can reduce or prevent weak welding defects caused by laser welding between thin metals while still utilizing conventional PCBs. [Prior art documents] [Patent documents]

[0025] [Patent Document 1] Korean Patent Publication No. 10-2016-0104931 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-086899 [Patent Document 3] Korean Patent Registration No. 10-0612905 Summary of the Invention [Problem to be solved by the invention]

[0026] As described above, an object of the present invention is to provide a laser welding apparatus and a welding method using the same that can reduce or prevent weak welding defects that may occur due to focal position deviation when laser welding thin metals. [Means for solving the problem]

[0027] In order to achieve the above-mentioned object, the present invention provides a laser welding apparatus including a lower jig, a laser welding unit that welds a metal placed on the top surface of a PCB placed on the lower jig to another metal, and an upper jig that supports at least a portion of the top surface of the PCB, at least a portion of the top surface of the metal, and at least a portion of the top surface of the other metal, wherein the upper jig is fixed and its vertical position is constant, or the upper jig can be fixed at a specific position when it moves up and down.

[0028] Here, the lower jig can be moved up and down by a moving part.

[0029] The upper jig supports at least a portion of the top surface of the other metal, and may additionally support at least one of the top surface of the PCB and the top surface of the metal.

[0030] The lower jig can be moved by a moving unit to a position fixed by the upper jig. That is, since the position fixed by the upper jig is constant, when the metal to be welded and the other metal are fixed at a constant height on the upper jig using the lower jig, the distance from the laser weld can be set constant in consideration of the thickness of the other metal and the thickness of the metal, which are measured in advance. Therefore, the focus of the laser weld can also be formed constant.

[0031] The upper jig may be pressed by the moving unit, but since the position of the upper jig is fixed in advance, at least a portion of the top surface of the PCB, at least a portion of the top surface of the metal, and at least a portion of the top surface of the other metal that contacts the upper jig have a constant height. Preferably, the position of the top surface of the other metal where welding is actually performed is constant. The moving unit itself may include an elastic member or a buffer member to prevent damage to the PCB, the metal, and the other metal when pressed to a certain extent. A non-limiting example may be a spring.

[0032] The upper jig is formed with a step portion, so that the other metal, the metal, and the PCB can be supported at the same time.

[0033] A support portion may be provided on a side of the PCB to support the upper jig. A separate support portion may be fixed to fix the position of the upper jig, and the lowered position of the upper jig may be fixed by the support portion.

[0034] The present invention also provides a laser welding apparatus including a lower jig and a laser welding unit that welds a metal placed on an upper surface of a PCB placed on the lower jig to another metal, and a vibration unit that can vibrate the PCB up and down. Here, the upper jig is not necessarily required, and the laser welding apparatus can be configured with only the lower jig.

[0035] The lower jig supports at least one surface of the lower portion of the PCB, and the metal is formed on one surface of the upper portion of the PCB.

[0036] The laser welding portion of the laser welding apparatus according to the present invention can move horizontally, but its vertical position is fixed and constant.

[0037] The vibration unit can vibrate the lower jig up and down, and when vibrating up and down together with the lower jig and the upper jig, the vibration unit may be disposed on either the lower jig or the upper jig.

[0038] The device further includes an upper jig that supports one or more of at least a portion of the top surface of the PCB, at least a portion of the top surface of the metal, and at least a portion of the top surface of the other metal, and the upper jig can vibrate up and down together with the lower jig.

[0039] In other cases, the assembly may further include an upper jig that supports at least a portion of the top surface of the PCB, at least a portion of the top surface of the metal, and at least a portion of the top surface of the other metal, the upper jig including an elastic and / or cushioning member, and the upper jig being movable separately from the lower jig.

[0040] In addition to the above two cases, the upper jig may be fixed in its vertical position, in which case the PCB may vibrate slightly due to the vibration of the lower jig.

[0041] The metal may be embedded in the PCB and have a thickness of 0.05 mm to 0.2 mm, and the metal may not protrude from the surface of the PCB.

[0042] The present invention also provides a welding method using the laser welding apparatus, comprising: 1) placing the PCB having the metal disposed on its upper surface on top of the lower jig; 2) fixing at least a portion of the upper surface of the PCB, at least a portion of the upper surface of the metal, and at least a portion of the upper surface of the other metal to the upper jig; and 3) laser welding the metal and the other metal together.

[0043] The present invention also provides a welding method using the laser welding apparatus, comprising the steps of: 1) placing the PCB with the metal disposed on the upper surface thereof on the upper side of the lower jig; 2) vibrating the PCB up and down; and 3) laser welding the metal and another metal. In this case, welding can be performed using only the lower jig, without the upper jig.

[0044] Step 3) can be performed before step 2), or steps 2) and 3) can be performed simultaneously. After step 1), the method can further include the step of 1-1) fixing at least a portion of the top surface of the PCB, at least a portion of the top surface of the metal, and at least a portion of the top surface of the other metal to the upper jig. Here, the upper jig and the lower jig vibrate simultaneously, or the upper jig is provided with an elastic and / or cushioning member so that the upper jig and the lower jig can move independently.

[0045] According to the present invention, when laser welding is performed, welding can be performed so that the laser trajectories do not overlap.

[0046] The present invention also provides an electrical device welded using the laser welding device.

[0047] The present invention can also be provided as a configuration in which the above-mentioned problems to be solved are combined in any desired manner. [Effects of the Invention]

[0048] As described above, the present invention provides a laser welding apparatus and a welding method using the same that can fix the focal point of a laser weld at a constant height by fixing the upper jig at a constant position, thereby reducing or preventing weak welding defects that may occur due to focal position deviation when laser welding thin metals.

[0049] In addition, the present invention provides a laser welding device and a welding method using the same that can intermittently focus the laser weld using vibration to reduce or prevent weak welding defects.

[0050] In addition, the laser welding device according to the present invention has the advantage of being able to reduce the manufacturing cost and thickness by performing welding without using the metal pads used in the prior art.

[0051] In particular, the present invention has the advantage of being able to reduce or prevent weak welding defects when welding two metals with a thickness of 0.1 mm or less. [Brief explanation of the drawings]

[0052] [Figure 1] 1 is a cross-sectional schematic diagram of a laser welding apparatus 10 according to the prior art. [Figure 2] 1 is a cross-sectional schematic view of another laser welding device 20 according to the prior art. [Figure 3] FIG. 10 is a diagram illustrating a pattern formed by laser welding. [Figure 4] 1 is a cross-sectional view showing a laser welding apparatus according to a first embodiment of the present invention. [Figure 5] FIG. 4 is a cross-sectional view showing a laser welding apparatus according to a second embodiment of the present invention. [Figure 6] 5A to 5C are cross-sectional views sequentially illustrating a welding method using a laser welding device according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view showing a laser welding apparatus according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing a laser welding apparatus according to a fourth embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing a laser welding apparatus according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0053] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person skilled in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiment of the present invention in detail, if it is determined that a detailed description of related well-known functions or configurations may unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

[0054] Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean excluding other elements, but means that other elements may also be included.

[0055] Hereinafter, a laser welding apparatus according to the present invention will be described with reference to the accompanying drawings.

[0056] FIG. 4 is a schematic cross-sectional view showing a laser welding apparatus according to a first embodiment of the present invention.

[0057] Referring to FIG. 4, a laser welding apparatus 1000 according to a first embodiment of the present invention includes a lower jig 1100, a laser welding unit 1200, an upper jig 1300, and a moving unit 1400.

[0058] The lower jig 1100 supports the PCB (Printed Circuit Board) 500 and may have a plate shape. For example, the lower jig 1100 may be made of a metal material, but is not limited thereto, as long as it is a material that can support the PCB 500 and is not damaged by a certain pressure.

[0059] Here, the PCB 500 may have metal 510 made of a conductive material embedded on the top surface of a board made of an electrically insulating material.

[0060] Here, the metal 510 may be copper foil, and its thickness may be 0.05 mm to 0.1 mm.

[0061] The other metal M may be an electrode lead connected at one side to an electrode tab protruding from the electrode assembly, and may have a thickness of 0.1 mm to 0.15 mm.

[0062] Possible materials for the metal 510 and other metals M may be one selected from copper, aluminum, tin, zinc, iron, gold, and silver, or an alloy thereof.

[0063] The laser welding unit 1200 uses the same laser welding machine as a normal laser welding machine used for welding thin metals, and therefore, the detailed configuration and detailed description thereof will be omitted.

[0064] In brief, the laser welding part 1200 is for welding between the metal 510 and another metal M, and may include a laser welding body (not shown), a laser welding head (not shown) provided at the bottom of the laser welding body, and a moving part (not shown) that can move the laser welding head horizontally.

[0065] The laser welding head includes a laser beam irradiation unit (not shown) that irradiates a laser beam, and is capable of performing laser welding between metals.

[0066] In addition, an exhaust unit (not shown) that can suck in air or the like is provided near the laser welding head, so that metal fumes that may be generated during the laser welding process between metals can be removed.

[0067] The upper jig 1300 can press a portion of the upper surface of the other metal M located above the metal 510, specifically a portion of the upper surface edge, to tightly fix the metal 510 and the other metal M together.

[0068] The upper jig 1300 may be hydraulic, but is not limited to this, as long as it can press the upper surface of the other metal M to tightly fix the metal 510 and the other metal M together.

[0069] Although the upper jig 1300 is shown pressing the upper surface of the other metal M in the drawing, it may also press and fix a part of the PCB 500 or the metal 510 as necessary.

[0070] The moving part 1400 is located below the lower jig 1100, supports the lower jig 1100, and can move up to press the lower surface of the lower jig 1100.

[0071] The lower jig 1100 rises due to the pressure of the moving part 1400 and is fixed to the upper jig 1300, which is fixed in a fixed position. The moving part 1400 pushes the metal 510 of the PCB 500 upward, reducing the thickness deviation of the metal 510 embedded in the PCB 500, which advantageously prevents the occurrence of weak welding defects due to thickness deviation of the metal 510 during laser welding. Because the tolerance of the other metal M is not large compared to the tolerance of the PCB and the laser welded part, when the other metal M is attached to the upper jig 1300, the contact point between the other metal M and the metal 510 is located at a fixed height.

[0072] The moving part 1400 may have a structure that further rises and presses the lower surface of the lower jig 1100 after the PCB 500 and the metal 510 are supported by the lower jig 1100 and the upper jig 1300 .

[0073] As an example, the moving part 1400 may be configured as a hydraulic structure to press and lift the lower jig 1100, but is not limited to this as long as it can lift the lower jig 1100 and reduce thickness deviation of the PCB 500 during welding.

[0074] Meanwhile, in the first embodiment, the position of the upper jig 1300 is fixed, so as an additional modification, the laser welded portion 1200 can be vibrated up and down to reduce weak welding defects due to additional tolerances.

[0075] FIG. 5 is a schematic cross-sectional view showing a laser welding apparatus 2000 according to a second embodiment of the present invention.

[0076] Referring to FIG. 5, the laser welding apparatus 2000 according to the second embodiment of the present invention is identical to the laser welding apparatus 1000 according to the first embodiment described in FIG. 4, except that it further includes the shape of the upper jig 2300, a moving unit 2400, and a supporting unit 2500, and therefore a description of the same components will be omitted.

[0077] The laser welding apparatus 2000 according to the second embodiment of the present invention includes a lower jig 2100 that supports the PCB 500, a laser welding section 2200 that welds the metal 510 of the PCB 500 to another metal M, an upper jig 2300 that presses a portion of the upper surface of the other metal M and the PCB 500, a moving section 2400 that presses the lower surface of the lower jig 2100, and a support section 2500 located on the side of the PCB 500.

[0078] The upper jig 2300 according to the second embodiment is formed with a step portion 2310 having the same height as the other metal M, so that the other metal M and the PCB 500 can be fixed at the same time, thereby maintaining their positions more stably.

[0079] The moving part 2400 according to the second embodiment may be an elastic body having a restoring force. Therefore, when the moving part 2400 rises and presses the lower jig 2100, if the pressure applied to the PCB 500 is excessive, the pressure can be alleviated, thereby preventing the PCB 500 from being damaged.

[0080] The moving part 2400 may be, for example, a spring, but is not limited thereto as long as it has a structure that can relieve excessive pressure applied to the PCB 500 when the moving part 2400 rises.

[0081] The supports 2500 are located on the sides of the PCB 500, respectively, and support the lower edge of the upper jig 2300 when the upper jig 2300 is lowered.

[0082] As described above, the support part 2500 has the advantage of supporting the lower edge of the descending upper jig 2300, thereby preventing the upper jig 2300 from descending more than necessary and damaging the PCB 500 or other metal M due to pressure. In addition, the support part 2500 can fix the position of the descended upper jig 2300 by fixing the position.

[0083] The support part 2500 has the advantage of maintaining a constant position at which the upper jig 2300 descends to apply pressure, and its height can be adjusted depending on conditions such as the thickness of the PCB 500 .

[0084] FIG. 6 is a cross-sectional view showing in sequence a welding method using a laser welding apparatus 2000 according to a second embodiment of the present invention.

[0085] Referring to FIG. 6, the welding method using the laser welding apparatus according to the present invention includes the steps of: 1) positioning the PCB 500 on the upper surface of the lower jig 2100; 2) fixing the metal 510 of the PCB 500 to the other metal M using the upper jig 2300; 3) pressing the lower surface of the lower jig 2100 using the moving part 2400; and 4) welding the metal 510 to the other metal M.

[0086] The step of placing the PCB 500 on the upper surface of the lower jig 2100 is a step of placing the PCB 500 on the upper surface of the lower jig 2100 and placing another metal M on the upper surface of the metal 510 of the PCB 500 .

[0087] The step in which the upper jig 2300 fixes the metal 510 of the PCB 500 and the other metal M is a step in which the upper jig 2300 descends and presses the upper surfaces of one or more of the PCB 500 and the other metal M located on the upper surface of the lower jig 2100 to fix them.

[0088] Here, a support portion 2500 may be provided on the side of the PCB 500, and the support portion 2500 can prevent the upper jig 2300 from descending more than necessary and damaging the PCB 500.

[0089] The step of pressing the lower surface of the lower jig 2100 via the moving part 2400 is a step in which the moving part 2400 presses the lower surface of the lower jig 2100 to raise it, thereby raising the PCB 500 seated on the lower jig 2100.

[0090] Here, by raising the PCB 500, thickness deviation can be reduced, thereby preventing poor welding. The support part 2500 has the advantage of maintaining a constant position at which the upper jig 2300 descends to apply pressure, and its height can be adjusted depending on conditions such as the thickness of the PCB 500.

[0091] The step of welding the metal 510 and the other metal M is a step of welding the metal 510 and the other metal M fixed by the lower jig 2100 and the upper jig 2300 .

[0092] FIG. 7 is a schematic cross-sectional view showing a laser welding apparatus 3000 according to a third embodiment of the present invention.

[0093] Referring to FIG. 7, a laser welding apparatus 3000 according to a third embodiment of the present invention includes a lower jig 3100 and a laser welding unit 3200.

[0094] The lower jig 3100 supports the PCB (Printed Circuit Board) 500 and may have a plate shape. For example, the lower jig 3100 may be made of a metal material, but is not limited thereto as long as it can support the PCB 500 and is not damaged by a certain pressure.

[0095] The lower jig 3100 may have a built-in vibrating unit (not shown), or the vibrating unit may be added separately, which allows the lower jig 3100 to vibrate in the vertical direction.

[0096] The vibration unit can repeatedly apply vibrations to the lower jig 3100 with an amplitude of ±0.2 mm, and by vibrating vertically, when the laser welding unit 3200 welds the metal 510 of the PCB 500 to another metal M, the vibration allows welding to be performed at an accurate position, reducing the occurrence of weak welding defects.

[0097] Here, the PCB 500 may have a metal 510 made of a conductive material inserted on the top surface of a board made of an electrically insulating material.

[0098] Here, the metal 510 may be copper foil, and its thickness may be 0.05 mm to 0.1 mm.

[0099] The other metal M may be an electrode lead connected at one side to an electrode tab protruding from the electrode assembly, and may have a thickness of 0.1 mm to 0.15 mm.

[0100] Possible materials for the metal 510 and other metals M may be one selected from copper, aluminum, tin, zinc, iron, gold, and silver, or alloys thereof.

[0101] The laser welding unit 3200 uses the same laser welding machine as a normal laser welding machine used for welding thin metals, so the detailed configuration and detailed description thereof will be omitted.

[0102] In brief, the laser welding part 3200 is for welding between the metal 510 and another metal M, and may include a laser welding body (not shown), a laser welding head (not shown) provided at the bottom of the laser welding body, and a moving part (not shown) that can move the laser welding head horizontally.

[0103] The laser welding head includes a laser beam irradiation unit (not shown) that irradiates a laser beam, and is capable of performing laser welding between metals.

[0104] In addition, an exhaust unit (not shown) that can suck in air or the like is provided near the laser welding head, so that metal fumes that may be generated during the laser welding process between metals can be removed.

[0105] As described above, the laser welding unit 3200 can perform welding at an accurate position by vertically vibrating the metal 510 and the other metal M due to the vibration unit of the lower jig 3100. In FIG. 7, when the laser welding unit 3200 moves horizontally (x direction) at the same height (y direction) due to the movement unit, the metal 510 and the other metal M are vibrated vertically by the vibration unit. This causes the laser to periodically focus on the contact point between the metal 510 and the other metal M, and at this time, the metal 510 and the other metal M are welded. When viewed from these cross sections, a dotted line-shaped welded portion can be formed. The intervals of the dotted line shapes to be welded are adjusted depending on the movement speed of the movement unit or the vibration period of the vibration unit.

[0106] The trajectory of the laser weld for welding is preferably as shown in Figure 3(b) to (f). In Examples 1 and 2, since there is no vibration, the welded portion can be shown as a solid line, but in Examples 3 to 5, since vibration is added, the welded portion is shown as a dotted line instead of a solid line. In the case of Figure 3(a), overlapping portions may result in over-welding, so a trajectory that does not overlap is preferable. Figures 3(b) to (f) are one example of a non-overlapping trajectory, and various shapes are possible as long as there is no overlap.

[0107] The vibration unit may be a device that converts the rotational motion of the motor into vibrational motion, or may be a rotating unit that does not coincide with the rotation axis of the motor. There are various other devices that can generate vibration, which can be selected by an ordinary engineer as needed.

[0108] The vibration part according to the present invention preferably has a vibration frequency of 1 Hz to 10,000 Hz, more preferably 10 Hz to 1,000 Hz, and most preferably 50 Hz to 500 Hz.

[0109] The vibration part according to the present invention preferably has an amplitude of 0.1 mm to 5 mm, more preferably 0.2 mm to 3 mm, and most preferably 0.3 mm.

[0110] FIG. 8 is a schematic cross-sectional view showing a laser welding apparatus 4000 according to a fourth embodiment of the present invention.

[0111] Referring to FIG. 8, the laser welding apparatus 4000 according to the fourth embodiment of the present invention is the same as the laser welding apparatus 3000 according to the third embodiment described in FIG. 7 except that it further includes an upper jig 4300, and therefore a description of the same components will be omitted.

[0112] The laser welding apparatus 4000 according to the fourth embodiment of the present invention includes a lower jig 4100 that supports the PCB 500, a laser welding portion 4200 that welds the metal 510 of the PCB 500 to another metal M, and an upper jig 4300 that presses a portion of the upper surface of the other metal M.

[0113] As described above, the upper jig 4300 has the advantage of being able to press the upper edge of the other metal M to tightly fix the metal 510 and the other metal M together, thereby improving welding quality.

[0114] Here, the upper jig 4300 can move together with the lower jig 4100 in conjunction with the up and down movement of the lower jig 4100 caused by the vibration unit.

[0115] FIG. 9 is a schematic cross-sectional view showing a laser welding apparatus 5000 according to a fifth embodiment of the present invention.

[0116] Referring to FIG. 9, the laser welding apparatus 5000 according to the fifth embodiment of the present invention is the same as the laser welding apparatus 3000 according to the third embodiment described in FIG. 7, except that it further includes an upper jig 5300 and an elastic member 5400, and therefore, a description of the same components will be omitted.

[0117] The laser welding apparatus 5000 according to the fifth embodiment of the present invention includes a lower jig 5100 that supports the PCB 500, a laser welding portion 5200 that welds the metal 510 of the PCB 500 to another metal M, an upper jig 5300 that presses the other metal M and a portion of the upper surface of the PCB 500, and an elastic member 5400.

[0118] The upper jig 5300 according to the fifth embodiment has a step portion formed at the same height as the other metal M, so that the other metal M and the PCB 500 can be fixed at the same time, and therefore the position can be maintained more stably. The upper jig 5300 does not need to move together with the lower jig 5100.

[0119] In addition, the upper jig 5300 has an elastic member 5400 having flexibility at its upper portion, which has the advantage of preventing damage due to excessive pressure when the upper jig 5300 presses the PCB 500 and other metal M. The upper jig 5300 may be provided with a separate moving means such as a piston for pressing.

[0120] The elastic member 5400 may be, for example, a spring, but is not limited thereto as long as it can relieve excessive pressure on the metal M and the PCB 500 .

[0121] The welding method using the laser welding apparatus according to Examples 3 to 5 includes the steps of positioning the PCB 500 on the upper surface of the lower jig 3100, 4100, 5100, vibrating the PCB 500 by a vibrating unit, and welding the metal 510 and another metal M together.

[0122] The step of placing the PCB 500 on the upper surface of the lower jig 3100, 4100, 5100 is a step of placing the PCB 500 on the upper surface of the lower jig 3100, 4100, 5100, and placing another metal M on the upper surface of the metal 510 of the PCB 500.

[0123] The step of vibrating the PCB 500 by the vibrating unit is a step in which the vibrating unit built into or attached to the lower jig 3100, 4100, 5100 vibrates so that the metal 510 of the PCB 500 and the other metal M can be positioned at the focus for welding.

[0124] The step of welding the metal 510 to the other metal M is a step of welding the metal 510 of the PCB 500 vibrated by the vibrating part to the other metal M at the moment when the metal 510 and the other metal M coincide with the focus of the laser L, and can be performed before or simultaneously with the previous step of vibrating the PCB 500 by the vibrating part.

[0125] In addition, when using the laser welding apparatus 4000 according to the fourth embodiment, a step of pressing and supporting the upper surface of the other metal (M) by the upper jig (4300) may be further included prior to the step of welding the metal (510) and the other metal (M).

[0126] In addition, when using the laser welding apparatus 5000 according to the fifth embodiment, prior to the step of welding the metal 510 and the other metal M, the step of the upper jig 5300 pressing and supporting the upper surfaces of the metal 510 and the other metal M of the PCB 500 may be further included.

[0127] The present invention also provides an electric device welded using the laser welding apparatus described above. The electric device may include an electrode assembly, a battery cell, a battery module, a battery pack, or a device including at least one of these.

[0128] Although specific portions of the present invention have been described in detail above, those skilled in the art will recognize that these specific techniques are merely preferred embodiments and do not limit the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope and technical spirit of the present invention, and it goes without saying that such changes and modifications are also included in the scope of the appended claims. [Explanation of symbols]

[0129] 10, 20, 1000, 2000, 3000, 4000, 5000 laser welding equipment 100, 1100, 2100, 3100, 4100, 5100 Lower jig 200, 1200, 2200, 3200, 4200, 5200 laser welded parts 300, 1300, 2300, 4300, 5300 Upper jig 2310 Multilayered section 1400, 2400 Mobile Unit 5400 Elastic members 2500 Support part 500, 600 PCBs 510, 610 metal M Other metals L Laser P Metal pad

Claims

1. A laser welding apparatus comprising: The lower jig and a laser welding unit for welding a metal placed on the upper surface of the PCB placed on the lower jig to another metal; Including, a vibration unit that can vibrate the PCB up and down; Including, The laser welding part is moved horizontally at the same height by a moving part, the lower jig has a plate shape and supports the PCB; the metal is copper foil, the other metal is an electrode lead, The intervals of the dotted lines in the cross section of the welding area are adjusted by the moving speed of the moving part or the vibration period of the vibration part. Device.

2. The vibration unit vibrates the lower jig up and down.

10. The apparatus of claim 1.

3. The apparatus further comprises: an upper jig that supports at least one of at least a portion of an upper surface of the PCB, at least a portion of an upper surface of the metal, and at least a portion of an upper surface of the other metal; The upper jig vibrates up and down together with the lower jig.

10. The apparatus of claim 1.

4. The apparatus further comprises: an upper jig that supports at least one of at least a portion of an upper surface of the PCB, at least a portion of an upper surface of the metal, and at least a portion of an upper surface of the other metal; the upper jig includes an elastic member and / or a buffer member; the upper jig moves separately from the lower jig; 10. The apparatus of claim 1.

5. The metal is embedded in the PCB and has a thickness of 0.05 mm to 0.2 mm; and The other metal has a thickness of 0.1 mm to 0.15 mm.

10. The apparatus of claim 1.

6. A laser welding method using the apparatus according to any one of claims 1 to 5, 1) placing the PCB with the metal disposed on top of the lower jig; 2) vibrating the PCB up and down; 3) laser welding the metal to another metal; A method comprising:

7. Step 3) is performed before step 2), or Step 2) and step 3) are carried out simultaneously; The method of claim 6.

8. The method further comprises: After step 1), 1-1) fixing at least one of at least a portion of an upper surface of the PCB, at least a portion of an upper surface of the metal, and at least a portion of an upper surface of the other metal to an upper jig; The method of claim 6.

9. An electrical device welded using the device according to any one of claims 1 to 5.

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