WO2023085336A1 - Procédé de soudage, dispositif de soudage et stratifié métallique - Google Patents

Procédé de soudage, dispositif de soudage et stratifié métallique Download PDF

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Publication number
WO2023085336A1
WO2023085336A1 PCT/JP2022/041791 JP2022041791W WO2023085336A1 WO 2023085336 A1 WO2023085336 A1 WO 2023085336A1 JP 2022041791 W JP2022041791 W JP 2022041791W WO 2023085336 A1 WO2023085336 A1 WO 2023085336A1
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Prior art keywords
irradiation
metal
laser beam
laser light
laser
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PCT/JP2022/041791
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English (en)
Japanese (ja)
Inventor
暢康 松本
俊明 酒井
昌充 金子
孝 繁松
和行 梅野
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古河電気工業株式会社
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Publication of WO2023085336A1 publication Critical patent/WO2023085336A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/03—Observing, e.g. monitoring, the workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/32—Bonding taking account of the properties of the material involved
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a welding method, a welding device, and a metal laminate.
  • Patent Document 1 a battery is known in which a plurality of tabs and terminals are joined by laser welding.
  • one of the objects of the present invention is to provide a novel improvement that can suppress, for example, the formation of gaps between a plurality of metal foils and a metal member and the cutting of a part of the metal foils. a welding method, a welding apparatus, and obtaining a metal laminate.
  • a metal member having a first surface facing a first direction and a plurality of metal foils are stacked on the first surface in the first direction. and irradiating a second surface of the plurality of metal foils opposite to the metal member in the first direction with a laser beam, wherein the metal member and the plurality of wherein, in the step of irradiating the metal foil with the laser beam, the laser beam is irradiated in a state in which wrinkles exceeding a predetermined height projecting in the first direction of the metal foil do not occur.
  • the predetermined height may be 0.2 [mm].
  • the laser light irradiation in the step of irradiating the laser light, the laser light irradiation may be performed multiple times.
  • the irradiation of the laser beam a plurality of times includes a first scan for scanning the spot of the laser beam in a predetermined section on the second surface, and a scan following the first scan. and a second scan of scanning a spot of laser light in a predetermined section on the second surface, and the end point of the first scan and the start point of the second scan may be separated from each other.
  • the start point of the first scan and the end point of the second scan may overlap.
  • the start point of the first scan and the start point of the second scan may overlap.
  • each irradiation of the laser beam is carried out between the end portion held by the holding mechanism of the metal member and the plurality of metal foils and the irradiation center of the current irradiation.
  • the distance in the second direction intersecting the first direction between, or the irradiation center and the current irradiation at the location where the metal member and the plurality of metal foils are welded and fixed by previous irradiation in multiple irradiations may be performed so that the distance in the second direction between the irradiation center of is 3 [mm] or less.
  • a position closer to the end held by the holding mechanism between the metal member and the plurality of metal foils is first irradiated with the laser light, and the end is held by the holding mechanism. Irradiation of the laser light to a position farther from the position may be performed later.
  • the plurality of irradiations of the laser beam include the first irradiation of the laser beam and the irradiation of the laser beam which is performed after the first irradiation and is farther from the end than the first irradiation.
  • a second irradiation with a longer scanning length than the first irradiation may be included, which is irradiation of the position with a laser beam.
  • the step of irradiating the laser beam in the step of irradiating the laser beam, two mutually separated ends of the laminate including the metal member and the plurality of metal foils are respectively held by the holding mechanism, and the plurality of laser beams are emitted from the holding mechanism.
  • the first irradiation of the laser beam to a plurality of locations away from each of the two ends, and a position between the two ends and between the first irradiation of at least two locations and a second irradiation of the laser light to the.
  • the scanning length of the second irradiation may be longer than the scanning length of the first irradiation at the at least two locations between which the second irradiation is located.
  • the laser beam irradiation in the step of irradiating the laser beam, may be performed a plurality of times so as to partially overlap each other to form a massive welded portion.
  • the plurality of metal foils and the plurality of metal foils are respectively held in the first direction.
  • the plurality of holding mechanisms separated in the second direction In between, the second surface may be irradiated with the laser light.
  • the distance between the plurality of holding mechanisms in the second direction may be 2 [mm] or more.
  • At least one of the plurality of holding mechanisms is separated from the laminate including the metal member and the plurality of metal foils in the second direction by the two holding members. Even if the absolute value of the difference between the thickness of the laminate in the first direction and the thickness of the intervening member in the first direction is 0.5 [mm] or less good.
  • the laser beam in the step of irradiating the laser beam, comprises a first laser beam that forms a first spot on the second surface and a second laser beam that forms a second spot on the second surface. and laser light.
  • the wavelength of the first laser beam may be 800 [nm] or more and 1200 [nm] or less, and the wavelength of the second laser beam may be 550 [nm] or less.
  • the wavelength of the second laser light may be 400 [nm] or more and 500 [nm] or less.
  • a second spot formed on the surface may at least partially overlap.
  • the metal foil may be made of a copper-based material.
  • the welding device of the present invention includes a metal member having a first surface facing a first direction, and a plurality of metal foils, the plurality of metal foils being stacked on the first surface in the first direction.
  • An optical head that irradiates on two sides, and a welding device in which the metal member and the plurality of metal foils are held in a state in which wrinkles exceeding a predetermined height protruding in the first direction of the metal foils do not occur. .
  • the welding device may include a holding mechanism that holds the metal member and the plurality of metal foils in a state in which wrinkles exceeding a predetermined height projecting in the first direction of the metal foils do not occur.
  • the optical head irradiates the laser beam under conditions that do not cause wrinkles exceeding the predetermined height protruding in the first direction in the metal foil as the metal foil expands due to the irradiation of the laser beam. may be performed.
  • the welding device of the present invention includes a metal member having a first surface facing a first direction, and a plurality of metal foils, the plurality of metal foils being stacked on the first surface in the first direction.
  • an optical head that irradiates the surface, a sensor that detects the height of wrinkles protruding in the first direction of the plurality of metal foils, and a height of the wrinkles detected by the sensor that is equal to or less than a predetermined value. and a controller for controlling operation of the light source.
  • the metal laminate of the present invention is, for example, a metal laminate in which a metal member having a first surface facing a first direction and a plurality of metal foils are welded together, At least one weld that penetrates the plurality of metal foils and reaches the metal member from a second surface opposite to the metal member in one direction, and on the second surface, the The distance between the center of irradiation at the welded portion and the pinching mark formed by pinching the metal laminate between the pinching members or the center of irradiation at another welded portion is 3 mm or less.
  • a novel and improved welding method that can suppress the formation of gaps between a plurality of metal foils and metal members and the cutting of some metal foils.
  • Devices and metal laminates can be obtained.
  • FIG. 1 is an exemplary schematic configuration diagram of a laser welding device according to the first embodiment.
  • FIG. 2 is an exemplary and schematic cross-sectional view of a metal laminate as an object to be processed by the laser welding apparatus of the embodiment.
  • FIG. 3 is an exemplary and schematic cross-sectional view of a battery including a metal laminate as an object to be processed by the laser welding apparatus of the embodiment.
  • FIG. 4 is an exemplary schematic diagram showing a beam (spot) of a laser beam formed on the surface of a metal laminate as an object to be processed by the laser welding apparatus of the embodiment.
  • FIG. 5 is a graph showing the light absorptance of each metal material with respect to the wavelength of the irradiated laser light.
  • FIG. 6 is a flow chart showing an example of a procedure of a welding method using the laser welding device of the embodiment.
  • FIG. 7 is an exemplary and schematic cross-sectional view showing a part of the metal laminate to be processed by the laser welding apparatus of the embodiment, and is a cross-sectional view when a preferable bonding state is obtained.
  • FIG. 8 is an exemplary and schematic cross-sectional view showing a part of the metal laminate as a processing target of the laser welding apparatus of the embodiment, in which a gap is generated between the metal member and the plurality of metal foils.
  • FIG. 5 is a cross-sectional view when an unfavorable bonding state is obtained; FIG.
  • FIG. 9 is an exemplary and schematic cross-sectional view showing a part of the metal laminate as a processing target of the laser welding apparatus of the embodiment, in which a part of the metal foil is cut and an unfavorable joining state is obtained.
  • FIG. 10 is a cross-sectional view when the FIG. 10 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 11 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 10 is a cross-sectional view when the FIG. 10 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 11 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of
  • FIG. 12 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 13 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 14 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 15 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 16 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 17 is an exemplary schematic plan view showing an example of a welded portion and a welding procedure on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 18 is an exemplary and schematic plan view showing an example of welding sites and welding procedures on the surface of a metal laminate to be processed by the laser welding apparatus of the embodiment.
  • FIG. 19 is an exemplary schematic configuration diagram of the laser welding device of the second embodiment.
  • FIG. 20 is an explanatory diagram showing the concept of the principle of the diffractive optical element included in the laser welding device of the second embodiment.
  • FIG. 21 is an exemplary schematic configuration diagram of a laser welding device according to the third embodiment.
  • Exemplary embodiments of the present invention are disclosed below.
  • the configurations of the embodiments shown below and the actions and results (effects) brought about by the configurations are examples.
  • the present invention can be realized by configurations other than those disclosed in the following embodiments.
  • the X direction is indicated by an arrow X
  • the Y direction is indicated by an arrow Y
  • the Z direction is indicated by an arrow Z.
  • the X-, Y-, and Z-directions intersect and are orthogonal to each other.
  • the scanning direction SD is represented by an arrow SD.
  • the Z direction is the normal direction of the surface Wa (machined surface, welded surface) of the workpiece W, the thickness direction of the metal foil 12 , and the stacking direction of the metal foil 12 and the metal laminate 10 .
  • ordinal numbers are given for convenience to distinguish directions, processes, laser beams, spots, parts, members, sites, etc., and do not indicate priority or order.
  • FIG. 1 is a schematic configuration diagram of a laser welding device 100 of the first embodiment.
  • the laser welding device 100 includes a laser device 111, a laser device 112, an optical head 120, an optical fiber 130, a sensor 140, and a control device 150.
  • Laser welding device 100 is an example of a welding device.
  • the laser devices 111 and 112 each have a laser oscillator, and are configured to output laser light with a power of, for example, several kW.
  • the laser devices 111 and 112 emit laser light with a wavelength of 380 [nm] or more and 1200 [nm] or less.
  • the laser devices 111 and 112 internally have laser light sources such as fiber lasers, semiconductor lasers (elements), YAG lasers, and disk lasers.
  • the laser devices 111 and 112 may be configured to output multimode laser light with a power of several kW as the total output of a plurality of light sources.
  • the laser device 111 outputs a first laser beam with a wavelength of 800 [nm] or more and 1200 [nm] or less.
  • Laser device 111 is an example of a first laser device.
  • the laser device 111 has a fiber laser or a semiconductor laser (element) as a laser light source.
  • the laser oscillator included in the laser device 111 is an example of a light source and can also be called a first laser oscillator.
  • the laser device 112 outputs a second laser beam with a wavelength of 550 [nm] or less.
  • Laser device 112 is an example of a second laser device.
  • the laser device 112 has a semiconductor laser (element) as a laser light source.
  • the laser device 112 preferably outputs a second laser beam with a wavelength of 400 [nm] or more and 500 [nm] or less.
  • the laser oscillator included in the laser device 112 is an example of a light source and can also be called a second laser oscillator.
  • the optical fiber 130 guides the laser beams output from the laser devices 111 and 112 to the optical head 120, respectively.
  • the optical head 120 is an optical device for irradiating the object W to be processed with laser light input from the laser devices 111 and 112 .
  • the optical head 120 includes a collimating lens 121, a condensing lens 122, a mirror 123, and a filter .
  • Collimating lens 121, condensing lens 122, mirror 123, and filter 124 may also be referred to as optics.
  • the optical head 120 is configured to be able to change its relative position with respect to the processing target W in order to scan the laser light L while irradiating the surface Wa of the processing target W with the laser light L. Relative movement between the optical head 120 and the workpiece W can be realized by moving the optical head 120, moving the workpiece W, or moving both the optical head 120 and the workpiece W.
  • the optical head 120 may be configured to be able to scan the surface Wa with the laser light L by having a galvanometer scanner or the like (not shown).
  • the collimating lenses 121 (121-1, 121-2) collimate the laser light input via the optical fiber 130, respectively.
  • the collimated laser light becomes parallel light.
  • the mirror 123 reflects the first laser light collimated by the collimating lens 121-1.
  • the first laser beam reflected by the mirror 123 travels in the opposite direction of the Z direction and travels toward the filter 124 . Note that the mirror 123 is not necessary in the configuration in which the first laser light is input so as to travel in the direction opposite to the Z direction in the optical head 120 .
  • the filter 124 is a high-pass filter that transmits the first laser beam and reflects the second laser beam without transmitting it.
  • the first laser beam passes through the filter 124 and travels in the opposite direction of the Z direction to the condenser lens 122 .
  • the filter 124 reflects the second laser beam collimated by the collimating lens 121-2.
  • the second laser beam reflected by the filter 124 travels in the opposite direction of the Z direction and travels toward the condenser lens 122 .
  • the condensing lens 122 converges the first laser beam and the second laser beam as parallel light, and irradiates the object W to be processed as laser light L (output light). That is, the optical head 120 outputs the laser beam L substantially along the direction opposite to the Z direction, and irradiates the workpiece W with the laser beam.
  • the object W to be processed is a metal laminate 10 in which a metal member 11 and a plurality of metal foils 12 are laminated in the Z direction.
  • the metal laminate 10 has a metal member 11 , a plurality of metal foils 12 and welded portions 14 .
  • the welded portion 14 mechanically and electrically connects the metal member 11 and the plurality of metal foils 12 .
  • the metal member 11, the plurality of metal foils 12, and the welded portion 14 are all conductors, and are all made of a copper-based material such as copper or a copper alloy.
  • the welded portion 14 mechanically and electrically connects the metal member 11 and the plurality of metal foils 12 . Note that the metal member 11, the plurality of metal foils 12, and the welded portion 14 may not be made of a copper-based material.
  • the sensor 140 can detect wrinkles as unevenness on the surface Wa, and is, for example, a non-contact camera, a laser displacement meter, or the like.
  • the control device 150 stops the laser devices 111 and 112, for example, when the height of wrinkles from the surface Wa exceeds a predetermined value. Also, the operation of the laser devices 111 and 112 can be controlled by, for example, reducing the output of the laser devices 111 and 112 .
  • FIG. 2 is a cross-sectional view of the metal laminate 10.
  • the metal member 11 has a plate-like shape extending across the Z direction. However, the metal member 11 is not limited to a plate-like member.
  • the plurality of metal foils 12 are stacked in the Z direction on the end surface 11a of the metal member 11 in the Z direction, that is, on the end surface 11a facing the Z direction.
  • the laser light L output from the optical head 120 is irradiated onto the surfaces Wa of the plurality of metal foils 12 on the side opposite to the metal member 11 in the Z direction.
  • the Z direction is an example of a first direction.
  • the end surface 11a is an example of a first surface.
  • the surface Wa is an example of the second surface, and can also be referred to as a laser beam L irradiation surface.
  • the back surface Wb is the surface of the metal laminate 10 opposite to the front surface Wa in the Z direction.
  • the metal laminate 10 is laser-welded by the laser welding apparatus 100, as shown in FIG. It is set in a posture in which the normal direction of the surface Wa is substantially parallel to the Z direction. That is, laser welding is performed in a state in which the metal laminate 10 is held by a plurality of holding mechanisms 210 as shown in FIG.
  • the holding mechanism 210 has two clamping members 211a and 211b spaced apart from each other in the Z direction.
  • the clamping members 211a and 211b are pressed by a pressing mechanism (not shown) with an appropriate pressing force toward each other in the Z direction.
  • the ends of the metal laminate 10 in the Y direction and in the opposite direction to the Y direction are held in the Z direction by holding members 211a and 211b of two holding mechanisms 210, respectively.
  • Each of the holding mechanisms 210 also holds a spacer 220 spaced apart from the metal laminate 10 in a direction crossing the Z direction together with the metal laminate 10 . That is, in each holding mechanism 210, the holding members 211a and 211b hold the metal laminate 10 and the spacer 220 therebetween. Spacer 220 is an example of an intervening member.
  • the direction crossing the Z direction is an example of the second direction.
  • the inventors found that if the difference between the Z-direction thickness T1 of the metal laminate 10 and the Z-direction thickness T2 of the spacer 220 is too large, the metal foil 12 wrinkles on the surface Wa. It was found that the wrinkles caused welding defects. From this point of view, the absolute value of the difference between the thickness T1 and the thickness T2 is preferably 0.5 [mm] or less.
  • the welded portion 14 extends from the surface Wa in the direction opposite to the Z direction.
  • the direction opposite to the Z-direction may also be referred to as the depth direction of weld 14 .
  • the laser beam L is scanned on the surface Wa in a direction that intersects the Z direction (scanning direction SD, see FIG. 7, etc.), so that the welded portion 14 has a cross-sectional shape substantially similar to that of FIG. It will also extend to SD.
  • FIG. 3 is a cross-sectional view of a battery 1 as an electrical product having a metal laminate 10.
  • FIG. A battery 1 is one application example of the metal laminate 10 .
  • the metal laminate 10 is an example of an electrical component as a conductor, and an example of an electrical component included in an electrical product.
  • An electrical component may also be referred to as a component part of an electrical product.
  • the battery 1 shown in FIG. 3 is, for example, a laminated lithium ion battery cell.
  • the battery 1 has two film-like exterior materials 20 .
  • a storage chamber 20 a is formed between the two exterior materials 20 .
  • a plurality of flat positive electrode materials 13p, a plurality of flat negative electrode materials 13m, and a plurality of flat separators 15 are accommodated in the storage chamber 20a.
  • the positive electrode material 13p and the negative electrode material 13m are alternately stacked with the separator 15 interposed therebetween.
  • a metal foil 12 extends from each of the plurality of positive electrode materials 13p and the plurality of negative electrode materials 13m.
  • FIG. 3 In the example of FIG.
  • the plurality of metal foils 12 extending from each of the positive electrode materials 13p are overlapped on the metal member 11 at the opposite end of the battery 1 in the Y direction, and the metal member 11 and the plurality of metal foils 12 A metal laminate 10 welded with a metal foil 12 is provided.
  • Metal member 11 constitutes a positive electrode terminal of battery 1 .
  • the plurality of metal foils 12 extending from each of the negative electrode materials 13m are overlapped on the metal member 11 at the Y-direction end of the battery 1, and the metal member 11 and the plurality of metal foils 12 are overlapped at the end.
  • a welded metal laminate 10 is provided. Also on the negative electrode side, only a portion of the metal member 11 is exposed outside the exterior material 20, and the other portion of the metal member 11, the plurality of metal foils 12, and the welded portion 14 are exposed outside the exterior material 20. not.
  • Metal member 11 constitutes a negative electrode terminal of battery 1 .
  • each metal laminate 10 is sandwiched between two exterior materials 20 . Airtightness or liquidtightness is ensured between the metal laminate 10 and the exterior material 20 by a sealing material or the like. For this reason, it is preferable that the surface Wa and the rear surface Wb of the metal laminate 10 have as little, as little, or no unevenness as possible.
  • the welding method of the present embodiment as will be described in detail later, it is possible to suppress the occurrence of welding defects, so that unevenness of the surface Wa due to welding defects can be reduced. Therefore, the metal laminate 10 welded by the welding method of this embodiment is suitable for the negative electrode terminal of the battery 1 .
  • a negative terminal is an example of an electrical component.
  • the metal laminate 10 or the metal member 11 can also be called an electrode tab or a tab.
  • the metal member 11 can also be called a conductive member.
  • FIG. 4 is a schematic diagram showing a beam (spot) of the laser light L irradiated onto the surface Wa.
  • the beam of the laser light L includes the first laser light beam B1 output from the laser device 111 and the second laser light beam B2 output from the laser device 112 .
  • Each of the beams B1 and B2 has, for example, a Gaussian-shaped power distribution in the radial direction of the cross section perpendicular to the optical axis direction of the beam.
  • the power distributions of beam B1 and beam B2 are not limited to Gaussian shapes.
  • the diameter of the circle representing the beams B1 and B2 is the beam diameter of each beam B1 and B2.
  • the beam diameter of each of the beams B1 and B2 is defined as the diameter of the region including the peak of the beam and having an intensity of 1/e2 or more of the peak intensity.
  • the beam diameter can be defined as the length of the region in which the intensity is 1/ e2 or more of the peak intensity in the direction perpendicular to the scanning direction SD.
  • a beam diameter on the surface Wa is called a spot diameter.
  • the beam of the laser light L is such that the beam B1 of the first laser light and the beam B2 of the second laser light overlap on the surface Wa, and the beam B2 is It is formed so that it is larger (broader) than the beam B1, and the outer edge B2a of the beam B2 surrounds the outer edge B1a of the beam B1.
  • the spot diameter D2 of the beam B2 is larger than the spot diameter D1 of the beam B1.
  • the beam B1 is an example of a first spot and the beam B2 is an example of a second spot.
  • the beam (spot) of the laser light L has a point-symmetrical shape with respect to the center point C. Therefore, in an arbitrary scanning direction SD , the spot shape will be the same. Therefore, when a moving mechanism for relatively moving the optical head 120 and the workpiece W for scanning the surface Wa of the laser beam L is provided, the moving mechanism should have at least a relatively translatable mechanism. In some cases, the relatively rotatable mechanism can be omitted.
  • FIG. 5 is a graph showing the light absorptance of each metal material with respect to the wavelength of the laser light L to be irradiated.
  • the horizontal axis of the graph in FIG. 5 is the wavelength, and the vertical axis is the absorptance.
  • FIG. 5 shows the relationship between wavelength and absorptance for aluminum (Al), copper (Cu), gold (Au), nickel (Ni), silver (Ag), tantalum (Ta), and titanium (Ti). It is shown.
  • the wavelength of the first laser beam, the wavelength of the second laser beam, and the wavelength of the workpiece W are adjusted so that the absorptance of the workpiece W for the second laser beam is higher than the absorptivity for the first laser beam.
  • a material is selected.
  • the scanning direction is the scanning direction SD shown in FIG.
  • a second laser beam is irradiated by a region B2f located in front of SD in FIG. 5 of the beam B2 of the second laser beam.
  • the portion to be welded is irradiated with the beam B1 of the first laser beam, and then the beam B2 of the second laser beam is irradiated with the second laser beam again by the region B2b located behind in the scanning direction SD.
  • a heat-conducting melted region is generated by irradiation of the second laser beam, which has a high absorptivity in the region B2f.
  • a deeper keyhole-type melted region is generated in the welded portion by the irradiation of the first laser beam.
  • the required depth is obtained by the lower power first laser beam compared to the case where the heat-conducting melted region is not formed. fused regions can be formed.
  • the welded portion changes its molten state due to the irradiation of the second laser beam, which has a high absorptivity in the region B2b.
  • the wavelength of the second laser light is preferably 550 [nm] or less, more preferably 500 [nm] or less.
  • the plurality of metal foils 12 expands due to thermal expansion and separates from the metal member 11.
  • gaps are formed between the metal foils 12 and the metal members 11 , and only the metal foils 12 are welded or between the metal foils 12 and the metal members 11 .
  • welding is performed with a gap left open.
  • the inventors have found that welding with such a gap can be prevented by setting appropriate conditions. The suitable conditions will be described later.
  • FIG. 6 is a flow chart showing an example of a laser welding method by the laser welding device 100.
  • the metal laminate 10 is held by two holding mechanisms 210, and set in a state in which the surface Wa is irradiated with the laser light L (S1 ).
  • the surface Wa is irradiated with a laser beam from the optical head 120 (S2).
  • the irradiation of the laser beam L is terminated, and when the irradiation of all the irradiation points on the surface Wa is not completed (in S3 No), S2 is executed. That is, when the irradiation of the laser beam L is performed on a plurality of locations on the surface Wa, S2 is executed a plurality of times. In each time of S2, the laser light L may be irradiated at a fixed point on the surface Wa, that is, spot-irradiated, or may be scanned along the surface Wa in a scanning direction SD that intersects the Z direction. .
  • the portion irradiated with the laser light L melts and then solidifies as the temperature drops, thereby welding the metal member 11 and the plurality of metal foils 12 together, and the metal laminate 10 is integrated. (solidification step).
  • cooling of the metal laminate 10 may be natural cooling or forced cooling using a cooling mechanism.
  • FIG. 7 is a cross-sectional view (a photographic image of a cross section) of the metal laminate 10 including the welded portion 14 when a preferable bonding state is obtained.
  • the welded portion 14 penetrates the plurality of metal foils 12 from the surface Wa in the direction opposite to the Z direction, reaches the inside of the metal member 11, and reaches the inside of the metal member 11. is eating into
  • FIG. 8 shows a state in which a gap G is formed between a plurality of metal foils 12 and the metal member 11.
  • the plurality of metal foils 12 are thermally expanded by being heated by the irradiation of the laser light L.
  • the plurality of metal foils 12 are buckled according to the elongation, and the gap G is generated. If the gap G in this case becomes large, as shown in FIG. An unfavorable bonding state is obtained in which the two are not mechanically and electrically connected to each other.
  • the inventors According to the intensive research of the inventors, on the surface Wa of the metal foil 12, wrinkles do not occur, or even if wrinkles occur, the height of the wrinkles, that is, the general portion of the surface Wa (wrinkles occur) It has been found that the gap G shown in FIG. 8 does not occur unless the height of the wrinkles in the Z direction from the flat portion where the surface is not flat does not exceed 0.2 [mm]. In addition, the inventors' intensive research has revealed that the wrinkles, regardless of thermal expansion, also cause the same gap G even when they are generated before the laser beam L is applied in the set state. bottom. That is, it was found that the holding mechanism 210 needs to hold the metal laminate 10 in a state in which wrinkles with a height in the Z direction exceeding 0.2 [mm] do not occur.
  • FIG. 9 shows a state in which a part of the metal foils 12 located near the ends in the Z direction is cut. Since the metal foil 12 is thin by itself, in a state in which the plurality of metal foils 12 are likely to come apart, depending on the irradiation intensity of the laser beam L, some of the metal foils 12 may be cut as shown in FIG. An unfavorable bonding state is obtained in which the metal foil 12 is not mechanically and electrically connected to the metal member 11 . Hereinafter, this phenomenon will be referred to as partial cutting S.
  • the irradiation time of the laser light L is set to a predetermined time or less, or the scanning length ls (see FIG. 12) of the laser light L is set to a predetermined length or less.
  • the gap G and the partial cut S can be suppressed. It is considered that this is because gaps G and partial cuts S can be suppressed by suppressing local increases in irradiation energy.
  • the metal laminate 10 includes 50 metal foils 12 made of a copper-based material having a thickness of 8 [ ⁇ m] and metal members 11 made of a copper-based material having a thickness of 1 [mm].
  • the holding mechanism 210 is fixed so that the distance in the direction intersecting the Z direction is 3 [mm], and the wavelength is 1070 [nm] and the output power is 800 [W].
  • the laser light L including a laser light and a second laser light having a wavelength of 450 [nm] and an output power of 500 [W] is irradiated onto the surface Wa (hereinafter referred to as condition A)
  • the laser light It was found that the irradiation time of L is preferably 0.1 [s] or less. Further, according to such a point of view, the irradiation of the laser beam L may be performed, for example, at a plurality of locations on the surface Wa, at positions separated from each other on the surface Wa, or at a plurality of times.
  • this condition (1) is a condition determined according to specific specifications, and the irradiation time and scanning length of each welding portion are different from each other. It was found that the larger the volume of the laminate 10 or the plurality of metal foils 12 and the larger the area of the surface Wa, the longer the length can be set.
  • the position of the end point of the previous irradiation and the position of the start point of the next irradiation are separated from each other in two successive irradiations.
  • the gap G and the partial cut S can be suppressed.
  • the gap G and the partial cutting S can be suppressed by suppressing the local increase in the irradiation energy, as in (1).
  • the position of the end point of the irradiation performed first and the position of the start point of the irradiation performed next are 2 [ mm] or more has been found to be preferable.
  • this condition (2) is a condition determined according to specific specifications, and the length of the interval between the previous end point and the current start point is , the larger the volume of the metal laminate 10 or the plurality of metal foils 12 and the larger the area of the surface Wa, the shorter it can be set.
  • the distance d1 is the distance between the edge 10e and the current irradiation center in the direction intersecting the Z direction
  • the distance d2 is the distance between the irradiation center of the previous fixed location and the current irradiation center intersecting the Z direction. is the distance in the direction.
  • the distances d1 and d2 are preferably 3 [mm] or less.
  • the irradiation site may also be referred to as an irradiation area, an irradiation range, or an irradiation position.
  • the distance Dw (see FIGS. 2 and 10) of the plurality of holding mechanisms 210 in the direction crossing the Z direction is set to a predetermined length or longer. It has been found that the gap G can be suppressed by this. It is considered that this is because the shorter the distance Dw in the line of sight opposite to the Z direction, the greater the amount of bending in the Z direction due to the extension of the plurality of metal foils 12 . As an example, in the case of condition A, it was found that the distance Dw is preferably 2 [mm] or more.
  • 10 to 18 are plan views of the metal laminate 10 showing examples of welding sites (irradiation sites) and welding procedures (irradiation procedures) that satisfy the above conditions (1) to (4).
  • the metal laminate 10 is sandwiched by a plurality of (two in this embodiment) holding mechanisms 210 spaced apart in the Y direction, as shown in FIG.
  • two holding members 211a and 211b are arranged in the Z direction. Therefore, the end 10e of the metal laminate 10 on the front surface Wa and the end 10e of the metal laminate 10 on the back surface Wb are aligned in the Z direction. Also, as shown in FIGS.
  • clamping members 211a and 211b are provided on the front surface Wa and the back surface Wb of the metal laminate 10 corresponding to the end portion 10e.
  • a level difference or a concave groove is generated as a pressing mark (not shown) caused by being sandwiched by the two.
  • the press trace is formed in a linear shape extending in the X direction. Press marks may also be referred to as pinch marks.
  • the metal laminate 10 is irradiated with spots of the laser beam L in the order of irradiation sites P1, P2, and P3 (welding sites), thereby forming a plurality of (three) welds 14. be done.
  • Each of the irradiation sites P1 to P3 extends for a predetermined length in the X direction at a substantially central portion in the Y direction between two ends 10e separated from each other in the Y direction.
  • the dashed arrow in the figure indicates the scanning direction of the spot of the laser light L on the surface Wa.
  • the irradiation site P2 is located in the opposite direction in the X direction to the irradiation site P1, and the irradiation site P3 is located in the opposite direction in the X direction to the irradiation site P2.
  • the spots are scanned in the X direction at each of the irradiation sites P1 to P3. Therefore, the start point p2s of the irradiation site P2 is separated from the end point p1e of the previous irradiation site P1, and the start point p3s of the irradiation site P3 is separated from the end point p2e of the previous irradiation site P2.
  • the energy given to the metal laminate 10 by the laser light L is suppressed from locally increasing.
  • the extension of the plurality of metal foils 12 and the bending (buckling) in the Z direction due to the extension are locally increased, thereby suppressing the occurrence of partial cutting S of the metal foils 12 .
  • the previous irradiation start point (for example, start point p1s) and the current irradiation end point (for example, end point p2e) overlap each other in the example of FIG. 10, they do not necessarily overlap.
  • the irradiation on the irradiation site P1 is an example of the first scan
  • the irradiation on the irradiation site P2 is an example of the second scan.
  • the metal laminate 10 is irradiated with the spot of the laser beam L in order of the irradiation sites P1, P2, and P3, thereby welding at a plurality of sites (three sites).
  • a portion 14 is formed.
  • the scanning direction, start point p3s and end point p3e at the irradiation site P3 are reversed from the example of FIG. 10, and the start point p2s and the start point p3s overlap.
  • the start point of the current irradiation can be separated from the end point of the previous irradiation in each of the irradiation sites P1 to P3, thereby obtaining the same effect as in the example of FIG.
  • the irradiation on the irradiation site P2 is an example of the first scan
  • the irradiation on the irradiation site P3 is an example of the second scan.
  • the metal laminate 10 is irradiated with spots of the laser beam L in the order of irradiation sites P1, P2, P3, P4, and P5, thereby forming a plurality of (five) welds 14. be done.
  • the spots of the laser light L are not scanned at the irradiation sites P1 to P4, but are fixed point irradiation.
  • the distance Dw between the two holding mechanisms 210 is longer, so the bending amount (buckling amount) in the Z direction due to the extension of the plurality of metal foils 12 is reduced. This makes it difficult for the gap G to occur.
  • FIGS. 10 the distance Dw between the two holding mechanisms 210 is longer, so the bending amount (buckling amount) in the Z direction due to the extension of the plurality of metal foils 12 is reduced. This makes it difficult for the gap G to occur.
  • FIGS. 10 the bending amount in the Z direction due to the extension of the plurality of metal foils 12 is reduced. This makes it difficult for the gap G to occur.
  • the laser beam L is irradiated at the irradiation sites P1 to P4 having a smaller distance d1 from the end 10e, and the irradiation sites P1 to P4 are solidified to form the welded portion 14.
  • the laser light L is irradiated onto the irradiation site P5 at a distance d2 from the irradiation sites P1 to P4.
  • the scanning length ls of the irradiation site P5 is longer than the scanning lengths of the irradiation sites P1 to P4 in FIGS.
  • the scan length can be set longer.
  • the irradiation time and scanning length at each irradiation site can be set longer as long as the conditions (3) and (4) are satisfied.
  • the irradiation of the irradiation sites P1 to P4 is an example of the first irradiation
  • the irradiation of the irradiation site P5 is an example of the second irradiation.
  • the metal laminate 10 is irradiated with spots of the laser beam L in the order of the irradiation sites P1, P2, P3, P4, P5, P6, and P7, thereby welding at a plurality of sites (seven sites).
  • a portion 14 is formed.
  • the number of irradiated regions is increased compared to the example of FIG.
  • the number and arrangement of irradiation sites can be set arbitrarily within the range satisfying the above conditions (1) to (4).
  • the irradiation of the irradiation sites P1 to P6 is an example of the first irradiation
  • the irradiation of the irradiation site P7 is an example of the second irradiation.
  • the metal laminate 10 is irradiated with spots of the laser beam L in the order of irradiation sites P1, P2, P3, P4, and P5, thereby forming a plurality of (five) welded portions 14. be done.
  • the spot of the laser light L is scanned at each of the irradiation sites P1 to P5.
  • the scanning length of each irradiated portion can be arbitrarily set within the range satisfying the above conditions (1) to (4).
  • the metal laminate 10 is irradiated with spots of the laser beam L in the order of the irradiation sites P1, P2, P3, P4, and P5, thereby forming a plurality of (five) welds 14. be done.
  • the scanning direction is along the Y direction at each of the irradiation sites P1 to P5. In this manner, the scanning direction of each irradiation site can be arbitrarily set within the range satisfying the above conditions (1) to (4). Note that the order of a plurality of irradiation sites and the scanning direction can be arbitrarily set within the range satisfying the above conditions (1) to (4), and are not limited to the example in FIG.
  • the metal laminate 10 is irradiated with spots of the laser beam L in the order of irradiation sites P11 to P13, P21 to P23, and P31 to P33, thereby forming welded portions 14 at a plurality of locations. be done.
  • the spot of the laser light L is also irradiated to the irradiation sites P41 to P43 and P51 to P53.
  • a plurality of adjacent irradiation sites may be set so as to be slightly shifted and arranged so as to partially overlap each other. As a result, a massive welded portion is formed by gathering a plurality of welded portions 14 .
  • the surface Wa is irradiated in the Z direction.
  • the laser light L is irradiated in a state in which wrinkles exceeding a predetermined height are not generated. According to such a configuration and method, for example, gaps G and partial cuts S caused by wrinkles can be suppressed, and a higher quality metal laminate 10 can be formed.
  • FIG. 19 is a schematic configuration diagram of a laser welding device 100A of the second embodiment.
  • the optical head 120 has a DOE 125 between the collimating lens 121-1 and the mirror 123.
  • the laser welding device 100A has the same configuration as the laser welding device 100 of the first embodiment.
  • the DOE 125 shapes the shape of the beam B1 of the first laser light (hereinafter referred to as beam shape).
  • the DOE 125 has, for example, a structure in which a plurality of diffraction gratings 125a with different periods are superimposed.
  • the DOE 125 can shape the beam shape by bending or superimposing the parallel beams in the direction affected by each diffraction grating 125a.
  • DOE 125 may also be referred to as a beam shaper.
  • the optical head 120 includes a beam shaper provided after the collimating lens 121-2 for adjusting the beam shape of the second laser beam, and a filter 124 provided after the beam shape of the first laser beam and the second laser beam. It may also have a beam shaper or the like that adjusts. By appropriately adjusting the beam shape of the laser light L using the beam shaper, it is possible to further suppress the occurrence of spatters and blowholes during welding.
  • FIG. 21 is a schematic configuration diagram of a laser welding device 100B of the third embodiment.
  • the optical head 120 has a galvanometer scanner 126 between the filter 124 and the condenser lens 122 . Except for this point, the laser welding device 100B has the same configuration as the laser welding device 100 of the first embodiment.
  • the galvanometer scanner 126 has two mirrors 126a and 126b, and by controlling the angles of the two mirrors 126a and 126b, the irradiated portion of the laser beam L can be detected without moving the optical head 120. It is a device that can be moved and scanned with a laser beam L. FIG. The angles of the mirrors 126a and 126b are changed by, for example, motors (not shown). Such a configuration eliminates the need for a mechanism for moving the optical head 120 and the workpiece W relative to each other, and provides an advantage that, for example, the device configuration can be made smaller.
  • the present invention can be applied to lithium-ion battery cells with configurations different from those of the above embodiments, and can also be applied to batteries other than lithium-ion battery cells.
  • the surface area of the molten pool may be adjusted by performing scanning by known wobbling, weaving, output modulation, or the like.
  • a surface layer made of other substances may be formed on the surface of the metal foil or metal member.
  • the present invention can be used for welding methods, welding equipment, and metal laminates.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Laser Beam Processing (AREA)

Abstract

L'invention concerne un procédé de soudage qui est destiné à souder ensemble, par exemple, une pluralité de feuilles métalliques et un élément métallique ayant une première surface faisant face à une première direction, et comprend : une étape consistant à retenir l'élément métallique et les feuilles métalliques dans un état dans lequel les feuilles métalliques sont stratifiées dans la première direction sur la première surface ; et une étape consistant à émettre un faisceau laser sur une seconde surface des feuilles métalliques situées sur le côté opposé à l'élément métallique dans la première direction. Dans l'étape consistant à émettre le faisceau laser, le faisceau laser est émis de manière à ne pas amener les feuilles métalliques à former des plis quelconques qui font saillie dans la première direction au-delà d'une hauteur prescrite. Ladite hauteur prescrite peut être définie à 0,2 [mm].
PCT/JP2022/041791 2021-11-10 2022-11-09 Procédé de soudage, dispositif de soudage et stratifié métallique WO2023085336A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001269787A (ja) * 2000-03-28 2001-10-02 Matsushita Electric Ind Co Ltd 溶接状態の判定方法
JP2019514694A (ja) * 2016-04-29 2019-06-06 ヌブル インク 電子パッケージング、自動車用電気機器、バッテリ、及び他の構成要素の可視レーザー溶接
WO2021132682A1 (fr) * 2019-12-25 2021-07-01 古河電気工業株式会社 Procédé de soudage de feuille métallique
US20210299785A1 (en) * 2020-03-24 2021-09-30 Corelase Oy Laser welding stacked foils

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001269787A (ja) * 2000-03-28 2001-10-02 Matsushita Electric Ind Co Ltd 溶接状態の判定方法
JP2019514694A (ja) * 2016-04-29 2019-06-06 ヌブル インク 電子パッケージング、自動車用電気機器、バッテリ、及び他の構成要素の可視レーザー溶接
WO2021132682A1 (fr) * 2019-12-25 2021-07-01 古河電気工業株式会社 Procédé de soudage de feuille métallique
US20210299785A1 (en) * 2020-03-24 2021-09-30 Corelase Oy Laser welding stacked foils

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