Composite bonding system, composite bonding method, and composite bonding structure

Abstract

The present invention provides a system that can reduce the probability of cracking occurring in laminated metal foil when joining laminated metal foil and metal materials. [Solution] The laminated metal foil W1 is ultrasonically bonded using ultrasonic vibration, resulting in a recess T as an ultrasonic bonding mark. ij A recess T is formed in the designated area of ​​the laminated metal foil W1. Furthermore, the recess T of the laminated metal foil W1 is placed on top of the metal material W2. ij When laser light LB is irradiated onto the material, the laminated metal foil W1 and the metal material W2 are joined together.

Description

[Technical Field]

[0001] This invention relates to a technique for joining multiple workpieces by a combination of ultrasonic bonding and laser welding. [Background technology]

[0002] Laser welding has been proposed for joining laminated metal foils (e.g., aluminum foil, aluminum alloy foil, copper foil, or copper alloy foil, etc.) (see, for example, Patent Document 1). The joined metal foils are used, for example, as electrodes in lithium-ion batteries, and efforts are being made to increase the thickness of the laminated metal foil, i.e., the number of metal foils constituting the laminated metal foil, in order to improve the conductivity of the electrodes. Furthermore, as shown in Figure 15, laser welding is also used to attach a metal material W2 constituting a current collector or terminal to the laminated metal foil W1 constituting the electrode. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2024-097640 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, stress may remain between the bead Bd, which is a laser welding mark formed on the laminated metal foil W1, and its adjacent area, and a fracture Rp may occur in the laminated metal foil W1, as shown in Figure 15.

[0005] Therefore, the present invention aims to provide a system that can reduce the probability of breakage occurring in laminated metal foil when joining laminated metal foil and metal materials, as well as a current collection structure in a secondary battery, etc. [Means for solving the problem]

[0006] The composite bonding system of the present invention is An ultrasonic bonding device that joins the laminated metal foil in a specified area by propagating ultrasonic vibrations induced in an ultrasonic vibration element through an ultrasonic bonding chip to the specified area of the laminated metal foil, and A laser welding device that welds the laminated metal foil joined by the ultrasonic bonding device to a metal material using laser light in at least one of the specified area of the laminated metal foil and an adjacent area of the specified area. A composite bonding system.

[0007] In the composite bonding system of the present invention, The laser welding device is configured to irradiate laser light to an overlapping area of the laminated metal foil arranged to overlap the metal material in at least one of the specified area and an adjacent area of the specified area, and weld the laminated metal foil and the metal material.

[0008] The composite bonding method of the present invention includes An ultrasonic bonding step of joining the laminated metal foil in a specified area by propagating ultrasonic vibrations induced in an ultrasonic vibration element through an ultrasonic bonding chip to the specified area of the laminated metal foil, and A laser welding step of welding the laminated metal foil joined in the ultrasonic bonding step to a metal material using laser light in at least one of the specified area of the laminated metal foil and an adjacent area of the specified area.

[0009] The composite bonded structure of the present invention has A composite ultrasonic weld mark is formed in the specified area of the laminated metal foil, and a laser weld mark is formed in at least one of the specified area and an area adjacent to the specified area.

[0010] According to the composite bonding system and composite bonding method of the said configuration, laminated metal foils are ultrasonically bonded using ultrasonic vibrations, thereby forming ultrasonic bonding marks in a designated area of ​​the laminated metal foil. Furthermore, by irradiating at least a portion of the designated area of ​​the laminated metal foil placed on a metal material, the laminated metal foil and the metal material constituting the current collector are bonded. Although stress due to solidification occurs near the laser welding marks (or beads), the laser output is adjusted to make the size of the melting target area or irradiation area smaller than the size of the designated area. As a result, the effect of solidification shrinkage is confined to the ultrasonic bonding marks, and the stress acts not on the individual metal foils, but on the aggregate of multiple ultrasonically bonded metal foils (ultrasonic bonding marks). Therefore, according to the composite bonding system and composite bonding method of the said configuration, and furthermore, the composite bonded structure of the said configuration manufactured therefrom, the probability of fracture caused by the stress in the laminated metal foil is reduced. [Brief explanation of the drawing]

[0011] [Figure 1] A diagram illustrating the configuration of a composite bonding system as one embodiment of the present invention. [Figure 2] Diagram illustrating the configuration of an ultrasonic bonding tip. [Figure 3] Flowchart of the ultrasonic bonding process. [Figure 4] Laser welding process flowchart. [Figure 5] A photograph of ultrasonically bonded laminated metal foil. [Figure 6] Partial cross-sectional image of ultrasonically bonded laminated metal foil. [Figure 7] Partial structural diagram of a composite joint structure. [Figure 8] Diagram illustrating the configuration of a composite joint structure as the first embodiment. [Figure 9] Diagram illustrating the configuration of a composite joint structure as a second embodiment. [Figure 10A] A bottom view of the horn tip in another embodiment. [Figure 10B] Side view of the horn tip in another embodiment. [Figure 11A] A diagram illustrating the structure of ultrasonic bonding marks formed on laminated metal foil in another embodiment. [Figure 11B] Diagram illustrating the configuration of a composite joint structure in another embodiment. [Figure 12A] An explanatory diagram relating to one aspect of laser welding. [Figure 12B] An explanatory diagram relating to other aspects of laser welding. [Figure 12C] An illustrative diagram of a composite joint structure. [Figure 13A] A bottom view of the horn tip in yet another embodiment. [Figure 13B] A side view of the horn tip in yet another embodiment. [Figure 14A] Furthermore, a diagram illustrating the structure of ultrasonic bonding marks formed on laminated metal foil in another embodiment. [Figure 14B] Furthermore, a diagram illustrating the configuration of a composite joint structure in another embodiment. [Figure 15] Partial cross-sectional photographs of laminated metal foil and metal material laser-welded using conventional technology. [Modes for carrying out the invention]

[0012] (Configuration of the composite bonding system) The composite bonding system shown in Figure 1, as one embodiment of the present invention, comprises an ultrasonic bonding device 1 and a laser welding device 2.

[0013] (Configuration of an ultrasonic bonding device) As shown in Figure 1, the ultrasonic bonding apparatus 1 comprises an ultrasonic vibration element 10, a horn tip 140 (ultrasonic bonding tip), an anvil 118, a control device 120, a high-frequency power supply 121, a translation drive device 122, a state sensor 124, and an interface device 126. The ultrasonic vibration element 10 comprises a substantially cylindrical first vibration element 111, a substantially cylindrical, substantially cylindrical, or substantially bottomed cylindrical intermediate vibration element 110, and a substantially cylindrical or substantially bottomed cylindrical second vibration element 112.

[0014] The first vibrating element 111 and the intermediate vibrating element 110 are coaxially connected by a mechanical coupling mechanism (such as a bolt and / or clamp mechanism) in the middle or intermediate part of the ultrasonic vibrating element 10. The intermediate vibrating element 110 and the second vibrating element 112 are coaxially connected by a mechanical coupling mechanism in the middle part of the ultrasonic vibrating element 10. The first vibrating element 111, the intermediate vibrating element 110, and the second vibrating element 112 may be integrally formed rather than being mechanically connected.

[0015] The intermediate vibration element 110 may be a component of the first vibration element 111. That is, the first vibration element 111 may be composed of two vibration elements. In this case, the first vibration element 111 and the intermediate vibration element 110 may be integrally configured rather than being mechanically connected. The intermediate vibration element 110 may be a component of the second vibration element 112. That is, the second vibration element 112 may be composed of two vibration elements. In this case, the second vibration element 112 and the intermediate vibration element 110 may be integrally configured rather than being mechanically connected.

[0016] As shown in Figure 1, the first vibrating element 111 is provided with a piezoelectric body 1112 whose axial direction is the direction of piezoelectric polarization.

[0017] As shown in Figure 1, the intermediate vibration element 110 has a substantially annular plate-shaped intermediate flange 102 that extends radially around its entire circumference at an intermediate position in its axial direction. The intermediate vibration element 110 is configured to be clamped or supported around its entire circumference by a clamping mechanism (not shown) at least at the intermediate flange 102. The intermediate flange 102 may be omitted if it is ensured that the intermediate vibration element 110 is supported by a mechanical support mechanism. As shown in Figure 1, the intermediate vibration element 110 is substantially cylindrical with an outer diameter that is substantially constant in the axial direction behind the intermediate flange 102 (to the left in Figure 1). As shown in Figure 1, the intermediate vibration element 110 is substantially cylindrical (a substantially frustoconical shape and a substantially cylindrical shape coaxially connected) with an outer diameter that continuously decreases towards the tip partway through.

[0018] As shown in Figure 1, the second vibration element 112 is provided with a frequency adjustment element 1120, which is a roughly regular octagon with rounded corners, extending radially around its entire circumference at an intermediate position in its axial direction. The frequency adjustment element 1120 adjusts the resonance frequencies of the longitudinal and torsional vibration components of the ultrasonic vibration.

[0019] As shown in Figure 1, the second vibration element 112 has a plurality of slits 1124 formed on its outer surface behind the frequency adjustment element 1120. The plurality of slits 1124 may also be formed on the outer surface of the second vibration element 112 in front of the frequency adjustment element 1120. The slits 1124 extend diagonally when viewed from the side of the second vibration element 112, or extend axially while being displaced circumferentially in phase. The N (N=2, 3, ...) slits 1124 may be arranged to have N rotational symmetry around the central axis of the second vibration element 112 (for example, N=8, 12, or 16).

[0020] As shown in Figure 1, the second vibrating element 112 is provided with a roughly regular octagonal tip portion 1126 with rounded corners that extends radially around its entire circumference at its axial tip position. The tip portion 1126 has multiple holes 1128 (or through holes) formed at each of the circumferentially spaced locations. The N (N=2, 3, ...) holes 1128 may be arranged to have N rotational symmetry (for example, N=4) around the central axis of the second vibrating element 112. Internal threads are provided on the inner surface of the holes 1128.

[0021] As shown in Figure 2, the horn tip 140 has a plurality of protrusions 142 that locally protrude at the tip that contacts the laminated metal foil W1. It is preferable that the amount or height of the protrusions 142 is greater than or equal to the total thickness of the plurality of metal foils constituting the laminated metal foil W1, relative to the tip of the horn tip 140. In the example in Figure 2, the tip of the horn tip 140 is substantially rectangular prism-shaped, but the tip of the horn tip 140 may have various shapes such as substantially cylindrical, substantially elliptical, substantially square prism-shaped, substantially frustoconical, or substantially frustopyramidal. In the example in Figure 2, the protrusions 142 are substantially frustoconical, but the protrusions 142 may have various shapes such as substantially frustopyramidal, substantially conical, substantially pyramidal, substantially hemispherical, substantially semi-ellipsoidal, or substantially prism-shaped. In the example in Figure 2, 14 protrusions 142 are arranged in a 2 (y direction) × 7 (x direction) matrix or square lattice, but the number of protrusions 142 may be less than or more than 14, and the protrusions 142 may be arranged in various regular arrangements such as a triangular lattice or a kagome lattice, as well as in an irregular arrangement.

[0022] As shown in Figure 1, the male thread at the base end of the horn tip 140 is screwed into the female thread in the hole 1128 at the tip 1126 of the second vibrating element 112, thereby detachably fixing the horn tip 140 to the second vibrating element 112. By preparing horn tips 140 of various shapes, the horn tip 140 can be appropriately replaced depending on the type of metal to be joined.

[0023] The male thread of the balancer, which adjusts the phase difference between longitudinal and torsional vibrations at the tip 1126 of the second vibrating element 112, and consequently at the horn tip 140, may be screwed into the female thread of the hole 1128, thereby allowing the balancer to be detachably fixed to the tip 1126 of the second vibrating element 112.

[0024] The anvil 118 is positioned perpendicularly to the tip of the horn tip 140. Multiple laminated metal foils W1 are placed on the upper surface of the anvil 118 as workpieces. The anvil 118 may be configured to be passively or actively displaced vertically in response to the pressure exerted on the horn tip 140 via the laminated metal foils W1.

[0025] The high-frequency power supply unit 121 is configured to excite the first vibration element 111 in the axial direction by applying a high-frequency AC voltage to the piezoelectric body 1112 of the first vibration element 111 in accordance with the power supplied from the commercial power supply (not shown). The translational drive unit 122 is equipped with a pressure block and is configured to apply pressure from the horn tip 140 to the laminated metal foil W1 by displacing a support mechanism such as a clamp mechanism that supports the intermediate vibration element 110 with the pressure block. The state sensor 124 includes a stroke sensor that outputs a signal according to the amount of displacement of the pressure block constituting the translational drive unit 122, as well as an amplitude sensor that outputs a signal according to the amplitude of the horn tip 140 (corresponding to a specified parameter). The amplitude sensor may be a sensor module composed of an imaging device and equipment that calculates the amplitude by analyzing the image acquired through the imaging device.

[0026] As specified parameters that change according to the progress of bonding of the laminated metal foil W1 and, by extension, the multiple metal foils constituting it, in addition to the amplitude A of the horn tip 140, the axial displacement, displacement velocity and / or displacement acceleration of the vibration element (e.g., the second vibration element 12) may also be measured as specified parameters.

[0027] The interface device 126 is configured, for example, as a display, which displays or outputs the displacement amount and / or pressure of the pressurizing block in response to the output signal of the state sensor 124, etc. The display may be a touch panel display and may be configured to accept setting operations that allow the user to directly or indirectly specify parameters, such as one of several bonding modes that define the time series pattern of the target pressure.

[0028] The control device 120 is composed of a microcomputer, and by extension, an arithmetic processing unit (CPU, microprocessor, processor core, etc.) and a storage device (ROM, RAM, etc.). The control device 120 is configured to control the displacement operation of the pressure block by the translation drive device 122 based on the time series of the displacement amount of the pressure block, which is represented by the output signal of the stroke sensor that constitutes the state sensor 124. The control device 120 is configured to control the power supplied to the piezoelectric body 1112 based on the amplitude of the horn tip 140 (corresponding to a specified parameter), which is represented by the output signal of the amplitude sensor that constitutes the state sensor 124, and thereby control the ultrasonic vibration power of the vibration elements (first vibration element 111, intermediate vibration element 110, and second vibration element 112) and the ultrasonic vibration power of the horn tip 140. As a state sensor 124, a pressure sensor is provided that outputs a signal corresponding to the pressure acting on the intermediate vibration element 110 from the pressurizing block of the translational drive device 122 (~pressure applied by the horn tip 140 to the laminated metal foil W1). Based on the output signal of the pressure sensor, the control device 120 may control the time series of the pressure to be constant or controlled in a specified manner.

[0029] (Configuration of laser welding equipment) As shown in Figure 1, the laser welding apparatus 2 is configured such that the laser light LB emitted in the laser oscillator 20 is irradiated from the output head 24 via the optical cable 22. The laser welding apparatus 2 further includes an optical system control device 220, a camera 222, and a relative displacement mechanism 240. The optical system control device 240 may be composed of a common processing unit with the control device 120. The relative displacement mechanism 240 is composed of a translational drive mechanism such as an xy stage or an xyz stage and, optionally, a tilting drive mechanism. The anvil 18 may constitute the relative displacement mechanism 240.

[0030] The optical system control device 220 identifies a designated area based on an image of the laminated metal foil W1 and / or metal material W2 ultrasonically bonded in that area, captured by the camera 222. The "area" such as the designated area is identified by a set of three-dimensional coordinate values ​​(x, y, z) representing the position in real space. Then, the optical system control device 220 identifies the designated area and / or at least a part of the area adjacent to the designated area as the welding target area. The optical system control device 220 adjusts the relative position between the output head 24 and the target object by driving the relative displacement mechanism 240 to adjust the irradiation position of the laser beam LB onto the target object (metal material W2 and / or the ultrasonically bonded laminated metal foil W1 placed on top of the metal material W2). The optical system control device 220 controls the operation of the laser oscillator 20 or the operation of the light-shielding plates constituting the optical system so that the laser beam LB is irradiated onto the target object at a timing when the irradiation position of the laser beam LB on the target object scans the welding target area or is included in the welding target area, and the irradiation of the laser beam LB is stopped at other timings.

[0031] (Composite joining method) One embodiment of the present invention of a composite bonding method includes an ultrasonic bonding step performed using an ultrasonic bonding apparatus 1 and a laser welding step performed using a laser welding apparatus 2.

[0032] (Ultrasonic bonding process) The procedure for the ultrasonic bonding process will be explained using the flowchart in Figure 3. The laminated metal foil W1 is placed on the anvil 18. The laminated metal foil W1 may be composed of various metal foils such as aluminum foil, aluminum alloy foil, copper foil, copper alloy foil, nickel foil, nickel alloy foil, and gold foil. The thickness of the metal foil (e.g., 5 to 250 μm) and the number of foils (e.g., 10 to 200) may be varied. For example, the laminated metal foil W1 is composed of 60 layers of aluminum foil with a thickness of 12 μm.

[0033] The translational drive device 122 drives the ultrasonic vibration element 10 and the horn tip 140 to approach the laminated metal foil W1 from above (Figure 3 / STEP 112). The x and y positions of the horn tip 140 are adjusted so that when the horn tip 140 descends, it contacts a designated area (ultrasonic bonding target area) of the laminated metal foil W1.

[0034] Furthermore, it is determined whether the horn tip 140 contacts a designated area of ​​the laminated metal foil W1 from above and whether the pressure P received from the laminated metal foil W1 is equal to or greater than the first designated pressure P1 (Figure 3 / STEP 114). The pressure P received by the horn tip 140 from the laminated metal foil W1 is measured based on the output signal of the pressure sensor constituting the state sensor 124. When the tip of the horn tip 140 is separated from the workpiece W1, P=0. When the tip of the horn tip 140 contacts the laminated metal foil W1 placed on the anvil 18, it receives a reaction force and P>0.

[0035] If the determination result is negative (Figure 3 / STEP114...NO), the translational drive device 122 drives the ultrasonic vibration element 10 and the tip of the horn tip 140 to approach the laminated metal foil W1 (Figure 3 / Coupler X1 → STEP112). This adjusts the position of the horn tip 140, and consequently the static pressure applied to the laminated metal foil W1 from the tip of the horn tip 140, so that it falls within the specified static pressure range (for example, 200N to 800N).

[0036] If the judgment result is positive (Figure 3 / STEP114...YES), ultrasonic vibration is generated in the ultrasonic vibration element 10 (Figure 3 / STEP116). Specifically, in response to power being supplied to the high-frequency power supply device 121 from a commercial power source (not shown) via a slip ring or the like, the high-frequency power supply device 121 applies a high-frequency AC voltage to the piezoelectric body 112 of the first vibration element 111. As a result, the first vibration element 111 vibrates in its axial direction at, for example, about 20 kHz, generating ultrasonic vibration. The ultrasonic vibration is transmitted from the first vibration element 111 to the intermediate vibration element 110 in its axial direction, and the amplitude of the ultrasonic vibration is amplified. Furthermore, the amplified ultrasonic vibration is transmitted from the intermediate vibration element 110 to the second vibration element 112 in its axial direction.

[0037] In this way, a portion of the longitudinal vibration component (the axial component of the second vibration element 112) of the ultrasonic vibration transmitted to the second vibration element 112 is converted into a torsional vibration component by the multiple slits 1124 formed on the outer surface of the second vibration element 112. The combined vibration resulting from the combination of the longitudinal and torsional vibration components is then transmitted to the horn tip 140 fixed to the tip of the second vibration element 112.

[0038] In response, the horn tip 140 displaces or vibrates in a circular or elliptical orbit in a plane perpendicular to the contact direction of the laminated metal foil W1. As a result, the amplitude and ultrasonic vibration power of the horn tip 140 gradually increase from the vibration start time t=t0. During this time, impurities on the contact surfaces between the metal foils constituting the laminated metal foil W1 are removed, and plastic deformation of the contact surfaces of the metal foils constituting the laminated metal foil W1 may be promoted. Then, after the rate of increase of the amplitude and ultrasonic vibration power of the horn tip 140 decreases significantly at time t=t1, the amplitude and ultrasonic vibration power of the horn tip 140 gradually increase. This is because oxide films and other substances on the metal constituting the bonding surface of the metal foils of the laminated metal foil W1 are removed, clean and activated metal atoms appear on the bonding surface, and the motion of the atoms becomes more active due to the temperature rise caused by frictional heat, resulting in mutual attraction between atoms.

[0039] During this process, ultrasonic composite vibrations are applied to the laminated metal foil W1 while adjusting the amount of pressure the horn tip 140 applies to the laminated metal foil W1 and / or the static pressure applied to the laminated metal foil W1. As a result, the multiple metal foils constituting the laminated metal foil W1 are solid-state bonded together.

[0040] It is determined whether the time derivative δA (= current amplitude A(k) - previous amplitude A(k-1)) of the amplitude A of the horn tip 140 is negative, and whether the amplitude A is less than or equal to the reference amplitude A0 (Figure 3 / STEP 118). The amplitude sensor constituting the state sensor 124 optically measures the amplitude A at a specified location on the horn tip 140 (for example, a location with a relatively large amplitude). Alternatively, it may be determined whether the amplitude A has decreased by the reference amplitude A0 (or a reference ratio based on the maximum value) with respect to the maximum value at which the amplitude A began to decrease. For example, the reference amplitude A0 may be directly or indirectly specified by the user through a touch panel display constituting the interface device 126, such as one of several junction modes in which the user defines the reference amplitude A0.

[0041] In addition to the amplitude A of the horn tip 140, the axial displacement, displacement velocity, and / or displacement acceleration of the ultrasonic vibration element 10 (e.g., the second vibration element 12) may be measured as values ​​of specified parameters that change according to the progress of bonding of the laminated metal foil W1.

[0042] If the determination result is negative (Figure 3 / STEP118...NO), ultrasonic vibrations are continuously generated in the vibration element (Figure 3 / Coupler X2 → STEP116). On the other hand, if the determination result is positive (Figure 3 / STEP118...YES), the translational drive device 122 moves the ultrasonic vibration element 10 and the horn tip 140 so as to move away from the laminated metal foil W1 (Figure 3 / STEP122).

[0043] Furthermore, it is determined whether the pressure P that the horn tip 140 receives from the laminated metal foil W1 has fallen below the second specified pressure P2 (Figure 3 / STEP 124). The second specified pressure P2 is set to a value smaller than the first specified pressure P1, for example, 0 or a very small value.

[0044] If the determination result is negative (Figure 3 / STEP124...NO), the translational drive device 122 moves the ultrasonic vibration element 10 and the horn tip 140 so that they are separated from the laminated metal foil W1 (Figure 3 / Coupler X4 → STEP122). This adjusts the z-direction position of the horn tip 140, and consequently the static pressure applied to the laminated metal foil W1 from the tip of the horn tip 140, to decrease.

[0045] If the judgment result is positive (Figure 3 / STEP124...YES), the generation of ultrasonic vibration in the ultrasonic vibration element 10 is stopped (Figure 3 / STEP126). For example, after time t=t2 when the amplitude of the horn tip 140 changes from increasing to decreasing and becomes less than or equal to the reference amplitude A0, the ultrasonic power of the horn tip 140 is controlled to become 0 with a slight response delay, and the series of ultrasonic bonding processes is stopped.

[0046] As a result of the ultrasonic bonding process, as shown in Figure 5, the laminated metal foil W1 has recesses T as ultrasonic bonding marks in designated areas located at positions corresponding to each of the multiple protrusions 142 at the tip of the horn tip 140. 11 ~T 17 , T 21 ~T 27 A recess T is formed. As shown in Figure 6, the laminated metal foil W1 is formed in the recess T ij At (i=1,2,j=1,2,‥,7), the metal foils are pressed into a roughly conical or frustoconical shape, and the multiple metal foils constituting the laminated metal foil W1 are solid-state bonded in the designated area. As shown in Figure 5, in plan view, the recess T ijEach of them has a substantially circular shape or a substantially elliptical shape with an ellipticity close to 1, and its aspect ratio (size in the x direction / size in the y direction) is included in the range of, for example, 0.90 to 1.10, 0.92 to 1.08, or 0.95 to 1.05. This is due to the fact that ultrasonic composite vibration is transmitted from the ultrasonic vibration element 10 to the horn tip 140, causing the tip of the horn tip 140 to displace in a substantially circular orbit or a substantially elliptical orbit instead of a straight orbit.

[0047] (Laser welding process) The procedure of the laser welding process will be described using the flowchart of FIG. 4. First, on the second workpiece or metal material W2 placed and fixed on a table (for example, an xy table), the laminated metal foil W1 ultrasonically joined as described above is arranged so as to overlap the designated area where the recesses T 11 ~T 17 、T 21 ~T 27 are formed. The metal material W2 may be composed of various metals such as aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, etc. The metal material W2 may be, for example, a metal plate with a thickness of 0.5 to 1.5 mm. The metal material W2 may be composed of, for example, an aluminum plate with a thickness of 1 μm. The metal material W2 may be another laminated metal foil W1 ultrasonically joined as described above.

[0048] The operation of the relative displacement mechanism 240 is controlled by the optical system control device 220, whereby the relative positions of the emission head 24, the laminated metal foil W1, and the metal material W2 are adjusted (FIG. 4 / STEP142). Moreover, a laser beam LB is irradiated to the recess T ij , preferably to the center of the designated area of the laminated metal foil W1 ultrasonically joined by the laser welding device 2 (FIG. 4 / STEP144). As a result, the laminated metal foil W1 and the metal material W2 are locally welded at the bottom (center) of the recess T ij . In order to avoid the uneven distribution of residual stress caused by the temperature change at the local welding point of the laminated metal foil W1, the recess T ijThe irradiation sequence of the laser beam LB to T may be adjusted. In the example in Figure 2, for example, T 11 →T 27 →T 21 →T 17 →T 12 →T 26 →T 22 →T 16 →T 13 →T 25 →T 23 →T 15 →T 14 →T 24 In that order, T 11 →T 17 →T 21 →T 27 →T 12 →T 16 →T 22 →T 26 →T 13 →T 15 →T 23 →T 25 →T 14 →T 24 In that order, each recess T ij A laser beam LB may be irradiated onto the material, and local welding between the laminated metal foil W1 and the metal material W2 may be performed sequentially.

[0049] Furthermore, the weldable recess T ij (Partial or all unwelded recess T) ij The presence or absence of ) is determined (Figure 4 / STEP146). Welding target recess T ij If it is determined that there is a problem (Figure 4 / STEP146...YES), the processes from the relative position adjustment process for the injection head 24, laminated metal foil W1, and metal material W2 (Figure 4 / STEP142) onward are repeatedly executed.

[0050] And the recess T to be welded ij If it is determined that there is no (Figure 4 / STEP146...NO), the laser welding process is terminated. As a result, a recess T as an ultrasonic bonding mark is formed in the laminated metal foil W1, as schematically shown in Figure 7. ij At the bottom (center), the composite bonded structure W0, to which the laminated metal foil W1 and metal material W2 are joined, is cleaned. The recess T, which is an ultrasonic bonding mark formed in the laminated metal foil W1, is cleaned.ij At the bottom (center), there is a bead Bd as a laser welding mark. ij It is formed.

[0051] (Effects and Benefits) According to the composite bonding system and composite bonding method of the said configuration, the laminated metal foil W1 is ultrasonically bonded using ultrasonic composite vibration, thereby forming a recess T as an ultrasonic bonding mark. ij The recess T is formed in the laminated metal foil W1 (see Figures 5 and 6). Furthermore, the recess T of the laminated metal foil W1 placed on the metal material W2 is formed in the laminated metal foil W1. ij When laser light LB is irradiated onto the material, the laminated metal foil W1 and the metal material W2 are joined together. The bead Bd is the laser welding mark. ij Although stress remains in the laminated metal foil W1 in the vicinity of this point, this stress acts not on the individual metal foils, but on the aggregate of multiple ultrasonically bonded metal foils. Therefore, the composite bonding system and composite bonding method of this configuration, and the composite bonded structure W0 manufactured therefrom, reduce the probability of fracture occurring in the laminated metal foil W1 due to this stress.

[0052] (Other embodiments of the present invention) Figure 8 shows a composite bonded structure as a first embodiment. In fabricating this composite bonded structure, first, a laminated metal foil W1 is ultrasonically bonded in a designated area to form an ultrasonic bonding mark Σ. Next, the laminated metal foil W1 is positioned so as to overlap the metal material W2 in a designated area in the lamination direction (z direction). Then, a laser beam LB is irradiated onto the ultrasonic bonding mark Σ of the laminated metal foil W1, and the metal material W2 is laser-welded at the ultrasonic bonding mark Σ of the laminated metal foil W1. As a result, a composite bonded structure having a laser welding mark Π is fabricated, as shown in Figure 8. This composite bonded structure may constitute, for example, the upper electrode of a battery such as a lithium secondary battery having a substantially rectangular parallelepiped housing.

[0053] Figure 9 shows a composite bonded structure as a second embodiment. In fabricating this composite bonded structure, first, an ultrasonic bonding mark Σ is formed by ultrasonic bonding of the laminated metal foil W1 in a designated area, which is the edge region. Alternatively, the laminated metal foil is processed so that an ultrasonic bonding mark Σ is formed by ultrasonic bonding of the laminated metal foil W1 in a designated area, and the ultrasonic bonding mark Σ becomes the edge. Next, the laminated metal foil W1 is arranged so as to overlap the metal material W2 in a designated area in a direction (y direction) perpendicular to the lamination direction (z direction). Then, laser light LB is irradiated onto the metal material W2 from the opposite side of the ultrasonic bonding mark Σ of the laminated metal foil W1, and laser welding is performed to the metal material W2 at the ultrasonic bonding mark Σ of the laminated metal foil W1. As a result, a composite bonded structure having a laser welding mark Π is fabricated, as shown in Figure 9. This composite bonded structure may constitute, for example, a side electrode (current collector plate) of a battery such as a lithium secondary battery having a substantially rectangular parallelepiped housing.

[0054] Figures 10A and 10B show the horn tip 140 in other embodiments. As shown in Figures 10A and 10B, the substantially rectangular plate-shaped tip of the horn tip 140 is provided with a protrusion 142 that extends in the longitudinal direction (x direction) of the rectangle and protrudes from the tip. Fine irregularities, such as a grid-like arrangement or a parallel, wave-like arrangement of irregularities, may be formed on the top surface of the protrusion 142.

[0055] As shown in Figure 11A, when the horn tip 140 is used, the laminated metal foil W1 is ultrasonically bonded in a designated strip-shaped region, thereby forming an ultrasonic bonding mark Σ. Furthermore, as shown in Figures 12A and 12B, the laminated metal foil W1 is positioned so as to overlap the metal material W2 in a designated region in its lamination direction (y direction). Then, as shown in Figure 12A, at the edge of the laminated metal foil W1, at least a portion of the edge of the laminated metal foil W1 and the ultrasonic bonding mark Σ, and the metal material W2 are irradiated from a direction inclined with respect to the lamination direction (y direction) of the laminated metal foil W1. Alternatively, as shown in Figure 12B, at the edge of the laminated metal foil W1, at least a portion of the edge of the laminated metal foil W1 and the ultrasonic bonding mark Σ, and the metal material W2 may be irradiated from a direction parallel to the lamination direction (y direction) of the laminated metal foil W1. As a result, as shown in Figures 11B and 12C, a composite bonded structure is fabricated having a laser welding mark Π extending from the ultrasonic bonding mark Σ of the laminated metal foil W1 to the metal material W2.

[0056] The second metal material W2 may be used in place of the anvil 118. Subsequently, the laminated metal foil W1 may be laser-welded to the second metal material W2 without being moved (or without changing its orientation). In this case, the translational drive device 122 may be configured such that the convex portion 142 at the tip of the horn tip 140 approaches and contacts the laminated metal foil W1 in the y direction shown in Figure 11B, rather than in the z direction shown in Figure 11A.

[0057] Figures 13A and 13B show horn tips 140 in yet another embodiment. As shown in Figures 13A and 13B, the substantially rectangular plate-shaped tip of the horn tip 140 is provided with a pair of protrusions 142 that extend parallel to the longitudinal direction (x direction) of the rectangle and project from the tip. Fine irregularities, such as a grid-like arrangement or a parallel, wavy pattern of irregularities, may be formed on the top surface of each protrusion 142.

[0058] By using the horn tip 140, as shown in Figure 14A, the laminated metal foil W1 is ultrasonically bonded in each of a pair of parallel strip-shaped regions designated as areas, thereby forming a pair of ultrasonic bonding marks Σ1 and Σ2. Furthermore, the laminated metal foil W1 is positioned so as to overlap the metal material W2 in the designated area in its lamination direction (y direction). Then, as shown in Figure 14A, in the strip-shaped region sandwiched between the pair of ultrasonic bonding marks Σ1 and Σ2 of the laminated metal foil W1, laser light LB is irradiated onto at least a portion of the laminated metal foil W1 and the metal material W2 from a direction inclined with respect to the lamination direction (y direction) of the laminated metal foil W1 or parallel to it (see Figures 12A and 12B). As a result, as shown in Figure 14B, a composite bonded structure having a laser welding mark Π extending from the laminated metal foil W1 to the metal material W2 is fabricated.

[0059] A second metal material W2 may be used in place of the anvil 118. Subsequently, the laminated metal foil W1 may be laser-welded to the second metal material W2 without being moved (or without changing its orientation). In this case, the translational drive device 122 may be configured such that the convex portion 142 at the tip of the horn tip 140 approaches and contacts the laminated metal foil W1 in the y direction shown in Figure 15B, rather than in the z direction shown in Figure 15A.

[0060] The ultrasonic bonding marks Σ formed by the horn tip 140, which has a fine uneven structure such as a grid-like arrangement or a parallel, wave-like extension on the top surface of each protrusion 142, have a surface shape corresponding to the fine uneven structure. Therefore, it is possible to suppress the reflection of laser light LB by the surface shape of the ultrasonic bonding marks Σ having this uneven structure, and thus it is also possible to suppress laser welding energy loss.

[0061] Furthermore, although the above embodiment uses a composite vibration generated by the second vibration element 112 torsion vibration, the same effect can be obtained even in ultrasonic welding where only axial vibration by the first vibration element 111 without torsion vibration is applied. When composite vibration is applied, the bonding load on the laminated metal foil W1 can be reduced, which is advantageous for the shape stability of the laminated metal foil W1. [Explanation of Symbols]

[0062] 10. Ultrasonic vibration element 102...Intermediate flange 110...Intermediate vibration element 111...First vibration element 1112... Piezoelectric material 112...Second vibration element 1120...Frequency adjustment element 1121...Cylindrical part 1122...Cylindrical part 1124... Slit 1126‥Tip 1128...hole 118... Anvil 120...Control device 121‥High frequency power supply equipment 122... Translational drive device 124... State sensor 126. Interface device 140... Horn tip 20. Laser oscillator 22. Optical cable 24... Ejection head 220... Optical System Control Device 222... Camera 240... Relative displacement mechanism LB... Laser light Bd 12 ...bead (laser welding mark) T ij ...recess (ultrasonic bonding mark) W0‥Composite bonded structure W1...Laminated metal foil W2‥Metal material Σ‥Ultrasonic bonding marks Π... Laser welding marks

Claims

1. An ultrasonic bonding apparatus that bonds a laminated metal foil in a designated area by propagating ultrasonic vibrations induced in an ultrasonic vibration element to that designated area of ​​the laminated metal foil via an ultrasonic bonding tip, The device includes a laser welding apparatus that uses laser light to weld the laminated metal foil, which has been joined by the ultrasonic bonding apparatus, to a metal material in at least one of the designated area of ​​the laminated metal foil and an adjacent area of ​​the designated area, using the laser welding apparatus. Composite bonding system.

2. In the composite bonding system according to claim 1, The laser welding apparatus is configured to weld the laminated metal foil and the metal material by irradiating the overlapping region of the laminated metal foil, which is arranged to overlap the metal material in at least one of the designated region and an adjacent region of the designated region, with laser light. Composite bonding system.

3. In the composite bonding system according to claim 2, The ultrasonic bonding apparatus is configured to bond the laminated metal foil in such a way that it forms local recesses corresponding to the protrusions in the laminated metal foil by transmitting ultrasonic vibrations induced in the ultrasonic vibration element to the designated region of the laminated metal foil corresponding to the protrusions, via the ultrasonic bonding tip having locally protruding protrusions. The laser welding apparatus is configured to weld the metal material and the laminated metal foil by irradiating laser light onto the recess formed in the designated area of ​​the laminated metal foil, which is joined by the ultrasonic bonding apparatus and is positioned to overlap the metal material. Composite bonding system.

4. In the composite bonding system according to claim 1, The laser welding apparatus is configured to weld the laminated metal foil and the metal material by irradiating the overlapping region of the metal material, which is arranged to overlap with at least one of the designated region of the laminated metal foil and the adjacent region of the designated region, with laser light. Composite bonding system.

5. An ultrasonic bonding process in which ultrasonic vibrations induced in an ultrasonic vibration element are propagated to a designated area of ​​a laminated metal foil via an ultrasonic bonding tip, thereby bonding the laminated metal foil in the designated area; The process includes a laser welding step in which the laminated metal foil, joined in the ultrasonic bonding step, is welded to a metal material using laser light in at least one of the designated area of ​​the laminated metal foil and an adjacent area of ​​the designated area, using laser light. Composite joining method.

6. A composite bonded structure composed of laminated metal foil and metal material joined together, A composite ultrasonic welding mark is formed in a designated area of ​​the laminated metal foil, and a laser welding mark is formed in at least one of the designated area and the area adjacent to the designated area. Composite bonded structure.

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