JP2012130935A - Laser-welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser-welding apparatus enabling reduction in the size and cost by reducing the number of drive sources compared to conventional cases and capable of reliably welding circular or polygonal welding target parts even when a dimensional tolerance of a workpiece etc. is large.SOLUTION: The laser-welding apparatus 14 irradiates the welding target parts 160 between bus bars 36 and terminals 30, 32 inserted into holes 42, 44, 46 formed on the bus bars 36 with laser beams 12 guided from a laser oscillator 60 to a first laser head 68. The first laser head 68 includes: a support member 110 provided rotatably with respect to a laser head body 86 via a fiber support pipe 88; a rotating motor 112 rotating the support member 110; a mirror 92 fixed to support shafts 120 122 journaled to the support member 110; and an angle changing mechanism 96 oscillating the mirror 92 in the peripheral direction of the support shaft 122 by using driving force of the rotating motor 112.

Description

  The present invention relates to a laser welding apparatus for laser welding a first workpiece and a second workpiece inserted into a hole formed in the first workpiece.

  In general, laser welding uses a focused laser beam as a heat source, and therefore has features such as a deeper penetration depth, a narrow bead width, and a faster welding speed than arc welding or the like. Yes. In laser welding having such a feature, in order to suppress the occurrence of welding defects, a gap between workpieces (for example, a gap between butt portions) is set narrow, and laser beam is reliably irradiated to the welding target portions of these workpieces. It is desirable to do.

  However, since there is usually a dimensional tolerance for the workpiece, there is a limit to narrowing the gap between the workpieces. Thus, a laser welding apparatus has been developed that can reliably weld these workpieces even when a certain gap exists between the workpieces.

  In Patent Document 1, when irradiating a laser beam to a linear abutting portion of two workpieces (workpieces) placed on a movable processing table, the abutting portion is utilized using a wedge plate. A technical idea has been proposed in which the laser beam is oscillated in a direction intersecting with the extending direction of the laser beam so that the locus of the laser beam is zigzag with respect to the abutting portion to widen the bead width.

  In Patent Document 2, a condensing lens for condensing laser light is swung in one direction by a motor, and a head portion including the condensing lens and the motor is separated around the optical axis of the laser light. A technical idea has been proposed in which the locus of the laser beam is zigzag with respect to a bending processing line by being rotated by a motor.

JP 2004-136307 A Japanese Patent Laid-Open No. 2-142893

  By the way, for example, in a battery module manufacturing process, a battery cell terminal may be inserted into a hole formed in the bus bar, and the bus bar and the terminal may be laser-welded. In this case, the shape of the welding object part of the bus bar and the terminal is circular or polygonal.

  However, since the invention described in Patent Document 1 described above is based on the assumption that the welding target portion has a linear shape, the locus of the laser beam cannot be zigzag with respect to the circular welding target portion.

  On the other hand, in the invention described in Patent Document 2, since a motor for rotating the head portion and a motor for swinging the condenser lens are required, the laser welding apparatus itself can be increased in size and cost can be increased. is there.

  The present invention has been made in consideration of such problems, and by reducing the number of drive sources as compared with the prior art, it is possible to reduce the size and cost, and even when the dimensional tolerance of the workpiece is large, the circular shape is reduced. An object of the present invention is to provide a laser welding apparatus capable of reliably welding a shape or a polygonal welding target part.

  The invention specified in claim 1 of the present application is oscillated from a laser oscillator to a welding target portion between a first workpiece and a second workpiece inserted into a hole formed in the first workpiece and guided to a laser head. A laser welding apparatus for irradiating laser light, wherein the laser head includes a laser head main body, a first mirror that reflects laser light oscillated from the laser oscillator, and the laser reflected by the first mirror. A second mirror that reflects light to the welding target portion, and a rotation driving unit that is provided in the laser head main body and that rotates the first mirror around an optical axis of incident laser light incident on the first mirror; Angle changing means for changing an inclination angle of the first mirror with respect to the incident laser beam using a rotational force of the rotation driving means.

  According to the invention specified in claim 1 of the present application, since the first mirror can be rotated around the optical axis of the incident laser beam, the laser beam reflected by the second mirror is circulated around the second workpiece. Can do. Thereby, even if the welding object part of a 1st workpiece | work and the said 2nd work is circular shape or polygonal shape, it becomes possible to irradiate a laser beam along this welding object part. In addition, since the tilt angle of the first mirror with respect to the incident laser beam can be changed, the laser beam reflected by the second mirror can be swung in a direction intersecting with the rotation direction. Thereby, the locus | trajectory of a laser beam can be made into a zigzag with respect to the said welding object part. Therefore, since the bead width can be widened, the first work and the second work are reliably welded even when there is a gap between the first work and the second work to some extent. be able to.

  Further, since the tilt angle of the first mirror is changed by the rotation driving means for rotating the first mirror, the number of drive sources is smaller than that of the conventional one. Thereby, size reduction and cost reduction of the laser welding apparatus itself can be achieved.

  In the present invention, the hole includes both a hole without a bottom and a hole with a bottom (a recess).

  The invention specified in claim 2 of the present application is the laser welding apparatus according to claim 1, wherein the rotation driving means is disposed coaxially with the optical axis of the incident laser light with respect to the laser head main body. It has a cylindrical support member provided rotatably, a drive source for rotationally driving the support member, and a support shaft provided on the support member for supporting the first mirror.

  According to the invention specified in claim 2 of the present application, the cylindrical support member disposed coaxially with the optical axis of the incident laser beam is provided rotatably with respect to the laser head main body and provided on the support member. Since the first mirror is supported by the support shaft, the first mirror can be easily rotated around the optical axis of the incident laser light by rotating the support member with a drive source.

  The invention specified in claim 3 of the present application is the laser welding apparatus according to claim 2, wherein the angle changing means is provided in a first gear provided in the laser head main body and in the support member. A second gear that meshes with one gear; and a conversion mechanism that converts a rotational motion of the second gear into a swinging motion in a circumferential direction of the support shaft.

  According to the invention specified in claim 3 of the present application, since the first gear provided in the laser head main body and the second gear provided in the support member are meshed, the support member is rotated by the drive source. As a result, the second gear rotates. Then, since the rotational movement of the second gear is converted into the swinging movement in the circumferential direction of the support shaft by the conversion mechanism, in the first mirror supported by the support shaft using the driving force of the drive source. The tilt angle with respect to the incident laser beam can be easily changed.

  The invention specified in claim 4 of the present application is the laser welding apparatus according to claim 3, wherein the conversion mechanism is for connecting the disc provided on the support shaft, the second gear, and the disc. A first pin that pivotally supports the coupling member at a position offset with respect to the rotation axis of the second gear, and the disk includes the coupling member. A second pin that pivotally supports the connecting member at a position that is offset with respect to the center line of the disk is provided, and the interval between the rotation axis of the second gear and the first pin is the center line of the disk and the It is characterized by being set smaller than the interval between the second pins.

  The connecting member is pivotally supported by the first pin provided on the second gear and the connecting member is pivotally supported by the second pin provided on the disc, so that the second gear is supported via the connecting member. Rotational force can be transmitted to the disc. At this time, since the distance between the rotation axis of the second gear and the first pin is set smaller than the distance between the center line of the disk and the second pin, the torque of the second gear is transmitted. The disc made will swing in the circumferential direction. As a result, the support shaft can be easily swung in the circumferential direction.

  The invention specified in claim 5 of the present application is the laser welding apparatus according to any one of claims 1 to 4, wherein the second workpiece is terminals of a plurality of battery cells constituting a battery module. The first work is a bus bar for electrically connecting terminals of the adjacent battery cells.

  According to the invention specified in claim 5 of the present application, the terminal of the battery cell and the bus bar constituting the battery module can be reliably laser-welded.

  As described above, according to the laser welding apparatus of the present invention, the first mirror is provided to be rotatable around the optical axis of the incident laser beam, and the tilt angle of the first mirror with respect to the incident laser beam can be changed. Therefore, even if there is a gap between the first workpiece and the second workpiece to some extent, the first workpiece and the second workpiece can be reliably welded. Further, since the tilt angle of the first mirror is changed by the rotation driving means for rotating the first mirror, the number of drive sources is smaller than that of the conventional one. Thereby, size reduction and cost reduction of the laser welding apparatus itself can be achieved.

1 is a perspective view of a laser welding system in which a laser welding apparatus according to an embodiment of the present invention is incorporated, and a battery module that is laser-welded by the laser welding apparatus. It is a disassembled perspective view of the battery module shown in FIG. It is a top view of the battery module shown in FIG. It is sectional drawing of the 1st laser head shown in FIG. It is sectional drawing along the VV line of FIG. 6A is an explanatory diagram for explaining the configuration of the changing mechanism, FIG. 6B is an explanatory diagram showing a state in which the bevel gear and the disc are rotating in opposite directions, and FIG. 6C is a rotation direction of the disc. FIG. 6D is an explanatory view showing a state where the bevel gear and the disc are rotating in the same direction. It is a flowchart which shows the procedure which laser-welds a battery module. It is a schematic diagram which shows the state which is welding the positive electrode terminal and external connection bus bar which comprise a battery module. It is a top view which shows typically the locus | trajectory and bead shape of a laser beam. It is sectional drawing of the 1st laser head which concerns on a modification. It is a top view which shows typically the locus | trajectory and bead shape of the laser beam in the battery module which concerns on a modification.

  Hereinafter, a laser welding apparatus according to the present invention will be described in detail with reference to the accompanying drawings by exemplifying preferred embodiments in relation to a laser welding system in which the laser welding apparatus is incorporated.

  The laser welding system 10 according to the present embodiment connects the terminals 30 and 32 and the bus bar 36 with the terminals 30 and 32 of the battery cells 20 constituting the battery module 18 inserted into the holes 42 of the bus bar 36. It is an apparatus for laser welding.

  As shown in FIG. 1, the laser welding system 10 according to the present embodiment basically includes a laser welding device 14 that outputs a laser beam 12 and a control unit 16 that controls the laser welding device 14. .

  First, the structure of the battery module 18 that is laser welded by the laser welding apparatus 14 will be described.

  As shown in FIGS. 1 to 3, the battery module 18 is configured as, for example, a lithium ion secondary battery, and includes a plurality (12 in the present embodiment) of battery cells 20 and the plurality of battery cells 20. And a connection portion 24 for connecting the plurality of battery cells 20 in series.

  Each battery cell 20 has a rectangular parallelepiped battery cell main body 28, and a positive electrode terminal 30 and a negative electrode as second works provided on one side surface of the battery cell main body 28 so as to be separated from each other in the longitudinal direction of the battery cell main body 28. Terminal 32.

  The plurality of battery cells 20 are arranged in a row so that the thickness directions of the battery cell bodies 28 are the same. At this time, the direction of the plurality of battery cells 20 is set so that terminals adjacent to each other in the thickness direction of the battery cell body 28 have opposite polarities. In the case 22, a plurality of separators 34 are provided between the adjacent battery cells 20 to support the battery cells 20.

  The positive electrode terminal 30 is made of a metal material such as aluminum, an aluminum alloy, copper, or a copper alloy, and is formed in a cylindrical shape. Since the negative electrode terminal 32 has the same configuration as the positive electrode terminal 30, detailed description thereof is omitted.

  The connection portion 24 includes a plurality of bus bars 36 serving as a first work that electrically connects a pair of the positive electrode terminal 30 and the negative electrode terminal 32 adjacent to each other in the thickness direction of the battery cell main body 28, and the battery cell main body 28 in the thickness direction. The external connection bus bar 38 for electrically connecting the positive electrode terminal 30a located on one end side and a first external terminal (not shown), the negative electrode terminal 32a located on the other end side in the thickness direction of the battery cell body 28, and not shown And an external connection bus bar 40 for electrically connecting the second external terminals.

  Each bus bar 36 is formed in a rectangular flat plate shape in plan view, and is made of a metal material such as aluminum, aluminum alloy, copper, or copper alloy. Each bus bar 36 is formed with a pair of holes 42, 42 into which the positive electrode terminal 30 and the negative electrode terminal 32 can be inserted, arranged in the longitudinal direction in a state of being separated from each other. Each hole 42 corresponds to the shape of the positive electrode terminal 30 and the negative electrode terminal 32 described above and opens in a circular shape.

  The external connection bus bar 38 has a hole 44 into which the positive terminal 30a can be inserted, and the external connection bus bar 40 has a hole 46 into which the negative terminal 32a can be inserted.

  The battery module 18 according to the present embodiment houses a plurality of battery cells 20 in a case 22 and arranges a plurality of bus bars 36, an external connection bus bar 38, and an external connection bus bar 40 on the plurality of battery cells 20. It is assembled by installing.

  At this time, the negative terminal 32 is inserted into one hole 42 of each bus bar 36, and the positive terminal 30 is inserted into the other hole 42 of each bus bar 36. The positive terminal 30 a is inserted into the hole 44 of the external connection bus bar 38, and the negative terminal 32 a is inserted into the hole 46 of the external connection bus bar 40.

  In this state, the positive electrode terminal 30, the negative electrode terminal 32, the bus bar 36, and the external connection bus bars 38, 40 have dimensional tolerances, so the bus bar 36 and the positive electrode terminal 30, the bus bar 36 and the negative electrode terminal 32, There are gaps S between the external connection bus bar 38 and the positive terminal 30a and between the external connection bus bar 40 and the negative terminal 32a (see FIG. 8).

  Next, the configuration of the laser welding apparatus 14 will be described. As shown in FIG. 1, the laser welding apparatus 14 branches from a laser oscillator 60 that oscillates laser light 12, an optical fiber 62 that transmits the laser light 12 oscillated from the laser oscillator 60, and the optical fiber 62. A first branch fiber 64 and a second branch fiber 66, a first laser head 68 connected to the first branch fiber 64, and a second laser head 70 connected to the second branch fiber 66 are provided.

The laser oscillator 60 is configured as a so-called fiber laser oscillator. However, as the laser oscillator 60, a YAG laser oscillator, a CO ₂ laser oscillator, a semiconductor laser oscillator, or the like may be appropriately selected.

  At the branch point of the optical fiber 62, a first state in which the laser light 12 guided to the optical fiber 62 is transmitted to the first branch fiber 64 and the transmission of the laser light 12 to the second branch fiber 66 is blocked, There is provided a laser switching unit 72 capable of transmitting the laser beam 12 guided to the optical fiber 62 to the second branch fiber 66 and switching to the second state in which the transmission of the laser beam 12 to the first branch fiber 64 is blocked. It has been.

  The laser welding apparatus 14 extends in one direction and supports the first laser head 68 so as to be movable, a first leg 76 that supports the first rail 74, and the first rail 74. A first moving motor 78 that moves the laser head 68 in the extending direction of the first rail 74, a second rail 80 provided in parallel with the first rail 74, and a second that supports the second rail 80. A leg portion 82 and a second moving motor 84 that moves the second laser head 70 in the extending direction of the second rail 80 are provided.

  As shown in FIGS. 4 and 5, the first laser head 68 includes a laser head main body 86 supported by the first rail 74, and a fiber provided in the laser head main body 86 and into which the first branch fiber 64 is inserted. A support tube 88, a fixture 90 for fixing the first branch fiber 64 inserted into the fiber support tube 88, and a plate-like mirror for reflecting the laser light 12 emitted from the first branch fiber 64 (first A mirror 92, and a rotation drive mechanism 94 that rotatably supports the mirror 92 around the optical axis of the laser beam 12 (incident laser beam 12a) incident on the mirror 92 (around the axis of the fiber support tube 88); An angle changing mechanism 96 that changes the tilt angle of the mirror 92 with respect to the incident laser beam 12a and the laser head main body 86 provided on the mirror 92 and reflected by the mirror 92 The laser light 12 and a battery module 18 annular mirror (second mirror) to be irradiated (see Figure 1) 98.

  The laser head main body 86 includes a disk-shaped base portion 102 in which a hole portion 100 in which a fiber support tube 88 can be disposed is formed, a thick side portion 104 that protrudes downward from an edge of the lower surface of the base portion 102, And a protruding portion 106 that protrudes downward from the edge of the lower surface of the side portion 104. A flange 108 for supporting a support member 110 described later is provided at the lower end of the fiber support tube 88.

  The rotation drive mechanism 94 includes a cylindrical support member 110 provided coaxially with an axis of the fiber support tube 88 in a rotatable state, and a rotation support mechanism 110 provided on the base 102 for rotationally driving the support member 110. A rotation motor (drive source) 112, a gear 116 provided on the rotation shaft 114 of the rotation motor 112, and a gear provided on the outer peripheral surface of the fiber support tube 88 via a rolling bearing 111 and meshing with the gear 116. 118 and a pair of support shafts 120 and 122 fixed to both side surfaces of the mirror 92 and rotatably supported by the support member 110 are provided.

  As can be understood from FIGS. 4 and 5, the support member 110 and the gear 118 are fixed to the outer ring of the rolling bearing 111. As a result, the support member 110 rotates together with the gear 118 around the axis of the fiber support tube 88. In the rotation drive mechanism 94 according to the present embodiment, a slide bearing or the like can be used instead of the rolling bearing 111.

  The mirror 92 is located on the axis of the support member 110, and the support member 110 has a notch 124 formed on the side to which the laser beam 12 reflected by the mirror 92 is guided. The support member 110 is provided with a condensing lens 126 for condensing the laser light 12 reflected by the mirror 92 (see FIG. 5). However, depending on the type of laser light, the condenser lens 126 may be omitted.

  The angle changing mechanism 96 includes a bevel gear 130 that is rotatably provided on a shaft 128 fixed to the outer peripheral surface of the support member 110, and an annular umbrella that is provided on the lower end surface of the side portion 104 and meshes with the bevel gear 130. It includes a gear 132 and a conversion mechanism 133 that connects the bevel gear 130 and the support shaft 122. The conversion mechanism 133 includes a disk 134 fixed to the end of the support shaft 122 and a connecting member 136 that connects the bevel gear 130 and the disk 134.

  As shown in FIG. 6A, the bevel gear 130 has an end face on the projecting portion 106 side that is offset with respect to the rotation axis Ax of the bevel gear 130 and a pin for rotatably supporting the connecting member 136. A (first pin) 138 is provided.

  The center line CL of the disk 134 is located on the axis of the support shaft 122, and is disposed on the surface of the disk 134 on the protruding portion 106 side so as to be offset from the center line CL of the disk 134. A pin (second pin) 140 for rotatably supporting the connecting member 136 is provided. 6A, the interval L1 between the rotation axis Ax of the bevel gear 130 and the pin 138 is set to be smaller than the interval L2 between the center line CL of the disc 134 and the pin 140. The reason for this will be described later.

  The mirror 98 is fixed to the inner surface of the projecting portion 106 and surrounds the mirror 92 from the outside of the support member 110 (see FIGS. 4 and 5). That is, the position of the mirror 98 in the axial direction of the laser head main body 86 is substantially the same as the position of the mirror 92. Further, the mirror 98 is formed in a triangular cross section, and is formed so that its reflection surface is directed obliquely downward. The inclination angle of the reflecting surface of the mirror 98 (inclination angle with respect to the axial direction of the fiber support tube 88) is defined according to the outer diameter of the positive electrode terminal 30 (negative electrode terminal 32). This is because if the tilt angle changes, the diameter of the locus 12b of the laser beam 12 irradiated to the battery module 18 changes (see FIG. 9).

  Since the second laser head 70 has the same configuration as the first laser head 68, a detailed description thereof is omitted.

  The control unit 16 drives the laser oscillation control unit 142 that controls the driving of the laser oscillator 60, the laser switching control unit 144 that controls the laser switching unit 72 to switch between the first state and the second state, and the first moving motor 78. A first moving motor control unit 146 that controls to move the first laser head 68 in the extending direction of the first rail 74 and a second moving motor 84 to drive and control the second laser head 70 of the second rail 80. A second movement motor control unit 148 that moves in the extending direction, a first rotation motor control unit 150 that drives and controls the rotation motor 112 that constitutes the first laser head 68, and a rotation motor 112 that constitutes the second laser head 70. And a second rotary motor control unit 152 that controls the driving of the motor.

  Next, a procedure for laser welding the battery module 18 using the laser welding system 10 described above will be described with reference to FIG.

  First, the above-described battery module 18 is disposed to face the first rail 74 and the second rail 80 so that the longitudinal direction (thickness direction of the battery cell main body 28) substantially coincides with the extending direction of the first rail 74. (Step S1).

  Subsequently, the first movement motor control unit 146 drives the first movement motor 78 to set the first laser head 68 at a position corresponding to the positive electrode terminal 30 a located on one end side in the longitudinal direction of the battery module 18. The second movement motor controller 148 drives and controls the second movement motor 84 to set the second laser head 70 at a position corresponding to the negative electrode terminal 32 located on one end side in the longitudinal direction of the battery module 18 (step). S2).

  Thereafter, the laser switching control unit 144 switches the laser switching unit 72 to the first state (step S3). Then, the laser oscillation control unit 142 drives the laser oscillator 60 to oscillate the laser beam 12 (step S4).

  As a result, the laser beam 12 oscillated from the laser oscillator 60 is guided to the first branch fiber 64 through the optical fiber 62. Then, as shown in FIG. 8, the laser beam 12 emitted from the first branch fiber 64 is reflected by the mirror 92 to the side where the projecting portion 106 is located, and is condensed by the condenser lens 126, and then the mirror 98. Is irradiated. The laser beam 12 applied to the mirror 98 is reflected by the mirror 98 toward the battery module 18 and is applied to the welding target portion 160. Here, the welding target portion 160 has a circular shape because the positive electrode terminal 30 and the negative electrode terminal 32 are cylindrical as described above.

  Further, the first rotary motor control unit 150 drives the rotary motor 112 constituting the first laser head 68 (step S5). When the rotary motor 112 is driven, the gear 116 of the rotary motor 112 rotates, and the gear 118 and the support member 110 rotate about the axis of the fiber support tube 88. When the support member 110 rotates, the support shafts 120 and 122 provided on the support member 110 also rotate together. Therefore, the mirror 92 fixed to the support shafts 120 and 122 also rotates in the same manner.

  As a result, the irradiation position of the laser beam 12 reflected by the mirror 92 on the mirror 98 moves as the mirror 92 rotates, so that the locus of the laser beam 12 on the mirror 98 becomes circular. Therefore, the laser beam 12 reflected by the mirror 98 goes around the positive terminal 30 (negative terminal 32). Therefore, the laser beam 12 can be irradiated along the circular weld target 160.

  Further, when the support member 110 rotates, the bevel gear 130 provided on the shaft 128 fixed to the support member 110 is engaged with the annular bevel gear 132 provided on the side portion 104 and engaged with the shaft 128. Rotate against. When the bevel gear 130 rotates, the rotational force is transmitted to the disk 134 via the connecting member 136.

  Here, as described above, the distance L1 between the rotation axis Ax of the bevel gear 130 and the pin 138 is set to be smaller than the distance L2 between the center line CL of the disk 134 and the pin 140. Due to the rotational force transmitted from the gear 130 via the connecting member 136, it will swing in the circumferential direction (FIGS. 6A to 6D). As a result, the mirror 92 swings by a predetermined angle (referred to as swing angle) θ in the circumferential direction of the support shaft 122 (FIG. 8). In other words, the inclination angle of the mirror 92 with respect to the optical axis of the incident laser beam 12a is changed.

  As a result, the irradiation position of the laser beam 12 reflected by the mirror 92 on the mirror 98 swings along the axial direction of the fiber support tube 88. Therefore, the laser beam 12 irradiated to the welding target portion 160 also swings in a direction intersecting with the rotation direction of the mirror 92 (the rotating direction of the laser beam 12). Therefore, as shown in FIG. 9, the locus 12 b of the laser beam 12 becomes zigzag with respect to the welding target portion 160.

  As a result, the width of the bead 162 can be made wider than the gap S of the welding target portion 160, so that the positive terminal 30a and the external connection bus bar 38 (the positive terminal 30 and the bus bar 36, the negative terminal 32 and the bus bar 36, the negative terminal 32a). And the external connection bus bar 40) can be reliably welded.

  After completion of welding (step S6), the laser oscillation control unit 142 controls the laser oscillator 60 to stop the oscillation of the laser beam 12 (step S7), and the first rotary motor control unit 150 performs the first laser. The drive of the rotary motor 112 constituting the head 68 is stopped (step S8).

  After that, the first moving motor control unit 146 drives the first moving motor 78, and in the longitudinal direction of the battery module 18, the negative electrode terminal 32 (positive electrode terminal 30) adjacent to the positive electrode terminal 30 (negative electrode terminal 32) that has been laser-welded. ) Is moved to a position corresponding to () (step S9).

  At this time, the laser switching control unit 144 switches the laser switching unit 72 to the second state (step S10), and the laser oscillation control unit 142 drives the laser oscillator 60 to oscillate the laser beam 12 (step S11). .

  Thereby, the laser beam 12 oscillated from the laser oscillator 60 is guided to the second branch fiber 66 through the optical fiber 62. Then, as described in step S4, the laser beam 12 emitted from the second branch fiber 66 is reflected by the mirror 92 and the mirror 98 and irradiated onto the welding target portion 160.

  The second rotary motor control unit 152 drives the rotary motor 112 that constitutes the second laser head 70 (step S12). Thereby, the laser beam 12 reflected by the mirror 98 circulates along the negative electrode terminal 32 (positive electrode terminal 30) along the welding target portion 160 while swinging in a direction intersecting with the extending direction of the welding target portion 160. The negative electrode terminal 32 (positive electrode terminal 30) and the bus bar 36 can be reliably welded.

  After the completion of welding (step S13), the laser oscillation control unit 142 controls the laser oscillator 60 to stop the oscillation of the laser light 12 (step S14), and the second rotary motor control unit 152 performs the second laser. The drive of the rotary motor 112 constituting the head 70 is stopped (step S15).

  Thereafter, the control unit 16 welds all (24 locations) of the external connection bus bar 38 and the positive terminal 30a, the bus bar 36 and the negative terminal 32, the bus bar 36 and the positive terminal 30, and the external connection bus bar 40 and the negative terminal 32a. It is determined whether or not welding has been completed for the portion 160 (step S16).

  When the control unit 16 determines that the welding has not been completed for all the welding target portions 160 (step S16: No), the second movement motor control unit 148 drives the second movement motor 84 and the battery module 18. The second laser head 70 is moved to a position corresponding to the positive electrode terminal 30 (negative electrode terminal 32) adjacent to the laser-welded negative electrode terminal 32 (positive electrode terminal 30) in the longitudinal direction (step S17). Then, the process after step S3 mentioned above is performed.

  On the other hand, when it determines with the control part 16 having completed welding about all the welding object parts 160 (step S16: Yes), the battery module 18 is conveyed to the following process (step S18). At this stage, the procedure for laser welding the battery module is completed.

  In the laser welding procedure described above, the welding operation (step S10 to step S14) of the second laser head 70 is performed while the first laser head 68 is moving, and the second laser head 70 is moving. Then, the welding operation (step S3 to step S8) of the first laser head 68 is performed.

  According to the laser welding apparatus 14 according to the present embodiment, the mirror 92 is rotated around the optical axis of the incident laser beam 12a by the driving force of the rotary motor 112, and the tilt angle of the mirror 92 is changed. That is, a drive source for rotating the mirror 92 around the optical axis of the incident laser beam 12a and a drive source for changing the tilt angle of the mirror 92 (swing the mirror 92 in the circumferential direction of the support shaft 122). Since the rotary motor 112 is also used, the number of drive sources can be reduced as compared with the conventional case. Thereby, size reduction and cost reduction of the laser welding apparatus 14 itself can be achieved.

  By the way, when the battery module 18 described above is welded using only one laser head, it is necessary to move the laser head in two directions. In particular, it takes time to move the laser head in the short direction of the battery module 18 (longitudinal direction of the battery cell main body 28).

  On the other hand, in the laser welding apparatus 14 according to the present embodiment, the first laser head 68 and the second laser head 70 that move only in the longitudinal direction of the battery module 18 are provided. Can be reduced. Thereby, the cycle time of the welding process of the battery module 18 can be shortened.

  In the laser welding apparatus 14 according to the present embodiment, the laser switching unit 72 is provided, so that the laser beam 12 oscillated from one laser oscillator 60 is selectively transmitted to the first laser head 68 or the second laser head 70. Can lead to. Thereby, the laser welding apparatus 14 can be reduced in size compared with the case where the laser oscillator corresponding to the first laser head 68 and the laser oscillator corresponding to the second laser head 70 are separately provided.

  Furthermore, as described above, since the second laser head 70 (first laser head 68) is moved while the first laser head 68 (second laser head 70) is performing the welding operation, the battery module The cycle time of the 18 welding processes can be further shortened.

  The first laser head 68 of the laser welding apparatus 14 according to the present embodiment is not limited to the configuration described above, and may be, for example, the first laser head 164 according to the modification shown in FIG. In this modification, the same reference numerals are given to the components common to the above-described embodiments, and detailed description thereof is omitted.

  Compared with the first laser head 68 shown in FIG. 5, the first laser head 164 is not provided with the notch 124 in the support member 110, and is provided with a mirror 166 instead of the mirror 98. The mirror 166 is fixed to the inner surface of the support member 110 and reflects the laser beam 12 reflected by the mirror 92 to the battery module 18 side. The mirror 166 has substantially the same size as the mirror 92 and is formed in a triangular cross section.

  In the first laser head 164 according to this modification, since the mirror 166 is provided on the support member 110, the relative position of the mirror 92 and the mirror 166 does not change when the support member 110 is rotated. Thereby, since the mirror 98 can be made into a compact configuration, the first laser head 68 (laser welding apparatus 14) can be further reduced in size and cost.

  Needless to say, the second laser head 70 may have the same configuration as the first laser head 164 according to the modification.

  The configuration of the battery module 18 can be arbitrarily changed. For example, as shown in FIG. 11, a square columnar positive electrode terminal 170 may be used instead of the positive electrode terminal 30, and a bus bar 172 may be used instead of the bus bar 36. A hole 174 having a shape corresponding to the shape of the positive electrode terminal is formed in the bus bar. Although not shown in detail, the negative electrode terminal 32 may be configured in the same shape as the positive electrode terminal 170, and the shapes of the external connection bus bars 38 and 40 may be changed in accordance with the shapes of these terminals.

  In this case, by increasing (adjusting) the swing angle θ described above, the laser beam 12 can be reliably irradiated onto the quadrangular welding target portion 160. Thereby, even when the gap S exists between the positive electrode terminal 170 and the bus bar 172, the gap S can be filled with the bead 176, so that the positive electrode terminal 170 and the bus bar 172 can be reliably welded. .

  The present invention is not limited to the above-described embodiment, and it is naturally possible to adopt various configurations without departing from the gist of the present invention.

  The laser welding apparatus according to the present invention can be applied to various products other than the battery module. In this case, the first workpiece and the second workpiece may be laser-welded using the laser welding apparatus according to the present invention with the concave portion formed in the first workpiece and the second workpiece inserted into the concave portion. .

DESCRIPTION OF SYMBOLS 10 ... Laser welding system 12 ... Laser beam 14 ... Laser welding apparatus 16 ... Control part 18 ... Battery module 30, 170 ... Positive electrode terminal 32 ... Negative electrode terminal 36, 172 ... Bus bar 38, 40 ... External connection bus bar 42, 44, 46 DESCRIPTION OF SYMBOLS 174 ... Hole 60 ... Laser oscillator 68 ... 1st laser head 70 ... 2nd laser head 86 ... Laser head main body 92 ... Mirror (1st mirror)
94: Rotation drive mechanism (rotation drive means)
96. Angle changing mechanism (angle changing means)
98 ... Mirror (second mirror) 110 ... Support member 112 ... Rotation motor (drive source) 130, 132 ... Bevel gear 133 ... Conversion mechanism 138 ... Pin (first pin)
140 ... Pin (second pin) 160 ... Welding target part Ax ... Axis of rotation CL ...

Claims (5)

A laser welding apparatus for irradiating a laser beam oscillated from a laser oscillator and guided to a laser head onto a welding target portion between a first workpiece and a second workpiece inserted into a hole formed in the first workpiece. ,
The laser head includes a laser head main body,
A first mirror that reflects the laser light oscillated from the laser oscillator;
A second mirror that reflects the laser beam reflected by the first mirror to the welding target part;
A rotation driving means provided in the laser head main body for rotating the first mirror around an optical axis of incident laser light incident on the first mirror;
An angle changing means for changing an inclination angle of the first mirror with respect to the incident laser light by using a rotational force of the rotation driving means. The laser welding apparatus according to claim 1, wherein
The rotational driving means is a cylindrical support member provided rotatably with respect to the laser head body in a state of being arranged coaxially with the optical axis of the incident laser light,
A drive source for rotationally driving the support member;
And a support shaft that is provided on the support member and supports the first mirror. The laser welding apparatus according to claim 2, wherein
The angle changing means includes a first gear provided in the laser head main body,
A second gear provided on the support member and meshing with the first gear;
A laser welding apparatus comprising: a conversion mechanism that converts a rotational motion of the second gear into a circumferential swing motion of the support shaft. The laser welding apparatus according to claim 3, wherein
The conversion mechanism includes a disk provided on the support shaft,
A connecting member for connecting the second gear and the disc,
The second gear is provided with a first pin that pivotally supports the connecting member at a position offset with respect to the rotation axis of the second gear;
The disk is provided with a second pin that pivotally supports the connecting member at a position offset with respect to the center line of the disk,
The laser welding apparatus, wherein an interval between a rotation axis of the second gear and the first pin is set to be smaller than an interval between a center line of the disc and the second pin. In the laser welding apparatus of any one of Claims 1-4,
The second work is a terminal of a plurality of battery cells constituting a battery module,
The laser welding apparatus, wherein the first workpiece is a bus bar for electrically connecting terminals of adjacent battery cells.

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