WO2014203489A1

WO2014203489A1 - Outer can sealing method and outer can sealing device

Info

Publication number: WO2014203489A1
Application number: PCT/JP2014/003059
Authority: WO
Inventors: ▲高▼弘内田; 秀寛島田
Original assignee: 株式会社アマダミヤチ
Priority date: 2013-06-17
Filing date: 2014-06-09
Publication date: 2014-12-24
Also published as: JP2015000423A

Abstract

[Problem] To achieve significant shortening of tact while facilitating condition-setting and improving processing precision and reproducibility in outer can sealing in which the joint formed on the side surface of the outer can and lid is welded by laser seam welding. [Solution] The outer can sealing device comprises: a scanner (38), which is disposed above an outer can (100) and a lid (102) that are supported by a can support (46) on a moving stage (24); a ring-shaped mirror (42) disposed around the outer can (100) and the lid (102) with the reflecting surface aimed diagonally upward; and a control unit for irradiating a laser beam (LB) from a laser oscillation unit onto the joint (104) via the scanner (38) and the ring-shaped mirror (42) and controlling the scanning motion of the scanner (38) so that the beam spot of the laser beam (LB) circles the side surface of the outer can (100) and the lid (102) on the joint (104).

Description

Exterior can sealing method and exterior can sealing device

The present invention relates to a technique for sealing an outer can that contains a battery or other electric component, and more particularly, an outer sheath for joining a seam formed on a side surface between a square outer can and a lid by laser seam welding. The present invention relates to a can sealing method and apparatus.

For example, in a lithium ion battery, a rectangular outer can having a flat rectangular parallelepiped shape is often used. In order to seal a rectangular outer can, it is necessary to join a seam formed between the outer can and a lid that closes the opening. In this case, there is a type in which a seam 104 is formed on the side surfaces of the outer can 100 and the lid 102 as shown in FIGS. The outer can 100 contains battery contents (not shown) such as a battery assembly and an electrolytic solution. In general, the corner of the outer can 100 is processed into a curved surface, that is, a rounded corner.

FIG. 14 shows a conventional technique for joining the seam 104 formed on the side surface of the outer can 100 and the lid 102 as described above by laser seam welding. In this prior art, an outer can 100 covered with a lid 102 stands vertically on a moving stage 106, and a laser oscillator or a laser beam is emitted beside the outer can 100 so as to irradiate the side joint 104 with the laser beam LB. The unit 108 is fixed horizontally, and the outer can 100 is moved on the moving stage 106 so that the beam spot BS of the laser beam LB goes around the side surface of the outer can 100 and the lid 102 relatively on the joint 104. . In this case, theoretically, the outer can 100 is linearly moved and swung on the moving stage 106 so that the joint 104 makes a round traversing the beam spot BS (fixed focusing position) of the laser beam LB horizontally. You just have to do. For this reason, the moving stage 106 includes a multi-axis moving mechanism, can move in the horizontal direction (X direction and Y direction), and can also move around the central axis (θ direction). ing.

Japanese Patent Laid-Open No. 11-77347

However, because the outer can 100 is square and the inertia of the moving stage 106 is large, it is very difficult to move the outer can 100 on the moving stage 106 by mixing linear motion and swivel motion. The speed cannot be moved. Note that a jig (not shown) for supporting the outer can 100 in a vertical posture is placed on the moving stage 106, and this jig also moves together with the outer can 100.

According to the above prior art, for example, as shown in FIG. 15, the second (opposite) long side from the starting point A set in the middle of the _first long side LS ₁ via the first short side SS _1. In laser seam welding of a half circumference reaching the intermediate passing point K of the side LS ₂ , the beam spot BS of the laser beam LB is formed on the joint 104 (the outer can 100 with the lid 102, hereinafter referred to as “outer can 100 / lid”). The beam spot moving speed when the side surface of the body 102 is relatively moved is divided into a plurality of small sections M ₁ to M ₁₀ as shown in FIG. However, independent speed control must be performed for each small section.

That is, from the start point A to the first passing point B forward by a certain distance (straight section M ₁ ), the workpiece (exterior can 100 / lid 102) is moved from a stationary state to a relatively high first for straight running. accelerate to reach the reference speed V _1. From the end point of the first long side LS ₁ to the second passing point C just before a certain distance from the first passing point B (straight section M ₂ ), the first reference speed V ₁ for straight traveling is set. maintain. From the second passing point C to the end of the first long side LS ₁ , that is, the third passing point D located at the starting end of the first corner (rounded corner) CN ₁ (straight section M ₃ ) Then, the moving speed of the workpiece (the outer can 100 / the lid 102) is lowered (decelerated) from the first reference speed V ₁ for straight traveling to the second reference speed V ₂ for lower turning.

Next, from the third passing point D to the end of the first rounded corner CN ₁ , that is, the fourth passing point E located at the starting end of the first short side SS ₁ (curved section M ₄ ) is for turning. The second reference speed V ₂ is maintained. Then, on the first short side SS ₁ , the vehicle travels straight from the second reference speed V ₂ for turning to the fifth passing point F (straight section M ₅ ) ahead of the fourth passing point E by a certain distance. To a first reference speed V ₁ for use. Then, from the fifth passing point F to the sixth passing point G that is a certain distance before the end of the first short side SS ₁ (straight section M ₆ ), the first reference speed V ₁ for straight traveling is set. maintain. Then, from the sixth passing point G to the end of the first short side SS ₁ , that is, the seventh passing point H located at the starting end of the second corner portion CN ₂ (straight section M ₇ ), the first pass again. Decelerate from the reference speed V ₁ to the second reference speed V ₂ for turning.

Next, from the seventh passing point H to the end of the second corner CN ₂ , that is, the eighth passing point I located at the starting end of the second long side LS ₂ (curving section M ₈ ) The second reference speed V ₂ is maintained. Then, on the second long side LS ₂ , the vehicle travels straight from the second reference speed V ₂ to the ninth passing point J (straight section M ₉ ) ahead of the eighth passing point I by a certain distance. Accelerate to the first reference speed V ₁ . The section (straight section M ₁₀ ) from the ninth passing point J to the passing point K on the second long side LS ₂ maintains the first reference speed V ₁ for straight traveling, Even after passing, the first reference speed V ₁ is maintained from the end of the second long side LS ₂ to a passing point (not shown) that is a certain distance ahead. Thereafter, independent speed control is performed for each small section in the same manner as described above, and when the beam spot BS of the laser beam LB returns to the start point A, the workpiece (the outer can 100 / the lid 102) is processed. The movement, that is, the moving operation of the moving stage 106 is stopped. At the same time, the laser oscillator or laser emission unit 108 stops the output of the laser beam LB.

As described above, in order to make the beam spot BS of the laser beam LB go around the joint 104 on the side surface of the workpiece (the outer can 100 / the lid 102), the moving stage 106 is moved at a high speed, a low speed, and a high speed. Complicated speed control with deceleration must be performed. Further, when the seam 104 is seam-welded at the corners (CN ₁ , CN ₂ ,...), The moving mechanism of the three axes (X axis, Y axis, θ axis) is simultaneously controlled by the moving stage 106 so that the laser The workpiece (exterior can 100 / lid 102) must be swung at right angles without leaving and deflecting the beam spot BS of the beam LB, and control of this swiveling movement is extremely difficult. For this reason, it is very difficult to determine the conditions for laser seam welding.

For this reason, in the above-described prior art, the beam spot BS of the laser beam LB is made to make a round on the joint 104 on the side surface of the workpiece (exterior can 100 / lid 102) (that is, from the start to the end of laser seam welding). Even if a high-performance high-speed moving stage is used, a long time of 10 to 15 seconds is required, and there is a problem in the tact surface of exterior can sealing.

The present invention solves the problems of the prior art as described above, and greatly shortens the tact time in the outer can sealing process in which the seam formed on the side surface of the outer can and the lid is joined by laser seam welding. In addition, an outer can sealing method and an outer can sealing device that make it easy to determine conditions and improve processing accuracy and reproducibility are provided.

In the outer can sealing method of the present invention, a seam formed on a side surface between a rectangular outer can that accommodates a battery or other electric component and a lid that closes an opening of the outer can is joined by laser seam welding. An outer can sealing method, wherein a scanner is disposed above the outer can that is vertically covered with the lid, and the light incident from the scanner is reflected toward the joint. An annular mirror is inclined and arranged around the lid, and a laser beam for laser seam welding output from a laser oscillation unit is irradiated to the joint through the scanner and the annular mirror, and the beam of the laser beam The scanning operation of the scanner is controlled so that the spot makes a round around the side surface of the outer can and the lid on the seam.

In addition, the outer can sealing device of the present invention uses laser seam welding to form a seam formed on the side surface between a rectangular outer can that accommodates a battery or other electrical component and a lid that closes the opening of the outer can. An outer can sealing device to be joined, wherein a can support that vertically supports the outer can covered with the lid, a laser oscillation unit that generates a laser beam for laser seam welding, and the can support A scanner disposed above the supported outer can and the lid and directing the laser beam from the laser oscillation unit to a reflecting surface provided around the outer can; and the outer can and the lid An annular mirror disposed in an annular shape on the periphery, having the reflection surface, and having the reflection surface directed obliquely upward so that the laser beam incident from the scanner is reflected to the joint; and the laser The laser beam from the vibrating section is irradiated to the joint through the scanner and the annular mirror, and the beam spot of the laser beam goes around the side surface of the outer can and the lid on the joint. And a control unit for controlling the scanning operation of the scanner.

In the present invention, the laser beam from the scanner is incident on the annular mirror disposed around the workpiece (exterior can / lid) and is reflected and reflected from the side surface of the workpiece (external can / lid). It is incident on the seam. On the seam, the workpiece material at the position where the laser beam is incident is instantaneously melted by the energy of the laser beam, and when the laser beam spot is moved to the other side, the melt is solidified to form a nugget. The Under the control of the control unit, the scanner scans the laser beam so that the incident position (or reflection position) of the laser beam makes one turn in the circumferential direction on the annular mirror, and thereby the work piece (external can / lid) The beam spot of the laser beam makes one turn (one turn) in the rotation direction on the joint of the side surface of the body. In this way, the seam of the side surface of the workpiece (exterior can / lid) is joined at each position in the circumferential direction by laser seam welding of optical scanning, and the external can is sealed with a short tact. The optical scanning method makes it easy to determine the conditions for laser seam welding.

In a preferred aspect of the present invention, the scanner includes a first-axis and second-axis galvano scanner for scanning the laser beam in a two-dimensional direction intersecting the optical axis of the laser beam. As a result, two-dimensional laser scanning can be performed at high speed and with high precision.

More preferably, the scanner includes a condensing lens arranged in front of the galvano scanner, and the focal length of the condensing lens is variable in the circumferential direction so that the laser beam is condensed at each joint in the circumferential direction. A third-axis focusing control unit for controlling the three-dimensional laser scanning. In this case, not only the time or tact time required for laser seam welding is shortened, but also the optical path length variation in the circumferential direction is optically corrected, and the mechanical error of the laser irradiation system is also optically corrected. Can also be done easily. Furthermore, even if the size of the workpiece (outer can / lid) is different, the laser irradiation unit of the same hardware can be used.

In another preferred embodiment of the present invention, a non-telecentric fθ lens is disposed between the scanner and the annular mirror. The non-telecentric fθ lens may be used in combination with the third axis focusing control unit, but can be used even when the third axis focusing control unit is not provided. In that case, the distance interval between the reflection point on the annular mirror and the joint is variably adjusted in the circulation direction so that the laser beam is condensed at each position in the circulation direction.

In another preferred embodiment, a telecentric fθ lens is disposed between the scanner and the annular mirror. This telecentric fθ lens focuses the laser beam incident from the scanner at a position on the optical path that is always parallel to the optical axis of the lens and directed vertically downward with a fixed focal length regardless of the incident position or angle of incidence. Shine. Therefore, in this case, the inclination angle formed with the horizontal line of the annular mirror is uniform in the circumferential direction so that the laser beam is condensed at each position in the circumferential direction, and the reflection point on the annular mirror and the joint are An arrangement configuration of annular mirrors is adopted so that the distance between them is uniform in the circumferential direction.

In another preferred embodiment, a configuration is adopted in which the annular mirror is divided into a plurality of plate mirrors in the circumferential direction. In this case, the inclination angle formed with the horizontal line of the annular mirror is adjusted for each plate mirror. Also, the angle in plan view facing the outer can of the annular mirror and the side surface of the lid is adjusted for each plate mirror.

In another preferred embodiment, a hollow and bottomed laser light path housing having a circular cross section or a corridor shape is provided in order to shield the optical path of the laser beam from the scanner to the annular mirror from the outside. In this case, a protective glass that transmits the laser beam reflected by the annular mirror to the outside may be attached to the inner peripheral wall of the laser beam path housing.

In another preferred embodiment, the shielding gas is supplied around the joint from above the outer can and the lid inside the laser beam path housing. Preferably, a partition for maintaining an atmosphere of shielding gas around the outer can and the lid is provided.

According to the outer can sealing method or the outer can sealing device of the present invention, in the outer can sealing process in which the seam formed on the side surface of the outer can and the lid is joined by laser seam welding by the above-described configuration and operation. As well as making it easy to determine conditions and improving machining accuracy and reproducibility.

It is a figure which shows the structure of the armored can sealing apparatus in one Embodiment of this invention. It is sectional drawing which shows the structure of the laser irradiation part in a 1st Example. It is a perspective view which shows the structure of the scanner optical system in a 1st Example, and the effect | action of a laser scanning. It is a top view which shows the arrangement | positioning structure (layout) of the annular mirror in 1st Example, and the effect | action of a laser scanning. It is a side view which shows one effect | action at the time of comprising an annular mirror with a division | segmentation type plate mirror. It is a side view which shows one effect | action at the time of comprising an annular mirror with a division | segmentation type plate mirror. It is sectional drawing which shows the structure of the laser irradiation part in a 2nd Example. It is a perspective view which shows the structure of the scanner optical system in a 2nd Example, and the effect | action of a laser scanning. It is sectional drawing which shows the structure of the laser irradiation part in a 3rd Example. It is a top view which shows the arrangement configuration of the annular mirror in a 3rd Example. It is a top view which shows the arrangement configuration of the annular mirror in one modification. It is a schematic sectional drawing which shows the position adjustment mechanism of the annular mirror in one Example. It is a schematic sectional drawing which shows the inclination angle adjustment mechanism of the annular mirror in one Example. It is a figure which shows the prior art for joining the joint of the side surface of a square-shaped exterior can and a cover body by laser seam welding. It is a figure which shows the structure of the square-shaped exterior can and lid which have a seam in the side surface. It is a perspective view for demonstrating the effect | action of the laser seam welding in the said prior art. It is a figure which shows the characteristic in which the relative moving speed of a laser beam changes on a joint in the laser seam welding of FIG.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[Configuration of the entire device]

FIG. 1 shows a configuration of an outer can sealing device according to an embodiment of the present invention. This outer can sealing device can be applied to, for example, an outer can sealing process for a prismatic lithium ion battery, and a rectangular outer can 100 as shown in FIG. 13 and a lid 102 for closing the opening of the outer can 100. The seam 104 formed on the side surface between the two is joined by laser seam welding. The material of the outer can 100 and the lid 102 as the workpieces may be any metal, but typically both are aluminum or an aluminum alloy.

The outer can sealing device includes a laser oscillator 10, a laser power source 12, a laser transmission system 14, a laser irradiation unit 16, a main control unit 18, a scanning control unit 20, a shield gas supply unit 22, a stage 24, and a touch panel 26. .

The laser oscillator 10 is, for example, a single mode fiber laser oscillator, and includes an oscillation optical fiber having a core doped with, for example, rare earth element ions as a light emitting element, and pumping light for pumping on one end face of the oscillation optical fiber. And a pair of optical resonator mirrors that resonately amplify and output light of a predetermined wavelength that is emitted in the axial direction from both ends of the oscillation optical fiber. Laser beam LB with a high frequency is output by Q-switched pulse oscillation. Alternatively, a long pulse or continuous wave laser beam LB is also possible.

The laser power source 12 supplies an excitation current to the light source (generally a laser diode) of the electro-optic excitation unit of the laser oscillator 10 under the control of the main control unit 18. Although not shown, it is possible to provide a power feedback mechanism that feeds back the power of the laser beam LB oscillated and output from the laser oscillator 10 to the laser power source 12 to control the excitation current.

The laser beam LB output from the laser oscillator 10 is folded back in a predetermined direction by, for example, a vent mirror 30 in the laser transmission system 14, and then condensed by the condenser lens 34 in the incident unit 32 to be transmitted by the transmission optical fiber 36. It is incident on one end face of. The transmission optical fiber 36 is made of, for example, an SI (step index) type fiber, and transmits the laser beam LB input from one end surface in the incident unit 32 to the laser irradiation unit 16.

The laser irradiation unit 16 is disposed with the reflecting surface obliquely upward around the scanner housing 38 connected to the end of the transmission optical fiber 36 and the workpiece (the outer can 100 / the lid 102) on the stage 24. An annular mirror 42 is provided.

In the scanner housing 38, a scanner optical system 44 (FIGS. 3 and 7), which will be described later, for scanning the laser beam LB received from the transmission optical fiber 36 toward the annular mirror 42 in a two-dimensional direction or a three-dimensional direction. ) Is provided. The annular mirror 42 has a height that faces the seam 104 on the side surface of the workpiece (the outer can 100 / the lid 102) supported by the can support 46 in a posture standing vertically on the moving stage 24, substantially horizontally. In a position, the workpiece (the outer can 100 / the lid 102) is arranged in an annular or corridor shape in a loop of a substantially rectangular shape or a substantially elliptic shape in plan view so as to surround the periphery of the workpiece (the outer can 100 / the lid body 102) (FIGS. 10). The configuration and operation of the scanner optical system 44 (FIGS. 3 and 7) and the annular mirror 42 in the scanner housing 38 will be described in detail later.

The stage 24 puts a workpiece (exterior can 100 / lid 102) integrally with the can support portion 46, preferably in the horizontal direction (X direction, Y direction), the vertical direction (Z direction) and / or the rotating direction ( It is possible to move in the θ direction). However, in this embodiment, the moving mechanism provided in the stage 24 is mainly used for positioning of the workpiece (exterior can 100 / lid 102), and the workpiece (exterior can 100 / lid) when performing laser seam welding. 102) It is not used as a scanning means for relatively moving the beam spot BS of the laser beam LB. Therefore, the stage 24 does not need to be expensive and can be moved at a high speed, and may be a low-speed and low-priced one. As described later, the can support portion 46 has a workpiece (exterior can 100 / lid 102). ) May be a stage that can only be moved up and down or adjusted in height.

When the sealing process or laser seam welding is performed on the workpiece (exterior can 100 / lid 102) in the outer can sealing device, the shield gas supply unit 22 is connected to the workpiece (external can) via the gas supply pipe 48. 100 / cover body 102) is supplied with shielding gas. As the shielding gas, an inert gas such as helium gas or argon gas or nitrogen gas is used.

The main control unit 18 includes a CPU (microcomputer), and controls the entire apparatus or each unit according to various programs (software) stored in the memory. In particular, the scanner optical of the laser irradiation unit 16 through the scanning control unit 20 is controlled. The operation of the system 44 (FIGS. 3 and 7) is controlled. Further, the main control unit 18 exchanges information (setting values, monitor information, etc.) with the user (workers, maintenance personnel, etc.) via the input unit 26a and the display unit 26b of the touch panel 26.

[Example 1 relating to laser irradiation unit]

FIG. 2 shows the configuration of the laser irradiation section 16 in the first embodiment, and particularly shows the configuration of the laser beam path housing 50 and the configuration in which the annular mirror 42 is attached in the laser beam path housing 50, together with the can support section. 46 shows a specific configuration example. 3 and 4 show the configuration of the scanner optical system 44 and the arrangement configuration (layout) of the annular mirror 42 in this embodiment, and the action of laser scanning in this embodiment.

In FIG. 3, the scanner optical system 44 includes a first axis galvano scanner 52 and a second axis galvano scanner 54 for scanning the laser beam LB in a two-dimensional direction intersecting the optical axis of the laser beam LB, and a galvano scanner (52 , 54), and a third-axis focusing controller 58 for variably controlling the focal length of the condensing lens 56. The condensing lens 56 is disposed on the optical path of the laser beam LB. It is configured as a three-dimensional scanner.

More specifically, in the scanner housing 38 (FIG. 1), a collimating lens 60, a movable diverging (concave) lens 62, a condenser lens 56, a first axis galvano scanner 52, and a second axis galvano scanner 54 are provided. The arrangement is as shown in FIG.

The collimating lens 60 is disposed near the side wall of the scanner housing 38 with the optical axis being horizontal. The galvanometer mirror 52a of the first axis galvano scanner 52 faces the collimating lens 60 horizontally in an inclined posture of about 45 °. The rotation driving unit of the first axis galvano scanner 52 is housed in a cylindrical galvano casing 52b and connected to the scanning control unit 20 (FIG. 1) via an electric cable 64 (1).

On the other hand, the galvano mirror 54a of the second-axis galvano scanner 54 faces vertically downward in an inclined posture of about 45 ° in the vicinity of the exit on the lower surface of the scanner housing 38. In the scanner housing 38, the first-axis galvanometer mirror 52a and the second-axis galvanometer mirror 54a are also diagonally opposed to each other at a predetermined intersecting angle. The rotation drive unit of the second axis galvano scanner 54 is housed in the galvano casing 54b and connected to the scanning control unit 20 via the electric cable 64 (2).

The focusing control unit 58 includes a condenser lens 56, a diverging (concave) lens 62, and a linear actuator 66 that moves the diverging lens 62 in the optical axis direction. The drive unit of the linear actuator 66 is connected to the scanning control unit 20 via an electric cable 64 (3).

In the scanner optical system 44, the laser beam LB emitted from the end face of the transmission optical fiber 36 with a predetermined divergence angle is converted into parallel light by the collimator lens 60, and the diverging lens 62 and the condenser lens 56 of the focusing control unit 58 are passed through. The light passes through the first axis galvanometer mirror 52a and the second axis galvanometer mirror 54a and sequentially reflects and reflects from the lower surface of the scanner housing 38 through the laser beam path housing 50 (FIG. 2). It is made to enter. Note that a protective glass (not shown) is provided at the exit of the lower surface of the scanner housing 38 to shield the atmosphere from the laser beam path housing 50 side.

In the focusing control unit 58, the parallel laser beam LB from the collimating lens 60 is diverged by a diverging lens 62 at a constant divergence angle, and is then condensed by a condensing lens 56. By moving the diverging lens 62 in the optical axis direction by the linear actuator 66, that is, by changing the relative distance between the diverging lens 62 and the condensing lens 56, the focal length of the condensing lens 56 can be varied. Can be controlled.

As shown in FIG. 3, the laser beam LB incident on the annular mirror 42 through the laser beam path housing 50 (FIG. 2) from the second-axis galvanometer mirror 54a provided at the final stage of the scanner optical system 44 is The light is reflected substantially horizontally toward the workpiece (exterior can 100 / lid 102) at a reflection angle corresponding to the incident angle, and travels straight and enters the joint 104. On the joint 104, the workpiece material at the position where the laser beam LB is incident is instantaneously melted by the energy of the laser beam LB, and when the beam spot BS of the laser beam LB moves to another (lateral), the melt is solidified. Nuggets are formed. When the beam spot BS of the laser beam LB goes around the side surface of the workpiece (exterior can 100 / lid 102) on the joint 104, the joint 104 is joined by laser seam welding at all the sites in the circumferential direction. Sealed.

In this embodiment, the first axis galvano scanner 52 and the second axis galvano scanner 54 of the scanner optical system 44 perform two-dimensional laser scanning under the control of the main control unit 18 or the scanning control unit 20 (FIG. 1). As a result, as shown in FIG. 4, the position P _LB of the laser beam LB incident on the annular mirror 42 (that is, the position of reflection) P _LB makes one turn (one turn) in the circulation direction. The beam spot BS makes one turn (one turn) in the turning direction.

During such two-dimensional laser scanning, the focusing control unit 58 is positioned on the optical axis of the diverging lens 62 (under the control of the main control unit 18 and the scanning control unit 20 (FIG. 1)). In other words, by dynamically variably controlling the focal length of the condensing lens 56 and thus the focal distance of the condensing lens 56, the laser beam LB reaches the joint 104 at each position in the circumferential direction as shown in FIGS. 5A and 5B. Condensed.

Software (control program, condition data, scanning position data, etc.) for causing the scanner optical system 44 to perform the three-dimensional laser scanning as described above is stored in the memory in the main control unit 18 and / or in the scanning control unit 20. It is stored in the memory and executed by the CPU in the main control unit 18 and / or the CPU in the scanning control unit 20. Condition data and scanning position data are acquired by simulation, calculation, experiment, test, or the like. When an experiment or test is performed for obtaining scanning position data, visible light (monitor light) can be used instead of the laser beam LB.

As shown in FIG. 4, the annular mirror 42 in this embodiment is constituted by a plurality of divided, for example, eight plate mirrors MR ₁ to MR ₈ . Here, the first plate mirror MR ₁ is a straight seam 104 LS extending to the first long side (long side on the left side of the drawing) LS ₁ of the workpiece (the outer can 100 / the lid 102). Opposite to ₁ . The second plate mirror MR ₂ faces the curved joint 104CN ₁ extending to the _first corner (lower left corner in the figure) CN ₁ of the workpiece (the outer can 100 / the lid 102). To do.

The third plate mirror MR ₃ includes a straight seam 104SS ₁ extending to the first short side (the lower short side in the figure) SS ₁ of the workpiece (the outer can 100 / the lid 102). opposite. The fourth plate mirror MR ₄ includes a curved seam 104CN ₂ extending to the _second corner (the lower right corner in the figure) CN ₂ of the workpiece (the outer can 100 / the lid 102). opposite.

The fifth plate mirror MR ₅ is the workpiece a second long side (the right side of the long side of the figure) seam 104LS ₂ straight lines extending in the LS ₂ and opposite (outer can 100 / lid 102) To do. The sixth plate mirror MR ₆ faces the curved joint 104CN ₃ extending to the _third corner (the upper right corner in the figure) CN ₃ of the workpiece (the outer can 100 / the lid 102). To do.

Then, the plate mirror MR ₇ The seventh workpiece (exterior can 100 / lid 102) a second short side of the seam of a straight line that extends SS ₂ (short sides of the upper side in FIG.) 104SS ₂ Opposite. Finally, the eighth plate mirror MR ₈ has a curved seam 104CN extending to the _fourth corner (upper left corner of the figure) CN ₄ of the workpiece (exterior can 100 / lid 102). Opposite to ₄ .

The inclination angles θ ₁ to θ ₈ formed with the horizontal lines of the plate mirrors MR ₁ to MR ₈ may all be uniform in the circumferential direction, but may be set or adjusted individually. From another viewpoint, as shown in FIGS. 5A and 5B, even if there is a difference or error in the inclination angles θ ₁ to θ ₈ of the plate mirrors MR ₁ to MR ₈ , the scanner optical system 44 as described above. By the three-dimensional laser scanning by, the laser beam LB reflected by any of the plate mirrors MR ₁ to MR ₈ can be condensed and incident on the joints 104 LS ₁ to 104 CN ₄ facing each other.

When the annular beam 42 having the arrangement shown in FIG. 4 is used to make the beam spot BS of the laser beam LB go around in the circulation direction on the joint 104 on the side surface of the workpiece (the outer can 100 / the lid 102). The laser scanning operation is controlled for each of the plate mirrors MR ₁ to MR ₈ .

That is, as shown in FIG. 4, when the laser beam spot BS is moved on the joint 104LS _{1 of} the first long side LS ₁ , the reflection point P _LB of the laser beam LB is set on the first plate mirror MR _1. Move. Then, when moving the laser beam spot BS over the seam 104CN ₁ of the first corner portion CN ₁ moves the reflection point P _LB of the laser beam LB on the second plate mirror MR _2.

Then, when moving the laser beam spot BS in the first upper seam 104SS ₁ of the short side SS ₁ moves the reflection point P _LB of the laser beam LB on the third plate mirror MR _3. Then, when moving the laser beam spot BS over the seam 104CN ₂ of the second corner portion CN ₂ moves the reflection point P _LB of the laser beam LB on the fourth plate mirror MR _4.

Thereafter, when the laser beam spot BS is moved on the joint 104LS ₂ ... In each section in the same manner as described above, the reflection point P of the laser beam LB on the plate mirror MR _5. Move _LB.

However, in the vicinity of the boundary between adjacent seam sections, the laser beam irradiation from two plate mirrors facing each other may overlap. For example, in the case of moving the reflection point P _LB of the laser beam LB on the first plate mirror MR _1, the laser beam spot BS in the late the first past the first seam 104LS ₁ long side LS ₁ it may enter the seam 104CN ₁ corner CN _1. Alternatively, in order to move the reflection point P _LB of the laser beam LB on the second plate mirror MR _2, even as the laser beam spot BS starts to move from the seam 104LS ₁ of the first long side LS ₁ Good. In short, the beam spot BS of the laser beam LB needs to make at least one round in the circumferential direction without creating a space on the joint 104 on the side surface of the workpiece (the outer can 100 / the lid 102). Irradiation with the laser beam LB may overlap several times at a certain location.

The speed of moving the reflection point P _LB of the laser beam LB on the annular mirror 42 in the circumferential direction, that the workpiece beam spot BS of the laser beam LB on the seam 104 of the side surface of the (exterior can 100 / lid 102) It is also possible to variably control the speed at which the is moved in the circulation direction. Further, the laser beam LB may be incident on the joint 104 with defocus within an allowable range.

In this embodiment, since the inertia of the scanner optical system 44 is so small that it can be ignored, for example, the laser beam LB can make a round on the annular mirror 42 at a scanning speed of 200 mm / sec. Thereby, for example, for a workpiece (external can 100 / lid 102) having a long side of 150 mm and a short side of 20 mm, laser seam welding of the side seam 104 can be completed within a few seconds. Thereby, the cycle time of exterior can sealing can be shortened to about 1/10 of the prior art.

Further, the control of condensing and irradiating the laser beam LB to the joint 104 on the side surface of the workpiece (exterior can 100 / lid 102) is flexible and can be performed by adjusting the two-dimensional or three-dimensional optical scanning of the scanner optical system 44. It can be done accurately. In particular, according to three-dimensional laser scanning, even if the optical path length of the laser beam LB fluctuates in the circulation direction, it can be optically corrected using the focusing control unit 58. Further, it is possible to optically correct mechanical errors in the laser irradiation unit 16, for example, errors in the arrangement position and inclination angle of the annular mirror 42 as described above, and the workpiece (exterior can 100 / lid Laser seam welding to the seam 104 on the side of the body 102) can be performed stably and accurately. It is also easy to determine the conditions for laser seam welding.

Furthermore, for a workpiece (exterior can 100 / lid 102) having a seam 104 on the side surface, the laser irradiation unit 16 of the same hardware may be used even if the size of the long side and / or the short side is different. Can respond. When the height size of the workpiece (the outer can 100 / the lid 102) changes, the side seam 104 can be adjusted to the reference height position by using the lifting mechanism of the stage 24.

In this embodiment, not only the tact time can be greatly shortened, but also the versatility, reproducibility and quality of exterior can sealing can be improved.

In FIG. 2, an annular mirror 42 is provided at a predetermined inclination angle at the bottom of a hollow (hollow) and bottomed laser light path housing 50 extending in a skirt shape from the lower surface of the scanner housing 38 in an annular or corridor-like cross section. It is done. The laser light path housing 50 is made of a light shielding plate material such as an aluminum plate, and shields the laser light path from the scanner optical system 44 to the annular mirror 42 from the outside.

The annular mirror 42 is provided with a heat dissipation mechanism that is made of a metal member having a high thermal conductivity, such as copper or aluminum, in the laser beam path housing 50, and has a flow path 71 through which a cooling medium (for example, cooling water) passes. Attached to the mirror support 70.

A protective glass 72 is attached to the inner peripheral wall of the laser beam path housing 50 at a height position facing the annular mirror 42. The laser beam LB reflected by the annular mirror 42 passes through the protective glass 72 and enters the seam 104 on the side surface of the workpiece (the outer can 100 / the lid 102). On the other hand, it is preferable that the protective glass 72 is attached in a replaceable or detachable manner because the evaporant generated from the welded portion (the joint 104) is likely to adhere and become dirty. Therefore, the protective glass 72 may be formed of double glass, the inner glass may be fixed and attached to block the atmosphere, and the outer glass may be detachably attached.

The can support portion 46 includes a base portion 74 on which a workpiece (exterior can 100 / lid 102) is placed, and the outer can 100 sandwiched from both sides near the joint 104, and the workpiece (exterior can 100 / lid 102). ) In a vertical posture, and a drive unit 82 for moving the movable clamp 78 forward and backward on the guide rail 80. As described above, the can support portion 46 has a function of positioning the workpiece (exterior can 100 / lid 102) and supporting it vertically.

Further, the can support part 46 is made of a metal having a high thermoelectric power, such as copper, for the

clamps

76 and 78, and the upper end of the

clamps

76 and 78 is brought into contact with the vicinity of the joint 104, so The excess heat generated at the seam 104 can be efficiently released without causing any heat.

Further, the can support portion 46 has four side wall portions 84 extending vertically upward from the base portion 74 to the vicinity of the lower end surface of the laser beam path housing 50. The side wall 84 extends in a ring shape along the lower end surface of the laser beam path housing 50, and in combination with the laser beam path housing 50, a partition wall 85 is formed around the workpiece (exterior can 100 / lid body 102). Form. On the other hand, a through-hole 83 is formed in the lower portion of the side wall portion 84 for allowing the shield gas to escape to the outside.

When laser seam welding is performed, the shield gas is supplied from the shield gas supply unit 22 to the inside of the partition wall 85 via the gas supply pipe 48, so that the workpiece (the outer can 100 / the lid 102) is made of the shield gas. It is wrapped in an atmosphere and shielded from the atmosphere. The partition wall 85 has a function of maintaining a shield gas atmosphere around the workpiece (the outer can 100 / the lid 102).

[Embodiment 2 regarding laser irradiation section]

6 and 7 show the configurations of the laser irradiation unit 16 and the scanner optical system 44 in the second embodiment.

The scanner optical system 44 of this embodiment does not include the third axis focusing control unit 58 (FIG. 3), and performs two-dimensional laser scanning by the first axis galvano scanner 52 and the second axis galvano scanner 54. It is configured as a two-dimensional scanner. On the other hand, in this embodiment, a telecentric-fθ lens 86 is optically disposed between the scanner optical system 44 and the annular mirror 42 and near the exit of the scanner housing 38 in terms of hardware.

In this case, the laser beam path housing 50 extends vertically downward with the atmosphere blocking glass 88 sandwiched between the telecentric-fθ lens 86. The telecentric-fθ lens 86 causes the laser beam LB incident from the scanner optical system 44 to always be directed vertically downward parallel to the optical axis of the lens regardless of the incident position or angle of incidence, on an optical path. It concentrates on the position of. In this embodiment, a laser beam LB transmitted through the telecentric-fθ lens 86 and having its optical path directed vertically downward passes through the laser optical path housing 50 and enters the annular mirror 42 from directly above, where it is reflected in the horizontal direction. Then, the light passes through the protective glass 72 and is focused and incident on the joint 104 of the workpiece (the outer can 100 / the lid 102).

In this embodiment, the inclination angle θ formed with the horizontal line of the annular mirror 42 is constant (generally θ = 45 °) in the circumferential direction, and the distance interval between the reflection point P _LB on the annular mirror 42 and the joint 104. Also, the arrangement configuration (layout) of the annular mirror 42 is adopted so as to be uniform in the circumferential direction. As a result, using the two-dimensional scanner optical system 44 and the telecentric-fθ lens 86 as described above, the laser beam LB is applied to the side surface of the workpiece (the outer can 100 / the lid 102) at each position in the circumferential direction. The seam 104 can be focused and irradiated, and laser seam welding of the seam 104 can be completed within a few seconds as in the first embodiment.

[Embodiment 2 regarding laser irradiation section]

FIG. 8 shows the configuration of the laser irradiation unit 16 and the scanner optical system 44 in the third embodiment.

In this embodiment, the scanner optical system 44 in the scanner housing 38 is configured by a two-dimensional scanner similar to the second embodiment, and a non-telecentric fθ lens 90 is provided between the scanner optical system 44 and the annular mirror 42. Deploy.

In this case, the optical path length from the non-telecentric-fθ lens 90 to the workpiece (exterior can 100 / lid 102) through the annular mirror 42 at the angular position in the circumferential direction is the focal length of the non-telecentric-fθ lens 90. The arrangement configuration (layout) of the annular mirror 42 may be devised so as to substantially match the above. For example, as shown in FIG. 9, each of the plate mirrors MR ₁ to MR ₈ constituting the annular mirror 42 is finely divided into a plurality or a plurality of plate piece mirrors mr giving a continuous reflecting surface in the circumferential direction. In addition, the inclination angle θ formed with the horizontal line of the annular mirror 42 is set to each plate so that the laser beam LB is focused on the joint 104 on the side surface of the workpiece (exterior can 100 / lid 102) at each position in the circumferential direction. Set or adjust for each mirror mr. The distance between the reflection point P _LB on the annular mirror 42 and the joint 104 may be set or adjusted for each individual plate mirror mr.

[Other Embodiments or Modifications]

Also in the first embodiment (FIGS. 2 and 3), non-telecentric- is provided between the three-dimensional scanner optical system 44 and the annular mirror 42 (in the vicinity of the exit of the scanner housing 38 in terms of hardware). An fθ lens 90 can be disposed. Even in that case, the focusing position on the optical axis of the laser beam LB is variably controlled by the focusing control unit 58.

The focusing control unit 58 can be modified in various ways. For example, the focusing control unit 58 of the first embodiment is a Galileo type that uses a diverging (concave) lens 62 for the first stage lens, but a Kepler type that uses a converging (convex) lens for the first stage lens is also possible. Further, a beam expander can be used as the focusing control unit 58.

In the present invention, as described above, the beam spot BS of the laser beam LB only needs to make at least one round in the circulation direction without creating a space on the joint 104 on the side surface of the workpiece (the outer can 100 / the lid 102). Therefore, irradiation with the laser beam LB may overlap a plurality of times at a certain location on the joint 104. Therefore, for example, as shown in FIG. 10, it is possible to adopt a configuration in which the reflecting surface of the annular mirror 42 extends continuously and endlessly in the circumferential direction. In this case, when the incident point (or reflection point) P _LB of the laser beam LB is made to make a round on the endless reflection surface of the annular mirror 42, the irradiation of the laser beam LB to the joint 104 is not interrupted, and the laser beam LB The beam spot BS goes around the side surface of the workpiece (the outer can 100 / the lid 102).

Further, when the corners CN ₁ , CN ₂ , CN ₃ , CN ₄ of the workpiece (exterior can 100 / lid 102) have a large radius R, plate mirrors MR ₂ , MR ₄ , MR ₆ , The reflecting surface of MR ₈ may be curved in the circumferential direction.

Further, as a hardware scanning adjustment mechanism around the annular mirror 42, as shown in FIG. 11, a mechanism for adjusting the separation distance and / or height position of the annular mirror 42 from the workpiece (not shown), As shown in FIG. 12, it is possible to provide a mechanism for variably adjusting the inclination angle θ formed with the horizontal line of the annular mirror 42.

As a modified example of the shield gas supply system, a partition structure of the laser beam path housing 50 surrounding the periphery and the upper part of the joint 104 on the side surface of the workpiece (exterior can 100 / lid 102) can be used. More specifically, as shown in FIG. 8, a nozzle 92 that ejects a shielding gas vertically downward can be provided inside the laser beam path housing 50. The illustrated nozzle 92 is configured, for example, as a planar nozzle having a slit-like outlet 94 having a slightly larger outline than the joint 104 in plan view, and sprays a shielding gas so as to flow vertically below the joint 104. Accordingly, the shielding effect of the shielding gas can be enhanced, and the evaporated material generated from the welded portion (seam 104) can be dropped to the bottom of the partition wall 85 without being scattered in the lateral direction (the protective glass 72 side). Thereby, the stain | pollution | contamination of the protective glass 72 decreases. From another point of view, the protective glass 72 and the annular mirror 42 can be disposed close to the workpiece (the outer can 100 / the lid 102).

In the above embodiment, the laser oscillator 10 is not limited to a single mode fiber laser oscillator, and may be another type of fiber laser oscillator, YAG laser oscillator, or the like. The laser transmission system 14 may be configured such that the transmission optical fiber 36 is omitted.

Further, the present invention is not limited to the outer can sealing process of the prismatic lithium ion battery as in the above embodiment, and any prismatic battery or a prismatic cell other than the battery in which a seam is formed on the side surface. The present invention can be applied to exterior can sealing processing (for example, a rectangular lithium ion capacitor).

DESCRIPTION OF SYMBOLS 10 Laser oscillator 12 Laser power supply 16 Laser irradiation part 18 Main control part 20 Scanning control part 22 Shield gas supply part 24 Stage 42 Annular mirror 44 Scanner optical system 46 Can support part 50 Laser optical path housing | casing 52 1st axis | shaft galvano scanner 54 2nd axis Galvano scanner 56 Condensing lens 58 Focusing control unit 60 Collimating lens 62 Diverging lens 70 Mirror support 72 Protective glass 85 Bulkhead 86 Telecentric-fθ lens 90 Non-telecentric-fθ lens 92 Nozzle

Claims

An outer can sealing method in which a seam formed on a side surface between a rectangular outer can that contains a battery or other electric component and a lid that closes an opening of the outer can is joined by laser seam welding,
A scanner is disposed above the outer can that is vertically covered with the lid, and an annular ring is formed around the outer can and the lid so that light incident from the scanner is reflected toward the joint. Tilt the mirror and place it
A laser beam for laser seam welding output from a laser oscillation unit is irradiated to the joint through the scanner and the annular mirror, and a beam spot of the laser beam is applied to the outer can and the lid on the joint. Controlling the scanning operation of the scanner so as to go around the side surface;
An outer can sealing method characterized by that.
A condenser lens is arranged in front of the scanner,
The focal length of the condenser lens is variably controlled in the circulation direction so that the laser beam is condensed at the joint at each position in the circulation direction.
The outer can sealing method according to claim 1.
The exterior can sealing method according to claim 2, wherein a non-telecentric fθ lens is disposed between the scanner and the annular mirror.
A non-telecentric fθ lens is disposed between the scanner and the annular mirror;
The distance between the reflection point on the mirror and the seam is variably adjusted in the circumference direction so that the laser beam is condensed at the seam at each position in the circumference direction.
The outer can sealing method according to claim 1.
The outer can sealing method according to claim 1, wherein an inclination angle formed with a horizontal line of the annular mirror is variably adjusted in a rotating direction.
The exterior can sealing method according to claim 1, wherein an angle in a plan view of the annular mirror facing the side surface of the exterior can and the lid body is variably adjusted in a circumferential direction.
A telecentric fθ lens is disposed between the scanner and the annular mirror;
The angle of inclination formed with the horizontal line of the annular mirror and the distance between the reflection point on the annular mirror and the joint are constant in the circulation direction so that the laser beam is focused on the joint at each position in the circumference direction. To align,
The outer can sealing method according to claim 1.
The outer can sealing method according to claim 1, wherein irradiation of the laser beam to the joint is not interrupted, and a beam spot of the laser beam goes around the side surface of the outer can and the lid.
The laser beam irradiation with respect to the joint is temporarily interrupted in the vicinity of the corners of the outer can and the lid while the beam spot of the laser beam goes around the side surfaces of the outer can and the lid. The outer can sealing method described.
An outer can sealing device that joins a seam formed on a side surface between a rectangular outer can that contains a battery or other electrical component and a lid that closes an opening of the outer can by laser seam welding,
A can support portion that vertically supports the outer can covered with the lid;
A laser oscillation unit for generating a laser beam for laser seam welding;
A scanner that is disposed above the outer can and the lid supported by the can support, and directs the laser beam from the laser oscillation unit to a reflective surface provided around the outer can and the lid; ,
Annularly arranged around the outer can and the lid, has the reflective surface, and the reflective surface is directed obliquely upward so that the laser beam incident from the scanner is reflected to the joint Mirror,
The laser beam from the laser oscillation unit is irradiated to the joint through the scanner and the annular mirror, and a beam spot of the laser beam goes around the side surface of the outer can and the lid on the joint. Thus, an outer can sealing device comprising: a control unit that controls a scanning operation of the scanner.
11. The outer can sealing apparatus according to claim 10, wherein the scanner includes a first axis and a second axis galvano scanner for scanning the laser beam in a two-dimensional direction intersecting with an optical axis of the laser beam.
The scanner includes a condensing lens arranged in front of the galvano scanner, and the focal length of the condensing lens is set in the revolving direction so that the laser beam is condensed at the joint at each position in the revolving direction. The outer can sealing device according to claim 10, further comprising a third-axis focusing control unit that is variably controlled.
The outer can sealing apparatus according to claim 11, further comprising a non-telecentric fθ lens disposed between the scanner and the annular mirror.
A non-telecentric fθ lens is disposed between the scanner and the annular mirror;
The distance interval between the reflection point on the annular mirror and the seam is variably adjusted in the circumference direction so that the laser beam is condensed at the seam at each position in the circumference direction.
The outer can sealing apparatus according to claim 10.
The outer can sealing device according to claim 10, wherein the annular mirror is divided into a plurality of plate mirrors in a circumferential direction.
The outer can sealing device according to claim 15, wherein an inclination angle formed with a horizontal line of the annular mirror is adjusted for each of the plate mirrors.
The outer can sealing device according to claim 15, wherein an angle in a plan view of the annular mirror facing the side surface of the outer can and the lid is adjusted for each of the plate mirrors.
A telecentric fθ lens is disposed between the scanner and the annular mirror;
The angle of inclination formed with the horizontal line of the annular mirror is uniform in the circumferential direction so that the laser beam is condensed at each position in the circumferential direction, and between the reflection point on the annular mirror and the joint. The distance interval of
The outer can sealing apparatus according to claim 10.
The outer can sealing device according to claim 10, wherein the reflection surface of the annular mirror continuously extends without interruption in a circumferential direction.
The outer can sealing device according to claim 10, wherein the reflecting surface of the annular mirror is divided at a position facing the corner of the outer can and the lid in the circumferential direction or in the vicinity thereof.
The exterior according to claim 10, further comprising a hollow and bottomed laser optical path housing having a circular cross section or a corridor shape in order to shield the optical path of the laser beam from the scanner to the annular mirror from the outside. Can sealing device.
The outer can sealing device according to claim 21, wherein a protective glass for transmitting the laser beam reflected by the annular mirror to the outside is attached to an inner peripheral wall of the laser beam path housing.
The exterior can sealing device according to claim 21, further comprising a shield gas supply unit configured to supply a shield gas around the joint from above the exterior can and the lid inside the laser beam path housing.
24. The outer can sealing device according to claim 23, further comprising a partition for maintaining an atmosphere of the shielding gas around the outer can and the lid.