JP2008000638A - Ultrasonic horn - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic horn which is wide in the range of welding conditions for many times of use and can secure a stable welding strength. <P>SOLUTION: This ultrasonic horn has: a plurality of rectangular flat parts disposed on the same plane in parallel on a processing plane 4a; and grooves of V-shaped sections between the flat parts. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic horn used in an ultrasonic welding machine used for joining a current collector foil and a lead of a lithium ion secondary battery.

  Conventionally, ultrasonic welding has been used to join a current collector foil and a lead of a lithium ion secondary battery.

  2A and 2B are diagrams for explaining the outline of ultrasonic welding used for joining the current collector foil and the lead, FIG. 2A is a perspective view, and FIG. 2B is a longitudinal sectional view of the lead. FIG. 2C is a cross-sectional view of the lead in the lateral direction. 3A and 3B are diagrams showing a conventional pyramid-shaped ultrasonic horn, in which FIG. 3A is a front view and FIG. 3B is a side view. 4A and 4B are diagrams showing a conventional pyramid shape with a flat tip, FIG. 4A is a front view, and FIG. 4B is a side view.

  As shown in FIG. 2, in the ultrasonic welding of the current collector foil and the lead of the lithium ion secondary battery, the current collector foil 2 and the metal lead 3 are stacked on the processed surface 1a of the anvil 1, The processed surface 4a of the ultrasonic horn 4 was pressed from above, and the ultrasonic horn 4 was vibrated to join the current collector foil 2 and the metal lead 3 together. The shape of the ultrasonic horn 4 at this time is a pyramid-shaped assembly processed at a constant pitch as shown in FIG. 3, and the pitch is 0.3 to 1.0 mm and the angle is 60 to 90 °. 4 or a pyramid-shaped assembly having a square flat portion at the tip thereof improved as shown in FIG. 4 (see Patent Document 1).

Japanese Patent Application Laid-Open No. 6-155051

  In the conventional ultrasonic bonding method, especially when the current collector foil and the metal lead are dissimilar metals and the thickness is thin, the setting range of the welding conditions for ensuring appropriate welding strength is narrow, and stable welding strength is ensured. It was difficult to continue.

  For example, in the case where the current collector foil is a copper foil having a thickness of 8 μm and the metal lead is a nickel having a thickness of 70 μm, the condition setting ranges for ensuring an appropriate welding state are: time: 10 to 200 msec, pressure: 0.05 to 1 MPa. The frequency is about 10 to 100 kHz, and if the amplitude range is narrow, the welding strength is weak, and if it is too wide, the foil is torn. Further, when welding is performed tens of thousands of times, the welding strength is weakened, and it is necessary to set the conditions again in order to secure the strength. That is, an object of the present invention is to provide an ultrasonic horn that has a wide welding condition range and ensures stable welding strength for many uses.

  As a result of diligent investigation to solve the above-mentioned problems, the present invention provides an ultrasonic horn that is used when a current collector foil and a metal lead are stacked on an anvil sandblasted surface and welded by pressing the ultrasonic horn. It has been found that the surface area of the ultrasonic horn increases the area where the ultrasonic horn comes into contact with the lead, and stable welding is possible by making the shape of the processed surface into a rectangular aggregate with the tip of the triangular prism shaped ridge cut. is there. The ultrasonic horn of the present invention includes a plurality of rectangular flat portions arranged on the same plane in parallel with each other on a processed surface, and a groove having a V-shaped cross section between the rectangular flat portions. Features. The rectangular flat portion preferably has a short side of 0.1 to 1.0 mm and a long side of 0.3 to 4.0 mm.

  According to the ultrasonic horn of the present invention, even when the current collector foil and the metal lead are dissimilar metals and the thickness is thin, the welding condition range in which stable welding strength can be secured is wide, and even when used many times It becomes possible to continue to secure stable welding strength.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing the shape of a processed surface of an embodiment of the ultrasonic horn of the present invention, FIG. 1 (a) is a front view, FIG. 1 (b) is a side view, and FIG. Is a bottom view.

  The ultrasonic connection between the current collector foil of the lithium ion secondary battery and the metal lead is made of the current collector foil 2 and the metal lead on the processed surface 1a on which the sandblasting treatment of the anvil 1 is performed as shown in FIG. The lead 3 is placed so as to be within the range of the processed surface 1a of the anvil, the processed surface 4a of the ultrasonic horn 4 is pressed from above, and the ultrasonic horn 4 is vibrated to thereby collect the current collector foil 2 and the metal. The manufactured lead 3 is joined. The current collector foil 2 is a copper foil (thickness: 5 to 20 μm) or an aluminum foil (thickness: 5 to 30 μm), and the lead 3 is a nickel material (thickness: 50 to 100 μm) or an aluminum material. (Thickness: 50 to 100 μm) is used. The ultrasonic horn 4 is pressed so as to be within the range of 3 to 4 mm in width of the lead 3, and the ultrasonic wave is generated and vibrated in the pressed state, whereby the current collector foil 2 and the metal lead 3 are connected. Join.

  As shown in FIG. 1, the ultrasonic horn 4 is an aggregate of a rectangular flat portion in which triangular prism shapes having a tip angle of 60 to 90 ° are arranged at a constant pitch and a tip of a ridge is shaved. The short side has a short side of 0.1 to 1.0 mm, a long side of 0.3 to 4.0 mm, and a pitch of 0.3 to 1.0 mm. If the short side exceeds 1.0 mm, the welding strength becomes weak, and if the long side is less than 0.3 mm, stable welding strength cannot be ensured as in the conventional case, and if it exceeds 4.0 mm, It will protrude.

  Compared with the prior art, the processing area of the ultrasonic horn that comes into contact with the lead is widened according to the present invention, so that the condition setting range for securing stable welding strength is widened, and the amplitude is also suppressed. , Durability is also improved.

The figure which shows the shape of the processing surface of the Example of the ultrasonic horn of this invention, Fig.1 (a) is a front view, FIG.1 (b) is a side view, FIG.1 (c) is a bottom view. FIG. 2 (a) is a perspective view, FIG. 2 (b) is a longitudinal sectional view of the lead, and FIG. 2 (c) is a diagram for explaining the outline of ultrasonic welding used for joining the current collector foil and the lead. FIG. The figure which shows the conventional pyramid-shaped ultrasonic horn, Fig.3 (a) is a front view, FIG.3 (b) is a side view. The figure which shows the conventional pyramid-shaped ultrasonic horn which made the front-end | tip flat, FIG. 4 (a) is a front view, FIG.4 (b) is a side view.

Explanation of symbols

1 Anvil 1a (Anvil) Processed Surface 2 Current Collector Foil 3 Lead 4 Ultrasonic Horn
4a Surface of ultrasonic horn

Claims (2)

  An ultrasonic horn comprising a plurality of rectangular flat portions arranged on the processing surface in parallel with each other on the same plane, and a groove having a V-shaped cross section between the rectangular flat portions.   The ultrasonic horn according to claim 1, wherein the rectangular flat portion has a short side of 0.1 to 1.0 mm and a long side of 0.3 to 4.0 mm.

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