JP2010184260A - Method for joining aluminum foils - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining aluminum foils which can directly weld layered aluminum foils. <P>SOLUTION: The method comprises an ultrasonic wave tacking step of layering a plurality of aluminum foils 1a, 1a... and applying ultrasonic waves thereto by ultrasonic wave heads H, H to break an oxide film in the aluminum foils 1a, 1a..., and thus to perform tacking, and a resistance welding step of, while pressing a layered part 3 formed by the ultrasonic wave tacking step, energizing the electrodes by a pair of electrodes, and welding the layered aluminum foils 1a, 1a.... <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for directly welding laminated aluminum foils.

  Conventionally, aluminum used for electrodes of capacitors and batteries is laminated with a plurality of sheet bodies (foil) in order to increase the capacity thereof, and the oxide film of the aluminum foil becomes an insulating layer, so that current does not flow easily and is welded to each other. It was considered difficult. Further, the current tends to flow out of the planned welding position, and there is a possibility that explosion will occur or the welded portion may be displaced.

Therefore, the laminated aluminum foil is locally processed to form protrusions in advance, thinning the oxide film on the surface of the aluminum foil or causing cracks, and with the aluminum foils connected to each other, the electrodes are centered on the protrusions. The present applicant has proposed a method of conducting resistance welding by energizing an electrode while pressing a welded portion (see Patent Document 1).
Also, a method of applying resistance to the electrode by energizing the electrode while pressing the electrode against the welded part in a state where the oxide film is locally broken by applying a high voltage (about 1500 V) and the aluminum foils are electrically connected to each other. Has also proposed (see Patent Document 2).

JP 2006-326622 A JP 2004-130331 A

However, according to the method described in Patent Document 1, it is extremely difficult to perform a protrusion forming process on a plurality of laminated aluminum foils, resulting in variations in conductivity, and heat cannot be concentrated on the welded portion, so that resistance welding is not reliable. . In addition, there is a drawback that quality problems are likely to occur.
In addition, the method described in Patent Document 2 has a drawback that the entire apparatus is relatively large because a high-voltage facility is essential.

  Accordingly, an object of the present invention is to provide a method for directly joining a large number of laminated aluminum foils efficiently and stably with high quality.

  Then, the joining method of the aluminum foil which concerns on this invention is a supersonic wave attachment process which laminates | stacks several aluminum foil, applies an ultrasonic wave with an ultrasonic head, destroys and temporarily attaches the oxide film of the said aluminum foil. And a resistance welding step of welding the aluminum foil laminated by energizing the electrodes while sandwiching the temporary attachment portion formed in the ultrasonic temporary attachment step with a pair of electrodes. It is.

  Further, the area of the tacked portion temporarily attached by the ultrasonic head is set to be larger than the area of the welded portion welded by the electrode.

  According to the joining method of the aluminum foil of the present invention, the aluminum foil can be resistance welded with a stable welding strength without causing problems such as explosions, and an excellent quality product can be easily and efficiently produced. can get.

It is the principal part expansion schematic which showed one Embodiment of the ultrasonic provisional process of this invention. It is the principal part expansion schematic which showed one Embodiment of the resistance welding process of this invention. It is principal part expansion explanatory drawing which showed the lamination | stacking state of the aluminum foil. It is operation | movement explanatory drawing in an ultrasonic provisional process. It is action explanatory drawing in a resistance welding process. It is principal part expansion explanatory drawing which showed the temporary attachment part and the welding part.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
First, as shown in FIG. 3, aluminum foil 1a, 1a ... is laminated | stacked. In FIG. 3, a simplified stack of 10 aluminum foils 1 a, 1 a... Is illustrated, but actually, about 10 to 100 aluminum foils 1 a, 1 a. Each aluminum foil 1a is coated with an oxide film 2a, and the oxide films 2a, 2a,... Are interposed as insulating layers between the laminated aluminum foils 1a, 1a,.

  The aluminum foil 1a has a thickness dimension t set to 10 μm to 50 μm. When the thickness dimension t is t <10 μm, there is a problem in strength and manufacturing as a capacitor or a battery electrode. Further, when the thickness dimension t is 50 μm <t, the amount of aluminum necessary for manufacturing a capacitor or the like having a predetermined capacity increases, resulting in waste.

Next, as shown in FIG. 1, the laminated aluminum foils 1a, 1a... And the terminal aluminum base plate B are pressed between a pair of cylindrical ultrasonic heads H.
As shown in FIG. 4, the aluminum foils 1a, 1a ... and the oxide films 2a, 2a ... vibrate in synchronization with the ultrasonic vibrations emitted from the ultrasonic heads H, H. The oxide films 2a, 2a,... Are cracked and broken at the initial stage of vibration. The aluminum foils 1a, 1a,... Are welded to each other by vibration energy and fill the gaps between the broken oxide films 2a, 2a,. In this way, the temporary attachment part 3 is formed between the ultrasonic heads H, H facing each other, and the aluminum foils 1a, 1a,. This process is called an ultrasonic provisioning process.

Thereafter, the aluminum foils 1 a, 1 a... In the temporarily attached state are taken out from the ultrasonic heads H, H of FIG. 1, and between the pair of cylindrical electrodes E, E set to have a smaller diameter than the ultrasonic heads H, H. The aluminum foils 1a, 1a... And the base plate B, which are installed and formed with the tacking portions 3, are clamped as shown in FIG.
As shown in FIG. 5, the electrodes E and E conduct resistance welding of the aluminum foils 1 a, 1 a. In this manner, a nugget N (a mixed metal) is formed between the electrodes E and E, and the aluminum foils 1a, 1a,. This process is called a resistance welding process.
Through the resistance welding process, the laminated aluminum foils 1a, 1a... And the aluminum base plate B are welded.

As shown in FIG. 6, the area S ₃ of the tack portion 3 formed by ultrasonic tack process, than the area S ₄ of the welded portion 4 to be welded by resistance welding process, it sets larger Yes. In other words, since the more the size of the contact surface of the electrodes E are widely formed area S ₃ of the temporarily attached portion 3, electrode E is in contact without removing the scope of Tack portion 3, ensures the welded portion 4 Weld. Here, the ultrasonic head H a plane size of the contact with the aluminum foil 1a surface and the area S ₃ of the temporarily attached portion 3, the welding portion electrode E is a planar size of the contact with the aluminum foil 1a surfaces 4 It is set to the area _{S 4.}

  The present invention can be modified in design. For example, the shapes of the temporary attachment portion 3 and the welded portion 4 are not limited to a circle, but are a single character or a polygon according to the shapes of the ultrasonic head H and the electrode E. It is good.

  As described above, in the present invention, a plurality of aluminum foils 1a, 1a,... Are stacked and ultrasonic waves are applied by the ultrasonic heads H, H to destroy the oxide films 2a, 2a,. Then, the electrodes E and E were laminated while sandwiching the temporary attachment part 3 formed in the ultrasonic provisional process by the ultrasonic provisional process and the pair of electrodes E and E. Are welded to the aluminum foils 1a, 1a, so that the laminated aluminum foils 1a, 1a can be joined by resistance welding. In particular, with relatively simple equipment, a large number of laminated aluminum foils 1a, 1a, ... can always be resistance-welded with a stable welding strength, and reliable and excellent quality products can be obtained easily and efficiently. It is done. In this way, stable bonding can be realized easily and quickly.

The area S ₃ of the tack portion 3, which is temporarily attached by ultrasonic head H is, than the area S ₄ of the welded portion 4 to be welded by the electrodes E, since the set to be larger, by resistance welding process When the resistance welding is performed by bringing the electrode E into contact with the range of the tacking portion 3 formed in the ultrasonic tacking step, it is easy to aim. Therefore, resistance heat generation can be concentrated reliably and a beautiful weld 4 can be formed.

Area of the area S ₄ welded portion of 1a aluminum foil 2a oxide film 3 Tack portion 4 welded portion H ultrasonic head E electrode S ₃ Tack portion

Claims (2)

A plurality of aluminum foils (1a) (1a)... Are laminated and ultrasonic waves are applied by the ultrasonic heads (H) (H), and the oxide films (2a) (2a) of the aluminum foils (1a) (1a). ) Ultrasonic tacking process for destroying and tacking ...
The aluminum laminated by energizing the electrodes (E) and (E) while sandwiching the temporary attachment portion (3) formed in the ultrasonic temporary attachment step with a pair of electrodes (E) and (E). A resistance welding step of welding the foils (1a) (1a)... The area (S ₃ ) of the temporary attachment part (3) temporarily attached by the ultrasonic head (H) is larger than the area (S ₄ ) of the weld part (4) welded by the electrode (E). The aluminum foil joining method according to claim 1, which is set to be large.

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