JP3229238B2 - Ultrasonic bonding method for metal foil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic bonding method in which an ultrasonic horn is applied to a metal foil laminated on a metal member to apply ultrasonic waves to the metal member to bond the metal foil to the metal member. Things.

[0002]

2. Description of the Related Art In recent years, the use of an electric double layer capacitor as an auxiliary power source for automobiles and the like has been studied.

As shown in FIG. 3, for example, the electric double-layer capacitor includes an anode electrode 12 having an anode current collector 11.
And a cathode electrode 14 having a cathode current collector 13 are arranged to face each other with a separator 15 interposed therebetween, thereby forming a basic cell 16. Each basic cell 16 is arranged so as to overlap with an adjacent basic cell 16, the anode electrode 12 is overlapped with the anode electrode 12, the cathode electrode 14 is overlapped with the cathode electrode 14, and the current collectors 11 and 13 are identical. By being sandwiched between the pole electrodes, the electrodes are shared by two superposed electrodes of the same pole. The plurality of basic cells 16 are stacked to form a capacitor element 17.

In the outermost layer on one side of the capacitor element 17, a separator 15 is disposed on the anode current collector 11, and in the outermost layer on the opposite side, the separator 15 is disposed on the cathode current collector 13. ing.

The anode electrode 12 and the cathode electrode 14 are formed in a thin plate shape using activated carbon paste, and the separator 15 is formed of a sheet-like fluororesin. The anode current collector 11 and the cathode current collector 13 are formed of a metal foil such as aluminum, and an anode extension lead 18 and a cathode extension lead 19 extend upward from one side, respectively. It has been formed. And
Each of the anode extension leads 18 and the cathode extension leads 19 are grouped for the same pole and joined to an electrode terminal (not shown).
The portion of the anode current collector 11 sandwiched between the anode electrodes 12 and 12 and the portion of the cathode current collector 13 sandwiched between the cathode electrodes 14 and 14 are both formed in a mesh shape.

An ultrasonic bonding method is known as a method for bonding aluminum foil such as the anode extension lead 18 and the cathode extension lead 19 to another metal member such as the electrode terminal. Conventionally, as shown in FIG. 2, in the ultrasonic bonding method, a plurality of aluminum foils 2 are laminated on a metal member 1 and an ultrasonic horn (not shown) is scanned over a bonding position of the uppermost aluminum foil 2. A plurality of aluminum foils 2 are solid-phase diffusion-bonded to the metal member 1 by applying ultrasonic waves while being in contact with each other, and a bonding portion 4 is formed at a portion where the ultrasonic horn is scanned. According to the ultrasonic bonding method, since the electrical resistance of the bonding portion 4 is reduced, the anode extension lead 18 of the capacitor element 17 is formed.
Also, it is suitable for use in joining the cathode extension lead 19 to the electrode element.

However, when the capacitor element 17 in which the anode extension lead 18 and the cathode extension lead 19 are bonded to the electrode element by ultrasonic bonding as described above is used in a place where vibration occurs in an automobile or the like, the vibration Is concentrated on the joint portion 4 and cracks are generated from the periphery of the joint portion 4, so that the aluminum foil 2 is easily broken.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic bonding method capable of solving such disadvantages and improving the bonding strength of a metal foil to a metal member.

[0009]

In order to achieve the above object, an ultrasonic bonding method according to the present invention comprises applying an ultrasonic wave to a metal foil laminated on a metal member and applying ultrasonic waves to the metal foil. In the ultrasonic bonding method of solid-phase diffusion bonding of the metal foil to the metal member, a metal plate is placed on a bonding position of the metal foil, and ultrasonic waves are applied through the metal plate to form the metal foil and When the metal plate is integrally solid-phase diffusion bonded to the metal member, one end of the metal plate is placed on a bonding position of the metal foil and the other end is mounted on the metal foil. Is disposed between the metal foil and the metal member so as to wrap the end of the metal foil, and ultrasonic waves are applied through the end of the metal plate placed on the joining position of the metal foil to apply the ultrasonic wave to the metal foil. And a metal plate integrally bonded to the metal member by solid phase diffusion bonding.

In general, in the ultrasonic bonding method, by applying ultrasonic vibration to the superposed metal materials, the metal in the portion where the ultrasonic vibration has acted vibrates, and the metal materials are mutually solid-phase diffusion bonded. However, the action of the ultrasonic vibration is strongest in the portion where the ultrasonic horn is in contact, and the diffusion amount of the metal is large in this portion. As a result, the strength of the metal structure is reduced around the portion where the ultrasonic horn is in contact, and in an extremely thin material such as a metal foil, a crack is generated from this portion when stress concentration occurs. Conceivable.

Therefore, according to the present invention, a metal plate is placed on the joining position of the metal foil, and an ultrasonic wave is applied through the metal plate, whereby an excessive ultrasonic wave is applied to the metal foil. Ultrasonic vibration is applied to the metal foil which prevents vibration from acting and which is sufficient for the metal foil to be solid-phase diffusion bonded and bonded to another metal material. Therefore, the metal foil is solid-phase diffusion bonded to the metal member together with the metal plate,
In addition, sufficient bonding strength can be obtained.

[0012]

[0013] According to the ultrasonic bonding method, since the end of the metal foil is wrapped by the metal plate, the metal foil is protected by the metal plate and handling is facilitated. Moreover, by applying ultrasonic waves through the end of the metal plate placed on the joining position of the metal foil, excessive ultrasonic vibration is applied to the metal foil as in the above-described embodiment. In addition, it is possible to obtain an effect that the ultrasonic vibration is applied to the metal foil enough to prevent the metal foil from being fused and to be bonded to the metal plate and the metal member by fusing the metal foil.

The ultrasonic bonding method of the present invention can be applied to a case where the metal foil is a single metal foil and a case where the metal foil is constituted by a plurality of laminated metal foils.

[0015]

Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing the ultrasonic bonding method of the present invention.

[0016]

In the ultrasonic bonding method according to the present invention, as shown in FIG. 1, a rectangular shape of 100 mm × 25 mm and a thickness of 0.05 mm is placed on a plate-like aluminum member 1 having a thickness of 0.8 mm.
Are laminated, and one end of each of the ten aluminum foils 2 is wrapped in an aluminum plate material 3 and laminated on the aluminum member 1. At this time, one end 3a of the aluminum plate 3 is placed on the joining position of the metal foil 2, and the other end 3b is arranged between the metal foil 2 and the metal member 1. And the end 3a of the aluminum plate 3
The ultrasonic wave is applied through the end 3a of the aluminum plate 3 by scanning an aluminum horn 2 in the width direction by contacting an ultrasonic horn (not shown). As a result, a joining portion 4 is formed at the joining position as shown by the imaginary line in FIG. 1, and the aluminum foil 2 and the aluminum plate material 3 are
Solid-phase diffusion bonding.

The aluminum plate member 3 can prevent an excessive ultrasonic vibration from acting on the adjacent uppermost aluminum foil 2, and can prevent the aluminum foil 2 and the aluminum member 1 from being excessively vibrated.
Any thickness can be used as long as it can apply ultrasonic vibrations that can vibrate and solid-phase diffusion bonding can be performed integrally with each other, and the thickness is not particularly limited. In joining, it is preferable to have a thickness in the range of 0.05 to 1.0 mm. Aluminum plate 3
Is thinner than the aluminum foil 2 and less than 0.05 mm, it is easily broken and handling becomes difficult. When the thickness of the aluminum plate 3 exceeds 1.0 mm, the output of the ultrasonic wave must be increased in order to integrally solid-phase diffusion-bond the aluminum foil 2 and the aluminum member 1 to each other. However, an increase in manufacturing costs is inevitable. Also,
More preferably, the aluminum plate 3 has a thickness in the range of 0.1 to 0.5 mm. When the thickness of the aluminum plate 3 is less than 0.1 mm, the effect of protecting the aluminum foil 2 may not be sufficiently obtained,
If the thickness of the aluminum plate 3 exceeds 0.5 mm, the strength of the aluminum plate 3 itself increases, and it may be difficult to wrap the end of the aluminum foil 2.

Next, a thickness of 0.05 mm, 0.1 mm,
Using three types of aluminum plates 3 of 0.5 mm, FIG.
The ultrasonic bonding was performed as described above, and the tensile strength of each aluminum foil 2 was measured. In the ultrasonic bonding, an ultrasonic horn (not shown) is pressed against the aluminum plate 3 with a pressing force of 60 to 70 psi, a frequency of 20 kHz and an output of 850 to 10
00w ultrasonic wave is applied for 0.5 to 0.6 seconds,
An mx 3 mm joint 4 was formed. In addition, the tensile strength of the aluminum foil 2 was measured in three places of the uppermost layer, the middle layer, and the lowermost layer among the ten aluminum foils 2 and the ten aluminum foils 2 as a whole. The results are shown in Table 1 below.

For comparison, as shown in FIG. 2, ten aluminum foils 2 are laminated on an aluminum member 1 and an ultrasonic horn (not shown) is directly brought into contact with the uppermost aluminum foil 2. The tensile strength of the aluminum foil 2 when ultrasonic bonding was performed by a conventional method of applying ultrasonic waves was measured. Dimensions of the aluminum member 1 and the aluminum foil 2, application conditions of ultrasonic waves,
The method for measuring the tensile strength of the aluminum foil 2 is all the same as described above. The results are shown in Table 1 below.

[0021]

[Table 1]

From Table 1, it can be seen that the ultrasonic bonding method of the present invention shown in FIG. 1 significantly improves the tensile strength of the uppermost aluminum foil 2 as compared with the conventional ultrasonic bonding method shown in FIG. It is clear that. Note that the tensile strength of the aluminum foil 2 is sufficient to prevent the occurrence of cracks when stress concentration occurs around the joint 4 due to vibration of an automobile or the like.

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

In the above embodiment, the number of the aluminum foils 2 is plural, but the number of the aluminum foils 2 may be only one. In the above-described embodiment, the ultrasonic bonding between aluminum is described as an example. However, the present invention can be applied to a metal material other than aluminum. Further, the metal member 1, the metal foil 2, and the metal plate 3 May be the same metal or different metals.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an ultrasonic bonding method according to the present invention.

FIG. 2 is a perspective view showing one embodiment of a conventional ultrasonic bonding method.

FIG. 3 is a perspective view showing a configuration example of an electric double layer capacitor.

[Explanation of symbols]

1: metal material, 2: metal foil, 3: metal plate, 4: bonding position.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Eisuke Komazawa 1-4-1, Chuo, Wako-shi, Saitama Pref. Honda Research Institute, Inc. (56) References JP-A-10-244380 (JP, A) Field surveyed (Int. Cl. ⁷ , DB name) B23K 20/10 H01G 9/016 H01M 4/64

Claims (2)

(57) [Claims] An ultrasonic bonding method in which an ultrasonic horn is applied to a metal foil laminated on a metal member to apply ultrasonic waves to the metal member so as to solid-phase diffusion-bond the metal foil to the metal member. when a metal plate is placed on the bonding position of the foil, integrally to solid phase diffusion bonding of the metal foil and the metal plate to the metal member by applying ultrasonic waves through the metal plate, the metal plate Has one end on the joining position of the metal foil.
Placed and the other end wraps around the end of the metal foil
And disposed between the metal foil and the metal member.
Through the end of the metal plate placed on the joint position of
Applying a wave to integrate the metal foil and metal plate with the metal member
Ultrasonic bonding method for metal foil, characterized in that solid-state diffusion bonding is performed on the metal foil. Wherein said metal foil is ultrasonic bonding method for a metal foil according to claim 1 Symbol mounting, characterized in that it is composed of a plurality of stacked metal foils.