JP2004247579A - Method for attaching lead to electrode foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent function drops of a capacitor due to an oxide film on the surface of the electrode foils. <P>SOLUTION: A laser beam is applied to the surface of an electrode foil 12 to remove an oxide film 12b and expose the base material 12a over the surface of the electrode foil 12, and a lead 16 is positioned on the base material 12a exposing over the surface of the electrode foil 12. Then the lead 16 and the electrode foil 12 are pierced by a needle to produce a burr 32 of the electrode foil 12 and the lead 16 on the outer side, and the burr 32 is crushed to connect the electrode foil 12 and the lead 16. Therefore, the oxide film 12b is not caught as an electric resistance between the base material 12a and the lead 16. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a lead mounting method for mounting a lead on an electrode foil having an insulating film formed on a surface of a base material, for example, an electrode foil of an aluminum electric field capacitor, an electric double layer capacitor or a lithium battery.
[0002]
[Prior art]
An aluminum electrolytic capacitor is composed of an element body obtained by stacking and winding an anode-side electrode foil (aluminum foil), electrolytic paper and a cathode-side electrode foil (aluminum foil), and leads drawn from each electrode foil. Each lead is electrically connected to each electrode foil.
[0003]
Conventionally, when a lead is physically and electrically connected to an electrode foil, a method called “needle caulking” has been used. In this method, a lead is positioned on the surface of an electrode foil, a needle is pierced into the lead and the electrode foil, and a burr of the electrode foil and the lead is generated on the side where the needle has penetrated. (See Patent Document 1).
[0004]
[Patent Document 1]
JP-A-7-106203
[0005]
[Problems to be solved by the invention]
However, in the prior art, the insulating oxide film (insulating film) formed on the surface of the electrode foil (aluminum foil) may become an electric resistance and increase the ESR (series resistance) of the capacitor. The function could be impaired.
[0006]
That is, in the related art, when a needle is pierced into the lead 1 and the electrode foil 2, as shown in FIG. 12, the oxide film 2b formed on the surface of the electrode foil 2 is caught between the base material 2a and the lead 1. This oxide film 2b may increase ESR (series resistance) between the lead 1 and the base material 2a.
[0007]
SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a method for attaching a lead to an electrode foil, which can surely join a lead to the electrode foil without increasing resistance due to an insulating film.
[0008]
[Means for Solving the Problems]
The invention described in claim 1 is a method for attaching a lead 16 to an electrode foil 12 in which an insulating film 12b is formed on a surface of a base material 12a. By irradiating the laser beam, the insulating film 12b is removed to expose the base material 12a on the surface of the electrode foil 12, and (b) the lead 16 is positioned on the base material 12a exposed on the surface of the electrode foil 12, (C) A needle 36a is pierced into a place where the base material 12a of the lead 16 and the electrode foil 12 is exposed, and a burr 32 of the electrode foil 12 and the lead 16 is generated on the side where the needle 36a has penetrated. This is a method of attaching the lead to the electrode foil by crushing the electrode foil 12 and the lead 16 to engage with each other.
[0009]
In the present invention, after the insulating film 12b on the surface of the electrode foil 12 is removed by laser light, the electrode foil 12 and the lead 16 are joined by "needle caulking". There is no fear that the insulating film 12b serving as an electric resistance is caught between the lead 16 and the lead 16.
[0010]
According to a second aspect of the present invention, in the first aspect of the present invention, “(e) after the step (d), irradiating the inner peripheral portion of the hole 48 formed by the needle 36a with a laser beam, The lead 16 and the base material 12a of the electrode foil 12 are welded. "
[0011]
In the present invention, since the lead 16 and the base material 12a of the electrode foil 12 are welded at the inner peripheral portion of the hole 48, they can be more reliably joined.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The “method of attaching leads to electrode foil” in one embodiment of the present invention is a method for attaching leads 16 to each of anode electrode foil 12 and cathode electrode foil 14 in aluminum electrolytic capacitor 10 as shown in FIG. What is used.
[0013]
The aluminum electrolytic capacitor 10 (FIG. 1) includes an element body 20 obtained by stacking and winding an anode-side electrode foil (aluminum foil) 12, an electrolytic paper 18, and a cathode-side electrode foil (aluminum foil) 14, and each electrode foil. A lead 16 is drawn out of the lead 12 and 14. The lead 16 is formed with a plate-like connecting portion 16 a as shown in FIG. 2 so as to facilitate connection with the electrode foils 12 and 14. ing.
[0014]
Hereinafter, the "method of attaching leads to the electrode foil" of this embodiment will be described with reference to FIGS. However, there is no difference between the case where the lead 16 is attached to the anode-side electrode foil 12 and the case where the lead 16 is attached to the cathode-side electrode foil 14. Therefore, only the case where the lead 16 is attached to the anode-side electrode foil 12 will be described below.
[0015]
In this embodiment, first, as shown in FIG. 3, the insulating film 12b on the surface of the electrode foil 12 is removed using a laser beam irradiation device 22. That is, since the electrode foil 12 has a structure in which an insulating oxide film (alumite) 12b is formed on the surface of a conductive base material (aluminum) 12a, the electrode foil 12 and the leads 16 are formed in a later step. Oxide film 12b is removed in advance in order to secure the electrical connection.
[0016]
The laser beam irradiating device 22 removes the oxide film 12b by irradiating a predetermined portion of the surface of the electrode foil 12 with a laser beam. The laser beam oscillating unit 24, the scanning head 26, and a device for connecting these components to each other. It is constituted by an optical fiber 28.
[0017]
The laser oscillating unit 24 includes a YAG rod 24a, a total reflection mirror 24b, an output mirror 24c, an excitation source 24d, a laser power supply 24e, and a condenser lens 24f, and adjusts power supplied from the laser power supply 24e to the excitation source 24d. Thereby, the output of the laser beam is set arbitrarily within a predetermined range.
[0018]
The scanning head 26 includes an X-axis scan mirror 26a driven by an X-axis galvanometer (not shown), a Y-axis scan mirror 26b driven by a Y-axis galvanometer (not shown), a collimator lens 26c, and a condenser lens 26d. By adjusting the angles of the X-axis scan mirror 26a and the Y-axis scan mirror 26b, the irradiation position of the laser beam on the oxide film 12b is arbitrarily set within a predetermined range.
[0019]
When removing the oxide film 12b using the laser beam irradiation device 22, as shown in FIG. 3, the focus of the condenser lens 26d is positioned with respect to the oxide film 12b on the surface of the electrode foil 12, and Irradiates laser light at output.
[0020]
When the removal of the oxide film 12b is completed, the lead 16 is positioned with respect to the base material 12a exposed on the surface of the electrode foil 12, as shown in FIG. 4, and then, as shown in FIG. 5 and FIG. A burr 32 (FIG. 6) is formed using the forming apparatus 30.
[0021]
The burr forming device 30 includes a support portion 34 that supports the electrode foil 12 and the lead 16, and a perforated portion 36 that perforates the electrode foil 12 and the lead 16. The support portion 34 includes a pedestal 34a for receiving the electrode foil 12 and a pressing portion 34b for pressing the lead 16 against the electrode foil 12, and the pedestal 34a has a hole 38 for receiving the burr 32. The pressing portion 34b is formed with a hole 40 through which the needle 36a of the perforated portion 36 is inserted. On the other hand, the piercing portion 36 is constituted by two needles 36a piercing the electrode foil 12 and the lead 16, and a driving portion 36b for moving the needle 36a in a direction approaching / separating from the support portion 34. I have.
[0022]
When forming the burr 32 (FIG. 6) using the burr forming apparatus 30, first, as shown in FIG. 5, the electrode foil 12 is received on the pedestal 34a of the support portion 34, and the lead 16 is connected to the electrode 16 by the pressing portion 34b. It is pressed against the foil 12 and fixed. Then, as shown in FIG. 6, the needle 36a is pushed down by the driving unit 36b, thereby piercing the lead 16 and the base material 12a of the electrode foil 12 where the base material 12a is exposed. Burrs 32 of the foil 12 and the leads 16 are generated.
[0023]
Then, the lead 16 pierced by the needle 36a is pressed against the base material 12a of the electrode foil 12, and the lead 16 and the electrode foil 12 are electrically connected (see FIG. 8). That is, since the oxide film 12b on the surface of the electrode foil 12 has been removed at the place where the needle 36a is pierced, the lead 16 and the base material 12a of the electrode foil 12 are directly in contact without interposing the oxide film 12b.
[0024]
After the burrs 32 are formed on the leads 16 and the electrode foil 12, as shown in FIG. 7, the burrs 32 are crushed using the press-contact device 42, and the leads 16 and the electrode foil 12 are engaged.
[0025]
The press-contact device 42 includes a lead-side pressing portion 44 for holding the lead 16 and an electrode-side pressing portion 46 for holding the burr 32. The lead-side pressing portion 44 includes a pressing plate 44a that is in contact with the lead 16, and a driving portion 44b that moves the pressing plate 44a in a direction to approach or separate from the lead 16, and includes The pressing portion 46 includes a pressing portion 46 a pressed against the burr 32, and a driving portion 46 b for moving the pressing portion 46 a in a direction of approaching or separating from the electrode foil 12.
[0026]
When the burrs 32 are crushed by using the pressing device 42, the pressing plate 44a is positioned on the surface of the lead 16 by the driving unit 44b, and the pressing unit 46a is pressed against the burrs 32 by the driving unit 46b.
[0027]
Then, as shown in FIG. 8, the burr 32 is pressed against the surface of the electrode foil 12, the lead 16 and the electrode foil 12 are engaged, and the lead 16 is prevented from being detached from the electrode foil 12.
[0028]
According to this embodiment, the lead 16 and the base material 12a of the electrode foil 12 are surely brought into contact with each other by removing the oxide film 12b in advance, so that the oxide film 12b provides an ESR (series resistance). Can be prevented from increasing, and the function deterioration of the aluminum electrolytic capacitor 10 can be prevented.
[0029]
In the above-described embodiment, the oxide film 12b is removed only on one surface of the electrode foil 12, but the oxide film 12b may be removed on both surfaces. In this case, the laser beam irradiation device 22 (FIG. 3) needs to be arranged not only on the upper surface side but also on the lower surface side of the electrode foil 12, but the laser oscillation unit 24 may be shared on both upper and lower sides.
[0030]
Further, in the above-described embodiment, the lead 16 and the electrode foil 12 are joined at two points, but may be joined at one point or three or more points.
[0031]
In the above-described embodiment, the joining operation is terminated when the lead 16 and the electrode foil 12 are engaged with each other. For example, as shown in FIG. The lead 16 and the electrode foil 12 may be welded to each other by irradiating the inner peripheral portion of the hole 48 formed by the laser beam with the laser beam. As the laser light irradiation device in this case, the device used for removing the oxide film 12b may be used with an increased output, or another laser light irradiation device may be used. Good.
[0032]
Further, in the above-described embodiment, the laser beam is applied to a plurality of locations (two locations) of the electrode foil 12 using the scanning head 26. For example, as shown in FIG. 10, the oxide film 12b will be removed. It is also possible to arrange the irradiation units 50 in correspondence with each of the positions described above, and to supply the laser light split by the laser oscillation unit 52 to each irradiation unit 50 through the optical fiber 54. Such a configuration using a plurality of irradiation units 50 is suitable when the leads 16 are attached to the electrode foil 12 of a large capacitor.
[0033]
In the above-described embodiment, the YAG laser is used to remove the oxide film 12b. However, an excimer laser, a glass laser, a CO2 laser, a semiconductor laser, or the like may be used instead. . However, for a device such as a CO2 laser that is difficult to transmit by an optical fiber, the transmission may be performed using a beam splitter 56 or a mirror 58 as shown in FIG.
[0034]
Further, the present invention is applicable to a case where leads are attached to an electrode foil of an electric double layer capacitor, a lithium battery or the like in addition to the aluminum electrolytic capacitor 10. That is, the present invention can be widely applied to a case where a lead is attached to an electrode foil on which an insulating film is formed.
[0035]
【The invention's effect】
According to the present invention, the insulating film is removed in advance by irradiating the surface of the electrode foil with a laser beam, so that when the needle is pierced into the lead and the electrode foil, the lead and the base material of the electrode foil are separated. The contact is made directly without the interposition of the insulating film. Therefore, there is no fear that the ESR (series resistance) is increased by the insulating film, and the function of the electrolytic capacitor can be prevented from deteriorating.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an aluminum electrolytic capacitor.
FIG. 2 is a perspective view showing a state where leads are attached to an electrode foil.
FIG. 3 is a view showing a step of removing an oxide film.
FIG. 4 is a view showing a step of positioning a lead with respect to an electrode foil.
FIG. 5 is a view showing a step of fixing a lead to an electrode foil.
FIG. 6 is a view showing a step of piercing a needle into a lead and an electrode foil.
FIG. 7 is a view showing a step of crushing burrs.
FIG. 8 is a view showing a state in which a lead and an electrode foil are engaged with each other.
FIG. 9 is a view showing a state in which a lead and an electrode foil are welded to each other.
FIG. 10 is a diagram showing a modification of the laser beam irradiation device.
FIG. 11 is a diagram showing another modification of the laser beam irradiation device.
FIG. 12 is a view showing a bonding state between a conventional lead and an electrode foil.
[Explanation of symbols]
12, 14 ... electrode foil 12a ... base material 12b ... oxide film 16 ... lead 22 ... laser beam irradiation device 30 ... burr forming device 32 ... burr 42 ... pressure welding device

Claims (2)

A lead mounting method for mounting a lead to an electrode foil having an insulating film formed on a surface of a base material,
(A) irradiating the surface of the electrode foil with a laser beam to remove the insulating film and expose the base material to the surface of the electrode foil;
(B) positioning the lead on the base material exposed on the surface of the electrode foil;
(C) a needle is pierced into a place where the base material of the lead and the electrode foil is exposed, and burr of the electrode foil and the lead is generated on a side where the needle penetrates;
(D) A method for attaching the lead to the electrode foil, wherein the burrs are crushed to engage the electrode foil and the lead. After the step (d), (e) irradiating the inner periphery of the hole formed by the needle with a laser beam to weld the lead and the base material of the electrode foil. Item 4. The method for attaching leads to an electrode foil according to Item 1.

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