JP2004079769A

JP2004079769A - Method for joining aluminium capacitor electrode

Info

Publication number: JP2004079769A
Application number: JP2002237815A
Authority: JP
Inventors: Hiroshi Okazaki; 岡崎　博司; Tomoyuki Yoshii; 吉井　智之; Jiro Ichimura; 市村　滋朗
Original assignee: Hitachi AIC Inc
Current assignee: Lincstech Circuit Co Ltd
Priority date: 2002-08-19
Filing date: 2002-08-19
Publication date: 2004-03-11
Anticipated expiration: 2022-08-19
Also published as: JP4019316B2

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the damages to an electrode foil at the time of connection, while mechanically connecting an aluminium foil material with a lead-out terminal, or the aluminium foil materials with each other as well as reliably and electrically connecting. <P>SOLUTION: The aluminium foil materials are electrically connected with each other, or the electrode foil is electrically connected with the lead-out terminal by a frictional and stirring joining. Further, as a frictional and stirring joining method, mutual foils of an aluminium material, or the foil and the lead-out terminal are overlapped, and a rotary element rotating at a high speed is brought into contact with one surface to join by friction heat, thereby preventing the occurrence of a damage or distortion of the foils or lead-out terminal to make a more stable electrical connection. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、アルミニウムコンデンサの電極の接合方法に関するもので、特に、少なくとも一方が、表面に絶縁性の被膜を有する電極箔に有効な電気的導通方法に関する。
なお、この明細書において、アルミニウムは、アルミニウムまたは、その合金を含む意味で用いる。
【０００２】
【従来の技術】
アルミニウムコンデンサに用いられている電極は、厚さが１０μｍから２００μｍ程度の帯状のアルミニウム箔材に、先端に外部と接続される外部引出部が溶接または突出されている、厚さが５０μｍから４００μｍ程度の薄板短冊状でアルミニウム材からなる引出端子を機械的で電気的に接続した構造になっている。
従来、帯状のアルミニウム箔材はエッチングして表面拡大処理し、化成処理により表面に耐圧絶縁被膜を設けるアルミニウム箔材や、またはエッチングしていないプレーンで表面に自然酸化絶縁被膜を設ける帯状のアルミニウム箔材を、一枚または複数枚使用している。
このアルミニウム箔材と引出端子、またはアルミニウム箔材どうしの接合において、機械的な接続だけでなく、電気的な接続のために、従来、冷間圧接法と呼ばれる物理的に圧力を加える方法が広く用いられている。
【０００３】
【発明が解決しようとする課題】
しかしながら、前記に述べた従来の技術では、コンデンサを小型化する目的で、電極箔表面を粗面化処理し、有効表面積を拡大していくと電極箔それ自身が脆くなりやすく、コンデンサ電極として組み立てる際、電極箔に破損の発生し、コンデンサ素子の電極として使用できなくなることから、コンデンサ小型化の隘路事項の一つになっていた。
【０００４】
本発明の目的とするところは、接続時における電極箔の破損の発生を防止しながら、アルミニウム箔材と引出端子、またはアルミニウム箔材どうしの機械的な接続だけでなく、確実な電気的な接続をとることにある。
【０００５】
【課題を解決するための手段】
上記の課題を解決するために、本発明は、アルミニウム材の、電極箔どうし、または、電極箔と引出端子を摩擦撹拌接合により電気的導通させることを特徴とするアルミニウムコンデンサ電極の接合方法を提供するものである。
【０００６】
また、摩擦撹拌接合方法として、アルミニウム材の、電極箔どうし、電極箔と引出端子、または、電極箔と薄板を重ね合わせ、一方の表面におおよそ１００００ｒｐｍから５０００００ｒｐｍの範囲で高速回転する、直径がおおよそ０．０２ｍｍから２ｍｍの回転素子を接触させて摩擦熱で接合させることにより、箔または引出端子の破損や歪の発生を防止し、より安定な電気的導通させることを特徴とするアルミニウムコンデンサ電極の接合方法を提供するものである。
【０００７】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて説明する。
図１の（ａ）は電極箔と引出端子を摩擦撹拌により接合する方法を説明するための断面を示している。図１の（ｂ）は、その接合後の、アルミニウムコンデンサの電極上面の概略図を示している。図２の（ａ）は、その接合部分の断面写真を示している。図２の（ｂ）は、その接合部分の上面写真を示している。
【０００８】
１は、引出端子で、先端に外部と接続される外部引出部２が溶接または突出されている、５０μｍから５００μｍ程度の薄板短冊状でアルミニウム材からなる。
３は、電極箔で５０μｍから２００μｍ程度の帯状のアルミニウム箔材で、エッチングして表面拡大処理し、化成処理により表面に耐圧絶縁被膜４を設けている。
【０００９】
５は、回転素子で、接合部分において、固体のまま回転しつつ移動し、摩擦熱により接合部分を軟化させ撹拌するものである。その材質はアルミニウム材よりも融点が高く、高温でも高度が高い材質である。その直径は小さすぎると電気的な接続が不十分になりやすく大きすぎると、回転数をあげないと接合部分表面が軟化しない前に接合表面部材が変形、ひび割れ、破損等により接合ができなくなる。回転数は高い方が作業速度は向上するが、回転素子の直径が大きくなると回転装置自体の発熱も大きくなる。回転素子の直径は０．０１ｍｍから５ｍｍ程度、好ましくは０．０２ｍｍから２ｍｍ程度、より好ましくは０．０５ｍｍから１ｍｍ程度が使用でき、１０００ｒｐｍ以上、好ましくは１００００ｒｐｍから５０００００ｒｐｍ、より好ましく３００００ｒｐｍから３０００００ｒｐｍ範囲で高速回転させる。
【００１０】
図１では引出端子と化成処理したエッチングアルミニウム箔材との接合を示しているが、エッチングしていないプレーンで表面に自然酸化絶縁被膜を設けたアルミニウム箔材でもよく、引出端子のかわりに、同じ化成処理したエッチングアルミニウム箔材を重ねても同様に接合できる。
なお、エッチングがより進み、貫通したピットの多いアルミニウム箔材どうしの接合の場合には、接合部分の箔材間に２０μｍから１００μｍ程度の薄板状のアルミニウム箔材を挿入してから接合すると電気的な接続がより確実になる。
【００１１】
【実施例】
以下、本発明の実施例について説明する。
厚さ１００μｍの帯状アルミニウム箔材のエッチング倍率を変えて静電容量を変化させ、化成電圧４００Ｖにて、化成処理したアルミニウム箔材に、厚さ２００μｍの薄板状引出端子を重ね合わせ、引出端子側から直径０．５ｍｍの回転素子を圧入し、押し付け力３ｋｇｆ、回転素子の回転数６００００ｒｐｍ、接合速度３ｍｍ／ｓｅｃにて摩擦撹拌接合による接合をおこなった。
同じ構成のもので、従来の冷間圧接法にて接合したものと比較したものの結果を表１に示す。
【００１２】
【表１】

【００１３】
静電容量が増加すると、つまり、エッチング倍率が増加すると、電極箔それ自身が脆くなりやすく、従来の方法では化成箔にひび割れ、破損が発生し、接合強度の低下、漏れ電流や接続抵抗の増加など、接合に不具合を生じ、高倍率に対応できないが、本発明による方法では充分高倍率に対応できる。
【００１４】
【発明の効果】
以上のように、アルミニウム材の、電極箔どうし、電極箔と引出端子、または、電極箔と薄板を重ね合わせて接合する場合において、摩擦撹拌接合を用いて接続すると、有効表面積を拡大し、さらに化成により脆くなっている電極箔を破損せることなく、電極箔どうし、または、引出端子と電極箔を接合させることができ、コンデンサ電極として組み立てる際の隘路事項の一つになっていた電極箔破損の問題を回避でき、有効表面積をこれまで以上に拡大し、引出端子との機械的な接続だけでなく、確実な電気的な接続が可能となり、コンデンサの小型化が可能となる。
また、小径で高速回転の摩擦撹拌接合の回転素子を用いることにより、電極箔、引出端子を歪ませることがなくなり、より安定な接続が可能となる。
【図面の簡単な説明】
【図１】本発明の接合する方法を説明するための図である。
【図２】本発明の接合の写真である。
【符号の説明】
１…引出端子　２…外部引出部　３…電極箔　４…絶縁被膜　５…回転素子　６…接合部分。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for joining electrodes of an aluminum capacitor, and more particularly to an electrical conduction method effective at least for an electrode foil having an insulating coating on the surface.
In this specification, aluminum is used to mean aluminum or an alloy thereof.
[0002]
[Prior art]
The electrode used for the aluminum capacitor has a strip-shaped aluminum foil material having a thickness of about 10 μm to 200 μm, and an external lead portion connected to the outside is welded or protruded at the tip. The thickness is about 50 μm to 400 μm. It has a structure in which draw-out terminals made of an aluminum material are mechanically and electrically connected to each other.
Conventionally, a strip-shaped aluminum foil material is etched to enlarge the surface and then subjected to a chemical conversion treatment to provide a pressure-resistant insulating film on the surface, or a strip-shaped aluminum foil provided with a natural oxide insulating film on the surface in an unetched plane. One or more materials are used.
In joining the aluminum foil material and the lead terminal or the aluminum foil material, not only mechanical connection but also electrical connection, conventionally, the method of applying physical pressure called the cold pressure welding method is widely used. Used.
[0003]
[Problems to be solved by the invention]
However, in the conventional technique described above, the electrode foil surface itself is likely to become brittle as the surface of the electrode foil is roughened and the effective surface area is increased in order to reduce the size of the capacitor, and the capacitor is assembled as a capacitor electrode. In this case, the electrode foil is damaged and cannot be used as an electrode of the capacitor element, which has been one of the bottlenecks in miniaturizing the capacitor.
[0004]
An object of the present invention is to prevent not only the occurrence of breakage of the electrode foil at the time of connection, but also the mechanical connection between the aluminum foil material and the lead terminal or the aluminum foil material, as well as the reliable electrical connection. It is to take.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a method for joining aluminum capacitor electrodes, wherein the electrode foils are made of aluminum material, or the electrode foil and the lead terminal are electrically connected by friction stir welding. Is what you do.
[0006]
In addition, as a friction stir welding method, aluminum foil, electrode foils, electrode foils and lead terminals, or electrode foils and thin plates are overlapped, and one surface is rotated at a high speed in a range of approximately 10,000 rpm to 500,000 rpm. A rotating element of 0.02 mm to 2 mm is brought into contact and joined by frictional heat, thereby preventing breakage or distortion of the foil or the lead-out terminal and providing more stable electrical conduction. It provides a joining method.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1A shows a cross section for explaining a method of joining the electrode foil and the lead terminal by friction stirring. FIG. 1B shows a schematic view of the upper surface of the electrode of the aluminum capacitor after the joining. FIG. 2A shows a cross-sectional photograph of the joint. FIG. 2B shows a top view photograph of the joint.
[0008]
Reference numeral 1 denotes an extraction terminal, which is formed of a thin aluminum plate having a thickness of about 50 μm to 500 μm and to which an external extraction section 2 connected to the outside is welded or protruded at the tip.
Reference numeral 3 denotes an electrode foil, which is a strip-shaped aluminum foil material of about 50 μm to 200 μm, which is subjected to surface enlargement processing by etching, and a pressure-resistant insulating film 4 is provided on the surface by chemical conversion treatment.
[0009]
Reference numeral 5 denotes a rotating element which moves while rotating in a solid state at the joint portion, and softens and stirs the joint portion by frictional heat. The material has a higher melting point than the aluminum material, and has a high altitude even at a high temperature. If the diameter is too small, the electrical connection tends to be insufficient, and if the diameter is too large, the joining surface member cannot be joined due to deformation, cracking, breakage, etc. before the joining portion surface does not soften unless the number of rotations is increased. The higher the rotation speed, the higher the working speed, but the larger the diameter of the rotating element, the greater the heat generated by the rotating device itself. The diameter of the rotating element may be about 0.01 mm to 5 mm, preferably about 0.02 mm to about 2 mm, more preferably about 0.05 mm to about 1 mm, and may be 1000 rpm or more, preferably 10,000 rpm to 500,000 rpm, more preferably 30,000 rpm to 300,000 rpm. Rotate at high speed.
[0010]
FIG. 1 shows the joining between the lead terminal and the etched aluminum foil material subjected to the chemical conversion treatment. However, an aluminum foil material provided with a natural oxide insulating film on the surface of an unetched plane may be used. Even if an etching aluminum foil material subjected to a chemical conversion treatment is overlapped, it can be similarly bonded.
In addition, in the case of joining aluminum foil materials having many pits that have been further etched and penetrated, a thin aluminum foil material of about 20 μm to 100 μm is inserted between the foil materials at the joining portion, and then the electrical connection is made. More secure connections.
[0011]
【Example】
Hereinafter, examples of the present invention will be described.
The capacitance is changed by changing the etching magnification of a 100 μm-thick strip-shaped aluminum foil material, and at a formation voltage of 400 V, a 200 μm-thick thin plate-shaped lead-out terminal is superimposed on the chemical-treated aluminum foil material, and the lead-out terminal side And a rotary element having a diameter of 0.5 mm was press-fitted, and welding by friction stir welding was performed at a pressing force of 3 kgf, a rotation speed of the rotary element of 60000 rpm, and a welding speed of 3 mm / sec.
Table 1 shows the results of comparisons with those of the same configuration, which were joined by a conventional cold welding method.
[0012]
[Table 1]

[0013]
When the capacitance increases, that is, when the etching magnification increases, the electrode foil itself tends to become brittle, and the conventional method causes cracks and breaks in the conversion foil, lowers the bonding strength, increases leakage current and increases connection resistance. For example, although the bonding cannot be performed at a high magnification due to a defect in the bonding, the method according to the present invention can sufficiently cope with a high magnification.
[0014]
【The invention's effect】
As described above, the aluminum material, between the electrode foils, the electrode foil and the lead terminal, or, in the case where the electrode foil and the thin plate are overlapped and joined, when connected using friction stir welding, the effective surface area is enlarged, Electrode foil can be joined to each other or the lead terminal and the electrode foil without damaging the electrode foil that has become brittle due to chemical formation, which is one of the bottlenecks when assembling as a capacitor electrode. Problem can be avoided, the effective surface area can be increased more than before, and not only mechanical connection with the lead-out terminal but also reliable electrical connection can be made, and the size of the capacitor can be reduced.
Further, by using a rotating element of small diameter and high-speed rotation of friction stir welding, the electrode foil and the lead-out terminal are not distorted, and more stable connection is possible.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a joining method according to the present invention.
FIG. 2 is a photograph of the joint of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Lead-out terminal 2 ... External lead-out part 3 ... Electrode foil 4 ... Insulating coating 5 ... Rotating element 6 ... Joining part.

Claims

A method for joining aluminum capacitor electrodes, comprising electrically connecting aluminum electrode foils, electrode foils and lead terminals, or electrode foils and thin plates by friction stir welding.

A rotating element having a diameter of about 0.02 mm to 2 mm, which is made of an aluminum material and has an electrode foil, an electrode foil and a lead terminal, or an electrode foil and a thin plate which are superimposed on each other and rotated on one surface at a high speed in a range of about 10,000 rpm to 500,000 rpm. A method for joining electrodes of an aluminum capacitor, wherein the electrodes are electrically connected by friction stir welding in which they are brought into contact with each other and frictional heat is applied.