JP2004186641A

JP2004186641A - Metallized film capacitor and manufacturing method thereof

Info

Publication number: JP2004186641A
Application number: JP2002355139A
Authority: JP
Inventors: Kohei Shioda; 浩平塩田; Toshiharu Saito; 俊晴斎藤; Hiroki Takeoka; 宏樹竹岡
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-12-06
Filing date: 2002-12-06
Publication date: 2004-07-02

Abstract

【課題】第１の電極引出し部にスリットを設けそのスリットにヒューズ部で電極容量形成部に接続した第１の金属蒸着電極と、スリットやヒューズを有しない第２の金属蒸着電極からなる金属化フィルムコンデンサは、通電時にコンデンサの温度が上昇し、耐電圧が低下することが課題となっていた。
【解決手段】メタリコン電極５に沿って金属蒸着のないスリット７を第１電極引出し部１ａに形成し、そのスリット７を横ぎって局部的にヒューズ部８を設けて、第１の電極引出し部１ａと第１の電極容量形成部１ｂを接続し、第１の金属蒸着電極の電極引出し部１ａの厚みを、スリットとヒューズ部がない、第２の金属蒸着電極２の第２の電極引出し部２ａの厚みよりも厚くする。
【選択図】図１A metallization includes a first metal deposition electrode provided with a slit in a first electrode lead-out portion, connected to the electrode capacitance forming portion by a fuse portion in the slit, and a second metal deposition electrode having no slit or fuse. The problem with film capacitors is that the temperature of the capacitor rises when energized and the withstand voltage decreases.
A slit (7) without metal deposition is formed in a first electrode lead portion (1a) along a metallikon electrode (5), and a fuse portion (8) is provided locally across the slit (7) to form a first electrode lead portion. 1a is connected to the first electrode capacitance forming portion 1b, and the thickness of the electrode lead portion 1a of the first metal deposition electrode is set to the second electrode lead portion of the second metal deposition electrode 2 having no slit and fuse portion. 2a.
[Selection diagram] Fig. 1

Description

【０００１】
【発明の属する技術分野】
本発明は、電子機器、電気機器や産業機器に用いられる金属化フィルムコンデンサに関するものである。さらに詳しくは、金属蒸着電極にヒューズ部を形成して自己保安機能を設けた金属化フィルムコンデンサに関するものである。
【０００２】
【従来の技術】
フィルムコンデンサは、一般に、金属箔を電極に用いるものと、誘電体フィルム上に設けた蒸着金属を電極に用いるものとに大別される。中でも、蒸着金属を電極とする金属化フィルムコンデンサは、金属箔のフィルムコンデンサに比べて電極の占める体積が小さく小型軽量化が図れることと、金属蒸着電極特有の自己回復性能（絶縁欠陥部で短絡が生じた場合に、短絡のエネルギーで欠陥部周辺の蒸着電極が蒸発・飛散して絶縁化し、コンデンサの機能が回復する性能）により絶縁破壊に対する信頼性が高いことから、従来から広く用いられている。
【０００３】
前記自己回復性能は金属蒸着電極の厚みが薄いほど良好（少ないエネルギーで金属蒸着電極が飛散するため）なことから、金属蒸着電極の中で容量部分を形成する有効電極部すなわち電極容量形成部の金属蒸着電極の厚みを薄くし、メタリコン電極と接続する部分の厚みを厚くしたヘビーエッジ部の構成も広く用いられている。このヘビーエッジ部構成により、コンデンサの耐電圧を高め、高電位傾度化を図ることができる。
【０００４】
このような金属化フィルムコンデンサの従来例について図４、図５を参照して以下に説明する。図４、図５において、第１の金属蒸着電極４１は、第１の電極引出し部４１ａと第１の電極容量形成部４１ｂから構成されていて、誘電体フィルム４２上にマージン部４３を除いて蒸着されている。第２の金属蒸着電極４４は第２の電極引出し部４４ａと第２の電極容量形成部４４ｂから構成されていて、誘電体フィルム４５上にマージン部４６を除いて蒸着されている。そして第１の金属蒸着電極４１はメタリコン電極４７を通じ第２の金属蒸着電極４４は反対側のメタリコン電極４８を通じてそれぞれ電極が引出されている。第１の金属蒸着電極４１はメタリコン電極４７に沿って伸びるスリット４９により、第１の電極引出し部４１ａと第１の電極容量形成部４１ｂに区分され、スリット４９内に局部的に設けられたヒューズ部５０により電気的に接続されている。５１は第１の電極容量形成部４１ｂを分割する分割スリットで、各分割電極は前記スリット４９内のヒューズ部５０により並列接続されている。一方、第２の金属蒸着電極４４はメタリコン電極４８を通じて電極が引出されているが、第２の電極引出し部４４ａと第２の電極容量形成部４４ｂとの間にスリットやヒューズ部はない。５２に示す矢印はメタリコン電極４７、４８よりそれぞれ第１の電極引出し部４１ａと第２の電極引出し部４４ａに流れる電流を示したものである。上記の金属蒸着フィルムコンデンサは、前述の自己回復時の短絡電流により絶縁欠陥部周囲のヒューズ部を溶断して絶縁欠陥部を電気回路から切り離す自己保安機能を形成するものである。
【０００５】
さらに近年では、前述の分割スリットを格子状に設け微細な分割電極に細分化してヒューズ部で並列接続した格子状分割電極も提唱されている。この構成では各分割電極の面積が小さくヒューズ溶断時の容量減少も小さくなるとともに、ヒューズ部の形状や各分割電極の面積を改良することにより、金属蒸着電極の絶縁回復性能も高めることができるため、さらに高電位傾度化すなわち誘電体フィルム１μｍあたりの電圧を高めることが図れるとされている。
【０００６】
そして１０〜１０００ｍｍ^２の面積からなる格子状分割電極と各分割電極間を接続する０．０５〜１．５ｍｍ幅の第１ヒューズ部を有し、かつメタリコン電極と接する電極引き出し部に沿って伸びるスリットと前記スリットを区分する第２ヒューズ部が設けられ、第２ヒューズ部の幅を第１ヒューズ部に対し２〜２０倍にした場合に直流での電位傾度１３０〜３５０Ｖ／μｍ、交流での電位傾度６０〜１２０Ｖ／μｍの金属化フィルムコンデンサが実現できると提唱されている（例えば、特許文献１）。
【０００７】
【特許文献１】
特開平８ー２５０３６７号公報
【０００８】
【発明が解決しようとする課題】
しかしながら、前述の自己保安機能を設けた金属化フィルムコンデンサは、自己保安機能の無い（ヒューズ部の無い）金属化フィルムコンデンサに比べて、通電時の電流による発熱が大きいという問題点があった。
【０００９】
すなわち、単に一定の直流電圧が印加され続ける場合にはコンデンサには電流が流れないため発熱は生じないが、交流電流やリプル電流、充放電電流、サージ電流等が流れた場合には、コンデンサが著しく発熱してしまう。コンデンサの温度上昇が大きくなると、耐電圧や長期信頼性が低下すると言う問題点があった。
【００１０】
特に、インバータの平滑用途のように、コンデンサに直流電圧をかけながら大きなリプル電流を通電する場合には、リプル電流による温度上昇のためにコンデンサの耐電圧が低下する課題があった。特に自動車用途に用いられた場合には、周囲温度が元々高いことから、大きな課題となっていた。そこで本発明は、上記従来の問題点に鑑み、通電時の温度上昇の少ない金属化フィルムコンデンサを提供することにある。
【００１１】
【課題を解決するための手段】
本発明者等は、上記課題に関して詳細に研究を進めた結果、前述の課題は、ヒューズ部を有する第１の金属蒸着電極における、電極引出し部（以下第１の電極引出し部と言う）からヒューズ部へ電流が流れ込む際に、第１の電極引出し部自体が発熱してしまうために、コンデンサが大きく温度上昇したり、第１の電極引出し部が劣化して誘電損失（ｔａｎδ）が悪化したりすることを見出した。
【００１２】
すなわち、第１の電極引出し部は、その端面全体でメタリコン電極から電流が流入するが、電流の流出部はヒューズ部しか無いために、第１の電極引出し部自体が、狭く長い電流経路となり、容易に発熱してしまう。なお、第２の金属蒸着電極の電極引出し部（以下第２の電極引出し部と言う）においても同様に端面全体でメタリコン電極から電流が流入するが、第２の金属蒸着電極にはスリットやヒューズが無いので、一様に電流が流れることから、発熱はほとんど生じない。
【００１３】
そして、前記第１の電極引出し部の厚みを、前記第２の電極引出し部の厚みよりも厚く形成した場合には、電流による発熱を、自己保安機能の無いコンデンサとほぼ同等にまで低減できることを見出した。
【００１４】
第１の電極引出し部の厚みは、第２の電極引出し部の厚みよりも厚くし、特に１．２倍以上（面抵抗値としては５／６倍以下）が望ましく、第１の電極引出し部の厚みを第２電極引出し部の厚みよりも１．５倍以上の厚み（面抵抗値としては２／３倍以下）にすることで、より一層大きな効果が得られることを究明し、これを課題解決の手段とした。
【００１５】
【発明の実施の形態】
本発明の目的は、各請求項に記載の構成とすることによって達成できるのであるが、以下には具体的な本発明の実施の形態について、図面を用いて説明する。
【００１６】
（実施の形態１）
図１は、本発明の実施の形態１の金属化フィルムコンデンサの要部断面図であり、図２は図１に用いた１対の金属化フィルムの鳥瞰図である。図１および図２において、第１の金属蒸着電極１および第２の金属蒸着電極２が誘電体フィルム３、４上にそれぞれ設けられ、両端面のメタリコン電極５、６を通じて電極が引き出されている。第１の金属蒸着電極１は、メタリコン電極５に沿って長手方向に伸びるスリット７により、第１の電極引出し部１ａと電極容量形成部１ｂに区分され、スリット７内に局部的に設けられたヒューズ部８により電気的に接続されている。なお、第２の金属蒸着電極２は、第２の電極引出し部２ａと電極容量形成部２ｂから形成されるが、これらを区分するスリットやヒューズ部は無く、電極引出し部２ａと電極容量形成部２ｂは一様に電気的に接続されている。そして、第１の電極引出し部１ａは第２の電極引出し部２ａよりも厚く形成されている。この構成により、自己保安機能を有し、しかも発熱の少ない金属化フィルムコンデンサを実現できる。なお、図２に示す２９は電極容量形成部２１ｂを分割する分割スリットである。
【００１７】
そして上記の実施の形態１において第１ならびに第２の金属蒸着電極１、２には、電極容量形成部１ｂ、２ｂの金属蒸着膜の厚みを薄くし、メタリコン電極５、６に接する部分の金属蒸着膜を厚くしたり、電極容量形成部１ｂ、２ｂの面抵抗値よりメタリコン電極５、６に接する部分の面抵抗値を低くしたりするヘビーエッジ部を構成することができる。
【００１８】
（実施の形態２）
図３は、本発明の実施の形態２の金属化フィルムコンデンサの１対の金属化フィルムの鳥瞰図である。図３において、第１の金属蒸着電極２１は、メタリコン電極２２に沿って伸びるスリット２３により、第１の電極引出し部２１ａと第１の電極容量形成部２１ｂに区分され、スリット２３内に局部的に設けられたヒューズ部２４により電気的に接続されている。さらに、第１の電極容量形成部２１ｂは、分割スリット２５により格子状に分割され、分割スリット２５内に局部的に設けられた第２のヒューズ部２６により並列接続されている。なお、第２の金属蒸着電極２７にはメタリコン電極２８に沿うスリットやヒューズは無く、第２の電極引出し部２７ａと第２の電極容量形成部２７ｂは一様に電気的に接続されている。そして、第１の電極引出し部２１ａは第２の電極引出し部２７ａよりも厚く形成されている。この構成により、自己保安機能を有し、かつ高電位傾度化が可能で、しかも発熱の少ない金属化フィルムコンデンサを実現できる。そして、実施の形態２においても実施の形態１と同様に第１ならびに第２の金属蒸着電極２１、２７には電極容量形成部２１ｂ、２７ｂの金属蒸着膜の厚みを薄くし、メタリコン電極２２、２８に接する部分の金属蒸着膜を厚くしたり、電極容量形成部２１ｂ、２７ｂの面抵抗値より、メタリコン電極２２、２８に接する部分の面抵抗値を低くしたりするヘビーエッジ部を構成することができる。
【００１９】
なお、実施の形態２においても実施の形態１と同様に第１の金属蒸着電極２１はマージン部２９を除いて誘電体フィルム上に、また、第２の金属蒸着電極２７はマージン部３０を除いて上記の誘電体フィルムとは別の誘電体フィルム上に蒸着して形成されている。また第１の電極引出し部２１ａはメタリコン電極２２に、第２の電極引出し部２７ａはメタリコン電極２８にそれぞれ接続されている。また実施の形態２においてでも実施の形態１と同様に金属蒸着膜の厚みや面抵抗値において、電極容量形成部２１ｂ、２７ｂの厚さをメタリコン電極２２、２８に接する部分より薄くしたり、メタリコン電極に接する部分の面抵抗値を電極容量形成部２１ｂ、２７ｂの面抵抗値より低くするヘビーエッジ部をもつ構成とすることが可能である。
【００２０】
（性能比較の例）
本発明の実施の形態１と２よりなる金属化フィルムコンデンサの性能について以下説明する。実施の形態１と２に使用する誘電体フィルムとしては、厚みが３．５μｍで幅が７０ｍｍのポリプロピレンフィルムを用いて２００μＦの小判型コンデンサ素子を作製し、ポリブチレンテレフタレート製のケースにおさめてエポキシ樹脂でモールドした。また、ヒューズ部８は０．６ｍｍ幅とし、分割スリット９は０．３ｍｍ幅とした。比較のために、従来技術よりなるコンデンサも作製した。
【００２１】
なお、金属蒸着電極の材質としては、第１と第２の電極容量形成部１ｂ、２ｂ、２１ｂ、２７ｂはアルミニウムを用いて形成し、第１と第２の電極引出し部１ａ、２ａ、２１ａ、２７ａは、アルミニウムの上にさらに亜鉛を蒸着した。また、電極引出し部１ａ、２ａ、２１ａ、２７ａの厚みは、誘電体フィルム上に電極を蒸着する際に、亜鉛の蒸発源上に開口部を有する固定マスクを配置し、前記開口部の面積を調整することにより、所定の厚みを得た。
【００２２】
このようにして作製した各コンデンサに、８５℃において１０ｋＨｚで実効値２０Ａの正弦波電流を１８０分間通電し、小判型素子表面の温度上昇値を測定した。なお、いずれのコンデンサにおいても１８０分後には温度上昇は飽和していた。
【００２３】
得られた結果を表１の温度上昇値に示す。実施の形態１、２と従来例１、２の比較から、明らかに本発明よりなるコンデンサは従来例に比べて温度上昇が小さい。
【００２４】
【表１】

【００２５】
次に各コンデンサに８５℃で前記リプル電流を通電した状態で、７００Ｖの直流電圧を印加し、１０００時間後の容量変化率を測定した。結果を表１の容量変化率に示す。明らかに本発明の実施の形態１、２よりなるコンデンサは従来例のコンデンサに比べて高電圧下での容量減少が小さく、高電位傾度で使用できる。これは、従来例においてはリプル電流による発熱のために誘電体フィルムの耐圧が低下するために、多くの個所で局所短絡によるヒューズ部の溶断が発生したのに対し、本発明の実施の形態ではリプル電流による発熱が抑制されることからヒューズ部の溶断も少なくなったためである。
【００２６】
なお、本発明の実施の形態２では、四角形状からなる分割電極を例として説明したが、本発明は四角形状の分割電極に限定するものではなく、他の形状、例えば菱形状や六角形状、三角形状の格子状分割電極においても同様の結果を得た。またヒューズ部の位置は前記四角形の各辺に設けたが、頂点に設けてもよい。
【００２７】
さらに、誘電体フィルムとしてポリプロピレンフィルムを用いて説明したが、他のフィルム例えばポリエチレンテレフタレートやポリフェニレンサルファイド、ポリエチレンナフタレート等においても同様の結果を得た。また実施の形態１における誘電体フィルム３および４として、それぞれ２枚以上のフィルムを重ねても、同様の効果を得た。
【００２８】
また蒸着する金属としてアルミニウム単独や亜鉛単独、あるいは亜鉛とアルミニウムの混合物を用いた場合にも同様の効果を得た。
【００２９】
また、本発明の実施の形態１では第１の金属蒸着電極１と第２の金属蒸着電極２は別々のフィルム３、４上に設けたが、金属蒸着電極１と２は同じ誘電体フィルムの裏表に設け、未蒸着の誘電体フィルムと重ねて積層、巻回しても良い。
【００３０】
また、本発明の実施の形態ではエポキシ樹脂でモールドした乾式小判型コンデンサの例を説明したが、絶縁油やワックスで含浸された湿式コンデンサでも同様の効果が得られる。またコンデンサの形状は丸型でもよい。
【００３１】
さらに、電極容量形成部１ｂ上に分割スリット９を設けて分割する場合の例を説明したが、金属化フィルムを積層してなる積層型コンデンサのように金属化フィルム１枚１枚が分離されている場合には、分割スリットは無くても良い。
【００３２】
【発明の効果】
以上の説明から明らかなように、本発明によれば、メタリコン電極と接続する電極引出し部に沿って伸びる蒸着金属の無いスリットと、前記スリットを区分するヒューズ部を有する第１の金属蒸着電極と、前記スリットを有しない第２の金属蒸着電極とを備え、前記第１の金属蒸着電極の電極引出し部の厚みを、前記第２の金属蒸着電極の電極引出し部の厚みよりも厚くすることにより、自己保安機能を有し、しかも電流通電時に発熱が少ない良好な金属化フィルムコンデンサを実現することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１における金属化フィルムコンデンサの断面図
【図２】本発明の実施の形態１における金属化フィルムの鳥瞰図
【図３】本発明の実施の形態２における金属化フィルムの鳥瞰図
【図４】従来技術における金属化フィルムコンデンサの断面図
【図５】従来技術における金属化フィルムの鳥瞰図
【符号の説明】
１、２１第１の金属蒸着電極
１ａ、２１ａ第１の電極引出し部
１ｂ、２７ｂ第１の電極容量形成部
２、２７第２の蒸着電極
２ａ、２７ａ第２の電極引出し部
３、４誘電体フィルム
３ａ、４ａマージン
５、６メタリコン電極
７スリット
８ヒューズ部
９、２５分割スリット
２４第１のヒューズ部
２６第２のヒューズ部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a metallized film capacitor used for electronic equipment, electric equipment and industrial equipment. More specifically, the present invention relates to a metallized film capacitor provided with a self-security function by forming a fuse portion on a metal deposition electrode.
[0002]
[Prior art]
In general, film capacitors are roughly classified into those using a metal foil as an electrode and those using a metal deposited on a dielectric film as an electrode. Among them, metallized film capacitors that use vapor-deposited metal as an electrode have a smaller volume and smaller weight compared to metal foil film capacitors, and have a self-healing performance unique to metal-deposited electrodes. In the case where a short circuit occurs, the deposition electrode around the defect is evaporated and scattered by the energy of the short circuit and becomes insulated, and the function of the capacitor recovers.) I have.
[0003]
The self-healing performance is better as the thickness of the metal-deposited electrode is smaller (because the metal-deposited electrode is scattered with less energy). The configuration of the heavy edge portion in which the thickness of the metal deposition electrode is reduced and the thickness of the portion connected to the metallikon electrode is increased is also widely used. With this heavy edge configuration, the withstand voltage of the capacitor can be increased, and a high potential gradient can be achieved.
[0004]
A conventional example of such a metallized film capacitor will be described below with reference to FIGS. 4 and 5, the first metal deposition electrode 41 is composed of a first electrode lead-out portion 41a and a first electrode capacitance forming portion 41b, and is formed on a dielectric film 42 except for a margin portion 43. Has been deposited. The second metal deposition electrode 44 includes a second electrode lead-out portion 44a and a second electrode capacitance forming portion 44b, and is deposited on the dielectric film 45 except for a margin portion. The first metal deposition electrode 41 is led out through a metallikon electrode 47 and the second metal deposition electrode 44 is pulled out through a metallikon electrode 48 on the opposite side. The first metal deposition electrode 41 is divided into a first electrode lead portion 41a and a first electrode capacitance forming portion 41b by a slit 49 extending along the metallikon electrode 47, and a fuse locally provided in the slit 49. They are electrically connected by the unit 50. Reference numeral 51 denotes a division slit for dividing the first electrode capacitance forming portion 41b. Each division electrode is connected in parallel by a fuse section 50 in the slit 49. On the other hand, the electrode of the second metal deposition electrode 44 is led out through the metallikon electrode 48, but there is no slit or fuse portion between the second electrode lead-out portion 44a and the second electrode capacitance forming portion 44b. Arrows indicated by 52 indicate currents flowing from the

metallikon electrodes

47 and 48 to the first electrode lead-out part 41a and the second electrode lead-out part 44a, respectively. The above-described metal-deposited film capacitor forms a self-protection function of blowing the fuse portion around the insulation defect portion by the short-circuit current at the time of the self-recovery and separating the insulation defect portion from the electric circuit.
[0005]
Further, in recent years, a lattice-shaped divided electrode in which the above-mentioned divided slits are provided in a lattice shape and divided into fine divided electrodes and connected in parallel by a fuse portion has been proposed. In this configuration, the area of each divided electrode is small, the capacity decrease when the fuse is blown is small, and the insulation recovery performance of the metal deposition electrode can be improved by improving the shape of the fuse portion and the area of each divided electrode. It is stated that the potential gradient can be further increased, that is, the voltage per 1 μm of the dielectric film can be increased.
[0006]
It has a grid-shaped divided electrode having an area of 10 to 1000 mm ^{2 and} a first fuse portion having a width of 0.05 to 1.5 mm connecting between the divided electrodes, and extends along an electrode lead portion in contact with the metallikon electrode. A second fuse portion for separating the slit and the slit is provided, and when the width of the second fuse portion is set to 2 to 20 times that of the first fuse portion, the potential gradient at DC is 130 to 350 V / μm and the gradient at AC is It has been proposed that a metallized film capacitor having a potential gradient of 60 to 120 V / μm can be realized (for example, Patent Document 1).
[0007]
[Patent Document 1]
JP-A-8-250367
[Problems to be solved by the invention]
However, the metallized film capacitor provided with the above-described self-security function has a problem in that heat generated by current when energized is greater than that of a metallized film capacitor without a self-security function (without a fuse portion).
[0009]
In other words, when a constant DC voltage is simply kept applied, no current flows through the capacitor and no heat is generated.However, when an AC current, a ripple current, a charge / discharge current, a surge current, or the like flows, the capacitor is not operated. It generates heat remarkably. When the temperature rise of the capacitor becomes large, there is a problem that the withstand voltage and the long-term reliability decrease.
[0010]
In particular, when a large ripple current is applied while a DC voltage is applied to a capacitor as in the case of smoothing an inverter, there has been a problem that the withstand voltage of the capacitor is reduced due to a rise in temperature due to the ripple current. In particular, when used for automobiles, the ambient temperature was originally high, so this was a major problem. The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a metallized film capacitor with a small rise in temperature during energization.
[0011]
[Means for Solving the Problems]
The present inventors have conducted detailed research on the above-mentioned problem, and as a result, the above-mentioned problem has been solved in that the first metal deposition electrode having the fuse portion has a fuse extending from an electrode lead portion (hereinafter, referred to as a first electrode lead portion). When current flows into the portion, the first electrode lead-out portion itself generates heat, so that the temperature of the capacitor rises significantly, or the first electrode lead-out portion deteriorates and the dielectric loss (tan δ) worsens. I found out.
[0012]
In other words, the first electrode lead-out portion has a current flowing in from the metallikon electrode over the entire end face, but the current outflow portion has only the fuse portion. Therefore, the first electrode lead-out portion itself becomes a narrow and long current path, It generates heat easily. Similarly, a current flows from the metallikon electrode over the entire end face also in the electrode lead-out portion of the second metal deposition electrode (hereinafter referred to as a second electrode lead-out portion). Since there is no current, the current flows uniformly, so that little heat is generated.
[0013]
When the thickness of the first electrode lead portion is formed to be thicker than the thickness of the second electrode lead portion, heat generated by current can be reduced to almost the same level as a capacitor having no self-protection function. I found it.
[0014]
The thickness of the first electrode lead-out portion is preferably larger than the thickness of the second electrode lead-out portion, and particularly preferably 1.2 times or more (5/6 times or less in sheet resistance). By making the thickness 1.5 times or more the thickness of the second electrode lead-out portion (2/3 times or less as the sheet resistance value), it was clarified that a greater effect could be obtained. It was a means of solving the problem.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The object of the present invention can be achieved by adopting the configuration described in each claim. Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
[0016]
(Embodiment 1)
FIG. 1 is a sectional view of a main part of a metallized film capacitor according to Embodiment 1 of the present invention, and FIG. 2 is a bird's-eye view of a pair of metallized films used in FIG. 1 and 2, a first metal deposition electrode 1 and a second metal deposition electrode 2 are provided on

dielectric films

3 and 4, respectively, and the electrodes are drawn out through

metallikon electrodes

5 and 6 on both end surfaces. . The first metal deposition electrode 1 is divided into a first electrode lead-out portion 1a and an electrode capacitance forming portion 1b by a slit 7 extending in the longitudinal direction along the metallikon electrode 5, and is provided locally in the slit 7. They are electrically connected by a fuse unit 8. The second metal deposition electrode 2 is formed of a second electrode lead-out portion 2a and an electrode capacitance forming portion 2b. However, there is no slit or fuse for separating these, and the electrode lead-out portion 2a and the electrode capacitance forming portion are not formed. 2b is electrically connected uniformly. And the 1st electrode lead-out part 1a is formed thicker than the 2nd electrode lead-out part 2a. With this configuration, it is possible to realize a metallized film capacitor having a self-security function and generating less heat. Incidentally, reference numeral 29 shown in FIG. 2 denotes a dividing slit for dividing the electrode capacity forming portion 21b.
[0017]
In the first embodiment, the first and second metal-deposited electrodes 1 and 2 are provided with a thin metal-deposited film of the electrode capacitance forming portions 1 b and 2 b, and the metal in the portions in contact with the

metallikon electrodes

5 and 6 are formed. It is possible to form a heavy edge portion in which the thickness of the deposited film is increased or the sheet resistance value of the portion in contact with the

metallikon electrodes

5, 6 is lower than the sheet resistance value of the electrode capacitance forming portions 1b, 2b.
[0018]
(Embodiment 2)
FIG. 3 is a bird's-eye view of a pair of metallized films of the metallized film capacitor according to Embodiment 2 of the present invention. In FIG. 3, the first metal deposition electrode 21 is divided into a first electrode lead portion 21 a and a first electrode capacitance forming portion 21 b by a slit 23 extending along the metallikon electrode 22, and a local portion is formed in the slit 23. Are electrically connected to each other by a fuse portion 24 provided at the first position. Further, the first electrode capacitance forming portion 21b is divided into a lattice by the dividing slit 25, and is connected in parallel by a second fuse portion 26 provided locally in the dividing slit 25. The second metal deposition electrode 27 has no slit or fuse along the metallikon electrode 28, and the second electrode lead-out portion 27a and the second electrode capacitance forming portion 27b are uniformly electrically connected. And the 1st electrode lead-out part 21a is formed thicker than the 2nd electrode lead-out part 27a. With this configuration, it is possible to realize a metallized film capacitor having a self-security function, capable of increasing the potential gradient, and generating less heat. Also, in the second embodiment, the thickness of the metal deposition film of the electrode capacitance forming portions 21b and 27b is reduced for the first and second

metal deposition electrodes

21 and 27 as in the first embodiment. Forming a heavy edge portion that increases the thickness of the metal vapor-deposited film at the portion in contact with 28 and lowers the sheet resistance at the portion in contact with the

metallikon electrodes

22 and 28 than the sheet resistance of the electrode capacitance forming portions 21b and 27b. Can be.
[0019]
In the second embodiment, as in the first embodiment, the first metal-deposited electrode 21 is formed on the dielectric film except for the margin 29, and the second metal-deposited electrode 27 is formed on the dielectric film except for the margin 30. It is formed by vapor deposition on a dielectric film different from the above dielectric film. The first electrode lead-out portion 21a is connected to the metallikon electrode 22, and the second electrode lead-out portion 27a is connected to the metallikon electrode 28. Also, in the second embodiment, as in the first embodiment, in the thickness and the sheet resistance of the metal deposition film, the thickness of the electrode capacitance forming portions 21b and 27b is made thinner than the portions in contact with the

metallikon electrodes

22 and 28, It is possible to adopt a configuration having a heavy edge portion in which the sheet resistance of the portion in contact with the electrode is lower than the sheet resistance of the electrode capacitance forming portions 21b and 27b.
[0020]
(Example of performance comparison)
The performance of the metallized film capacitor according to Embodiments 1 and 2 of the present invention will be described below. As a dielectric film used in the first and second embodiments, a 200 μF small-sized capacitor element was manufactured using a 3.5 μm thick and 70 mm wide polypropylene film, and was placed in a polybutylene terephthalate case to obtain an epoxy film. Molded with resin. The width of the fuse portion 8 was 0.6 mm, and the width of the split slit 9 was 0.3 mm. For comparison, a capacitor according to the related art was also manufactured.
[0021]
As the material of the metal deposition electrode, the first and second electrode

capacitance forming portions

1b, 2b, 21b, 27b are formed using aluminum, and the first and second electrode lead portions 1a, 2a, 21a, In 27a, zinc was further evaporated on aluminum. The thickness of each of the electrode lead portions 1a, 2a, 21a, and 27a is set such that when depositing an electrode on a dielectric film, a fixed mask having an opening is disposed on a zinc evaporation source, and the area of the opening is reduced. By adjusting, a predetermined thickness was obtained.
[0022]
A sine wave current having an effective value of 20 A at 85 ° C. and a frequency of 20 A was applied to each capacitor for 180 minutes at 85 ° C., and the temperature rise of the surface of the oval element was measured. The temperature rise was saturated in all the capacitors after 180 minutes.
[0023]
The obtained results are shown in the temperature rise values in Table 1. From a comparison between the first and second embodiments and the conventional examples 1 and 2, the capacitor according to the present invention clearly has a smaller temperature rise than the conventional example.
[0024]
[Table 1]

[0025]
Next, a DC voltage of 700 V was applied in a state where the ripple current was applied to each capacitor at 85 ° C., and the capacitance change rate after 1000 hours was measured. The results are shown in the capacity change rate in Table 1. Obviously, the capacitors according to the first and second embodiments of the present invention have a smaller capacity reduction under a high voltage than the conventional capacitors, and can be used with a high potential gradient. This is because, in the conventional example, since the withstand voltage of the dielectric film is reduced due to heat generation due to the ripple current, the fuse portion is blown due to a local short circuit in many places, whereas in the embodiment of the present invention. This is because the heat generated by the ripple current is suppressed, so that the fusing of the fuse portion is reduced.
[0026]
In the second embodiment of the present invention, a quadrangular divided electrode has been described as an example.However, the present invention is not limited to a quadrangular divided electrode, and other shapes, such as a rhombic shape and a hexagonal shape, may be used. Similar results were obtained with a triangular grid-shaped divided electrode. Further, although the position of the fuse portion is provided on each side of the square, it may be provided at the vertex.
[0027]
Furthermore, although the description has been made using a polypropylene film as the dielectric film, similar results were obtained with other films such as polyethylene terephthalate, polyphenylene sulfide, and polyethylene naphthalate. Similar effects were obtained even when two or more films were stacked as

dielectric films

3 and 4 in the first embodiment.
[0028]
Similar effects were obtained when aluminum alone, zinc alone, or a mixture of zinc and aluminum was used as the metal to be deposited.
[0029]
Further, in Embodiment 1 of the present invention, the first metal deposition electrode 1 and the second metal deposition electrode 2 are provided on

separate films

3 and 4, but the metal deposition electrodes 1 and 2 are formed of the same dielectric film. It may be provided on the front and back, and may be laminated and wound on an undeposited dielectric film.
[0030]
In the embodiment of the present invention, an example of a dry type oval type capacitor molded with epoxy resin has been described. However, the same effect can be obtained with a wet type capacitor impregnated with insulating oil or wax. The shape of the capacitor may be round.
[0031]
Furthermore, an example in which the dividing slit 9 is provided on the electrode capacitance forming portion 1b to divide the electrode capacitor forming portion 1b has been described. However, as in the case of a multilayer capacitor in which metallized films are laminated, each metallized film is separated. If there is, there is no need to provide a split slit.
[0032]
【The invention's effect】
As is apparent from the above description, according to the present invention, a metal-free metal-equipped slit extending along an electrode lead portion connected to a metallikon electrode, and a first metal-deposited electrode having a fuse portion for dividing the slit are provided. A second metal vapor deposition electrode having no slit, by making the thickness of the electrode lead portion of the first metal vapor deposition electrode larger than the thickness of the electrode lead portion of the second metal vapor deposition electrode. A good metallized film capacitor having a self-protection function and generating less heat when current is supplied can be realized.
[Brief description of the drawings]
1 is a cross-sectional view of a metallized film capacitor according to a first embodiment of the present invention; FIG. 2 is a bird's-eye view of a metallized film according to a first embodiment of the present invention; Bird's-eye view of the film [Fig. 4] Cross-sectional view of a metallized film capacitor in the prior art [Fig. 5] Bird's-eye view of the metallized film in the prior art [Explanation of reference numerals]
Reference numerals 1, 21 First metal deposition electrodes 1a, 21a First electrode lead portions 1b, 27b First electrode

capacitance forming portions

2, 27 Second deposition electrodes 2a, 27a Second

electrode lead portions

3, 4, dielectric Films 3a,

4a Margins

5, 6 Metallicon electrode 7 Slit 8 Fuse section 9, 25 Split slit 24 First fuse section 26 Second fuse section

Claims

Winding or laminating metalized films that have been metallized except for the margins provided on one side of the front and back surfaces of separate dielectric films or the same dielectric film so that each margin is located on the opposite side A metallized film capacitor having metallikon electrodes formed at both ends, wherein the metallized film includes a metal deposition surface formed of an electrode lead-out portion connected to the metallikon electrode at one end and an electrode capacitance forming portion. A metal-free metal-deposited surface, a slit having no metal deposited extending along the electrode lead-out portion, and a fuse portion which divides the slit locally across the slit and connects an electrode capacitance forming portion to the electrode lead-out portion. And a second metal deposition surface having no slit, and a second metal deposition surface having no slit and having an electrode lead portion and an electrode capacitance formation portion continuously and uniformly formed. A metallized film capacitor comprising: a metal deposition electrode; and wherein the thickness of the electrode lead portion of the first metal deposition electrode is larger than the thickness of the electrode lead portion of the second metal deposition electrode. .

Winding or laminating metalized films that have been metallized except for the margins provided on one side of the front and back surfaces of separate dielectric films or the same dielectric film so that each margin is located on the opposite side A metallized film capacitor having metallikon electrodes formed at both ends, wherein the metallized film includes a metal deposition surface formed of an electrode lead-out portion connected to the metallikon electrode at one end and an electrode capacitance forming portion. A metal-free metal-deposited surface, a slit having no metal deposited extending along the electrode lead-out portion, and a fuse portion which divides the slit locally across the slit and connects an electrode capacitance forming portion to the electrode lead-out portion. And a second metal deposition surface having no slit, and a second metal deposition surface having no slit and having an electrode lead portion and an electrode capacitance formation portion continuously and uniformly formed. A metal deposition electrode, wherein the sheet resistance value of the electrode lead portion of the first metal deposition electrode is set lower than the sheet resistance value of the electrode lead portion of the second metal deposition electrode. Metallized film capacitors.

The first and second metal vapor deposition electrodes are configured such that the electrode lead-out portion forms a heavy edge portion in the metal vapor deposition film thickness that is thicker than the metal vapor deposition film thickness of the electrode capacitance forming portion. 3. The metallized film capacitor according to claim 1, wherein the thickness of the heavy edge portion of the electrode is larger than the thickness of the heavy edge portion of the second metal deposition electrode.

The first and second metal-deposited electrodes are configured such that the electrode lead-out portion forms a heavy edge portion that is lower in sheet resistance than the electrode-capacitance forming portion in sheet resistance. The metallized film capacitor according to claim 1, wherein a sheet resistance value of the heavy edge portion is set lower than a sheet resistance value of the heavy edge portion of the second metal deposition electrode.

The first metal-deposited electrode includes a division slit for dividing an electrode capacitance forming portion, which is an effective electrode portion, and a fuse portion locally provided in the division slit. 5. The metallized film capacitor according to any one of 4.

The first metal-deposited electrode includes a division slit for dividing an electrode capacitance forming portion, which is an effective electrode portion, into a grid, and a fuse portion locally provided in the division slit. A metallized film capacitor according to claim 5.

Except for a margin portion provided at one end in the width direction of the dielectric film on both front and back surfaces of a separate dielectric film or the same dielectric film, the amount of evaporated metal adhering on the dielectric film is determined by an opening. A metallized film deposited using a fixed mask having, wound or laminated such that the margin part is on the opposite side in the width direction of the metallized film, and metallikon electrodes at both ends in the width direction of the metallized film. A method of manufacturing a metallized film capacitor for manufacturing a formed metallized film capacitor, wherein the metallized film is uniform except for a first metal deposition electrode having a split electrode having a fuse portion and a margin portion. And a second metal-deposited electrode without a split electrode, wherein both the first and second metal-deposited electrodes are on the side closer to the metallikon electrode. It is configured to form a heavy edge portion having a large metal deposition thickness connected to the metallicon electrode, and the thickness of the heavy edge portion of the first metal deposition electrode is larger than the thickness of the heavy edge portion of the second metal deposition electrode. A method for producing a metallized film capacitor, characterized in that it is produced by depositing a metal so as to be thick.