JP2004363431A

JP2004363431A - Metalized film capacitor

Info

Publication number: JP2004363431A
Application number: JP2003161773A
Authority: JP
Inventors: Kohei Shioda; 浩平塩田; Hiroki Takeoka; 宏樹竹岡; Toshiharu Saito; 俊晴斎藤; Tomoyuki Yamagata; 知之山形
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-06-06
Filing date: 2003-06-06
Publication date: 2004-12-24

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a conventional metalized film capacitor including lattice shaped split electrodes, having electrode separate slits along an electrode lead-out part, the slits being connected by electrode lead-out fuse parts that the temperature of the capacitor is increased at application of power, and the withstanding voltage of the capacitor has been decreased. <P>SOLUTION: The capacitor is configured such that a current flowing from a metallicon electrode 1 via an electrode lead-out 2 to respectively each of small unit capacitors 7 adjacent to each other along electrode separation slits 3 through a plurality of (two or over) electrode lead-out fuses 4 to each of them small unit capacitors 7 are adjacent to each other. Thus, a metalized film having lattice shaped small unit capacitor parts is provided with electrode separation slits without a vapor-deposit metal along the electrode lead-out part; and electrode lead-out fuse parts formed partially traversing the electrode separation slits, at least two or over, that is, a plurality of the electrode lead-out fuses are provided to each of the small unit capacitors adjacent to each electrode lead-out fuse, so that the semiconductor integrated circuit can be realized with a self-protective function, that is, the metalized film capacitor with less heat generation at current conduction and usable at a high potential gradient. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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、金属蒸着電極部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】
金属化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、金属箔を電極に用いるもの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、誘電体フィルムに施した金属蒸着電極部特有の自己回復性能すなわち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金属蒸着電極が蒸発・飛散してその蒸発・飛散部分が絶縁化し、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（例えば特許文献１参照）。
【０００３】
このような金属化フィルムコンデンサについて図３を参照して説明する。図３において、金属蒸着電極部３１内に金属部分が無い分割スリット３２を格子状に設けて微細な小単位コンデンサ部分３３に区分し、分割スリット３２に部分的に形成した小単位コンデンサ間ヒューズ部３４により前記小単位コンデンサ部分３３を並列接続することが行われている。これは、前述の自己回復時の短絡電流により絶縁欠陥部周囲の小単位コンデンサ間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とともに、小単位コンデンサ部分の面積が小さく分割できることから、小単位コンデンサ間ヒューズ部の溶断による電極容量減少も小さくなり、誘電体フィルム１μｍのあたりの電圧を高める高電位傾度化が図れるとされている。
【０００４】
そして１０〜１０００ｍｍ^２の面積からなる格子状に分割された小単位コンデンサ部分３３と各小単位コンデンサ部分３３を接続する０．０５〜１．５ｍｍ幅の小単位コンデンサ間ヒューズ部３４が有り、かつメタリコン電極３５と隣接する電極引出し部３６に沿った部分に電極分離スリット３７を設けている。この電極分離スリット３７内に設けた電極引出しヒューズ部３８は、電極引出し部３６と電極分離スリット３７に隣接する小単位コンデンサ部分３３を導通する役目を果たしている。前記分割スリット３２内に設けた小単位コンデンサヒューズ部３４とは幅寸法が異なっている。すなわち、電極引出しヒューズ部３８の幅を前記小単位コンデンサ間ヒューズ部３４の幅に対し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ことが開示されている。
【０００５】
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、自己保安機能として働く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。
【０００６】
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。そしてコンデンサの温度上昇が大きくなると、コンデンサの耐電圧や長期信頼性が低下するため、この問題は解消すべき大きな課題となっていた。
【０００７】
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。
【０００８】
かかる従来の課題はメタリコン電極３５から電極引出し部３６を通して電極引出しヒューズ部３８へ電流が流れ込む際に、電極引出し部３６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することに起因することが明らかになり、また電極引出し部３６が劣化してｔａｎδが悪化したりすることを究明した。
【０００９】
すなわち、図３において、コンデンサを流れる電流は、メタリコン電極３５から端面全体で流れ込み図３の矢印３９で示すように、電極引出し部３６を長手方向に流れた後矢印４０に示す方向に流れ、電極引出しヒューズ部３８を通じて矢印４１の方向に流れ、隣接する小単位コンデンサ部分３３に至るのであり、電極引出し部３６自体が、幅が狭くて電極引出しヒューズ部３８に至るのに長い電流経路を通ることになっているため、発熱してしまうことが本発明者等の究明によって判明した。
【００１０】
【特許文献１】
特開平８−２５０３６７号公報
【００１１】
【発明が解決しようとする課題】
前記従来例の技術的な問題点に鑑み、本発明が解決しようとする課題は、通電時の発熱を小さく、すなわちコンデンサの温度上昇を小さくし、かつ自己保安性能の高い金属化フィルムコンデンサを提供することにある。
【００１２】
【課題を解決するための手段】
上記目的を達成するために請求項１記載に係る発明は、電極引出し部と電極分離スリットに隣接する各小単位コンデンサ部分とを電極分離スリットを部分的に横切って形成した電極引出しヒューズ部によって導通する構成において、各小単位コンデンサ部分はそれぞれ複数の電極引出しヒューズ部によって前記電極引出し部に導通することとした。
【００１３】
この構成によれば、メタリコン電極から電極引出し部を経由して電極分離スリットに隣接する各小単位コンデンサ部分に流れ込む電流は少なくとも２つ以上の複数の電極引出しヒューズ部を通すことになる。従って図３に示す様なメタリコン電極、電極引出し部を経由して一つの電極引出しヒューズ部を通って電流が各小単位コンデンサ部分に流れ込むのに比較して電流経路が短くなり、電極引出し部の発熱が少ない。これによりコンデンサの温度上昇も、従来例より小さく、コンデンサの耐電圧や長期信頼性の低下が少ない。
【００１４】
また、請求項２記載に係る発明のように、電極分離スリットに沿った各小単位コンデンサ部分毎に存在する複数の電極引出しヒューズ部の位置は、前記電極分離スリットに沿う各小単位コンデンサ部分同士の隣接点を中心として前記電極分離スリット上のそれぞれ相反する方向の対称位置とすることにより、メタリコン電極から、電極引出し部を経由して複数の電極引出しヒューズ部より各小単位コンデンサ部分に流れる電流経路の長さは、各小単位コンデンサ部分の何れもが均等となる。従って電流経路の長さの不均等に起因して電極引出し部のなかで局部的に温度が上昇することはない。
【００１５】
また、請求項３記載の発明のように、電極引出しヒューズ部を電極分離スリット上に等間隔で形成する構成とすることにより、電極引出しヒューズ部の位置が等間隔になる。従って電極引出し部を流れる電流は等間隔に存在する電極引出しヒューズ部を通ることとなり、電極引出し部を流れる電流が不均等になることがなく、局部的に電流が多く流れる部分がないので電極引出し部に局部的な温度上昇がない。
【００１６】
また、請求項４記載の発明のように、電極引出しヒューズ部の幅を小単位コンデンサ間ヒューズ部の幅以下としても、各小単位コンデンサ部分の各辺にある小単位コンデンサ部分間ヒューズ部よりも電極分離スリットにある電極引出しヒューズ部間の間隔は狭く、すなわち小単位コンデンサ部分間ヒューズ部よりも電極引出しヒューズ部の方が設置密度が多いため電極引出し部は円滑に電流が流れることになり局部的な温度上昇は従来例よりも少ない。
【００１７】
また、請求項５記載の発明のように、電極引出しヒューズ部を０．１ｍｍ以上で０．５ｍｍ以下の幅とすることにより、１００℃における自己保安機能の動作性の低下がなく、かつ電極引出しヒューズ部の形成がし易い生産性の利点がある。
【００１８】
また、請求項６記載に係る発明のように１枚の誘電体フィルムの両面に金属蒸着膜を形成した両面金属蒸着フィルムと、金属が蒸着されていない誘電体フィルムとを重ね合わせることにより、すなわち一方の金属蒸着フィルムの誘電体フィルムと他方の金属蒸着フィルムの誘電体フィルムを共通の１枚の誘電体フィルムとすることにより金属蒸着フィルムは１枚でよく、生産工数を減らすことができる。
【００１９】
また、本発明による金属化フィルムコンデンサは自己発熱が小さく、温度上昇が小さいので、電気モータの制御を行うインバータ用平滑コンデンサとか、使用温度環境の厳しい自動車用途のコンデンサとして最適である。
【００２０】
【発明の実施の形態】
本発明の目的は、各請求項に記載した構成を要部とすることにより達成できるのであるが、以下には図を参照しながら具体的な構成の実施例を説明する。
【００２１】
（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金属化フィルムおよびこれに接続するメタリコン電極を示す鳥瞰図である。図１において金属化フィルムは、一側端でメタリコン電極１と接続する電極引出し部２を有し、前記電極引出し部２に沿って長手方向に伸びる蒸着金属の無い電極分離スリット３と、前記電極分離スリット３を部分的に横切って形成された電極引出しヒューズ部４を備えている。また金属化フィルムの有効電極部は分割スリット５により格子状に区分され、前記分割スリット５を部分的に横切って形成された小単位コンデンサ間ヒューズ部６により並列接続された小単位コンデンサからなっている。そして、前記電極引出しヒューズ部４は、電極分離スリット３に沿って隣接する各小単位コンデンサ部分７のそれぞれに対して２本設けられている。前記電極引出しヒューズ部４が電極分離スリット３上に設けられている位置は、電極分離スリット３に沿う各小単位コンデンサ部分同士の隣接点８を中心として電極分離スリット３上のそれぞれ相反する方向の対称位置としている。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。
【００２２】
図１を参照して説明すると、メタリコン電極１の端面全体から流れる電流は、図１の矢印１０で示すように電極引出し部２を図１の横方向に流れた後矢印１１に示す方向に流れ電極引出しヒューズ部４を通じて矢印１２の方向に流れ電極分離スリット３に隣接する小単位コンデンサ部分７に至る。そしてこの電極引出しヒューズ部４は電極分離スリット３に沿っている各小単位コンデンサ部分７にそれぞれ２本あるため、図３で示した従来の１本しかない金属化フィルムにおける場合のようにメタリコン電極３５の端面から流れる電流が電極引出しヒューズ部３８に至る経路よりも短いことになる。従って本実施例では発熱の少ない金属化フィルムコンデンサにすることができる。９は絶縁マージン部である。
【００２３】
また、図２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金属化フィルムおよびこれに接続するメタリコン電極を示す鳥瞰図である。なお、図１に示した構成部分と同じ構成部分には同じ符号を付与し詳細な説明を省略する。図２からわかるように、電極引出しヒューズ部４は、隣接する小単位コンデンサ部分７に対して２本づつ、ほぼ等間隔に設けられている。この構成により、さらに発熱が少なく、高電位傾度で使用可能な金属化フィルムコンデンサを実現できる。
【００２４】
次に、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特性例について説明する。
【００２５】
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、図１および図２に示す構成の金属化フィルムを作製した。なお、ヒューズ幅の影響を検討するために、電極引出しヒューズ部４および小単位コンデンサ間ヒューズ部６の幅を変えて各金属化フィルムを作製した。この金属化フィルムと、同一幅でスリットやヒューズ部がない金属化フィルム（所謂ベタ蒸着フィルム）を、絶縁マージン部が異なる側に配置されるよう重ねて巻回し、２００μＦの小判型コンデンサ素子を作製して、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、比較のために、図３に示す従来技術よりなるコンデンサも作製した。なお、いずれの場合も蒸着金属としては、アルミニウムを用いた。
【００２６】
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。得られた結果を次の表１に示す。
【００２７】
【表１】

【００２８】
実施の形態１、２と従来例の比較から、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明らかに小さい。
【００２９】
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に示す。本発明よりなるコンデンサは従来例に比べて高電圧下での容量減少が明らかに小さく、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フィルムの耐圧が低下するために、多くの個所で局部短絡によるヒューズ溶断が発生したのに対し、本発明の実施の形態１、２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。
【００３０】
さらに、各コンデンサに対して、８５℃および１００℃で自己保安機能の試験を行った。試験方法は、まず、７００ＶＤＣを２４時間連続印加した後、２４時間毎に３５ＶＤＣづつ昇圧して、各電圧での２４時間後の容量の変化率を測定した。そして、容量が試験前の初期値に対して９７％以上減少した場合に、自己保安機能が動作したとみなした。また、試験中にコンデンサがショート状態に至った場合には、自己保安機能が不良とみなした。得られた結果を表１に示す。電極引出しヒューズ部の幅が小単位コンデンサ間ヒューズ部よりも太い場合や、電極引出しヒューズ部の幅が０．５ｍｍを超える場合には、８５℃では問題なく動作したが、１００℃における自己保安機能の動作性が低下した。したがって、電極引出しヒューズ部の幅は小単位コンデンサ間ヒューズ部の幅以下、もしくは０．５ｍｍ以下とすることが望ましい。なお、０．１ｍｍ未満の幅では、ヒューズ部の形成自体が困難となることから、電極引出しヒューズ部の幅は、０．１〜０．５ｍｍとすることが望ましい。
【００３１】
なお、前記実施の形態では、四角形状からなる小単位コンデンサ部分を例として説明したが、本発明はこれに限定するものではなく、他の形状、例えば六角形状、三角形状の格子状の小単位コンデンサ部分においても同様の結果を得た。
【００３２】
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。また誘電体フィルムとして、２枚以上のフィルムを重ねても、同様の効果を得た。
【００３３】
また蒸着金属として亜鉛、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。
【００３４】
また、分割スリットにより小単位コンデンサ部分が形成される態様とベタ蒸着電極は別々のフィルムに設けても、これらまたは同じパターンの金属蒸着を同じフィルムの表裏に設け、未蒸着のフィルムと重ねて積層、巻回しても良い。
【００３５】
また、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。またコンデンサ形状は丸型でもよい。
【００３６】
【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、格子状の小単位コンデンサ部分を有する金属化フィルムにおいて、電極引出し部に沿う蒸着金属の無い電極分離スリットと、電極分離スリットを部分的に横切って形成された電極引出しヒューズ部を備え、前記電極引出しヒューズ部を隣接する小単位コンデンサ部分のそれぞれに対して少なくとも２本以上すなわち複数設けることにより、自己保安機能を有し、しかも電流通電時に発熱が少なく、高電位傾度で使用可能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の鳥瞰図
【図２】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３】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メタリコン電極
２電極引出し部
３電極分離スリット
４電極引出しヒューズ部
５分割スリット
６小単位コンデンサ間ヒューズ部
７小単位コンデンサ部分
８隣接点
９絶縁マージン部[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 portion.
[0002]
[Prior art]
In general, metallized film capacitors are roughly classified into those using a metal foil for an electrode and those using a metal deposited on a dielectric film for an electrode. Among them, the metallized film capacitor using a vapor-deposited metal as the electrode has a smaller volume and smaller weight than the electrode using a metal foil as the electrode, and has a characteristic characteristic of the metal-deposited electrode portion applied to the dielectric film. Self-healing performance, that is, when a short circuit occurs in an insulation defect, the metal deposition electrode around the defect evaporates and scatters due to the energy of the short circuit, and the evaporated and scattered part is insulated, and the capacitor recovers its function. Because of its high reliability against destruction, it has been widely used (for example, see Patent Document 1).
[0003]
Such a metallized film capacitor will be described with reference to FIG. In FIG. 3, a divided slit 32 having no metal portion in a metal deposition electrode portion 31 is provided in a lattice shape and divided into fine small unit capacitor portions 33, and a small unit capacitor fuse portion formed partially in the divided slit 32. 34, the small unit capacitor portions 33 are connected in parallel. This is because the short-circuit current at the time of self-recovery mentioned above blows the fuse between the small unit capacitors around the insulation defect and forms a self-protection function that separates the insulation defect from the electric circuit. Since it can be divided into small pieces, the decrease in electrode capacity due to the blowing of the fuse portion between the small unit capacitors is also small, and a high potential gradient that increases the voltage per 1 μm of the dielectric film can be achieved.
[0004]
There is a small unit capacitor portion 33 divided into a lattice having an area of 10 to 1000 mm ² and a small unit capacitor inter-unit fuse portion 34 having a width of 0.05 to 1.5 mm for connecting each small unit capacitor portion 33, and An electrode separation slit 37 is provided in a portion along the electrode lead-out portion 36 adjacent to the metallikon electrode 35. The electrode extraction fuse portion 38 provided in the electrode separation slit 37 serves to conduct the electrode extraction portion 36 and the small unit capacitor portion 33 adjacent to the electrode separation slit 37. The width dimension is different from the small unit capacitor fuse portion 34 provided in the division slit 32. That is, when the width of the electrode lead-out fuse portion 38 is 2 to 20 times the width of the small-unit capacitor fuse portion 34, the DC potential gradient is 130 to 350 V / μm, and the AC potential gradient is 60 to 120 V / μm. It is disclosed that a μm metallized film capacitor can be realized.
[0005]
However, the metallized film capacitor provided with the above-described self-security function has a problem in that heat generated by a current when energized is larger than that of a metallized film capacitor having no fuse portion serving as a self-security function.
[0006]
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 increases, the withstand voltage and long-term reliability of the capacitor decrease, and this problem has been a major problem to be solved.
[0007]
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.
[0008]
Such a conventional problem is caused by the fact that when the current flows from the metallikon electrode 35 to the electrode extraction fuse portion 38 through the electrode extraction portion 36, the electrode extraction portion 36 itself generates heat, so that the temperature of the capacitor greatly increases. And the fact that the electrode lead portion 36 is deteriorated and tan δ is deteriorated.
[0009]
That is, in FIG. 3, the current flowing through the capacitor flows from the metallikon electrode 35 over the entire end face, and flows in the electrode lead portion 36 in the longitudinal direction as shown by the arrow 39 in FIG. The current flows in the direction of arrow 41 through the extraction fuse portion 38 and reaches the adjacent small unit capacitor portion 33. The electrode extraction portion 36 itself has a narrow width and passes through a long current path to reach the electrode extraction fuse portion 38. It has been found by the inventors of the present invention that heat is generated.
[0010]
[Patent Document 1]
JP-A-8-250367
[Problems to be solved by the invention]
In view of the technical problems of the conventional example, the problem to be solved by the present invention is to provide a metallized film capacitor that generates less heat when energized, that is, reduces the temperature rise of the capacitor and has high self-protection performance. Is to do.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that the electrode lead portion and each small unit capacitor portion adjacent to the electrode separation slit are electrically connected by an electrode lead fuse portion formed partially across the electrode separation slit. In this configuration, each small unit capacitor portion is electrically connected to the electrode lead portion by a plurality of electrode lead fuse portions.
[0013]
According to this configuration, the current flowing from the metallikon electrode to the small unit capacitor portion adjacent to the electrode separation slit via the electrode extraction portion passes through at least two or more of the electrode extraction fuse portions. Therefore, the current path is shorter than the current flowing into each small unit capacitor portion through one electrode extraction fuse portion via the metal interconnection electrode and the electrode extraction portion as shown in FIG. Low fever. As a result, the temperature rise of the capacitor is smaller than that of the conventional example, and the decrease in the withstand voltage and the long-term reliability of the capacitor is small.
[0014]
Further, as in the invention according to claim 2, the positions of the plurality of electrode lead-out fuse portions that are present for each small unit capacitor portion along the electrode separation slit are different from each other for each small unit capacitor portion along the electrode separation slit. Currents flowing from the metallikon electrode to the small unit capacitor portions from the plurality of electrode lead-out fuse portions via the electrode lead-out portions by setting the symmetrical positions in the opposite directions on the electrode separation slits with the adjacent point as the center. The length of the path is equal for each of the small unit capacitor portions. Therefore, the temperature does not locally increase in the electrode lead portion due to the uneven length of the current path.
[0015]
In addition, as in the third aspect of the present invention, by forming the electrode extraction fuse portions on the electrode separation slit at equal intervals, the positions of the electrode extraction fuse portions are equal. Therefore, the current flowing through the electrode lead portion passes through the electrode lead fuse portion which is present at equal intervals, the current flowing through the electrode lead portion does not become uneven, and there is no portion where a large amount of current flows locally. There is no local temperature rise in the part.
[0016]
Further, as in the invention according to claim 4, even if the width of the electrode lead-out fuse portion is set to be equal to or smaller than the width of the fuse portion between the small unit capacitors, the width is smaller than that of the fuse portion between the small unit capacitor portions on each side of each small unit capacitor portion. The gap between the electrode extraction fuses in the electrode separation slit is narrow, that is, the electrode extraction fuse has a higher installation density than the fuse for the small unit capacitor part, so that the current flows smoothly in the electrode extraction fuse and the local area. The typical temperature rise is smaller than in the conventional example.
[0017]
Further, as in the invention according to claim 5, by setting the width of the electrode drawing fuse portion to be 0.1 mm or more and 0.5 mm or less, the operability of the self-protection function at 100 ° C. is not reduced, and the electrode drawing is performed. There is an advantage in productivity that the fuse portion can be easily formed.
[0018]
Further, by superposing a double-sided metal vapor-deposited film in which a metal vapor-deposited film is formed on both sides of one dielectric film as in the invention according to claim 6, and a dielectric film on which no metal is vapor-deposited, By using the dielectric film of one metal-deposited film and the dielectric film of the other metal-deposited film as one common dielectric film, only one metal-deposited film is required, and the number of production steps can be reduced.
[0019]
Further, the metallized film capacitor according to the present invention has a small self-heating and a small temperature rise, and is therefore most suitable as a smoothing capacitor for an inverter for controlling an electric motor or a capacitor for an automobile used in a severe operating temperature environment.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
The object of the present invention can be achieved by making the configuration described in each claim a main part. Hereinafter, an embodiment of a specific configuration will be described with reference to the drawings.
[0021]
(Embodiment 1)
FIG. 1 is a bird's-eye view showing a metallized film of a metallized film capacitor according to a first embodiment of the present invention and metallikon electrodes connected thereto. In FIG. 1, the metallized film has an electrode lead portion 2 connected to a metallikon electrode 1 at one side end, and has an electrode separation slit 3 having no metal deposited and extending in the longitudinal direction along the electrode lead portion 2; An electrode extraction fuse portion 4 formed partially across the separation slit 3 is provided. Further, the effective electrode portion of the metallized film is divided into a lattice shape by the division slits 5 and is composed of small unit capacitors connected in parallel by small unit inter-capacitor fuse portions 6 formed partially across the division slits 5. I have. Further, two electrode extraction fuse portions 4 are provided for each of the small unit capacitor portions 7 adjacent along the electrode separation slit 3. The position where the electrode extraction fuse portion 4 is provided on the electrode separation slit 3 is set in the opposite direction on the electrode separation slit 3 around the adjacent point 8 of each small unit capacitor portion along the electrode separation slit 3. The position is symmetric. With this configuration, it is possible to realize a metallized film capacitor having a self-security function and generating less heat.
[0022]
Referring to FIG. 1, the current flowing from the entire end face of the metallikon electrode 1 flows through the electrode lead portion 2 in the horizontal direction in FIG. It flows in the direction of arrow 12 through the electrode extraction fuse portion 4 and reaches the small unit capacitor portion 7 adjacent to the electrode separation slit 3. Since there are two electrode pull-out fuse portions 4 in each small unit capacitor portion 7 along the electrode separation slit 3, as in the case of the conventional metallized film having only one electrode shown in FIG. The current flowing from the end face 35 is shorter than the path leading to the electrode extraction fuse section 38. Therefore, in this embodiment, a metallized film capacitor that generates less heat can be obtained. 9 is an insulation margin part.
[0023]
FIG. 2 is a bird's-eye view showing the metallized film of the metallized film capacitor according to the second embodiment of the present invention and the metallikon electrodes connected thereto. The same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted. As can be seen from FIG. 2, the electrode lead fuse portions 4 are provided at substantially equal intervals, two by two, with respect to the adjacent small unit capacitor portion 7. With this configuration, it is possible to realize a metallized film capacitor that generates less heat and can be used with a high potential gradient.
[0024]
Next, an example of characteristics of the metallized film capacitor according to the first and second embodiments of the present invention will be described.
[0025]
Using a polypropylene film having a thickness of 3.5 μm and a width of 70 mm, a metallized film having the configuration shown in FIGS. 1 and 2 was produced. In addition, in order to examine the influence of the fuse width, each metallized film was manufactured by changing the width of the electrode lead-out fuse portion 4 and the fuse portion 6 between the small unit capacitors. This metallized film and a metallized film having the same width and without slits or fuses (so-called solid vapor-deposited film) are superposed and wound so that the insulation margins are arranged on different sides, thereby producing a 200 μF oval capacitor element. Then, it was put in a case made of polybutylene terephthalate and molded with epoxy resin. For comparison, a capacitor according to the prior art shown in FIG. 3 was also manufactured. In each case, aluminum was used as the metal to be deposited.
[0026]
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. The results obtained are shown in Table 1 below.
[0027]
[Table 1]

[0028]
From the comparison between the first and second embodiments and the conventional example, the capacitor according to the present invention has a significantly smaller temperature rise than the conventional example.
[0029]
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. Table 1 shows the results. The capacitor according to the present invention has a significantly smaller capacity decrease under a high voltage than the conventional example, and can be used with a high potential gradient. This is because, in the conventional example, the fuse was blown due to a local short circuit in many places because the withstand voltage of the film was lowered due to the heat generated by the ripple current. This is because the generation of heat by the current is suppressed, so that the fusing of the fuse portion is reduced.
[0030]
In addition, each capacitor was tested for self-security at 85 ° C and 100 ° C. In the test method, first, 700 VDC was applied continuously for 24 hours, then the voltage was increased by 35 VDC every 24 hours, and the rate of change in capacity at each voltage after 24 hours was measured. Then, when the capacity decreased by 97% or more from the initial value before the test, it was considered that the self-security function was operated. When the capacitor was short-circuited during the test, the self-security function was considered to be defective. Table 1 shows the obtained results. When the width of the electrode lead fuse part was wider than the small unit capacitor-to-capacitor fuse part, or when the width of the electrode lead fuse part exceeded 0.5 mm, it operated without any problem at 85 ° C. Operability decreased. Therefore, it is desirable that the width of the electrode lead fuse portion is equal to or less than the width of the fuse portion between the small unit capacitors, or 0.5 mm or less. If the width is less than 0.1 mm, the formation of the fuse portion itself becomes difficult. Therefore, the width of the electrode lead fuse portion is desirably 0.1 to 0.5 mm.
[0031]
In the above-described embodiment, the small unit capacitor portion having a square shape has been described as an example, but the present invention is not limited to this, and other shapes such as a hexagonal shape, a triangular lattice-like small unit may be used. Similar results were obtained in the capacitor part.
[0032]
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 a dielectric film.
[0033]
Similar effects were obtained when zinc or a mixture of zinc and aluminum was used as the metal to be deposited.
[0034]
Also, even if the mode in which the small unit capacitor portion is formed by the split slit and the solid deposition electrode are provided on separate films, these or the same pattern of metal deposition is provided on the front and back of the same film, and is laminated on an undeposited film. , May be wound.
[0035]
Further, in the embodiment, the example of the dry type oval type capacitor molded with the epoxy resin has been described, but 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.
[0036]
【The invention's effect】
As is apparent from the above description, according to the present invention, in the metallized film having the lattice-shaped small unit capacitor portion, the electrode separation slit without the vapor-deposited metal along the electrode lead portion, and the electrode separation slit are partially formed. It has an electrode drawing fuse portion formed across, and has a self-security function by providing at least two or more, ie, a plurality of, said electrode drawing fuse portions for each of the adjacent small unit capacitor portions, and has a self-protection function, and at the time of current supply. It is possible to realize a metallized film capacitor that generates less heat and can be used with a high potential gradient.
[Brief description of the drawings]
FIG. 1 is a bird's-eye view of a metallized film according to Embodiment 1 of the present invention. FIG. 2 is a bird's-eye view of a metallized film according to Embodiment 2 of the present invention. ]
DESCRIPTION OF SYMBOLS 1 Metallicon electrode 2 Electrode extraction part 3 Electrode separation slit 4 Electrode extraction fuse part 5 Split slit 6 Fuse part between small unit capacitors 7 Small unit capacitor part 8 Adjacent point 9 Insulation margin part

Claims

A pair of metal-deposited films provided with an insulating margin at one end of the dielectric film and an electrode lead-out portion connected to the metallikon electrode at the other end are provided with the positions of the insulating margin and the metallikon electrode opposite to each other. In the metallized film capacitor wound or laminated so that at least one of the pair of metal-deposited films has an elongated electrode separation slit parallel to the electrode lead-out portion, an effective electrode portion, Are divided into a lattice shape by a dividing slit, and a large number of small unit capacitor portions are connected in parallel by a small unit inter-capacitor fuse portion partially crossing the dividing slit, and the electrode extraction portion and the electrode separating slit are formed. Each of the adjacent small unit capacitor portions is connected to an electrode extraction hole formed partially across the electrode separation slit. Be configured to conduct the over's unit, metallized film capacitors, characterized in that the turned to the electrode lead-out portion by a plurality of electrode lead-out fuse portion respectively each small unit capacitors moiety.

The positions of the plurality of electrode extraction fuse portions individually present in each of the small unit capacitor portions along the electrode separation slit are respectively located on the electrode separation slits around the adjacent point between the small unit capacitor portions along the electrode separation slit. 2. The metallized film capacitor according to claim 1, wherein the metallized film capacitors are symmetrical in opposite directions.

3. The metallized film capacitor according to claim 1, wherein the electrode drawing fuse portions are formed at equal intervals on the electrode separation slit.

4. The metallization according to claim 1, wherein the width of the electrode drawing fuse portion is smaller than the width of the fuse portion between the small unit capacitors which connects the small unit capacitor portions to each other across the separation slit. Film capacitor.

The metallized film capacitor according to any one of claims 1 to 4, wherein the electrode lead fuse portion has a width of 0.1 mm or more and 0.5 mm or less.

The double-sided metal-deposited film in which a metal-deposited film is formed on both sides of one dielectric film and a dielectric film on which no metal is deposited are overlapped with each other. Metallized film capacitors.

7. The metallized film capacitor according to claim 1, wherein the metalized film capacitor is used as an inverter smoothing capacitor.

7. The metallized film capacitor according to claim 1, wherein the metallized film capacitor is used for an automotive capacitor.