JP4419213B2

JP4419213B2 - Electrolytic capacitor element impregnation method and impregnation apparatus

Info

Publication number: JP4419213B2
Application number: JP17060499A
Authority: JP
Inventors: 宏次芦野
Original assignee: Nippon Chemi Con Corp
Current assignee: Nippon Chemi Con Corp
Priority date: 1999-06-17
Filing date: 1999-06-17
Publication date: 2010-02-24
Anticipated expiration: 2019-06-17
Also published as: JP2000357639A

Description

【０００１】
【発明の属する技術分野】
本発明は、電解コンデンサ素子に電解液を含浸する含浸方法及び含浸装置に係り、特に、電気的特性の優れた電解コンデンサ素子を作製することができる電解コンデンサ素子の含浸方法及び含浸装置に関するものである。
【０００２】
【従来の技術】
従来から、電解コンデンサ素子に電解液を含浸する方法として、複数の電解コンデンサ素子のリード線をクランプ治具によって整列挾持して電解コンデンサ素子を真空含浸槽内に搬送し、その真空含浸槽内を真空状態にして電解コンデンサ素子の本体内部の空気を排除した後、電解液を供給してこれを電解コンデンサ素子の本体内部に含浸させる方法及び装置が用いられている。
【０００３】
しかし、上述したような従来の含浸方法及び装置によると、真空含浸槽に供給される電解液は大気中に解放されていて、電解液の内部に空気を含んでいるため、その電解液が真空含浸槽へ供給されたとき、その電解液の内部に含まれていた空気が細かい気泡となって拡散し、その一部が電解コンデンサ素子内部へ電解液と共に浸入してピンホール状の未含浸部分を形成してしまい、電解コンデンサ素子を用いた電解コンデンサの電気的特性を劣化させるという欠点があった。
【０００４】
また、真空含浸槽内において、電解液中の空気が急速に泡となって拡散するので、電解液が沸騰状態となって各部に飛び跳ね、例えばリード線に付着して、後工程での半田付け作業での半田付け不良の原因となる欠点があった。さらに、これが、自動組立機の稼動率を低下させる原因ともなっていた。
【０００５】
さらに、電解液の脱泡が真空含浸槽内で行われるため、真空含浸槽内の圧力を必要とされる真空度にまで高めるためには比較的長い時間を要し、含浸作業の作業効率が低下すると共に、大型の電解コンデンサ素子の中心部にまで十分電解液を含浸させることができないという欠点があった。また、このような現象は、高耐圧の電解コンデンサに使用される粘度の高い電解液においては著しく、粘度の高い電解液を含浸させるためには大型の装置を用いなければならないという欠点があった。
【０００６】
また、真空含浸の終了後、真空含浸槽内の残余の電解液を貯留槽へ返送するためダイヤフラム式ポンプ等の専用ポンプを備えていたので、装置が大型となると共に製作費が高価となる欠点があった。
【０００７】
このような種々の問題点を解決するため、特公平７−８２９７３号公報に示されたように、真空とした貯留槽内で電解液中の空気を真空脱泡した後、その電解液を真空含浸槽へ真空圧により吸い上げて供給して、電解コンデンサ素子に電解液を含浸させる含浸方法及び装置が提案されている。
【０００８】
【発明が解決しようとする課題】
しかしながら、上述したような従来の電解コンデンサ素子の含浸方法では、電解液の発泡等の影響で、充分な真空度を得ることが非常に困難であり、そのために所望の含浸ができなかった。すなわち、コンデンサ素子に、粘度の高い電解液を含浸する場合や、大型のコンデンサ素子に電解液を含浸する場合には、電解液をコンデンサ素子の中心部にまで充分に含浸させることができず、静電容量やＥＳＲ等の所望の電気的特性が得られなかった。
【０００９】
本発明は、上述したような従来技術の問題点を解決するために提案されたものであり、その目的は、電解液を含浸槽に注入する際の電解液の減圧状態を保持し、高真空状態における電解液の発泡を防止して、充分な含浸状態を得ることができる電解コンデンサ素子の含浸方法及び含浸装置を提供することにある。
【００１０】
【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、請求項１に記載の電解コンデンサ素子の含浸方法は、電解コンデンサ素子に電解液を含浸させる含浸槽と、前記電解液を貯留する貯留槽を配設し、両者を開閉弁を介して連結し、乾燥状態にした含浸槽内に、前記電解コンデンサ素子と適量の水分とを収容し、含浸槽及び貯留槽内を所定の気圧に減圧して、含浸槽内の水分を気化させると共に、貯留槽内の電解液を脱泡させ、含浸槽を密閉状態にした後、前記貯留槽内の電解液を含浸槽内に供給し、含浸槽の前記密閉状態を所定時間維持した後、含浸槽内を大気圧に戻すことにより、前記電解液を電解コンデンサ素子に含浸させることを特徴とするものである。
【００１１】
また、請求項４に記載の電解コンデンサ素子の含浸装置は、上記請求項１に記載の発明を装置の観点から捉えたものであって、電解コンデンサ素子を収容して電解液を含浸させる含浸槽と、前記電解液を貯留する貯留槽と、前記含浸槽及び貯留槽内の圧力を所定のタイミングに従って真空とする真空制御装置とを有する電解コンデンサ素子の含浸装置において、前記含浸槽内を乾燥状態にした後、前記電解コンデンサ素子と適量の水分とを含浸槽内に収容し、含浸槽及び貯留槽内を所定の気圧に減圧して、含浸槽内の水分を気化させると共に、貯留槽内の電解液を脱泡させ、含浸槽を密閉状態にした後、前記貯留槽内の電解液を含浸槽内に供給し、所定時間、含浸槽の密閉状態を維持した後、含浸槽内を大気圧に戻すように構成したことを特徴とするものである。
【００１２】
上記のような構成を有する請求項１あるいは請求項４に記載の発明によれば、予め含浸槽内を乾燥させ、この含浸槽内に電解コンデンサ素子と適量の水分とを収容し、この水分を気化させることによって含浸槽内に水蒸気を存在させ、この水蒸気と電解液とが、減圧下、密閉容器内で相互に作用することにより、含浸槽内の気圧を電解液を注入する前よりさらに減少させることができるので、高真空状態から大気圧に戻す際の加圧幅が大きくなる。また、電解液は液相を維持しているので、電解液の含浸効率が大幅に向上し、素子内部並びにピット内に電解液がより効率良く浸透することができる。
【００１３】
請求項２に記載の電解コンデンサ素子の含浸方法は、請求項１に記載の電解コンデンサ素子の含浸方法において、乾燥状態にした含浸槽内に、電解コンデンサ素子を水分を含んだ状態で収容し、含浸槽及び貯留槽内を所定の気圧に減圧して、電解コンデンサ素子の水分を含浸槽内で気化させると共に、貯留槽内の電解液を脱泡させることを特徴とするものである。
【００１４】
また、請求項５に記載の電解コンデンサ素子の含浸装置は、上記請求項２に記載の発明を装置の観点から捉えたものであって、請求項４に記載の電解コンデンサ素子の含浸装置において、前記電解コンデンサ素子を、水分を含んだ状態で含浸槽内に収容し、含浸槽及び貯留槽内を所定の気圧に減圧して、電解コンデンサ素子の水分を含浸槽内で気化させるように構成したことを特徴とするものである。
【００１５】
上記のような構成を有する請求項２あるいは請求項５に記載の発明によれば、電解コンデンサ素子を水分を含んだ状態で含浸槽内に収容し、この電解コンデンサ素子に含まれる水分を含浸槽内で気化させることによって含浸槽内に水蒸気を存在させることができるので、上記請求項１あるいは請求項４に記載の発明と同様の作用・効果を得ることができる。
【００１６】
請求項３に記載の電解コンデンサ素子の含浸方法は、請求項１または請求項２に記載の電解コンデンサ素子の含浸方法において、前記貯留槽を前記含浸槽の上部に配設し、両者を開閉弁を介して連結し、含浸槽を密閉状態にした後、前記貯留槽内の電解液を含浸槽内に自由落下により供給することを特徴とするものである。
【００１７】
また、請求項６に記載の電解コンデンサ素子の含浸装置は、上記請求項３に記載の発明を装置の観点から捉えたものであって、請求項４または請求項５に記載の電解コンデンサ素子の含浸装置において、前記貯留槽を前記含浸槽の上部に配設し、両者を開閉弁を介して連結し、含浸槽を密閉状態にした後、前記貯留槽内の電解液を含浸槽内に自由落下により供給するように構成したことを特徴とするものである。
【００１８】
上記のような構成を有する請求項３あるいは請求項６に記載の発明によれば、貯留槽内で脱泡した電解液を、貯留槽と含浸槽の気圧差を利用することなく含浸槽内に供給することができるので、電解液の状態が移送中に変化することを防止できる。
【００１９】
請求項７に記載の発明は、請求項４乃至請求項６のいずれか一に記載の電解コンデンサ素子の含浸装置において、含浸槽内に電解コンデンサ素子を収容する手段が、内側容器と外側容器とからなる二重容器であり、前記電解液が前記内側容器にのみ供給されるように構成されていることを特徴とするものである。
上記のような構成を有する請求項７に記載の発明によれば、含浸処理の際に電解液によって濡れるのは内側トレイのみであるので、含浸処理終了後に、内側トレイだけを交換すれば良い。
【００２０】
【発明の実施の形態】
以下、本発明に係る電解コンデンサ素子の含浸装置の一つの実施の形態を、図面を参照して具体的に説明する。
【００２１】
［１．構成］
本実施形態の電解コンデンサ素子の含浸装置１は、図１に示したように、含浸槽２、貯留槽３及び真空制御装置４をその主たる構成要素としている。
【００２２】
（含浸槽）
含浸槽２は、その内部に搬送された複数のコンデンサ素子に電解液を含浸するためのものであって、含浸槽２には、その一側面に開閉可能な蓋２１が設けられ、この開口部より含浸槽内部に、複数のコンデンサ素子を搭載した１または２以上の含浸トレイ２２ａ、２２ｂ…を装着し、取り出すことができるように構成されている。このように、含浸槽２は、その内部に含浸トレイ２２ａ、２２ｂ…を装着することにより二重構造とされている。
【００２３】
また、含浸槽２には、含浸槽２と真空制御装置４とを連結するパイプ２３の開閉を制御する第１のバルブ２４、前記各含浸トレイ２２ａ、２２ｂ…と後述する貯留槽３とを連結するパイプ２５ａ、２５ｂ…の開閉を制御する第２のバルブ２６ａ、２６ｂ…、及び含浸槽２を大気に開放する第３のバルブ２７が設けられている。
【００２４】
（貯留槽）
貯留槽３は、電解液３１を貯留すると共に、電解液３１を真空脱泡して含浸槽２へ供給するものであって、貯留槽３には、貯留槽３と真空制御装置４とを連結するパイプ３２の開閉を制御する第４のバルブ３３、前記含浸槽２内に装着された各含浸トレイ２２ａ、２２ｂ…と貯留槽３とを連結するパイプ２５ａ、２５ｂ…、及び貯留槽３を大気に開放する第５のバルブ３４が設けられている。また、貯留槽３は、前記含浸槽２の上部に配設され、第２のバルブ２６ａ、２６ｂ…を開くことによって、内部に収納された電解液３１が、下部に配設された含浸槽２内に自由落下により供給されるように構成されている。
なお、素子に含浸する電解液３１としては、多価アルコール（例えば、エチレングリコール、グリセリン等）を溶媒とし、各種溶質、添加剤を溶解したものを使用する。
【００２５】
（真空制御装置）
真空制御装置４は、前記含浸槽２及び貯留槽３内の圧力を真空にするためのものであって、公知の真空ポンプ４１によって駆動され、真空計４２の測定値に基づいて、真空度を制御するように構成されている。
【００２６】
［２．含浸方法］
本発明の電解コンデンサ素子の含浸方法においては、含浸槽２内に装着するコンデンサ素子を乾燥させないこと、及び、含浸槽２内を乾燥状態にすることが必須要件である。
すなわち、コンデンサ素子は、通常、陽極箔等と共に巻回される紙製のセパレータに重量比で２〜５％の水分が含まれているので、乾燥処理を施さずに、素子内に水分を残留させた状態のままで含浸槽２内に装着する。あるいは、いったんコンデンサ素子を乾燥させ、恒温恒湿器と真空容器等で所定の水分量をガス置換することにより、素子内に水分を含ませても良い。この場合は、コンデンサ素子内に含有される水分量を定常化することができる。なお、恒温恒湿器と真空容器等でガス置換する水分量としては、セパレータ重量比で２〜５％が望ましい。素子中に含まれる水分量が多すぎると、製品として使用した場合の内部圧力の上昇が早まるためである。
【００２７】
一方、含浸槽内を乾燥状態にするとは、含浸槽内に電解液中に含まれるエチレングリコール等の多価アルコールが存在しない状態にすることを意味する。すなわち、本実施形態においては、含浸槽２は内部に含浸トレイ２２を備えることにより二重構造化されているので、含浸処理のたびに含浸トレイ２２を交換することにより、トレイ内にエチレングリコール等の多価アルコールが存在しない状態にする。
【００２８】
そして、第２のバルブ２６、第３のバルブ２７及び第５のバルブ３４を閉じ、第１のバルブ２４及び第４のバルブ３３を開けた状態で、真空ポンプ４１により、含浸槽２及び電解液が貯留されている貯留槽３内を所定の気圧に減圧する。一定気圧（例えば、５Ｔｏｒｒ）に達したら、真空制御装置４により、含浸槽２及び貯留槽３内を一定時間（約５分間）、この気圧に維持する。
【００２９】
これにより、含浸槽２内において、コンデンサ素子は一定時間（約５分間）、一定の気圧下、例えば水の蒸気圧以下で放置され、脱気されることにより、コンデンサ素子に含まれる水分が蒸発し始め、その水蒸気が被含浸物であるコンデンサ素子の内部の空気を外部に押し出しながら、含浸槽２内に一定の水蒸気を存在させ、また、素子内（エッチングピット内）にも一定の水蒸気を存在させることができる。一方、素子を放置した含浸槽２内と同気圧にされた貯留槽３内においては、電解液３１が脱気（脱泡）される。
【００３０】
続いて、第１のバルブ２４を閉じ、第２のバルブ２６を開けて、自由落下により、貯留槽３内の電解液３１を含浸槽２内の含浸トレイ２２ａ、２２ｂ…に供給する。各含浸トレイに所定量の電解液３１が供給された時点で、第２のバルブ２６を閉じ、一定時間放置する。なお、貯留槽３から含浸槽２に電解液３１を注入する際、含浸槽２は密閉状態にされている。
【００３１】
そして、第３のバルブ２７を開けて、含浸槽２内を大気圧に戻す。このときの加圧で、電解液が素子内に含浸される。その後、含浸槽２内から含浸トレイ２２ａ、２２ｂ…を取り出し、含浸槽内に未処理の素子を搭載した新たな含浸トレイをセットして、上記の処理を繰り返す。
【００３２】
［３．作用・効果］
本発明者が鋭意検討を重ねた結果、上記の含浸方法によれば、含浸槽内の気圧は結果的に電解液の蒸気圧以下に下がるものの、電解液はなおも発泡することなく液相を維持することができることが判明した。
【００３３】
すなわち、図２中、点線で示したように、従来の含浸方法においては、真空度が５Ｔｏｒｒに達するまで真空ポンプを駆動して真空制御を行い、電解液を注入した後も、同様に真空ポンプを駆動して真空制御を行い、５Ｔｏｒｒを維持していた。
【００３４】
これに対し、本実施形態の含浸方法においては、図２中、実線で示したように、従来と同様に真空度が５Ｔｏｒｒに達するまでは真空ポンプを駆動して真空制御を行うが、電解液注入以降、含浸槽内を密閉して真空制御を遮断すると、含浸槽内の気圧は電解液を注入する前よりさらに減少することが判明した。
その結果、高真空状態から大気圧に戻す際の加圧幅が従来と比べて大きくなり、また、電解液は液相を維持しているので、電解液の含浸効率が大幅に向上し、素子内部並びにピット内に電解液がより効率良く浸透するようになることが分かった。
【００３５】
上述したように含浸槽内の気圧が電解液を注入する前よりさらに減少する理由は、エチレングリコール等の多価アルコールと含浸槽内に存在する水蒸気とが、減圧下、密閉容器内で相互に作用したためと考えられる。
【００３６】
ここで、本発明を前記の特公平７−８２９７３号公報に記載された従来の真空含浸方法と比較検討した結果について述べる。すなわち、前記の特公平７−８２９７３号公報に記載された従来の真空含浸方法では、コンデンサ素子に連続的に含浸する場合、含浸槽内でのコンデンサ素子の脱気工程に先立って、予め含浸槽内を乾燥させていない。そのため、コンデンサ素子の脱気工程において、コンデンサ素子内に水分が存在している場合には、エチレングリコール等の多価アルコールが付着して乾燥していない含浸槽内で、水蒸気となった水分とエチレングリコールとが相互に作用してしまい、本発明のような、含浸槽に電解液を供給する際の減圧効果が得られない。
【００３７】
また、本発明者は、貯留槽から含浸槽に電解液を供給するために貯留槽の気圧を大気圧に戻し、含浸槽との気圧差によって電解液を供給すると、移送中に電解液の状態が変化し、上記のような減圧効果を得ることができないことを確認している。従って、従来の含浸方法では、充分な真空度を得ることができず、結果として、コンデンサ素子に充分な電解液を含浸させることはできない。
【００３８】
【実施例】
続いて、本発明の含浸方法による効果を、実施例を用いてより具体的に説明する。
なお、表１に示したように、乾燥処理を施した、水分を含まないコンデンサ素子を用いた電解コンデンサを従来例とし、乾燥処理を施していないコンデンサ素子を用いた電解コンデンサを比較例及び実施例として、各条件下、それぞれ静電容量、ＥＳＲ特性を調べた。
【００３９】
また、表中、水分「○」は、乾燥処理を施していないコンデンサ素子を用いたことを意味し、水分「×」は、乾燥処理を施したコンデンサ素子を用いたことを意味する。密閉「○」は、電解液注入後、含浸中真空ポンプを停止し、第１のバルブを密閉したことを意味し、密閉「×」は、電解液注入後、第１のバルブを開いたままにし、含浸中真空ポンプを継続して作動させ、一定気圧を保持したことを意味する。さらに、放置時間は、電解液注入後、第２のバルブを閉じて放置した時間を示している。
【００４０】
さらに、製品仕様は、４５０Ｖ４７０μＦ（ケースサイズ：３５φ５０Ｌ）であり、素子内のセパレータとしては、クラフト紙を用いた。さらに、電解液の組成は、溶媒として、エチレングリコール（ＥＧ）、グリセリンあるいはγ−ブチロラクトンを用い、溶質として１，６−デカンジカルボン酸を用いた。
【００４１】
【表１】

【００４２】
表１から明らかなように、従来例１と実施例１とを比較すると、ＥＳＲは約２５〜３０％低減し、静電容量は約２．３％増加した。また、乾燥処理を施していないコンデンサ素子を用いた比較例１と従来例１とを比較すると、ＥＳＲは約７〜１０％低減し、静電容量は約１．４％増加した。さらに、比較例１と実施例１とを比較すると、ＥＳＲは約２０〜２５％低減し、静電容量は約０．９％増加した。
これらの結果から、乾燥処理を施していないコンデンサ素子を用いた方が、ＥＳＲは低減し、さらに、密閉処理を施した方がＥＳＲはさらに低減することが判明した。
【００４３】
また、電解液の溶媒としてγ−ブチロラクトンを用いた比較例２においては、ＥＳＲは大幅に上昇しており、電解液の溶媒としてはエチレングリコールを用いることが望ましいことが判明した。
また、実施例１と実施例２とを比較すると、電解液の溶媒としてエチレングリコールを用いた方が、グリセリンを用いるよりＥＳＲの低減効果が大きいことが判明した。さらに、実施例１と実施例３とを比較すると、５分間放置した場合と１０分間放置した場合とで、大きな差は見られないことから、放置時間は５分以上であれば良いことが分かった。
【００４４】
このように、本発明の含浸方法によれば、素子への電解液浸透量の向上、エッチングピット内の減圧によるピット内への電解液浸透量の向上により、静電容量、ＥＳＲ特性が向上することが判明した。また、従来と同程度の性能を求めるのであれば、含浸時間の短縮が期待される。
【００４５】
［４．他の実施形態］
本発明は、上述した実施形態に限定されるものではなく、以下のような種々の変形例が考えられる。
すなわち、貯留槽、含浸槽内を同一気圧に減圧し、かつ制御できるのであれば、それぞれの槽に別個にポンプを取り付けても良い。この場合、真空制御装置は各ポンプ毎に設置するか、全ポンプを同時に制御するように構成する。
【００４６】
また、含浸トレイの構造は任意であり、公知のチャック等を用いることも可能である。さらに、図３に示したように、含浸トレイ２２ａ、２２ｂ…を、内側トレイ２８と外側トレイ２９とから構成された二重構造としても良い。この場合、貯留槽３と連結するパイプ２５ａ、２５ｂ…の先端部は、それぞれ含浸トレイ２２ａ、２２ｂ…の内側トレイ２８内に位置するように配設する。そして、含浸処理のたびに内側トレイ２８のみを交換するようにしても良い。また、含浸槽内を１回毎に洗浄、乾燥させれば、含浸トレイは不要であり、その場合は一度に多量の素子に電解液を含浸することができる。
【００４７】
さらに、貯留槽内で脱泡した電解液を含浸槽内に供給する方法としては、気圧差を利用しない供給方法が望ましく、上記の実施形態のような“自由落下”の他に、“ピストンを用いて電解液を押し出す方法”を用いることもできる。
【００４８】
【発明の効果】
以上説明したように、本発明においては、電解液を含浸槽に注入する際の電解液の減圧状態を保持し、高真空状態における電解液の発泡を防止して、充分な含浸状態を得ることができる電解コンデンサ素子の含浸方法及び含浸装置を提供することができる。
【図面の簡単な説明】
【図１】本発明による電解コンデンサ素子の含浸装置の一実施形態の構成を示す概略図
【図２】含浸槽内における真空制御パターンを示す図
【図３】二重構造化された含浸トレイの構成を示す斜視図
【符号の説明】
１…電解コンデンサ素子の含浸装置
２…含浸槽
３…貯留槽
４…真空制御装置
２１…蓋
２２…含浸トレイ
２３…パイプ
２４…第１のバルブ
２５…パイプ
２６…第２のバルブ
２７…第３のバルブ
２８…内側トレイ
２９…外側トレイ
３１…電解液
３２…パイプ
３３…第４のバルブ
３４…第５のバルブ
４１…真空ポンプ
４２…真空計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impregnation method and an impregnation apparatus for impregnating an electrolytic capacitor element with an electrolytic solution, and more particularly to an impregnation method and an impregnation apparatus for an electrolytic capacitor element capable of producing an electrolytic capacitor element having excellent electrical characteristics. is there.
[0002]
[Prior art]
Conventionally, as a method for impregnating an electrolytic capacitor element with an electrolytic solution, lead wires of a plurality of electrolytic capacitor elements are aligned and held by a clamp jig, and the electrolytic capacitor elements are conveyed into a vacuum impregnation tank. 2. Description of the Related Art A method and apparatus are used in which a vacuum is removed and air inside the body of the electrolytic capacitor element is removed, and then an electrolytic solution is supplied and impregnated inside the body of the electrolytic capacitor element.
[0003]
However, according to the conventional impregnation method and apparatus as described above, the electrolytic solution supplied to the vacuum impregnation tank is released into the atmosphere and contains air inside the electrolytic solution. When supplied to the impregnation tank, the air contained in the electrolyte solution diffuses as fine bubbles, and a part of the air enters the electrolytic capacitor element together with the electrolyte solution to cause the pinhole-shaped unimpregnated portion. As a result, the electrical characteristics of the electrolytic capacitor using the electrolytic capacitor element are deteriorated.
[0004]
Also, in the vacuum impregnation tank, the air in the electrolyte rapidly diffuses as bubbles, so the electrolyte becomes boiled and jumps to each part, for example, adheres to the lead wire and is soldered in the later process There was a defect that caused soldering failure in work. Furthermore, this has been a cause of lowering the operation rate of the automatic assembly machine.
[0005]
Furthermore, since defoaming of the electrolyte is performed in the vacuum impregnation tank, it takes a relatively long time to increase the pressure in the vacuum impregnation tank to the required degree of vacuum, and the work efficiency of the impregnation work is improved. In addition to the reduction, there is a drawback that the electrolytic solution cannot be sufficiently impregnated to the center of the large electrolytic capacitor element. In addition, such a phenomenon is remarkable in a high-viscosity electrolytic solution used in a high-voltage electrolytic capacitor, and there is a drawback that a large apparatus must be used to impregnate a high-viscosity electrolytic solution. .
[0006]
In addition, after the vacuum impregnation is completed, a dedicated pump such as a diaphragm pump is provided to return the remaining electrolyte in the vacuum impregnation tank to the storage tank, so that the apparatus becomes large and the manufacturing cost is high. was there.
[0007]
In order to solve such various problems, as shown in Japanese Examined Patent Publication No. 7-821973, air in the electrolytic solution is degassed in a vacuum storage tank, and then the electrolytic solution is evacuated. An impregnation method and apparatus have been proposed in which an electrolytic capacitor element is impregnated with an electrolytic solution by sucking and supplying the impregnation tank by vacuum pressure.
[0008]
[Problems to be solved by the invention]
However, in the conventional method for impregnating an electrolytic capacitor element as described above, it is very difficult to obtain a sufficient degree of vacuum due to the influence of foaming of the electrolytic solution, and thus the desired impregnation cannot be achieved. That is, when the capacitor element is impregnated with a high-viscosity electrolyte solution, or when the large capacitor element is impregnated with the electrolyte solution, the electrolyte solution cannot be sufficiently impregnated to the center of the capacitor element, Desired electrical characteristics such as capacitance and ESR could not be obtained.
[0009]
The present invention has been proposed in order to solve the problems of the prior art as described above, and its purpose is to maintain a reduced pressure state of the electrolytic solution when the electrolytic solution is injected into the impregnation tank, and to achieve a high vacuum. It is an object of the present invention to provide an electrolytic capacitor element impregnation method and an impregnation apparatus capable of preventing foaming of an electrolytic solution in a state and obtaining a sufficient impregnation state.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, an electrolytic capacitor element impregnation method according to claim 1 is provided with an impregnation tank for impregnating an electrolytic capacitor element with an electrolytic solution and a storage tank for storing the electrolytic solution, The electrolytic capacitor element and an appropriate amount of water are accommodated in a dry impregnation tank connected through an on-off valve, and the impregnation tank and the storage tank are depressurized to a predetermined pressure, After evaporating moisture and defoaming the electrolyte in the storage tank and making the impregnation tank sealed, the electrolyte in the storage tank is supplied into the impregnation tank and the sealing state of the impregnation tank is maintained for a predetermined time. After the maintenance, the electrolytic capacitor element is impregnated with the electrolytic solution by returning the inside of the impregnation tank to atmospheric pressure.
[0011]
According to a fourth aspect of the present invention, there is provided an impregnation apparatus for electrolytic capacitor elements, which captures the invention according to the first aspect from the viewpoint of the apparatus, and contains an electrolytic capacitor element and impregnates an electrolytic solution. And an impregnating apparatus for an electrolytic capacitor element having a storage tank for storing the electrolytic solution, and a vacuum controller for evacuating the impregnation tank and the pressure in the storage tank in accordance with a predetermined timing. After that, the electrolytic capacitor element and an appropriate amount of water are accommodated in an impregnation tank, and the impregnation tank and the storage tank are depressurized to a predetermined pressure to evaporate the water in the impregnation tank. After the electrolyte solution is degassed and the impregnation tank is sealed, the electrolyte solution in the storage tank is supplied into the impregnation tank, and the impregnation tank is kept sealed for a predetermined time. That it was configured to return to It is an.
[0012]
According to the invention described in claim 1 or claim 4 having the above-described configuration, the inside of the impregnation tank is dried in advance, and the electrolytic capacitor element and an appropriate amount of water are accommodated in the impregnation tank. Vaporization causes water vapor to exist in the impregnation tank, and this water vapor and electrolyte interact with each other in a sealed container under reduced pressure, thereby further reducing the pressure in the impregnation tank from before the electrolyte was injected. Therefore, the pressurization width when returning from the high vacuum state to the atmospheric pressure is increased. Moreover, since the electrolytic solution maintains the liquid phase, the impregnation efficiency of the electrolytic solution is greatly improved, and the electrolytic solution can penetrate more efficiently into the element and the pit.
[0013]
The method for impregnating an electrolytic capacitor element according to claim 2 is the method for impregnating an electrolytic capacitor element according to claim 1, wherein the electrolytic capacitor element is contained in a dry impregnation tank in a state containing moisture, The inside of the impregnation tank and the storage tank is depressurized to a predetermined pressure so that the moisture of the electrolytic capacitor element is vaporized in the impregnation tank and the electrolytic solution in the storage tank is degassed.
[0014]
An impregnation device for an electrolytic capacitor element according to claim 5 captures the invention according to claim 2 from the viewpoint of the device, and the impregnation device for electrolytic capacitor element according to claim 4, The electrolytic capacitor element is housed in an impregnation tank in a state of containing water, and the impregnation tank and the storage tank are depressurized to a predetermined pressure so that the moisture of the electrolytic capacitor element is vaporized in the impregnation tank. It is characterized by this.
[0015]
According to the invention described in claim 2 or claim 5 having the above-described configuration, the electrolytic capacitor element is contained in the impregnation tank in a state containing moisture, and the moisture contained in the electrolytic capacitor element is impregnated with the impregnation tank. Since the water vapor can be present in the impregnation tank by being vaporized in the inside, the same actions and effects as the invention of the first or fourth aspect can be obtained.
[0016]
The electrolytic capacitor element impregnation method according to claim 3 is the electrolytic capacitor element impregnation method according to claim 1 or 2, wherein the storage tank is disposed above the impregnation tank, and both are opened and closed. Then, after the impregnation tank is sealed, the electrolytic solution in the storage tank is supplied into the impregnation tank by free fall.
[0017]
An impregnation apparatus for an electrolytic capacitor element according to a sixth aspect captures the invention according to the third aspect from the viewpoint of the apparatus, and the electrolytic capacitor element according to the fourth or fifth aspect. In the impregnation apparatus, the storage tank is disposed in the upper part of the impregnation tank, and both are connected via an on-off valve, and after the impregnation tank is sealed, the electrolytic solution in the storage tank is freely introduced into the impregnation tank. It is characterized by being configured to be supplied by dropping.
[0018]
According to invention of Claim 3 or Claim 6 which has the above structures, electrolyte solution degassed in the storage tank is put into the impregnation tank without using the pressure difference between the storage tank and the impregnation tank. Since it can supply, it can prevent that the state of electrolyte solution changes during transfer.
[0019]
According to a seventh aspect of the present invention, in the electrolytic capacitor element impregnation apparatus according to any one of the fourth to sixth aspects, the means for accommodating the electrolytic capacitor element in the impregnation tank includes an inner container, an outer container, A double container comprising: the electrolyte solution is configured to be supplied only to the inner container.
According to the seventh aspect of the invention having the above-described configuration, only the inner tray is wetted by the electrolytic solution during the impregnation treatment, and therefore only the inner tray needs to be replaced after the impregnation treatment.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an impregnation apparatus for electrolytic capacitor elements according to the present invention will be described in detail with reference to the drawings.
[0021]
[1. Constitution]
As shown in FIG. 1, the electrolytic capacitor element impregnation apparatus 1 of this embodiment includes an impregnation tank 2, a storage tank 3, and a vacuum control device 4 as main components.
[0022]
(Impregnation tank)
The impregnation tank 2 is for impregnating a plurality of capacitor elements conveyed therein with an electrolytic solution, and the impregnation tank 2 is provided with a lid 21 that can be opened and closed on one side surface thereof. Further, one or two or more impregnation trays 22a, 22b... Mounted with a plurality of capacitor elements can be mounted inside the impregnation tank and taken out. Thus, the impregnation tank 2 has a double structure by mounting the impregnation trays 22a, 22b.
[0023]
Further, the impregnation tank 2 is connected to a first valve 24 for controlling the opening and closing of a pipe 23 connecting the impregnation tank 2 and the vacuum control device 4, the respective impregnation trays 22 a, 22 b. Are provided with second valves 26a, 26b... For controlling the opening and closing of the pipes 25a, 25b... And a third valve 27 for opening the impregnation tank 2 to the atmosphere.
[0024]
(Reservoir)
The storage tank 3 stores the electrolytic solution 31 and supplies the electrolytic solution 31 to the impregnation tank 2 by vacuum degassing. The storage tank 3 is connected to the storage tank 3 and the vacuum control device 4. The fourth valve 33 that controls the opening and closing of the pipe 32 to be opened, the pipes 25a, 25b,... That connect the respective impregnation trays 22a, 22b,. A fifth valve 34 is provided to open. Moreover, the storage tank 3 is arrange | positioned by the upper part of the said impregnation tank 2, and the electrolyte solution 31 accommodated in the inside is opened by opening 2nd valve | bulb 26a, 26b ... The impregnation tank 2 arrange | positioned by the lower part. It is configured to be supplied by free fall.
As the electrolytic solution 31 impregnated in the element, a solution in which various solutes and additives are dissolved using a polyhydric alcohol (for example, ethylene glycol, glycerin, etc.) as a solvent is used.
[0025]
(Vacuum control device)
The vacuum control device 4 is used to evacuate the pressure in the impregnation tank 2 and the storage tank 3, and is driven by a known vacuum pump 41 to adjust the degree of vacuum based on the measured value of the vacuum gauge 42. Configured to control.
[0026]
[2. Impregnation method]
In the electrolytic capacitor element impregnation method of the present invention, it is essential that the capacitor element mounted in the impregnation tank 2 is not dried and that the impregnation tank 2 is in a dry state.
In other words, the capacitor element usually contains 2 to 5% of water by weight in a paper separator wound with an anode foil or the like, so that moisture remains in the element without being subjected to drying treatment. It is mounted in the impregnation tank 2 as it is. Alternatively, the capacitor element may be once dried, and moisture may be contained in the element by gas-substituting a predetermined amount of moisture with a constant temperature and humidity chamber and a vacuum container. In this case, the amount of water contained in the capacitor element can be made steady. In addition, as a moisture content which carries out gas substitution with a constant temperature and humidity chamber, a vacuum vessel, etc., 2 to 5% is desirable by separator weight ratio. This is because if the amount of moisture contained in the element is too large, the internal pressure rises when used as a product.
[0027]
On the other hand, making the inside of the impregnation tank dry means that the polyhydric alcohol such as ethylene glycol contained in the electrolytic solution does not exist in the impregnation tank. That is, in this embodiment, since the impregnation tank 2 has a double structure by providing the impregnation tray 22 inside, by replacing the impregnation tray 22 every impregnation treatment, ethylene glycol or the like is placed in the tray. The polyhydric alcohol is not present.
[0028]
Then, the second valve 26, the third valve 27, and the fifth valve 34 are closed, and the first valve 24 and the fourth valve 33 are opened. Is depressurized to a predetermined atmospheric pressure. When a certain atmospheric pressure (for example, 5 Torr) is reached, the inside of the impregnation tank 2 and the storage tank 3 is maintained at this atmospheric pressure by the vacuum controller 4 for a certain time (about 5 minutes).
[0029]
As a result, in the impregnation tank 2, the capacitor element is left for a certain time (about 5 minutes) at a certain atmospheric pressure, for example, below the vapor pressure of water, and deaerated, whereby the water contained in the capacitor element evaporates. Then, while the water vapor pushes out the air inside the capacitor element, which is the impregnated material, constant water vapor is present in the impregnation tank 2, and constant water vapor is also generated in the element (in the etching pit). Can exist. On the other hand, the electrolytic solution 31 is degassed (defoamed) in the storage tank 3 having the same atmospheric pressure as the impregnation tank 2 in which the element is left.
[0030]
Subsequently, the first valve 24 is closed, the second valve 26 is opened, and the electrolytic solution 31 in the storage tank 3 is supplied to the impregnation trays 22a, 22b,. When a predetermined amount of electrolytic solution 31 is supplied to each impregnation tray, the second valve 26 is closed and left for a predetermined time. In addition, when inject | pouring the electrolyte solution 31 from the storage tank 3 to the impregnation tank 2, the impregnation tank 2 is sealed.
[0031]
And the 3rd valve | bulb 27 is opened and the inside of the impregnation tank 2 is returned to atmospheric pressure. With the pressurization at this time, the electrolytic solution is impregnated in the element. Thereafter, the impregnation trays 22a, 22b,... Are taken out from the impregnation tank 2, a new impregnation tray on which an untreated element is mounted is set in the impregnation tank, and the above processing is repeated.
[0032]
[3. Action / Effect]
As a result of repeated studies by the inventor, according to the above impregnation method, although the atmospheric pressure in the impregnation tank eventually falls below the vapor pressure of the electrolytic solution, the electrolytic solution still does not foam and does not foam. It was found that it can be maintained.
[0033]
That is, as shown by the dotted line in FIG. 2, in the conventional impregnation method, the vacuum pump is driven until the degree of vacuum reaches 5 Torr, vacuum control is performed, and after the electrolyte is injected, the vacuum pump is similarly applied. To control the vacuum and maintain 5 Torr.
[0034]
On the other hand, in the impregnation method of the present embodiment, as shown by the solid line in FIG. 2, the vacuum pump is driven to control the vacuum until the degree of vacuum reaches 5 Torr as in the conventional case. After the injection, it was found that when the inside of the impregnation tank was sealed and the vacuum control was interrupted, the pressure in the impregnation tank was further reduced than before the electrolyte was injected.
As a result, the pressure range when returning from a high vacuum state to atmospheric pressure is larger than in the past, and the electrolyte solution maintains a liquid phase, so the impregnation efficiency of the electrolyte solution is greatly improved, and the element It was found that the electrolyte solution penetrates more efficiently into the inside and into the pit.
[0035]
As described above, the reason why the atmospheric pressure in the impregnation tank is further reduced than before the electrolyte is injected is that the polyhydric alcohol such as ethylene glycol and the water vapor present in the impregnation tank are mutually reduced in a sealed container under reduced pressure. It is thought that it acted.
[0036]
Here, the result of comparing the present invention with the conventional vacuum impregnation method described in the above Japanese Patent Publication No. 7-82773 will be described. That is, in the conventional vacuum impregnation method described in the above-mentioned Japanese Examined Patent Publication No. 7-821973, when the capacitor element is continuously impregnated, the impregnation tank is previously provided prior to the deaeration process of the capacitor element in the impregnation tank. The inside is not dried. Therefore, in the deaeration process of the capacitor element, when moisture is present in the capacitor element, the moisture converted into water vapor in the impregnation tank where polyhydric alcohol such as ethylene glycol adheres and is not dried. The ethylene glycol interacts with each other, and the pressure reducing effect when supplying the electrolytic solution to the impregnation tank as in the present invention cannot be obtained.
[0037]
Further, the present inventor returns the atmospheric pressure of the storage tank to the atmospheric pressure in order to supply the electrolytic solution from the storage tank to the impregnation tank, and supplies the electrolytic solution by the atmospheric pressure difference from the impregnation tank. It has been confirmed that the pressure reducing effect as described above cannot be obtained. Therefore, the conventional impregnation method cannot obtain a sufficient degree of vacuum, and as a result, the capacitor element cannot be impregnated with a sufficient electrolytic solution.
[0038]
【Example】
Next, the effects of the impregnation method of the present invention will be described more specifically using examples.
As shown in Table 1, an electrolytic capacitor using a capacitor element that does not contain moisture that has been subjected to a drying process is a conventional example, and an electrolytic capacitor that uses a capacitor element that has not been subjected to a drying process is a comparative example and an implementation. As an example, capacitance and ESR characteristics were examined under each condition.
[0039]
Further, in the table, moisture “◯” means that a capacitor element that has not been subjected to drying treatment is used, and moisture “x” means that a capacitor element that has been subjected to drying treatment is used. Sealing “O” means that the vacuum pump was stopped during impregnation after the electrolyte injection, and the first valve was sealed, and sealing “X” means that the first valve was kept open after the electrolyte injection. And the vacuum pump was continuously operated during the impregnation to maintain a constant atmospheric pressure. Furthermore, the standing time indicates the time when the second valve is closed after the electrolyte is injected.
[0040]
Further, the product specification is 450V470 μF (case size: 35φ50L), and kraft paper was used as the separator in the element. Furthermore, the composition of the electrolytic solution used ethylene glycol (EG), glycerin or γ-butyrolactone as a solvent, and 1,6-decanedicarboxylic acid as a solute.
[0041]
[Table 1]

[0042]
As is apparent from Table 1, when the conventional example 1 and the example 1 are compared, the ESR is reduced by about 25 to 30%, and the capacitance is increased by about 2.3%. Further, when Comparative Example 1 using a capacitor element not subjected to drying treatment was compared with Conventional Example 1, ESR was reduced by about 7 to 10%, and capacitance was increased by about 1.4%. Further, when Comparative Example 1 and Example 1 were compared, ESR was reduced by about 20 to 25%, and capacitance was increased by about 0.9%.
From these results, it was found that the ESR was reduced by using the capacitor element that had not been subjected to the drying treatment, and that the ESR was further reduced by the sealing treatment.
[0043]
Further, in Comparative Example 2 in which γ-butyrolactone was used as a solvent for the electrolytic solution, the ESR was significantly increased, and it was found that it is desirable to use ethylene glycol as the solvent for the electrolytic solution.
Further, comparing Example 1 and Example 2, it was found that the use of ethylene glycol as the solvent of the electrolytic solution had a greater effect of reducing ESR than the use of glycerin. Furthermore, when Example 1 and Example 3 are compared, there is no significant difference between when left for 5 minutes and when left for 10 minutes. It was.
[0044]
As described above, according to the impregnation method of the present invention, the capacitance and ESR characteristics are improved by improving the amount of electrolyte permeating into the device and improving the amount of electrolyte permeating into the pit by reducing the pressure inside the etching pit. It has been found. In addition, if the same level of performance as before is required, the impregnation time can be shortened.
[0045]
[4. Other Embodiments]
The present invention is not limited to the above-described embodiment, and various modifications as described below are possible.
That is, if the inside of a storage tank and an impregnation tank can be pressure-reduced and controlled to the same atmospheric pressure, you may attach a pump separately to each tank. In this case, the vacuum control device is installed for each pump or is configured to control all the pumps simultaneously.
[0046]
Further, the structure of the impregnation tray is arbitrary, and a known chuck or the like can be used. Further, as shown in FIG. 3, the impregnation trays 22 a, 22 b... May have a double structure including an inner tray 28 and an outer tray 29. In this case, the tip ends of the pipes 25a, 25b... Connected to the storage tank 3 are arranged so as to be located in the inner trays 28 of the impregnation trays 22a, 22b. Then, only the inner tray 28 may be replaced every time the impregnation process is performed. Further, if the inside of the impregnation tank is washed and dried each time, the impregnation tray is unnecessary, and in that case, a large amount of elements can be impregnated with the electrolytic solution at one time.
[0047]
Furthermore, as a method of supplying the electrolyte degassed in the storage tank to the impregnation tank, a supply method that does not use a pressure difference is desirable. In addition to “free fall” as in the above-described embodiment, It is also possible to use the “method of extruding an electrolytic solution by using”.
[0048]
【The invention's effect】
As described above, in the present invention, a reduced pressure state of the electrolytic solution when the electrolytic solution is injected into the impregnation tank is maintained, and foaming of the electrolytic solution in a high vacuum state is prevented to obtain a sufficiently impregnated state. It is possible to provide an impregnation method and an impregnation apparatus for electrolytic capacitor elements.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the configuration of an embodiment of an impregnation apparatus for electrolytic capacitor elements according to the present invention. FIG. 2 is a diagram showing a vacuum control pattern in an impregnation tank. Perspective view showing configuration [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electrolytic capacitor element impregnation apparatus 2 ... Impregnation tank 3 ... Storage tank 4 ... Vacuum control apparatus 21 ... Lid 22 ... Impregnation tray 23 ... Pipe 24 ... First valve 25 ... Pipe 26 ... Second valve 27 ... Third Valve 28 ... inner tray 29 ... outer tray 31 ... electrolyte 32 ... pipe 33 ... fourth valve 34 ... fifth valve 41 ... vacuum pump 42 ... vacuum gauge

Claims

An impregnation tank for impregnating the electrolytic capacitor element with the electrolytic solution and a storage tank for storing the electrolytic solution are disposed, and both are connected via an on-off valve, and the electrolytic capacitor element and the electrolytic capacitor element are placed in a dry state. An appropriate amount of water is stored, the impregnation tank and the storage tank are depressurized to a predetermined pressure, the moisture in the impregnation tank is vaporized, the electrolyte in the storage tank is degassed, and the impregnation tank is sealed After supplying the electrolytic solution in the storage tank into the impregnation tank, maintaining the sealed state of the impregnation tank for a predetermined time, and then returning the inside of the impregnation tank to atmospheric pressure, the electrolytic solution is supplied to the electrolytic capacitor element. A method for impregnating an electrolytic capacitor element, comprising impregnating.

The electrolytic capacitor element is accommodated in a dry impregnation tank in a state of containing moisture, and the impregnation tank and the storage tank are depressurized to a predetermined pressure to vaporize the electrolytic capacitor element in the impregnation tank. 2. The electrolytic capacitor element impregnation method according to claim 1, wherein the electrolytic solution in the storage tank is degassed.

The storage tank is disposed in the upper part of the impregnation tank, both are connected via an on-off valve, the impregnation tank is sealed, and then the electrolytic solution in the storage tank is supplied into the impregnation tank by free fall. The method for impregnating an electrolytic capacitor element according to claim 1 or 2, wherein the electrolytic capacitor element is impregnated.

An electrolysis having an impregnation tank for containing an electrolytic capacitor element and impregnating with an electrolytic solution, a storage tank for storing the electrolytic solution, and a vacuum control device for evacuating the pressure in the impregnation tank and the storage tank according to a predetermined timing In the impregnation device for capacitor elements,
After the inside of the impregnation tank is dried, the electrolytic capacitor element and an appropriate amount of water are accommodated in the impregnation tank, and the impregnation tank and the storage tank are depressurized to a predetermined pressure to vaporize the water in the impregnation tank. And after degassing the electrolyte in the storage tank and sealing the impregnation tank, supplying the electrolyte in the storage tank into the impregnation tank and maintaining the sealed state of the impregnation tank for a predetermined time An electrolytic capacitor element impregnation apparatus characterized in that the inside of the impregnation tank is returned to atmospheric pressure.

The electrolytic capacitor element is housed in an impregnation tank in a state of containing water, and the impregnation tank and the storage tank are depressurized to a predetermined pressure so that the moisture of the electrolytic capacitor element is vaporized in the impregnation tank. The impregnation apparatus for electrolytic capacitor elements according to claim 4.

The storage tank is disposed in the upper part of the impregnation tank, both are connected via an on-off valve, the impregnation tank is sealed, and then the electrolytic solution in the storage tank is supplied into the impregnation tank by free fall. 6. The electrolytic capacitor element impregnation apparatus according to claim 4, wherein the impregnation apparatus is configured as described above.

The means for accommodating the electrolytic capacitor element in the impregnation tank is a double container comprising an inner container and an outer container, and the electrolytic solution is configured to be supplied only to the inner container. The impregnation apparatus for electrolytic capacitor elements according to any one of claims 4 to 6.