JP3931983B2

JP3931983B2 - Structure of electric lead part, electric device having the lead part structure, battery and assembled battery

Info

Publication number: JP3931983B2
Application number: JP2003182508A
Authority: JP
Inventors: 弘志屋ケ田; 牧宏乙幡
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2003-06-26
Filing date: 2003-06-26
Publication date: 2007-06-20
Anticipated expiration: 2023-06-26
Also published as: JP2005019213A

Description

【０００１】
【発明の属する技術分野】
本発明は、電気デバイスにおいて他のデバイスとの電気的接続のために用いられる電気リード部の構造、その構造を有する電気デバイス、電池、および組電池に関する。
【０００２】
【従来の技術】
携帯電話、ノート型パソコン、デジタルスチルカメラ、ビデオカメラといった携帯機器等の電源として用いられる電池には、軽量化、薄型化が強く要求されている。また、国際的な地球環境の保護のための省資源化や省エネルギ化の要請が高まるなか、モータ駆動用のバッテリ（電池）を搭載する電気自動車やハイブリッド電気自動車の開発が急速に進められつつある。これら電気自動車等に搭載される電池にも、操舵特性、航続距離を向上させるため、軽量化、薄型化が求められている。
【０００３】
このような要請を受け、電池を軽量かつ薄型とするため、その外装体にアルミニウムなどの金属層と熱溶着性の樹脂層とを積層して薄いシートとなしたラミネート材を用いた電池が開発されている（例えば、特許文献１参照）。
【０００４】
図１１に、ラミネート材を外装体とした従来の平型電池の一例を示す。図１１に示す電池おいて、ラミネート材からなる外装体１０２内には、セパレータを介して正極板および負極板を積層した電池要素（不図示）が、電解液とともに密封収納されている。外装体１０２の一辺からは、正極板に接続された正極端子１０４が延出している。また、外装体１０２の、正極端子１０４が延出している辺と反対側の辺からは、負極板に接続された負極端子１０８が延出している。リチウムイオン電池などの非水電解質電池の場合、正極端子１０４としてはアルミニウムが、また、負極端子１０８としては銅またはニッケルが、その電気的特性により多く用いられている。
【０００５】
このような構成の電池では、所望の電圧を得るためには複数の電池を直列接続する必要がある。その際には、例えば、電池を一列に並べ、正極端子を、その隣の電池の負極端子と接合し、組電池を構成する。
【０００６】
【特許文献１】
特開２００２−２０３５２４号公報
【０００７】
【発明が解決しようとする課題】
しかしながら、上述した従来の電池では、正極端子と負極端子とが互いに異なる金属で構成されているので、複数の電池を直列接続した場合に、異なる金属同士が接合されることになる。異なる金属同士が接合されている場合、両者の接合部に結露水などの電解液が存在すると、これら３者間に局部電池が形成され、陽極側の金属（イオン化傾向の大きい方の金属）が腐食するという問題が生じる。これは局部電池腐食とも呼ばれ、異なる金属同士の接合部が外気に曝されており、結露等によって接合部に電解液の一種である水が付着したような場合に、一般に起こり得る問題である。端子が腐食すると、端子の電気抵抗が上昇して電池の特性が低下するばかりでなく、電池の信頼性も低下する。
【０００８】
また、上述した局部電池腐食の問題は、両極の端子が互いに異なる金属からなる電池を直列接続した場合に限らず、固体電解コンデンサ、水系あるいは非水系電解コンデンサなどの電解コンデンサ、電気二重層コンデンサ、変圧器、ランプ、モータ、抵抗器など、リード端子を備えたその他の電気デバイスにおいても、他のデバイスとの電気的接続のため、あるいは材料費の低減等のために、リード端子が材質の異なる金属との接合部を有する構成となる場合には、同様に発生し得る。
【０００９】
そこで本発明は、局部電池の形成による端子の腐食を防止することによって、電気的特性を長期にわたって維持できる電気リード部の構造、電気デバイス、電池、および組電池を提供することを目的とする。
【００１０】
【課題を解決するための手段】
上記目的を達成するための本発明の電気リード部の構造は、電気デバイスのデバイス本体から延出して設けられた一対の電気リード部のうち一方の電気リード部の構造であって、デバイス本体から延出した第１の端子部材と、デバイス本体の外側で第１の端子部材と接合されて他のデバイスと電気的に接続される、一対の電気リード部の他方と同じ材質からなる第２の端子部材と、熱可塑性樹脂を含む２枚または２つ折りにした１枚のフィルムからなり、第１の端子部材と第２の端子部材との接合部を第１および第２の端子部材の厚さ方向両側から挟んで包囲した状態でフィルムを熱融着することによって、接合部を外気と触れなくするように被覆した被覆樹脂とを有する。そして、第１の端子部材と第２の端子部材とは、一方がアルミニウム板からなり、かつ、他方が銅板またはめっきされた銅板からなり、フィルムを通して接合部の被覆状態を目視できる程度に前記フィルムが透明である。
【００１１】
そして、本発明の電気デバイスは、デバイス本体と、デバイス本体から延出した正極および負極のリード部を有する電気デバイスにおいて、正極および負極のリード部のいずれか一方に、上記の構造を適用したものである。
【００１２】
上記のとおり構成された本発明の構造では、第1の端子部材と第２の端子部材とがデバイス本体の外側で接合されている。第1の端子部材と第２の端子部材とは互いに材質が異なっており、外気に接していると、その接合部では結露等により局部電池が形成されるおそれがある。しかし、両端子部材の接合部は、熱可塑性樹脂からなるフィルムを熱融着することによって形成された被覆樹脂で被覆され、外気とは遮断されているので、局部電池が形成されることはない。したがって、第２の端子部材を、接続される相手側のデバイスのリード部の材質と同じ材質とすることで、２つのデバイスを単純に接続するだけで、結露等が生じても局部電池が形成されるおそれのない接続が可能となる。また、被覆樹脂を構成するフィルムは透明であるので、フィルムを通して、第１の端子部材と第２の端子部材との接合部の被覆状態を目視で確認することができるようになる。
【００１３】
上記の発明において、第1の端子部材と第２の端子部材とを、それらの端部同士を互いに重ね合わせて接合した構成とし、第1の端子部材と第２の端子部材とが重なり合っている領域で、第１および第２の端子部材の幅方向両側端とフィルムとの間に充填材を充填することで、充填樹脂による接合部の被覆がより確実になされる。この場合、充填材としては、熱可塑性樹脂を用いることができる。
【００１４】
また本発明は、上記の電気リード部の構造を利用した電池および組電池を提供する。
【００１５】
すなわち本発明の電池は、外装体内に気密封止された電池要素と、該電池要素に接続されて前記外装体から延出した正極および負極のリード部を有する電池において、リード部のいずれか一方は、電池要素に接続されて外装体から延出した第１の端子部材と、外装体の外側で第１の端子部材の先端部と接合され、リード部のもう一方と同じ材質からなる第２の端子部材とを有し、第１の端子部材と第２の端子部材とは、一方がアルミニウム板からなり、かつ、他方が銅板またはめっきされた銅板からなり、第１の端子部材と第２の端子部材との接合部は、熱可塑性樹脂を含む２枚または２つ折りにした１枚のフィルムを第１および第２の端子部材の厚さ方向両側から挟んで包囲した状態で熱融着することによって形成された被覆樹脂で、外気と触れなくするように被覆され、フィルムは、フィルムを通して接合部の被覆状態を目視できる程度に透明であることを特徴とする。
【００１６】
本発明の電池は、正極または負極のリード部に上述した本発明の構造を適用し、正極のリード部の先端部と負極のリード部の先端部とはともに同じ材質としているので、この電池を直列接続する場合はそのまま接続して組電池を構成しても、局部電池が形成されることによる腐食の問題は生じない。
【００１７】
また、上述した本発明の電気リード部の構造を利用すれば、外装体内に気密封止された電池要素と、電池要素に接続されて外装体から延出した、アルミニウム板からなる正極のリード部および銅板からなる負極のリード部を有する複数の電池を直列に接続した組電池において、２つの電池間での正極のリード部と負極のリード部との接合部は、熱可塑性樹脂を含む２枚または２つ折りにされた１枚のフィルムを正極および負極のリード部の厚さ方向両側から挟んで包囲した状態で熱融着することで形成された被覆樹脂で、外気と触れなくするように被覆され、フィルムは、フィルムを通して接合部の被覆状態を目視できる程度に透明であることを特徴とする組電池を構成することもできる。
【００１８】
【発明の実施の形態】
次に、本発明の実施形態について図面を参照して説明する。
【００１９】
（第１の実施形態）
図１は、本発明の第１の実施形態による平型電池の外観斜視図である。図２は、図１に示す平型電池の分解斜視図である。
【００２０】
本実施形態の平型電池１は、フィルム外装電池とも呼ばれ、電池要素３と、電池要素３に設けられた正極集電部３ａおよび負極集電部３ｂと、電池要素３を電解液とともに収納する外装体２と、正極集電部３ａに接続された正極リード部４と、負極集電部３ｂに接続された負極リード部８とを有する。
【００２１】
外装体２は、電池要素３を上下から挟んで包囲する２枚の外装フィルム２ａ，２ｂからなり、これら外装フィルム２ａ，２ｂの周縁部を熱融着することで、電池要素３が気密封止される。また、外装フィルム２ａ，２ｂの少なくとも一方には、電池要素３の外形状に合せた凹部が形成されており、電池要素３は、この凹部で形成される空間内に収納される。このように外装フィルム２ａ，２ｂに凹部を形成することで、電池要素３を気密封止したときに外装フィルム２ａ，２ｂにシワを発生し難くなる。外装フィルム２ａ，２ｂとしては、電池要素３を収納している空間内の気密性を維持できるものであれば特に限定されないが、金属箔と熱可塑性樹脂とを積層したラミネートフィルムが好ましく用いられる。
【００２２】
電池要素３は、複数の正極板と複数の負極板とを、セパレータを介在させた状態で交互に積層した構造を有している。各正極板および各負極板にはそれぞれタブが突出して形成されており、これらタブが極性ごとに一括して超音波溶接され、それぞれ正極集電部３ａおよび負極集電部３ｂが構成される。正極板と負極板とは、互いに異なる材質で構成されている。本実施形態では、正極板をアルミニウム箔で構成し、負極板を銅箔で構成した。したがって、正極集電部３ａはアルミニウムからなり、負極集電部３ｂは銅からなる。
【００２３】
上述した構造は積層型と呼ばれるが、電池要素３は捲回型であってもよい。捲回型は、正極板、負極板、およびセパレータを帯状に形成し、これらを積層した後、捲回し、さらに圧縮して扁平状とし、正極板および負極板から延びたタブをそれぞれ正極リード部４および負極リード部８に接続したものである。
【００２４】
負極リード部８は、１枚の銅板９からなる。銅板９と負極集電部３ｂとは同じ材質であるので、両者は良好に接合されている。
【００２５】
正極リード部４は、第１の端子部材であるアルミニウム板５と、第２の端子部材である銅板６と、被覆樹脂７とからなる。アルミニウム板５は、その一端部が正極集電部３ａと接合されて、他端側が外装体２から延出している。アルミニウム板５と正極集電部３ａとは同じ材質であるので、両者は良好に接続されている。銅板６は、その一端部が、アルミニウム板５の、外装体２から延出している部分の少なくとも一部と重なり合って接合されている。アルミニウム板５と銅板６との接合には、超音波溶接、レーザ溶接、あるいは合金溶接などを用いることができる。アルミニウム板５と正極集電部３ａとの接合、および負極側の銅板９と負極集電部３ｂとの接合も同様である。なお、正極側の銅板６および負極側の銅板９は、局部電池腐食の問題が生じない金属材料、例えばニッケルなどでめっきされていてもよい。
【００２６】
正極リード部４および負極リード部８のサイズは、厚さが１ｍｍ〜２ｍｍであることが好ましく、幅が１ｍｍ〜１００ｍｍであることが好ましい。これらの範囲外では、所望の大きさの電流を流すことが困難になったり、必要以上のスペース浪費や重量増大の原因となる。
【００２７】
被覆樹脂７は、この正極リード部４の少なくともアルミニウム板５と銅板６との接合部、すなわち、アルミニウム板５と銅板６とが互いに重なり合っている領域を、外気と触れなくするように被覆している。
【００２８】
以下に、この接合部の被覆について、図３および図４を参照しつつ、より詳しく説明する。図３は、図１に示す正極リード部の分解斜視図であり、図４は、図１に示す正極リード部の、延出方向に沿った断面図である。
【００２９】
被覆樹脂７は、アルミニウム板５と銅板６との接合部（以下、単に接合部ともいう）を含む範囲でアルミニウム板５および銅板６を覆うのに十分な面積を持つ２枚の被覆フィルム７ａ，７ｂからなる。これら被覆フィルム７ａ，７ｂは熱可塑性樹脂を含んでおり、被覆フィルム７ａ，７ｂを正極リード部４の板厚方向両側から挟み、加熱することで、熱可塑性樹脂が溶融し、被覆フィルム７ａ，７ｂが接合部の周囲で融着する。これによって、アルミニウム板５と銅板６との接合部が外気に対して遮断される。ここでは、被覆樹脂７として２枚の被覆フィルム７ａ，７ｂを用いた場合で説明するが、１枚の被覆フィルムを２つ折りにして、接合部を含む範囲でアルミニウム板５および銅板６を挟んでもよい。
【００３０】
被覆フィルム７ａ，７ｂの加熱方法としては、被覆フィルム７ａ，７ｂに含まれる熱可塑性樹脂をその溶融温度以上の温度まで加熱することのできる方法であれば特に限定されるものではないが、簡易な方法として、熱風を吹き付ける方法、ヒータを内蔵したローラやブロックなどの加圧部材を押し付けて加熱する方法などが挙げられる。熱風を吹き付ける方法は、広範囲にわたって加熱することができる。加圧部材で加圧しつつ加熱する方法は、局所的な加熱が可能である。
【００３１】
被覆フィルム７ａ，７ｂに含まれる熱可塑性樹脂は、特に限定されないが、金属との密着性に優れる材料が好ましく用いられる。このような熱可塑性樹脂としては、エチレン−酢酸ビニル系共重合体、酸変性ポリエチレン、酸変性ポリプロピレン、これらの共重合体、ポリアクリル酸、ポリアクリル酸エステル、ポリメタクリル酸エステルなどのアクリル樹脂、およびアイオノマーなどが挙げられる。
【００３２】
また、特に加圧部材で加圧しつつ加熱する場合、被覆フィルム７ａ，７ｂが熱可塑性樹脂のみで構成されていると、溶融した樹脂が加圧部材に付着してしまうおそれがある。そこで、被覆フィルム７ａ，７ｂが他の物に付着するのを防止するために、被覆フィルム７ａ，７ｂを、一方の面を熱可塑性樹脂層、それと反対側の面を、一方の面を構成する樹脂よりも融点の高い耐熱樹脂層とした積層フィルムとし、熱可塑性樹脂層を内側として接合部を被覆することが好ましい。これにより、接合部を被覆する際には被覆フィルム７ａ，７ｂを熱可塑性樹脂層の溶融温度以上、かつ耐熱樹脂層の溶融温度よりも低い温度で加熱すれば、内側の層は溶融するが外側の層は溶融しないので、被覆フィルム７ａ，７ｂが加圧部材に付着することなく、接合部を確実に被覆することができる。このような耐熱樹脂としては、ポリエチレンテレフタレートやポリエチレンナフタレートなどのポリエステル、ナイロンなどのポリアミド、ポリイミド、およびポリフェニレンサルファイドなどが挙げられる。
【００３３】
被覆フィルム７ａ，７ｂを積層フィルムとする場合、熱可塑性樹脂層と耐熱樹脂層との二層フィルムであってもよいが、両層の間にガスバリア層など、所望の機能を有する層を介在させてもよい。
【００３４】
以上説明したように、正極リード部４をアルミニウム板５と銅板６とを接合した構造とすることで、図５に示すように、複数の平型電池１を直列接続した直列型の組電池とする場合、正極リード部４と負極リード部８とをそのまま接合しても、両者の接合部は同じ材質であるので、結露等が生じたとしても局部電池腐食の問題は発生しない。また、正極リード部４と負極リード部８との接合は、同じ金属同士の接合であるので、容易に行うことができる。一方、正極リード部４においては、アルミニウム板５と銅板６とが接合された構造となっているが、両者の接合部は被覆樹脂７で被覆されて外気と遮断されているので、この部分においても局部電池腐食という問題は発生しない。その結果、構造に起因するリード部の腐食を防止することができ、腐食による電気抵抗値の上昇も抑制されるので、出力電圧や電流容量といった所望の電池特性を長期にわたって維持し、結果的に信頼性を向上させることができる。
【００３５】
被覆樹脂７による接合部の被覆は、電池要素３を外装体２内に気密封止した後に行ってもよいし、正極リード部４を電池要素３と接続する前に、予めアルミニウム板５と銅板６とを接合し、その接合部を被覆樹脂７で被覆した正極リード部４をアセンブリとして作製しておき、作製した正極リード部４のアセンブリを電池要素３と接続し、その後、電池要素３を外装体２内に気密封止してもよい。被覆樹脂７による被覆時の、部品のハンドリング性なども含めた作業の容易性を考慮すると、電池要素３との接続前に、アルミニウム板５と銅板６とを接合しその接合部を被覆樹脂７で被覆した正極リード部４を予め作製しておくことが好ましい。
【００３６】
上述した説明では、平型電池１単体で、正極リード部４を、異なる金属同士を接合し、その接合部を被覆樹脂７で被覆した構成とした例を示したが、図６に示すように、平型電池１’単体では、正極リード部をアルミニウム板５のみで構成するとともに負極リード部を銅板９のみで構成し、その平型電池１’を直列接続する際に、正極リード部と負極リード部との接合部を被覆樹脂７で被覆して直列型の組電池を構成することもできる。
【００３７】
ところで、図５および図６に示した直列型の組電池は、所望の電圧を得るために平型電池１，１’を直列接続したものであるが、これに加えてさらに、所望の電流容量を得ようとした場合は、直列型の組電池をさらに並列接続する。この際、例えば図５に示した直列型の組電池をさらに複数並列に接続する場合を例に挙げると、図７に示すように、直列型の組電池を平型電池１の厚み方向に重ね、上下の組電池間で、正極リード部４と負極リード部８との接合部をさらに接合する。正極リード部４を、予め先端部に負極リード部８と同じ材質の金属を接合した構造としておくことで、複数の平型電池１を並列接続する場合も、結果的には同じ金属同士の接合でよいので、容易に接合することができ、しかも局部電池腐食も生じない。
【００３８】
また、上述した説明では、図３にも示したように、正極リード部４におけるアルミニウム板５と銅板６との接合部を、２枚の被覆フィルム７ａ，７ｂで挟み、これを加熱することで被覆フィルム７ａ，７ｂを密着させていた。この際、特に、被覆フィルム７ａ，７ｂの加熱を加圧部材で行う場合、図８に示すように、正極リード部４の幅方向両側における正極リード部４の長手方向に沿った隙間１７ａ、およびアルミニウム板５と銅板６との段差部における正極リード部４の幅方向に沿った隙間１７ｂが形成されることがある。この隙間１７ａ，１７ｂは、加熱によって軟化した被覆フィルム７ａ，７ｂが正極リード部４の厚み方向における段差に十分に追従しない場合に形成され易く、その隙間１７ａ，１７ｂの大きさは、アルミニウム板５の厚さや銅板６の厚さなどに依存する。
【００３９】
このような隙間１７ａ，１７ｂのうち特に、正極リード部４の幅方向両側の隙間１７ａは、アルミニウム板５と銅板６との接合部を外気と連通させる経路にもなり得る。
【００４０】
そこで、被覆フィルム７ａ，７ｂを透明な樹脂で構成し、上述した隙間１７ａの存在を、被覆フィルム７ａ，７ｂを通して目視で確認できるようにすることが好ましい。ここで、「透明」とは、完全に透明である必要はなく、隙間１７ａの存在が目視で確認できる程度に透明であればよい。
【００４１】
このように被覆フィルム７ａ，７ｂを透明な樹脂で構成することで、被覆樹脂７によるアルミニウム板５と銅板６との接合部の被覆が完全になされているか否かを容易に確認することができる。そして、隙間１７ａの存在が確認された場合は、その正極リード部４を不良品として扱う。不良品として扱われた正極リード部４は、以降の平型電池１の製造工程から排除され、廃棄されるか、またはアルミニウム板５および銅板６の再利用のために修理工程へ回される。
【００４２】
なお、図６に示したように平型電池１’を直列接続した際にその正極リード部と負極リード部との接合部を被覆樹脂７で被覆する構成の場合、その被覆に上記のような不良が発生すると、組電池全体が不良品となってしまう。それに対し、正極リード部４自身を、アルミニウム板５と銅板６とを接合したアセンブリとして作製しておくことで、被覆樹脂７による被覆工程で不良が発生したとしても、その不良品の廃棄あるいは修理に伴う工数は最小限で済む。
【００４３】
（第２の実施形態）
図９は、本発明の第２の実施形態による、平型電池の正極リード部の構造を示す図であり、（ａ）はその平面図、（ｂ）は（ａ）のＢ‐Ｂ線断面図である。なお、図９では、第１の実施形態と同じ構成については第１の実施形態で参照した符号と同じ符号を付し、その詳細な説明は省略する。
【００４４】
図９に示すように、本実施形態では、被覆樹脂７は、被覆フィルム７ａ，７ｂと、充填材１１とを有している。充填材１１は、アルミニウム板５および銅板６の幅方向両側端の、少なくとも両者が重なり合っている領域で、被覆樹脂７との間に充填されている。
【００４５】
このように充填材１１を付加することで、例えば図８に示した隙間１７ａに相当する、アルミニウム板５と銅板６との接合部を外気と連通し得る部分が充填材１１で充填され、実質的にはこの隙間１７ａが形成されない構成となっている。その結果、接合部をより確実に外気と遮断した状態で被覆することができ、局部電池腐食をより確実に防止することができる。
【００４６】
本実施形態では、アルミニウム板５および銅板６の幅方向両側端において被覆樹脂７に隙間が形成されるのを防止した構成であるので、第１の実施形態と比べると、被覆フィルム７ａ，７ｂを透明とする必要性は低い。しかしながら、本実施形態においても、充填材１１の充填量のばらつきによっては隙間が生じる場合もあるので、被覆フィルム７ａ，７ｂを透明とすることは好ましいことである。
【００４７】
充填材１１としては、熱可塑性樹脂を好ましく用いることができる。充填材１１として熱可塑性樹脂を用いた場合、正極リード部４の作製は、例えば、以下のようにして行うことができる。
【００４８】
まず、図１０（ａ）に示すように、アルミニウム板５と銅板６とを接合した後、その接合部の幅方向両側端に、それぞれ充填材１１である熱可塑性樹脂を、例えばホットメルト接着剤で取り付ける。次いで、図１０（ｂ）に示すように、２枚の被覆フィルム７ａ，７ｂで、被覆する部分を挟み、被覆フィルム７ａ，７ｂを加熱する。これにより、被覆フィルム７ａ，７ｂが溶融し、アルミニウム板５および銅板６に密着するが、これと同時に、充填材１１も軟化あるいは溶融し、被覆フィルム７ａ，７ｂの間で被覆フィルム７ａ，７ｂと一体化し、図９（ｂ）に示したように、アルミニウム板５と銅板６との接合部でその幅方向両側端に隙間なく充填される。このように、被覆フィルム７ａ，７ｂへの加熱時に加えられる熱を利用して充填材１１を軟化あるいは溶融させるためには、充填材１１を構成する熱可塑性樹脂を、被覆フィルム７ａ，７ｂに含まれる熱可塑性樹脂の融点と同じかそれ以下の樹脂とすることが好ましい。さらには各熱可塑性樹脂を相溶性の組み合わせとするのが好ましく、さらに好ましくは同じ樹脂材料を用いるとよい。
【００４９】
軟化あるいは溶融する前の充填材１１の形状は、溶融後に周囲の部材（被覆フィルム７ａ，７ｂ、アルミニウム板５および銅板６）と隙間なく密着できる形状であれば特に制限はないが、充填材１１の使用量を最小限とするためには、接合部の幅方向両側端に沿ったロッド状であることが好ましい。また、その寸法としては、長手方向については、正極リード部４の長手方向での接合部の長さ以上であることが好ましく、正極リード部４の厚さ方向については、アルミニウム板５の厚さと銅板６の厚さとを合せた寸法以上であることが好ましい。
【００５０】
充填材１１としては、上述した熱可塑性樹脂の他に、紫外線硬化性樹脂を用いることもできる。この場合、充填材１１の硬化は、被覆フィルム７ａ，７ｂの間に充填された後、被覆フィルム７ａ，７ｂを通して紫外線を照射することで行われるので、被覆フィルム７ａ，７ｂは、透明な樹脂など、紫外線を透過する樹脂を用いる必要がある。充填材１１として紫外線硬化性樹脂を用いた場合、充填材１１の充填方法としては、例えば、被覆フィルム７ａ，７ｂで接合部を被覆した後に、図８に示した隙間１７ａの部分に微細なチューブ等によって紫外線硬化性樹脂を充填し、その後、被覆フィルム７ａ，７ｂを通して紫外線を照射し、紫外線硬化性樹脂を硬化させる方法が挙げられる。
【００５１】
以上、代表的な幾つかの実施形態を挙げて本発明を説明したが、本発明は、上述した実施形態に限定されるものではなく、本発明の思想の範囲内で種々の変更を加えることができる。
【００５２】
例えば、上述した実施形態では、正極リード部を、先端側が負極リード部と同一の材質となるように２種類の金属を接合した構造としたが、正極リード部を１種類の金属で構成し、その代わりに、負極リード部を先端側が正極リード部と同一の材質となるように２種類の金属を接合しその接合部を被覆樹脂で被覆した構成としてもよい。
【００５３】
また、上述した実施形態では本発明を電池のリード部に適用した例を示したが、本発明は、所望の機能を発揮するデバイス本体とそこから延出した正極および負極のリード部とを有し、結露等により局部電池が形成されそれによる腐食よって電気的特性の劣化が生じるおそれのある種々の電気デバイスにおいて、そのリード部の構造に適用することができる。その場合、リード部の先端の、他の相手方のデバイスと接続される端子部材の材質を、相手方のデバイスのリード部と同じ材質とすれば、これらのデバイスを単純に接続するだけで、リード部の接合部に局部電池が形成されることはなくなる。本発明が適用し得る電気デバイスの例として、固体電解コンデンサ、水系あるいは非水系電解コンデンサなどの電解コンデンサ、電気二重層コンデンサ、変圧器、ランプ、モータ、抵抗器などが挙げられる。
【００５４】
【発明の効果】
以上説明したように本発明によれば、互いに材質の異なる端子部材同士の接合部を、熱可塑性樹脂を含むフィルムを熱融着することによって形成した被覆樹脂で被覆することで、接合部が外気に対して遮断されるので、結露等が生じても接合部に局部電池が形成されることがなくなり、局部電池が形成されることによる腐食を防止することができる。その結果、リード部、電気デバイスの電気的特性を長期にわたって維持し、信頼性を向上させることができる。本発明は特に、同じ構造のものを直列に接続することが多い電池に適用すると効果的である。
【００５５】
また、被覆樹脂を構成するフィルムを透明とすると、接合部の被覆状態を目視で確認することができる。さらに、端子部材とフィルムとの間に充填材を充填することで、接合部の被覆をより確実に行うことができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態による平型電池の外観斜視図である。
【図２】図１に示す平型電池の分解斜視図である。
【図３】図１に示す正極リード部の分解斜視図である。
【図４】図１に示す正極リード部の、延出方向に沿った断面図である。
【図５】図１に示す平型電池を直列接続した組電池の概略側面図である。
【図６】正極リード部と負極リード部の材質が異なる平型電池を直列接続し、その接続部を被覆樹脂で被覆した組電池の概略側面図である。
【図７】図５に示す組電池をさらに並列接続した場合の概略側面図である。
【図８】図１に示す平型電池の正極リード部に発生する被覆樹脂内の隙間を説明する図であり、（ａ）は正極リード部の平面図、（ｂ）はそのＡ−Ａ線断面図である。
【図９】本発明の第２の実施形態による、平型電池の正極リード部の構造を示す図であり、（ａ）はその平面図、（ｂ）は（ａ）のＢ‐Ｂ線断面図である。
【図１０】本発明の第２の実施形態において、充填材を熱可塑性樹脂とした場合の、正極リード部の接合部の被覆方法の一例を説明する図である。
【図１１】ラミネート材を外装体とした従来の平型電池の一例を示す外観斜視図である。
【符号の説明】
１，１’ 平型電池
２外装体
２ａ，２ｂ外装フィルム
３電池要素
３ａ正極集電部
３ｂ負極集電部
４正極リード部
５アルミニウム板
６銅板
７被覆樹脂
７ａ，７ｂ被覆フィルム
８負極リード部
９銅板
１１充填材
１７ａ，１７ｂ隙間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of an electrical lead portion used for electrical connection with other devices in an electrical device, an electrical device having the structure, a battery, and an assembled battery.
[0002]
[Prior art]
Batteries used as power sources for portable devices such as mobile phones, notebook computers, digital still cameras, and video cameras are strongly required to be light and thin. In addition, the development of electric vehicles and hybrid electric vehicles equipped with motor-driven batteries (batteries) is rapidly advancing in response to increasing demands for resource saving and energy saving to protect the global environment. is there. In order to improve steering characteristics and cruising distance, batteries mounted on these electric vehicles and the like are also required to be lighter and thinner.
[0003]
In response to these demands, in order to make the battery lighter and thinner, a battery that uses a laminate made of a thin sheet by laminating a metal layer such as aluminum and a heat-weldable resin layer on its outer package has been developed. (For example, refer to Patent Document 1).
[0004]
FIG. 11 shows an example of a conventional flat battery having a laminate material as an exterior body. In the battery shown in FIG. 11, a battery element (not shown) in which a positive electrode plate and a negative electrode plate are laminated via a separator is hermetically housed together with an electrolytic solution in an exterior body 102 made of a laminate material. A positive terminal 104 connected to the positive plate extends from one side of the exterior body 102. Further, a negative electrode terminal 108 connected to the negative electrode plate extends from a side of the exterior body 102 opposite to the side where the positive electrode terminal 104 extends. In the case of a nonaqueous electrolyte battery such as a lithium ion battery, aluminum is often used as the positive electrode terminal 104 and copper or nickel is frequently used as the negative electrode terminal 108 due to its electrical characteristics.
[0005]
In the battery having such a configuration, it is necessary to connect a plurality of batteries in series in order to obtain a desired voltage. In that case, for example, the batteries are arranged in a line, and the positive electrode terminal is joined to the negative electrode terminal of the adjacent battery to constitute an assembled battery.
[0006]
[Patent Document 1]
JP 2002-203524 A
[0007]
[Problems to be solved by the invention]
However, in the conventional battery described above, since the positive electrode terminal and the negative electrode terminal are made of different metals, different metals are joined when a plurality of batteries are connected in series. When different metals are joined, if an electrolyte such as condensed water is present at the joint between the two, a local battery is formed between these three, and the anode side metal (the metal with the higher ionization tendency) The problem of corrosion occurs. This is also called local battery corrosion, and it is a problem that can occur in general when joints of different metals are exposed to the outside air, and water that is a type of electrolytic solution adheres to the joints due to condensation or the like. . When the terminal is corroded, not only the electric resistance of the terminal increases and the characteristics of the battery deteriorate, but also the reliability of the battery decreases.
[0008]
In addition, the above-mentioned problem of local battery corrosion is not limited to the case where batteries of different electrodes are connected in series with each other, but also an electrolytic capacitor such as a solid electrolytic capacitor, an aqueous or non-aqueous electrolytic capacitor, an electric double layer capacitor, In other electrical devices with lead terminals, such as transformers, lamps, motors, resistors, etc., lead terminals are made of different materials for electrical connection with other devices or to reduce material costs. In the case of a configuration having a joint portion with a metal, it can occur in the same manner.
[0009]
Therefore, an object of the present invention is to provide a structure of an electrical lead part, an electrical device, a battery, and an assembled battery that can maintain electrical characteristics over a long period of time by preventing corrosion of a terminal due to formation of a local battery.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, the structure of the electric lead portion of the present invention is provided to extend from the device body of the electric device.A pair ofElectrical leadOf one of the electrical leadsA first terminal member extending from the device body, and electrically connected to another device by being joined to the first terminal member outside the device body.A second electrode made of the same material as the other of the pair of electrical lead portions.2 terminal members and a thermoplastic resin2 sheets or 1 folded sheetIt consists of a film, and the joint between the first terminal member and the second terminal memberSandwiched from both sides in the thickness direction of the first and second terminal membersBy heat fusing the film in an enclosed state,The jointTo avoid touching the outside airWith coated resinTo do. The first terminal member and the second terminal member are made of an aluminum plate and the other is made of a copper plate or a plated copper plate so that the covering state of the joint portion can be seen through the film. Is transparent.
[0011]
The electrical device of the present invention is an electrical device having a device main body and positive and negative lead portions extending from the device main body, and the structure described above is applied to either the positive or negative lead portion. It is.
[0012]
  In the structure of the present invention configured as described above, the first terminal member and the second terminal member are joined on the outside of the device body. The first terminal member and the second terminal member are made of different materials. If the first terminal member and the second terminal member are in contact with the outside air, a local battery may be formed due to condensation or the like at the joint. However, the joint portion of both terminal members is covered with a coating resin formed by heat-sealing a film made of a thermoplastic resin, and is blocked from the outside air, so that a local battery is not formed. . Therefore, the second terminal member is made of the same material as the material of the lead part of the counterpart device to be connected, so that a local battery can be formed even if condensation occurs by simply connecting the two devices. Connection without fear of being lost.Moreover, since the film which comprises coating | coated resin is transparent, the covering state of the junction part of a 1st terminal member and a 2nd terminal member can be visually confirmed through a film.
[0013]
  In the above inventionThe secondThe first terminal member and the second terminal member have a configuration in which their end portions are overlapped and joined to each other, and the first terminal member and the second terminal memberButOverlapIn the right area,First and second terminal membersBoth sides of the width directionBy filling the filler between the film and the film, the joint portion is more reliably covered with the filling resin. In this case, a thermoplastic resin can be used as the filler.
[0014]
The present invention also provides a battery and an assembled battery using the structure of the electrical lead part.
[0015]
  That is, the battery of the present invention is a battery having a battery element hermetically sealed in an exterior body and positive and negative lead parts connected to the battery element and extending from the exterior body. Is connected to the battery element and extends from the exterior bodyFirst1 terminal member, and a second terminal member made of the same material as the other of the lead portion, joined to the tip of the first terminal member outside the exterior body,One of the first terminal member and the second terminal member is an aluminum plate, and the other is a copper plate or a plated copper plate,The joint portion between the first terminal member and the second terminal member includes a thermoplastic resin.2 sheets or 1 folded sheetFilmSandwiched from both sides in the thickness direction of the first and second terminal membersA coating resin formed by heat-sealing in an enclosed stateSo as not to touch the outside airCoveredThe film is transparent so that the covering state of the joint can be visually observed through the film.It is characterized by that.
[0016]
In the battery of the present invention, the structure of the present invention described above is applied to the lead portion of the positive electrode or the negative electrode, and the tip portion of the lead portion of the positive electrode and the tip portion of the lead portion of the negative electrode are made of the same material. In the case of series connection, even if the assembled battery is configured as it is, the problem of corrosion due to the formation of the local battery does not occur.
[0017]
  Moreover, if the structure of the electrical lead part of the present invention described above is used, the battery element hermetically sealed in the exterior body, and connected to the battery element and extended from the exterior body,Made of aluminum platePositive electrodeLead partandMade of copper plateIn an assembled battery in which a plurality of batteries having negative electrode lead portions are connected in series, between the two batteriesPositiveLead partAnd the negative leadThe joint of includes a thermoplastic resin2 sheets or 1 sheet folded in halfFilmHold the lead part of the positive and negative electrodes from both sides in the thickness directionA coating resin formed by heat sealing in an enclosed stateSo as not to touch the outside airCoveredThe film is transparent so that the covering state of the joint can be visually observed through the film.An assembled battery characterized by this can also be configured.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0019]
(First embodiment)
FIG. 1 is an external perspective view of a flat battery according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the flat battery shown in FIG.
[0020]
The flat battery 1 of this embodiment is also called a film-clad battery, and stores the battery element 3, the positive current collector 3a and the negative current collector 3b provided in the battery element 3, and the battery element 3 together with the electrolyte. And the negative electrode lead portion 8 connected to the negative electrode current collector portion 3b.
[0021]
The exterior body 2 includes two exterior films 2a and 2b surrounding and sandwiching the battery element 3 from above and below, and the battery element 3 is hermetically sealed by heat-sealing the peripheral portions of the exterior films 2a and 2b. Is done. Further, at least one of the exterior films 2a and 2b is formed with a recess that matches the outer shape of the battery element 3, and the battery element 3 is accommodated in a space formed by the recess. By forming the recesses in the exterior films 2a and 2b as described above, it becomes difficult for the exterior films 2a and 2b to be wrinkled when the battery element 3 is hermetically sealed. The exterior films 2a and 2b are not particularly limited as long as the airtightness in the space in which the battery element 3 is stored can be maintained, but a laminate film in which a metal foil and a thermoplastic resin are laminated is preferably used.
[0022]
The battery element 3 has a structure in which a plurality of positive plates and a plurality of negative plates are alternately stacked with a separator interposed therebetween. Each positive electrode plate and each negative electrode plate are formed with protruding tabs, and these tabs are ultrasonically welded together for each polarity to constitute a positive electrode current collector 3a and a negative electrode current collector 3b, respectively. The positive electrode plate and the negative electrode plate are made of different materials. In the present embodiment, the positive electrode plate is made of aluminum foil, and the negative electrode plate is made of copper foil. Therefore, the positive electrode current collector 3a is made of aluminum, and the negative electrode current collector 3b is made of copper.
[0023]
The structure described above is called a stacked type, but the battery element 3 may be a wound type. In the winding type, a positive electrode plate, a negative electrode plate, and a separator are formed in a strip shape, and after laminating these, the wound plate is wound and further compressed into a flat shape. 4 and the negative electrode lead portion 8.
[0024]
The negative electrode lead portion 8 is composed of a single copper plate 9. Since the copper plate 9 and the negative electrode current collector 3b are made of the same material, both are well bonded.
[0025]
The positive electrode lead portion 4 includes an aluminum plate 5 that is a first terminal member, a copper plate 6 that is a second terminal member, and a coating resin 7. The aluminum plate 5 has one end joined to the positive electrode current collector 3 a and the other end extending from the exterior body 2. Since the aluminum plate 5 and the positive electrode current collector 3a are made of the same material, both are well connected. One end portion of the copper plate 6 overlaps and is joined to at least a part of a portion of the aluminum plate 5 extending from the exterior body 2. For joining the aluminum plate 5 and the copper plate 6, ultrasonic welding, laser welding, alloy welding, or the like can be used. The same applies to the joining between the aluminum plate 5 and the positive electrode current collector 3a and the joining between the negative electrode side copper plate 9 and the negative electrode current collector 3b. In addition, the copper plate 6 on the positive electrode side and the copper plate 9 on the negative electrode side may be plated with a metal material that does not cause a problem of local battery corrosion, such as nickel.
[0026]
As for the size of the positive electrode lead part 4 and the negative electrode lead part 8, the thickness is preferably 1 mm to 2 mm, and the width is preferably 1 mm to 100 mm. Outside these ranges, it becomes difficult to pass a current of a desired magnitude, and it causes unnecessary space wasting and weight increase.
[0027]
The coating resin 7 coats at least a joint portion of the positive electrode lead portion 4 between the aluminum plate 5 and the copper plate 6, that is, a region where the aluminum plate 5 and the copper plate 6 overlap each other so as not to come into contact with outside air. Yes.
[0028]
Hereinafter, the covering of the joint portion will be described in more detail with reference to FIGS. 3 and 4. 3 is an exploded perspective view of the positive electrode lead portion shown in FIG. 1, and FIG. 4 is a cross-sectional view of the positive electrode lead portion shown in FIG. 1 along the extending direction.
[0029]
The coating resin 7 includes two coating films 7a having a sufficient area to cover the aluminum plate 5 and the copper plate 6 in a range including a joint portion (hereinafter also simply referred to as a joint portion) between the aluminum plate 5 and the copper plate 6. 7b. These covering films 7a and 7b contain a thermoplastic resin. The covering films 7a and 7b are sandwiched from both sides in the plate thickness direction of the positive electrode lead portion 4 and heated to melt the thermoplastic resin, and the covering films 7a and 7b. Fuses around the joint. Thereby, the junction part of the aluminum plate 5 and the copper plate 6 is interrupted | blocked with respect to external air. Here, the case where two coating films 7a and 7b are used as the coating resin 7 will be described. However, it is also possible to fold one coating film in half and sandwich the aluminum plate 5 and the copper plate 6 within a range including the joint portion. Good.
[0030]
The method for heating the coating films 7a and 7b is not particularly limited as long as it is a method capable of heating the thermoplastic resin contained in the coating films 7a and 7b to a temperature equal to or higher than its melting temperature, but is simple. Examples of the method include a method of blowing hot air and a method of heating by pressing a pressure member such as a roller or a block having a built-in heater. The method of blowing hot air can be heated over a wide range. The method of heating while pressurizing with a pressurizing member is capable of local heating.
[0031]
The thermoplastic resin contained in the covering films 7a and 7b is not particularly limited, but a material having excellent adhesion to a metal is preferably used. Examples of such thermoplastic resins include ethylene-vinyl acetate copolymers, acid-modified polyethylene, acid-modified polypropylene, copolymers thereof, acrylic resins such as polyacrylic acid, polyacrylic acid ester, and polymethacrylic acid ester, And ionomers.
[0032]
In particular, when heating is performed while applying pressure with a pressure member, if the coating films 7a and 7b are made of only a thermoplastic resin, the molten resin may adhere to the pressure member. Therefore, in order to prevent the coating films 7a and 7b from adhering to other objects, one surface of the coating films 7a and 7b is composed of the thermoplastic resin layer on one side and the other side thereof. It is preferable to form a laminated film having a heat-resistant resin layer having a melting point higher than that of the resin, and to cover the bonding portion with the thermoplastic resin layer as the inner side. As a result, when coating the joint, if the coating films 7a and 7b are heated at a temperature equal to or higher than the melting temperature of the thermoplastic resin layer and lower than the melting temperature of the heat-resistant resin layer, the inner layer melts but the outer layer melts. Since this layer does not melt, the joint film can be reliably coated without the covering films 7a and 7b adhering to the pressure member. Examples of such a heat-resistant resin include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyamides such as nylon, polyimides, and polyphenylene sulfide.
[0033]
When the cover films 7a and 7b are laminated films, a two-layer film of a thermoplastic resin layer and a heat-resistant resin layer may be used, but a layer having a desired function such as a gas barrier layer is interposed between both layers. May be.
[0034]
As described above, by forming the positive electrode lead portion 4 in a structure in which the aluminum plate 5 and the copper plate 6 are joined, as shown in FIG. 5, a series assembled battery in which a plurality of flat batteries 1 are connected in series, In this case, even if the positive electrode lead portion 4 and the negative electrode lead portion 8 are joined as they are, the joint portions of the two are made of the same material, so that the problem of local battery corrosion does not occur even if condensation occurs. Moreover, since the joining of the positive electrode lead part 4 and the negative electrode lead part 8 is joining of the same metals, it can be performed easily. On the other hand, the positive electrode lead portion 4 has a structure in which the aluminum plate 5 and the copper plate 6 are joined, but the joint portion of both is covered with the coating resin 7 and is shielded from the outside air. However, the problem of local battery corrosion does not occur. As a result, corrosion of the lead due to the structure can be prevented, and an increase in electrical resistance value due to corrosion is suppressed, so that desired battery characteristics such as output voltage and current capacity can be maintained over a long period of time. Reliability can be improved.
[0035]
The joint portion may be covered with the coating resin 7 after the battery element 3 is hermetically sealed in the exterior body 2, or before the positive electrode lead portion 4 is connected to the battery element 3, the aluminum plate 5 and the copper plate are preliminarily connected. 6, a positive electrode lead portion 4 whose joint portion is covered with a coating resin 7 is prepared as an assembly, the assembly of the prepared positive electrode lead portion 4 is connected to the battery element 3, and then the battery element 3 is The outer package 2 may be hermetically sealed. Considering the ease of work including the handling of parts when coating with the coating resin 7, the aluminum plate 5 and the copper plate 6 are bonded to each other before the connection with the battery element 3, and the bonded portion is coated with the coating resin 7. It is preferable that the positive electrode lead portion 4 coated with is prepared in advance.
[0036]
In the above description, an example in which the positive electrode lead portion 4 is formed by joining the different metals to each other and covering the joint portion with the coating resin 7 in the flat battery 1 alone is shown in FIG. In the flat battery 1 ′ alone, the positive electrode lead portion is composed only of the aluminum plate 5 and the negative electrode lead portion is composed only of the copper plate 9, and when the flat battery 1 ′ is connected in series, the positive electrode lead portion and the negative electrode The joint portion with the lead portion may be covered with the coating resin 7 to form a series assembled battery.
[0037]
Incidentally, the series assembled battery shown in FIG. 5 and FIG. 6 is obtained by connecting flat batteries 1 and 1 ′ in series in order to obtain a desired voltage. When it is going to obtain, a series type assembled battery is further connected in parallel. In this case, for example, when a plurality of series-type assembled batteries shown in FIG. 5 are connected in parallel, as shown in FIG. 7, the series-type assembled batteries are stacked in the thickness direction of the flat battery 1 as shown in FIG. Further, the joint between the positive electrode lead portion 4 and the negative electrode lead portion 8 is further joined between the upper and lower assembled batteries. Since the positive electrode lead portion 4 has a structure in which a metal of the same material as that of the negative electrode lead portion 8 is bonded to the tip portion in advance, even when a plurality of flat batteries 1 are connected in parallel, as a result, the same metal is bonded to each other. Therefore, it can be easily joined and local battery corrosion does not occur.
[0038]
In the above description, as shown in FIG. 3, the joining portion between the aluminum plate 5 and the copper plate 6 in the positive electrode lead portion 4 is sandwiched between the two coating films 7 a and 7 b and heated. The covering films 7a and 7b were in close contact. At this time, in particular, when the covering films 7a and 7b are heated by the pressure member, as shown in FIG. 8, the gap 17a along the longitudinal direction of the positive electrode lead portion 4 on both sides in the width direction of the positive electrode lead portion 4, and A gap 17b may be formed along the width direction of the positive electrode lead portion 4 at the step portion between the aluminum plate 5 and the copper plate 6. The gaps 17a and 17b are easily formed when the coating films 7a and 7b softened by heating do not sufficiently follow the step in the thickness direction of the positive electrode lead portion 4, and the sizes of the gaps 17a and 17b are the same as those of the aluminum plate 5. , The thickness of the copper plate 6 and the like.
[0039]
Among these gaps 17a and 17b, in particular, the gaps 17a on both sides in the width direction of the positive electrode lead portion 4 can also serve as a path for communicating the joint between the aluminum plate 5 and the copper plate 6 with the outside air.
[0040]
Therefore, it is preferable that the covering films 7a and 7b are made of a transparent resin so that the presence of the gap 17a can be visually confirmed through the covering films 7a and 7b. Here, “transparent” does not need to be completely transparent, and may be transparent so that the presence of the gap 17a can be visually confirmed.
[0041]
Thus, by comprising covering film 7a, 7b with transparent resin, it can be confirmed easily whether covering of the junction part of the aluminum plate 5 and the copper plate 6 by the coating resin 7 is made | formed completely. . When the presence of the gap 17a is confirmed, the positive electrode lead portion 4 is treated as a defective product. The positive electrode lead portion 4 treated as a defective product is excluded from the subsequent manufacturing process of the flat battery 1 and discarded or sent to a repair process for reuse of the aluminum plate 5 and the copper plate 6.
[0042]
In addition, when the flat battery 1 'is connected in series as shown in FIG. 6, in the case where the joint portion between the positive electrode lead portion and the negative electrode lead portion is covered with the coating resin 7, the covering is as described above. When a defect occurs, the entire assembled battery becomes a defective product. On the other hand, by preparing the positive electrode lead part 4 itself as an assembly in which the aluminum plate 5 and the copper plate 6 are joined, even if a defect occurs in the coating process with the coating resin 7, the defective product is discarded or repaired. The amount of man-hours involved is minimal.
[0043]
(Second Embodiment)
9A and 9B are diagrams showing the structure of the positive electrode lead portion of the flat battery according to the second embodiment of the present invention, where FIG. 9A is a plan view thereof, and FIG. 9B is a cross-sectional view taken along line BB of FIG. FIG. In FIG. 9, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.
[0044]
As shown in FIG. 9, in this embodiment, the coating resin 7 includes coating films 7 a and 7 b and a filler 11. The filler 11 is filled between the aluminum resin 5 and the copper resin 6 and the covering resin 7 in at least the regions where the both sides overlap each other.
[0045]
By adding the filler 11 in this way, for example, the portion corresponding to the gap 17a shown in FIG. 8 that can communicate the joint between the aluminum plate 5 and the copper plate 6 with the outside air is filled with the filler 11, and substantially Specifically, this gap 17a is not formed. As a result, it is possible to cover the joint portion in a state in which the joint portion is more reliably shielded from the outside air, and local battery corrosion can be more reliably prevented.
[0046]
In this embodiment, since it is the structure which prevented the clearance gap from being formed in the coating resin 7 in the width direction both ends of the aluminum plate 5 and the copper plate 6, compared with 1st Embodiment, coating film 7a, 7b is provided. The need for transparency is low. However, even in this embodiment, a gap may be generated depending on the variation in the filling amount of the filler 11, so it is preferable to make the covering films 7 a and 7 b transparent.
[0047]
As the filler 11, a thermoplastic resin can be preferably used. When a thermoplastic resin is used as the filler 11, the positive electrode lead portion 4 can be produced, for example, as follows.
[0048]
First, as shown in FIG. 10A, after the aluminum plate 5 and the copper plate 6 are joined, the thermoplastic resin as the filler 11 is respectively attached to the both ends of the joined portion in the width direction, for example, a hot melt adhesive. Attach with. Next, as shown in FIG. 10B, the portions to be covered are sandwiched between the two coating films 7a and 7b, and the coating films 7a and 7b are heated. As a result, the covering films 7a and 7b are melted and are in close contact with the aluminum plate 5 and the copper plate 6. At the same time, the filler 11 is also softened or melted, and the covering films 7a and 7b As shown in FIG. 9B, the both sides of the width direction are filled without gaps at the joint portion between the aluminum plate 5 and the copper plate 6. Thus, in order to soften or melt the filler 11 using the heat applied to the coating films 7a and 7b, the thermoplastic resin constituting the filler 11 is included in the coating films 7a and 7b. It is preferable to use a resin having the same or lower melting point than the thermoplastic resin to be obtained. Furthermore, it is preferable to make each thermoplastic resin a compatible combination, and it is more preferable to use the same resin material.
[0049]
The shape of the filler 11 before being softened or melted is not particularly limited as long as it is a shape that can be in close contact with surrounding members (coating films 7a and 7b, the aluminum plate 5 and the copper plate 6) after being melted. In order to minimize the amount of use, a rod shape is preferable along both side ends of the joint portion in the width direction. In addition, the length is preferably equal to or greater than the length of the joint in the longitudinal direction of the positive electrode lead portion 4 in the longitudinal direction, and the thickness direction of the positive electrode lead portion 4 is equal to the thickness of the aluminum plate 5. It is preferable that the thickness is equal to or larger than the total thickness of the copper plate 6.
[0050]
As the filler 11, an ultraviolet curable resin can be used in addition to the above-described thermoplastic resin. In this case, the filling material 11 is cured by filling the space between the covering films 7a and 7b and then irradiating with ultraviolet rays through the covering films 7a and 7b. Therefore, the covering films 7a and 7b are made of a transparent resin or the like. It is necessary to use a resin that transmits ultraviolet rays. In the case where an ultraviolet curable resin is used as the filler 11, the filling method of the filler 11 is, for example, a fine tube in the gap 17a shown in FIG. 8 after covering the joint with the coating films 7a and 7b. For example, a method of filling the ultraviolet curable resin by the method, and then irradiating the ultraviolet rays through the coating films 7a and 7b to cure the ultraviolet curable resin.
[0051]
The present invention has been described above with some typical embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications are made within the scope of the idea of the present invention. Can do.
[0052]
For example, in the above-described embodiment, the positive electrode lead portion has a structure in which two kinds of metals are joined so that the tip side is made of the same material as the negative electrode lead portion, but the positive electrode lead portion is made of one type of metal, Instead, the negative electrode lead portion may have a configuration in which two kinds of metals are bonded so that the tip side is made of the same material as the positive electrode lead portion, and the bonded portion is covered with a coating resin.
[0053]
In the above-described embodiment, an example in which the present invention is applied to a battery lead portion has been described. However, the present invention includes a device body that exhibits a desired function and positive and negative electrode lead portions that extend from the device body. In addition, the present invention can be applied to the structure of the lead portion in various electric devices in which a local battery is formed due to condensation or the like, and the electrical characteristics may be deteriorated due to corrosion. In that case, if the material of the terminal member connected to the other device at the tip of the lead portion is the same material as the lead portion of the other device, the lead portion can be simply connected. No local battery is formed at the junction. Examples of electrical devices to which the present invention can be applied include solid electrolytic capacitors, electrolytic capacitors such as aqueous or non-aqueous electrolytic capacitors, electric double layer capacitors, transformers, lamps, motors, resistors, and the like.
[0054]
【The invention's effect】
As described above, according to the present invention, the joint between the terminal members of different materials is covered with the coating resin formed by heat-sealing a film containing a thermoplastic resin, so that the joint is exposed to the outside air. Therefore, even if dew condensation or the like occurs, a local battery is not formed at the joint, and corrosion due to the formation of the local battery can be prevented. As a result, the electrical characteristics of the lead part and the electrical device can be maintained over a long period of time, and the reliability can be improved. The present invention is particularly effective when applied to batteries in which the same structure is often connected in series.
[0055]
Moreover, when the film which comprises coating resin is made transparent, the coating state of a junction part can be confirmed visually. Furthermore, filling the filler between the terminal member and the film makes it possible to more reliably cover the joint portion.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a flat battery according to a first embodiment of the present invention.
2 is an exploded perspective view of the flat battery shown in FIG. 1. FIG.
3 is an exploded perspective view of the positive electrode lead portion shown in FIG. 1. FIG.
4 is a cross-sectional view of the positive electrode lead portion shown in FIG. 1 along the extending direction. FIG.
FIG. 5 is a schematic side view of an assembled battery in which the flat batteries shown in FIG. 1 are connected in series.
FIG. 6 is a schematic side view of an assembled battery in which flat batteries having different materials for a positive electrode lead part and a negative electrode lead part are connected in series and the connection part is covered with a coating resin.
7 is a schematic side view when the assembled batteries shown in FIG. 5 are further connected in parallel. FIG.
8A and 8B are diagrams for explaining gaps in the coating resin generated in the positive electrode lead portion of the flat battery shown in FIG. 1, wherein FIG. 8A is a plan view of the positive electrode lead portion, and FIG. It is sectional drawing.
9A and 9B are diagrams showing a structure of a positive electrode lead portion of a flat battery according to a second embodiment of the present invention, wherein FIG. 9A is a plan view thereof, and FIG. 9B is a cross-sectional view taken along line BB of FIG. FIG.
FIG. 10 is a diagram for explaining an example of a method of covering the joint portion of the positive electrode lead portion when the filler is a thermoplastic resin in the second embodiment of the present invention.
FIG. 11 is an external perspective view showing an example of a conventional flat battery using a laminate material as an exterior body.
[Explanation of symbols]
1,1 'flat battery
2 exterior body
2a, 2b exterior film
3 Battery elements
3a Cathode current collector
3b Negative electrode current collector
4 Positive lead part
5 Aluminum plate
6 Copper plate
7 Coating resin
7a, 7b coating film
8 Negative lead part
9 Copper plate
11 Filler
17a, 17b clearance

Claims

The structure of one of the electrical lead portions of a pair of electrical lead portions provided extending from the device body of the electrical device,
A first terminal member extending from the device body;
A second terminal member made of the same material as the other of said joined to the said first terminal member outside of the device body Ru are other devices electrically connected to the pair of electrical leads,
It consists of two sheets containing a thermoplastic resin, or one film folded in two, and the joining portion between the first terminal member and the second terminal member is on both sides in the thickness direction of the first and second terminal members. by heat-sealing the film while sandwiching is surrounded from possess a coating resin covering the junction so as to not contact with the outside air,
One of the first terminal member and the second terminal member is an aluminum plate, and the other is a copper plate or a plated copper plate,
The film is transparent to such an extent that the covering state of the joint portion can be visually observed through the film.
Electric lead structure.

The film is a laminated film having a layer made of the thermoplastic resin and a layer made of a heat-resistant resin having a higher melting point than the thermoplastic resin on opposite surfaces, and the layer made of the thermoplastic resin The structure of the electrical lead part according to claim 1, wherein the joint part is covered with the inside as a side.

The structure of the electric lead part according to claim 2, wherein the thermoplastic resin is an ethylene-vinyl acetate copolymer, an acrylic resin, or an ionomer.

The first terminal member and the second terminal member are joined with their end portions overlapped with each other, and the first terminal member and the second terminal member overlap each other. Then, the structure of the electric lead part according to any one of claims 1 to 3, wherein a filler is filled between both ends of the first and second terminal members in the width direction and the film.

The structure of the electric lead part according to claim 4, wherein the filler is a thermoplastic resin.

In an electrical device having a device body and positive and negative lead portions extending from the device body,
Either one of the lead part of the said positive electrode and a negative electrode has the structure of any one of Claim 1 thru | or 5, The electrical device characterized by the above-mentioned.

In a battery having a battery element hermetically sealed in an exterior body, and positive and negative lead portions connected to the battery element and extending from the exterior body,
One of the lead portion, the first terminal member extending from the outer body is connected to the battery element, is joined to the distal end portion of the first terminal member outside of said outer body, said A second terminal member made of the same material as the other of the lead portions;
One of the first terminal member and the second terminal member is an aluminum plate, and the other is a copper plate or a plated copper plate,
The joint portion between the first terminal member and the second terminal member is formed on two sides of the first and second terminal members in the thickness direction of one or two folded films containing a thermoplastic resin. It is covered with a coating resin formed by heat-sealing in a state surrounded and sandwiched from, so as not to touch the outside air ,
The battery , wherein the film is transparent to such an extent that a covering state of the joint portion can be visually observed through the film .

The film is a laminated film having a layer made of the thermoplastic resin and a layer made of a heat-resistant resin having a higher melting point than the thermoplastic resin on opposite surfaces, and the layer made of the thermoplastic resin The battery according to claim 7, wherein the joint portion is covered with the inside of the battery.

The thermoplastic resin is an ethylene-vinyl acetate copolymer or an acrylic resin. The battery according to claim 8, which is an ionomer.

The first terminal member and the second terminal member are joined such that their end portions are overlapped with each other, and the first terminal member and the second terminal member overlap each other. in the filler between the both width-directional side end and the film of the first and second terminal members is filled, the battery according to any one of claims 7 to 9.

The battery according to claim 10, wherein the filler is a thermoplastic resin.

The first terminal member is made of an aluminum plate , the second terminal member is made of a copper plate or a plated copper plate , and the first terminal member and the second terminal member are joined together. The battery according to any one of claims 7 to 11, wherein the lead part has a positive lead part.

The assembled battery formed by connecting the some battery of any one of Claim 7 thru | or 12 in series.

A battery element hermetically sealed in an exterior body and a plurality of batteries connected to the battery element and extending from the exterior body, each having a positive electrode lead portion made of an aluminum plate and a negative electrode lead portion made of a copper plate In the assembled battery connected to
The joint between the lead portion of the positive electrode and the lead portion of the negative electrode between the two batteries is made of two sheets containing a thermoplastic resin or one folded film of the positive electrode and the negative electrode lead portion. It is covered with a coating resin formed by heat-sealing in a state of being surrounded by being sandwiched from both sides in the thickness direction, so as not to come into contact with outside air ,
The assembled battery , wherein the film is transparent to such an extent that a covering state of the joint portion can be visually observed through the film .