JP5034137B2

JP5034137B2 - WELDING MANUFACTURING METHOD, pedestal, and battery manufacturing method

Info

Publication number: JP5034137B2
Application number: JP2000373559A
Authority: JP
Inventors: 文哉佐藤; 秋治佐々木; 千秋安西; 博安斎
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2000-11-01
Filing date: 2000-11-01
Publication date: 2012-09-26
Anticipated expiration: 2020-11-01
Also published as: JP2002144047A

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a welded article, by which two or more works to be welded different in material can easily be subjected to the electric resistance welding with high reliability, and to provide a pedestal used therefore and a manufacturing method of a battery by using the pedestal. SOLUTION: An aluminum plate 11 and a nickel plate 12 are placed on the pedestal 20, and a welding rod 30 is pressed against the works 10 to be welded to perform the electric resistance welding. A placement surface 20a of the pedestal 20 is formed of a metal of the melting point higher than that of the works 10. In addition, the metal preferably has the heat conductivity at 700 deg.C to be >=10 W/mK, and the electric volume resistivity at 100 deg.C to be <=30 μΩcm. The aluminum plate 11 can be prevented from being adhered to the pedestal 20, and the aluminum plate 11 can be prevented from being excessively melted, and a large welding current can be allowed to flow in a welded part 10a.

Description

【０００１】
【発明の属する技術分野】
本発明は、溶接対象物を台座に載置し、溶接棒を押し当てて電気抵抗溶接する溶接物の製造方法、それに用いる台座、およびそれを用いる電池の製造方法に関する。
【０００２】
【従来の技術】
近年、電子技術の進歩に伴い、カメラ一体型ＶＴＲ（ビデオテープレコーダ），携帯電話あるいは携帯用コンピュータなどのポータブル電子機器が数多く普及し、それらの小型化および軽量化が図られている。そこで、それらに使用するポータブル電源として、電池、特に二次電池の開発が進められている。中でも、リチウムイオン二次電池は、高エネルギー密度を実現できるものとして注目されており、とりわけ、薄型で折り曲げ可能な形状の自由度が高いものの研究開発が活発に進められている。
【０００３】
このような電池としては、例えば、電解質に漏液のおそれがない固体化されたものを用い、正極端子板に約０．１ｍｍの厚さの薄いアルミニウム板を用い、負極端子板に約０．１ｍｍの厚さの薄いニッケル板を用いたものが知られている。この正極端子板および負極端子板には、外部と接続するためのニッケル板などよりなる配線板が溶接されている。この溶接、特に正極端子板と配線板との溶接は、従来、超音波溶接により行われている。薄いアルミニウム板とニッケル板とを電気抵抗溶接することが技術的に難しいからである。
【０００４】
電気抵抗溶接が難しい第１の理由は、アルミニウムとニッケルとの融点の差にある。アルミニウムの融点は６６０℃であるのに対してニッケルの融点は１４５５℃であり、その差は約８００℃と大きく異なる。また、アルミニウムの沸点は２４８６℃であるのに対してニッケルの沸点は２７３１℃と、沸点も大きく異なっている。
【０００５】
電気抵抗溶接が難しい第２の理由は、アルミニウム板の表面に形成されている酸化皮膜（酸化アルミニウム）の存在にある。酸化アルミニウムの融点は２０５０℃と高く、アルミニウム板とニッケル板とを電気抵抗溶接する場合には、溶接部の温度を約２０５０℃以上にして、この薄い酸化皮膜を溶解する必要がある。ここで、アルミニウムの表面の酸化アルミニウム膜は一般にアルミナと呼ばれており、化学式はＡｌ_２Ｏ_３である。
【０００６】
よって、電気抵抗溶接の電圧・電流・時間を十分に強く設定すると、溶接部のアルミニウム板が完全に溶解して穴が空いてしまったり、あるいは溶接部のアルミニウム板が沸点に達し、アルミニウムが蒸発して周囲に激しく飛散してしまう。逆に、電気抵抗溶接の電流を弱くすると、アルミニウム板のみが溶解し、ニッケル板が溶解しないため、アルミニウムとニッケルとの合金層が形成されず、溶接できない。そのため、実際の製品の量産工程において、薄いアルミニウム板とニッケル板とを電気抵抗溶接することは難しく、もし電気抵抗溶接できたとしても、不良率が大きく、信頼性に著しく欠けていた。また、溶接強度が弱かった。
【０００７】
なお、正極端子板を負極端子板と同様にニッケル板により構成すれば電気抵抗溶接することができるが、正極端子板をニッケル板により構成すると、電池内部において電気的に反応し、溶解してしまう場合もあるので好ましくない。また、正極端子板と配線板とを半田付けすることも考えられるが、正極端子板を構成する薄いアルミニウム板が高温になると電池内部も高温になり、電池が劣化してしまうので、半田付けすることは難しい。すなわち、従来は超音波溶接しか方法がなかった。
【０００８】
【発明が解決しようとする課題】
しかしながら、超音波溶接では次のような問題点があった。第１に、超音波溶接の振動強度と振幅時間の設定幅が小さく、溶接の最適条件の維持が難しい。第２に、溶接強度を安定させることが難しく、大量に製品を製造する量産工程においてある割合の溶接不良が発生する場合がある。第３に、超音波溶接装置が抵抗溶接装置よりも高価であり、量産のための設備費用が高くなる。第４に、超音波溶接装置が抵抗溶接装置よりも大きく、より大きな床スペースが必要である。そこで、薄いアルミニウム板とニッケル板とを電気抵抗溶接により溶接する技術の開発が要望されていた。
【０００９】
本発明はかかる問題点に鑑みてなされたもので、その目的は、１００℃における電気体積抵抗値が１３．６μΩ・ｃｍ未満の材料の異なる２つ以上の溶接対象物を容易にかつ高い信頼性で電気抵抗溶接することができる溶接物の製造方法、それに用いる台座、およびそれを用いた電池の製造方法を提供することにある。
【００１０】
【課題を解決するための手段】
本発明による溶接物の製造方法は、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ未満の材料の異なる２つ以上の溶接対象物を台座に載置し、溶接棒を押し当てて電気抵抗溶接するに際し、台座を、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、載置部よりも熱伝導率の大きい放熱部とにより構成するにより構成するものである。
【００１１】
本発明による台座は、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、前記載置部よりも熱伝導率の大きい放熱部とにより構成されたものである。
【００１２】
本発明による電池の製造方法は、電極端子板に配線板が溶接された電池を製造するものであって、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ未満の材料の異なる電極端子板と配線板とを台座に載置し、溶接棒を押し当てて電気抵抗溶接するに際し、台座を、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、載置部よりも熱伝導率の大きい放熱部とにより構成するものである。
【００１３】
本発明による溶接物の製造方法では、台座を、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、載置部よりも熱伝導率の大きい放熱部とにより構成するので、溶接時に台座が溶接対象物と共に溶解し、台座に溶接対象物が付着してしまうことが防止される。また、台座の放熱効果により溶接対象物の過溶解が防止される。更に、台座にも溶接電流が流れるので、溶接対象物の溶接部により大きな溶接電流が流れる。
【００１４】
本発明による台座では、少なくとも載置面を融点が３４０７℃よりも高い金属により構成しているので、また、本発明による電池の製造方法では、本発明の溶接物の製造方法を用いているので、本発明の溶接物の製造方法と同様に、溶接対象物の付着、過溶解が防止され、溶接部に大きな溶接電流が流れる。
【００１５】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照して詳細に説明する。
【００１６】
図１は、本発明の一実施の形態に係る溶接物の製造方法およびそれに用いる溶接装置を表すものである。なお、本実施の形態では、溶接対象物１０として材料の異なるアルミニウム板１１と、ニッケル板１２とを溶接する場合について説明する。ここで、アルミニウム板１１はアルミニウムを含むアルミニウム系合金板でも良く、ニッケル板１２はニッケルを含むニッケル系合金板でもよい。
【００１７】
この溶接装置は、溶接対象物１０を載置する台座２０と、溶接対象物１０に押し当てて溶接対象物１０に電流を流す一対の溶接棒３０とを備えている。溶接棒３０は、図示しない電気溶接制御装置に接続されており、溶接対象物１０を溶接する際の条件を設定できるようになっている。
【００１８】
台座２０は、少なくとも溶接対象物１０の載置面２０ａが、溶接対象物１０よりも融点の高い高融点金属により構成されることが好ましい。融点を高くすることにより、溶接時に台座２０が溶接対象物１０と共に溶解し、台座２０に溶接対象物１０が付着してしまうことを防止できるからである。また、金属は熱伝導率が高いので放熱効果を期待でき、アルミニウム板１１の過溶解および沸騰を防止することができるからである。更に、金属は導電性を有しているので台座２０にも溶接電流が流れ、溶接対象物１０の溶接部１０ａにより大きな溶接電流を流すことができるからである。
【００１９】
本実施の形態では、溶接対象物１０であるアルミニウム板１１の融点が６６０℃、ニッケル板１２の融点が１４５５℃であるので、少なくとも載置面２０ａは、ニッケル板１２の融点１４５５℃よりも高い融点を有する高融点金属により構成されることが好ましい。更に、載置面２０ａとニッケル板１２との融点の差は大きい方が有利である。
【００２０】
また、台座２０の少なくとも載置面２０ａは、７００℃における熱伝導率が１０Ｗ／ｍＫ以上の金属により構成されることが好ましい。熱伝導率が低すぎると、放熱効果を期待できず、アルミニウム板１１の過溶解および沸騰を有効に防止することができないからである。なお、電気溶接制御装置が小さい場合には、台座２０の少なくとも載置面２０ａは、７００℃における熱伝導率が２００Ｗ／ｍＫ以下の金属により構成されることが好ましい。電気溶接制御装置の電流・電圧容量が小さく、溶接最大電流が約３００Ａ〜８００Ａ以下の場合には、熱伝導率が高すぎると、溶接対象物１０に熱が蓄積されず、溶接することができない場合があるからである。ちなみに、７００℃における熱伝導率で規定するのは、溶接時において溶接部１０ａに直接接触する載置面２０ａの部分は７００℃程度に加熱されていると考えられるからである。
【００２１】
更に、台座２０の少なくとも載置面２０ａは、１００℃における電気体積抵抗率が３０μΩｃｍ以下の金属により構成されることが好ましい。載置面２０ａの電気体積抵抗率が高すぎると、溶接電流の大半がニッケル板１２とアルミニウム板１１とを平面方向に流れてしまい、溶接対象物１０の溶接部１０ａの垂直方向に大きな溶接電流を流すことができず、溶接部１０ａを十分に加熱することができないからである。また、載置面２０ａの電気体積抵抗率が高すぎると、溶接電流の約２０〜７０％がアルミニウム板１１の２つの溶接部１０ａを結ぶ平面方向に流れてしまい、アルミニウム板１１の温度がより高くなり、アルミニウム板１１の溶接部１０ａが過度に溶解し、穴が形成されてしまう場合があるからである。すなわち、アルミニウム板１１の発熱量が小さくなるようにした方が好ましい。ちなみに、１００℃における電気体積抵抗率で規定するのは、溶接時において載置面２０ａの溶接電流が流れる溶接部１０ａ近傍部分は１００℃程度に加熱されると考えられるからである。
【００２２】
少なくとも載置面２０ａを構成する金属としては、具体的には、白金（Ｐｔ），鉄（Ｆｅ），クロム（Ｃｒ），ジルコニウム（Ｚｒ），チタン（Ｔｉ），モリブデン（Ｍｏ），パラジウム（Ｐｄ），タングステン（Ｗ）およびイリジウム（Ｉｒ）からなる群のうちの少なくとも１種を含むものが好ましい。本明細書において金属というのは、合金も含む広い概念である。これらの物性（融点，７００℃における熱伝導率および１００℃における電気体積抵抗率）を表１に示す。
【００２３】
【表１】

【００２４】
台座２０の厚さ（載置面２０ａに対して垂直な方向の厚さ）は、台座２０全体が上述したような金属により構成される場合には、例えば１ｍｍ以上とされることが好ましい。薄すぎると、十分な放熱効果を得ることができず、しかも台座２０の溶接部間抵抗値が大きくなるので、十分に大きな溶接電流を流せなくなり、更に、台座２０が溶接棒３０の圧力で変形してしまうからである。
【００２５】
なお、台座２０は全体が上述したような金属により構成されていてもよいが、図２に示したように、上述したような金属よりなる載置部２１と、この載置部２１よりも熱伝導率の大きい放熱部２２とを有するように構成されていてもよい。台座２０全体を単一の金属で構成するようにすれば製作は容易であるが、載置部２１と放熱部２２とを有するように構成すれば、高融点金属よりなる載置部２１により溶接対象物１０の付着を防止しつつ放熱部２２により溶接部１０ａの放熱を促進し、アルミニウム板１１の過溶解をより効果的に防止することができるからである。また、上述したような金属は高価なものが多く、載置部２１のみをこれらの金属により構成するようにすれば台座２０の費用を安くすることができるという利点もあるからである。更に、何回も電気抵抗溶接を行うことにより載置部２１に凹凸ができたり、劣化した場合、載置部２１のみを交換することにより放熱部２２を再利用することができるからである。よって、図２に示したように載置部２１と放熱部２２とを有する台座２０は、溶接対象物１０が接触する部分の溶解を防止でき、かつ最大限に放熱できるので好ましい。
【００２６】
放熱部２２を構成する材料としては、具体的には、銀（Ａｇ），銅（Ｃｕ），アルミニウム（Ａｌ）および金（Ａｕ）からなる群のうちの少なくとも１種を含む金属が好ましい。これらの１００℃における熱伝導率を表２に示す。１００℃における熱伝導率を示すのは、溶接時における放熱部２２の温度は１００℃程度であると考えられるからである。なお、白金の１００℃における熱伝導率は７２Ｗ／ｍＫである。
【００２７】
【表２】

【００２８】
載置部２１の厚さは、例えば０．５ｍｍ〜２ｍｍ程度が好ましく、約１ｍｍであればより好ましい。厚さが薄すぎると、溶接棒３０の圧力により載置部２１が変形したり、また放熱部２２が溶解して変形してしまうからであり、厚すぎると、放熱効果が低下し溶接強度がすこし低下してしまう可能性があり、また台座２０の費用も高くなってしまうからである。放熱部２２の厚さは、例えば５ｍｍ以上であることが好ましい。厚さが薄すぎると、十分な冷却効果が得られず、台座２０自体も高温となり酸化および劣化してしまうからである。
【００２９】
載置部２１と放熱部２２とは、例えば、接合面が凹凸のないように平らに鏡面仕上げされた後、ねじあるいは上下に配置された支え金具などにより機械的に密着するように圧力が加えられて接合されている。なお、載置部２１は放熱部２２の上に載せてあるだけでもよい。電気抵抗溶接時に載置部２１と放熱部２２とを密着させる方向に数ｋｇ以上の力が印加され熱的に結合するからである。また、載置部２１と放熱部２２とは、数Ｍｇ以上のかなり高い圧力を上下からかけることにより、溶接接合されていてもよい。但し、機械的に接合させる方が、載置部２１の交換が容易であり、かつ安定性および密着性も優れているので好ましい。
【００３０】
載置部２１と放熱部２２とを機械的に接合する場合には、例えば、図３に示したように、載置部２１と放熱部２２との間に、シリコン系の接着剤，シリコンオイルあるいは熱伝導性シートなどよりなる密着層２３を介在させるようにしてもよい。このようにすれば、載置部２１と放熱部２２との密着性を簡単に保持することができ、放熱性をより高めることができるので好ましい。
【００３１】
また、載置部２１と放熱部２２とをろう付けにより接合するようにしてもよい。このようにすれば、載置部２１を交換する際の簡便性には劣るものの、載置部２１と放熱部２２との密着性に優れ、放熱性に優れると共に、簡単に製作することができるので好ましい。ろう材としては、例えば、銀含有の銀ろう、鉛含有の半田、または銅含有の鉛フリー半田がある。但し、鉛含有の半田を用いると、放熱性が少し低下してしまう。
【００３２】
溶接棒３０は、硬度・導電率・熱伝導性が高いことが必要であり、例えば、クロム銅またはアルミナ分散強化銅などの銅合金により構成されている。溶接棒３０の先端形状は、例えば、図４（Ａ）に示したような半球形状、同（Ｂ）に示したような円錐形状、同（Ｃ）に示したような円柱形状、同（Ｄ）に示したような円錐の先端を平らに切断した台形形状、同（Ｅ）に示したような半球の先端を平らに切断した半球と平面とを組み合わせた形状、または同（Ｆ）に示したような四角錐形状（ピラミッド形状）などの多角錐形状とされることが好ましい。
【００３３】
中でも、半球形状は溶接棒３０の最も好ましい先端形状である。この形状によれば、溶接棒３０を溶接対象物１０に押し当てたとき、溶接棒３の先端の中心部に高い圧力が加えられ、溶接電流が集中して流れるので、そのごく小さな範囲において温度が上昇し、溶接対象物１０が溶解されて合金層が形成され易い。また、合金層が形成される場所が必ず溶接棒３０の中心に固定されるので、溶接電流が流れる２箇所の溶接部１０ａの距離が固定され、溶接条件が安定して好ましい。更に、溶接棒３０を溶接対象物１０に押し当てた時の圧力は溶接棒３０の中心から周囲に向かって弱くなるので、溶接棒３０の中心部において溶接対象物１０が溶解しても、その周辺では完全に溶解せず、溶接対象物１０に穴が形成されにくい。ここで溶接電流は、圧力に比例して溶接棒３０の中心から周囲に向かって弱くなる。
【００３４】
有効な半球状の先端形状は、例えば、円柱の直径が０．５ｍｍ〜１０ｍｍであり、先端の半球の半径が０．５ｍｍ〜５ｍｍのものである。最適な半球状の先端形状は、溶接棒３０の先端から１０ｍｍ上部の円柱の直径が３ｍｍであり、溶接棒３０の先端から１ｍｍ上部の円柱の直径が１．５ｍｍであり、先端の半球の半径が１．５ｍｍのものである。
【００３５】
円錐形状は、半球形状とほぼ同様に作用し、比較的良好な先端形状である。円錐の先端角度は１４０度〜１７５度の鈍角が好ましく、円柱の直径は０．５ｍｍ〜５ｍｍが好ましい。最適な円錐の先端形状は、溶接棒３０の先端から１０ｍｍ上部の円柱の直径が３ｍｍであり、溶接棒３０の先端から１ｍｍ上部の円柱の直径が１．５ｍｍであり、先端の円錐の角度が１７０度のものである。先端の角度を９０度以下の鋭角とすると、中心部に高い圧力が印加され、溶接対象物１０に穴が開いてしまったり、あるいは溶接電流が流れる面積が小さくなってしまう可能性があるので、好ましくない。なお、多角錐形状も円錐形状と同様である。
【００３６】
円柱形状は例えばニッケル板同士を溶接する際の最も一般的な形状であるが、溶接のための電流値がばらついてしまうので、溶接強度もばらついてしまう傾向があり、ある割合の溶接不良が発生してしまう可能性がある。例えば、電気抵抗溶接時に溶接棒３０を溶接対象物１０に押し当てたとき、溶接棒３０先端の円形中のさらに小さなある部分に高い圧力が加えられ、そこに溶接電流が流れるので、溶接棒３０先端の酸化状態および劣化状態、台座２０の状態、あるいは溶接対象物１０の表面状態に応じて、溶接毎に溶接部の場所が偶発的に移動してしまう。よって、２つの溶接部１０ａの間の距離を一定に保つことができず、２本の溶接棒３０間の抵抗値および電流値が変化してしまい、溶接部１０ａの温度が変化し、溶接強度が変化してしまい好ましくない。更に、溶接時の電圧あるいは電流を高くした場合、溶接対象物１０が完全に溶解されてしまい穴が開いてしまう可能性もある。但し、先端部の面積は半球形状よりも広いので、大きな面積で合金層が形成される可能性がある。また、溶接に繰り返し用いた後の研磨作業が極めて簡単であり、作業コストも安価であるという利点がある。
【００３７】
円錐の先端を平らに切断した台形形状、あるいは半円の先端を平らに切断した形状も、半球形状とほぼ同様に作用し、比較的良好な先端形状である。また、高い圧力が加えられる面積を比較すると半球形状よりも広く、大きな面積で合金層が形成される可能性がある。但し、溶接時の電圧あるいは電流をかなり高くした場合、溶接対象物１０が完全に溶解されてしまい穴が開いてしまう可能性があり、好ましくない場合もある。
【００３８】
本実施の形態では、このような溶接装置を用い、次のようにしてアルミニウム板１１とニッケル板１２とを溶接する。
【００３９】
まず、台座２０の載置面２０ａの上にアルミニウム板１１とニッケル板１２とを重ねて載せる。その際、アルミニウム板１１の方、すなわち融点の低い方を台座側とする。台座２０による放熱効果により過溶融を防止するためである。次いで、一対の溶接棒３０を下方に移動させ、予め設定された重さにより上方からニッケル板１２を押し付ける。このとき、溶接棒３０の先端の直下部において、ニッケル板１２とアルミニウム板１１とは圧力により密着し、アルミニウム板１１は台座２０に密着する。
【００４０】
続いて、図示しない電気溶接制御装置により、予め定められた時間の電圧波形または電流波形で一対の溶接棒３０に電圧を印加する。溶接電流は、プラス電極の溶接棒３０→ニッケル板１２→アルミニウム板１１→台座２０→アルミニウム板１１→ニッケル板１２→マイナス電極の溶接棒３０の順番に、約数１０ｍｓ程度の短時間流れる。これにより、溶接棒３０の直下部におけるニッケル板１２とアルミニウム板１１との接合部、すなわち溶接部１０ａが溶解し、溶けあう。電気溶接制御装置により溶接電流が停止されると、溶接部１０ａが急速に冷却され、合金層が形成され、溶接される。
【００４１】
その際、台座２０に接しているアルミニウム板１１の表面は、台座２０の放熱効果により冷却されており、融点の高い酸化皮膜で覆われてもいるので、融点に到達しない。また、台座２０の少なくとも載置面２０ａは、溶接対象物１０よりも融点の高い高融点金属により構成されているので、溶解されない。よって、台座２０とアルミニウム板１１との合金層は形成されにくい。更に、台座２０は、自身の放熱効果により温度の上昇が抑制され、高温による酸化が防止される。加えて、台座２０が載置部２１と放熱部２２とを有する場合には、溶接部１０ａにおける発熱がより効率的に放熱される。
【００４２】
溶接時の電圧、電圧印加時間などは、ニッケル板１２が溶解するために最低必要な値とすればよい。例えば、最大電圧を０．５Ｖ〜５Ｖ、最大電流を１００Ａ〜３０００Ａ、電圧印加時間を５ｍｓ〜４０ｍｓとする。一例を挙げれば、電圧を約１．１Ｖ、電流を約１０００Ａ、電圧印加時間を約１０ｍｓとする。印加する電圧の波形は直流電圧波形でも交流電圧波形でもよい。但し、直流の方がより短時間で大電流を流すことができるので、溶接部１０ａの温度を早く上昇させることができ、好ましい。よって、アルミニウム板１１を冷却できる短時間において、溶接部１０ａに合金層を形成できる。また、制御方式は、印加電圧制御方式でも印加電流制御方式でもよい。印加電圧制御方式であれば溶接部１０ａの発熱量が一定となるので好ましく、また印加電流制御方式であれば、溶接対象物１０、溶接棒３０および台座２０の載置面２０ａの表面状態または抵抗値が変化しても一定の電流が流れるので、ニッケル板１２およびアルミニウム板１１の接合する部分の発熱量が一定となり、好ましい。
【００４３】
なお、数百回〜数千回の溶接毎に、台座２０の載置面２０ａを研磨剤が塗布されたバフや砥石や紙やすりで磨き、載置面２０ａの表面の酸化物やアルミニウム付着物を除去するクリーニング作業を行うことが好ましい。台座２０の載置面２０ａの抵抗値が増大し、溶接電流が台座２０に流れにくくなり、溶接強度が不安定となるからである。また、数千回の溶接毎に、溶接棒３０の先端を磨く研磨作業を行うことが好ましい。例えば、先端の酸化あるいは劣化の層が薄い場合には紙やすりで磨き、酸化あるいは劣化の層が厚い場合にはエンドミルなどの切削加工機械で０．２ｍｍ程度以上削ることにより、酸化していない金属部分を露出させる。更に、数万回以上の溶接毎に、台座２０または台座２０の載置部２１および溶接棒３０を新品に交換することが好ましい。
【００４４】
このように本実施の形態によれば、台座２０の少なくとも載置面２０ａを溶接対象物１０よりも融点の高い高融点金属、例えば１４５５℃よりも融点の高い高融点金属により構成するようにしたので、アルミニウム板１１とニッケル板１２のように材料の異なる溶接対象物１０を電気抵抗溶接しても、溶接対象物１０が台座２０に付着することを防止することができると共に、溶接対象物１０の過溶解を防止することができ、かつ溶接部１０ａに大きな溶接電流を流すことができる。よって、溶接対象物１０を強固に電気抵抗溶接することができる。また、電気溶接制御装置の設定範囲が広いので、大量に溶接する場合においても溶接強度を安定させることができる。更に、アルミニウム板１１を冷却しながら溶接するので、アルミニウムが沸騰し、周囲に激しく飛び散ることがなく、作業の安全性を向上させることができると共に、掃除の手間を省くことができる。
【００４５】
特に、台座２０の少なくとも載置面２０ａを７００℃における熱伝導率が１０Ｗ／ｍＫ以上の金属により構成するようにすれば、溶接対象物１０を適度に加熱し、かつ適度に放熱することにより過溶解および沸騰を有効に防止することができる。
【００４６】
また、台座２０の少なくとも載置面２０ａを１００℃における電気体積抵抗率が３０μΩｃｍ以下の金属により構成するようにすれば、台座２０にも溶接電流が適度に流れ、溶接部１０ａの垂直方向に大きな溶接電流を流すことができ、溶接部１０ａを局所的に十分に加熱することができる。
【００４７】
更に、台座２０が載置部２１と放熱部２２とを有するように構成すれば、溶接対象物１０を適度に加熱しつつ放熱効果をより高めることができると共に、費用を安くでき、再利用も可能となる。例えば、台座２０を白金のみで構成すると、台座２０の大きさが１０×１０×１０ｍｍの場合には約４万円以上になってしまう。ところが、１０×１０×１ｍｍの白金よりなる載置部２１と、１０×１０×９ｍｍの銀よりなる放熱部２２とにより構成すると、８千円以下にすることができる。
【００４８】
加えて、溶接棒３０の先端形状を半球形状、円錐形状、円錐の先端を平らに切断した台形形状、半球の先端を平らに切断した半球と平面とを組み合わせた形状、または多角錐形状とすれば、溶接電流の流れる範囲をごく小さくすることができ、溶接部１０ａを容易に加熱することができる。また、２箇所の溶接部１０ａの距離を高い精度で一定とすることができるので、溶接条件を安定させることができる。特に半球形状とすれば、より高い効果が得られる。
【００４９】
なお、本実施の形態では、溶接対象物１０としてアルミニウム板１１とニッケル板１２とを溶接する場合について説明したが、本発明は、材料の異なる２つ以上の溶接対象物を溶接する場合に広く適用することができる。例えば、ニッケル板１２に変えて、ニッケル板と鉄板とを張り合わせた金属板（クラッド材）とアルミニウム板１１とを溶接する場合も同様である。この場合、溶接されるのが金属板のうちのニッケル板の部分とアルミニウム板１１であれば、溶接対象物はニッケル板であり、溶接対象物の融点というのはアルミニウム板およびニッケル板の融点を指す。
【００５０】
この溶接物の製造方法は、例えば、次のような電池の製造方法に用いることができる。
【００５１】
図５は本実施の形態に係る溶接物の製造方法を用いた電池の製造方法およびそれにより製造される電池の構造を表すものである。図６は図５のＩ−Ｉ線に沿った断面構造を表すものである。この電池は、正極端子板４１および負極端子板４２を取り付けた電池素子５０を外装部材６０の内部に封入したものである。電池素子５０は、正極５１と負極５２とが電解質５３を介して積層された構成を有している。
【００５２】
正極５１は、例えば、正極集電体層５１ａと正極合剤層５１ｂとにより構成されており、正極端子板４１は正極集電体層５１ａに接続されている。正極集電体層５１ａは、例えばアルミニウム箔により構成されており、正極合剤層５１ｂは、例えば、正極材料と、カーボンブラックあるいはグラファイトなどの導電剤と、ポリフッ化ビニリデンなどの結着剤とを含有して構成されている。正極材料としては、リチウム（Ｌｉ）を含有するリチウム複合酸化物あるいはリチウム複合硫化物、またはリチウムを含有しない金属硫化物あるいは酸化物、または特定の高分子材料などが好ましく、電池の使用目的に応じてそれらのいずれか１種または２種以上が選択される。
【００５３】
負極５２は、例えば、負極集電体層５２ａと負極合剤層５２ｂとにより構成されており、負極端子板４２は負極集電体層５２ａに接続されている。負極集電体層５２ａは、例えば銅箔により構成されており、負極合剤層５２ｂは、例えば、負極材料と、ポリフッ化ビニリデンなどの結着剤とを含有して構成されている。負極材料は、例えば、炭素材料あるいはケイ素化合物などのリチウムを吸蔵および離脱することが可能な材料、またはリチウム金属あるいはリチウム合金などのリチウムを析出および溶解することが可能な材料を含んでいる。
【００５４】
電解質５３は、いわゆるゲル状電解質あるいは有機固体電解質と呼ばれるものにより構成されており、例えば、高分子化合物と、必要に応じて可塑剤と、電解質塩としてのリチウム塩とを含んでいる。正極５１と負極５２との間には、図示しないセパレータが必要に応じて配置されていてもよい。
【００５５】
正極端子板４１は、例えば厚さが約０．０５ｍｍ〜０．１５ｍｍ程度の薄いアルミニウム板により構成されている。負極端子板４２は、例えば厚さが約０．０５ｍｍ〜０．１５ｍｍ程度の薄いニッケル板により構成されている。正極端子板４１および負極端子板４２には、例えば厚さが約０．１ｍｍ〜０．２ｍｍ程度の薄いニッケル板あるいはニッケル板と鉄板とが張り合わされた金属板よりなる配線板７１，７２がそれぞれが溶接されている。
【００５６】
このような電池は、次のようにして製造することができる。
【００５７】
まず、所定の方法により電池素子５０を作製し、電池素子５０に正極端子板４１および負極端子板４２を接続して、外装部材６０の内部に電池素子５０を封入する。次いで、正極端子板４１に配線板７１を上述した溶接物の製造方法により電気抵抗溶接する。すなわち、正極端子板４１および配線板７１よりも融点の高い高融点金属よりなる台座２０を用い、正極端子板４１を台座２０側にして正極端子板４１と配線板７１とを台座２０に載置し、図１に示したようにして溶接棒３０を押し当てて電圧を印加する。ここでは、上述した方法を用いているので、アルミニウム板よりなる正極端子板４１が台座２０に付着することなく、正極端子板４１と配線板７１とが強固に溶接される。
【００５８】
続いて、負極端子板４２に配線板７２を電気抵抗溶接する。その際、上述した方法により行うようにしてもよいが、負極端子板４２も配線板７２も共にニッケル板により構成されているので、従来の台座８０、すなわち銅あるいは銅合金、または非金属であるベーク板により構成されたものを用い、電気抵抗溶接してもよい。これにより、図５に示した電池が完成する。
【００５９】
また、図７に示したような電池を製造する場合にも、本実施の形態に係る溶接物の製造方法を用いることができる。この電池は、正極端子板４１および負極端子板４２の先端部に溝４１ａ，４２ａが設けられていることを除き、図５に示した電池と同様の構成を有している。
【００６０】
このような電池では、正極端子板４１の先端部に溝４１ａが設けられているので、溶接電流が正極端子板４１を通りにくくなり、溶接電流の大部分は台座２０または配線板１１を通ることになる。このため、溶接強度がより強固になる。
【００６１】
ちなみに、配線板７１にも正極端子板４１および負極端子板４２と同様の溝を設けると、プラス電極の溶接棒３０→配線板７１→マイナス電極の溶接棒３０に流れる電流もなくなってしまうため、配線板７１の溶接部の温度上昇が妨げられ、あまりよい効果は期待できない。よって、配線板７１，７２には溝を設けない方が好ましい。
【００６２】
このように、本実施の形態によれば、薄いアルミニウム板よりなる正極端子板とニッケル板などよりなる配線板とを電気抵抗溶接により強固に溶接することができる。ところで、従来の超音波溶接では、溶接強度が強固であるための設定条件の幅が極めて狭いので、溶接強度を強固に保つことが極めて難しく、アタッチメントの形状や位置関係が少しでも変化すると不良品率が高くなってしまう可能性があったのに対し、本実施の形態によれば、溶接強度が強固であるための設定条件の幅が広いので、溶接強度を強固に保つことが容易であり、不良品率を極めて低くすることができる。また、電気抵抗溶接装置は、超音波溶接よりも安価なため、設備費用を削減することもできる。
【００６３】
【実施例】
更に、本発明の具体的な実施例について、図１を参照して詳細に説明する。
【００６４】
（実施例１，２）
実施例１として、台座２０を白金により構成し、上記実施の形態において説明したようにして溶接対象物１０としてアルミニウム板１１とニッケル板１２とを電気抵抗溶接した。その際、印加電圧制御方式により直流電圧を印加し、最大電圧は１．２Ｖ、最大電流は１０００Ａ、電圧印加時間は１０ｍｓとした。実施例２として、台座２０を鉄により構成したことを除き、実施例１と同様にしてにアルミニウム板１１とニッケル板１２とを電気抵抗溶接した。
【００６５】
そののち、アルミニウム板１１の側の溶接痕および台座２０の載置面２０ａの状態を光学顕微鏡により観察した。また、溶接したアルミニウム板１１とニッケル板１２とを引き剥がし、引き剥がした後のニッケル板１２の状態を光学顕微鏡により観察した。それらの結果を図８ないし図１３に示す。図８は実施例１のアルミニウム板１１の溶接痕、図９は実施例１の台座２０の状態、図１０は実施例１の引き剥がし後の状態、図１１は実施例２のアルミニウム板１１の溶接痕、図１２は実施例２の台座２０の状態、図１３は実施例２の引き剥がし後の状態をそれぞれ表すものである。
【００６６】
また、本実施例に対する比較例１，２として、台座を銅（比較例１）あるいはセラミック（比較例２）により構成したことを除き、本実施例と同様にしてにアルミニウム板とニッケル板とを電気抵抗溶接した。比較例１，２についても、本実施例と同様に、アルミニウム板側の溶接痕、台座の状態および引き剥がした後のニッケル板１２の状態を光学顕微鏡により観察した。それらの結果を図１４ないし図１９に示す。図１４は比較例１のアルミニウム板１１の溶接痕、図１５は比較例１の台座２０の状態、図１６は比較例１の引き剥がし後の状態、図１７は比較例２のアルミニウム板１１の溶接痕、図１８は比較例２の台座２０の状態、図１９は比較例２の引き剥がし後の状態をそれぞれ表すものである。
【００６７】
図８ないし図１３から分かるように、本実施例によれば、台座２０とアルミニウム板１１とが溶接されたり、アルミニウムが台座２０に付着したりすることははほとんど見られず、溶接部１０ａの状態も良好であった。更に、図１０および図１３から分かるように、引き剥がし後の状態を見ても、溶接部１０ａのアルミニウムがニッケル板１２に付着していることから、強固に溶接されていることが確認された。また、台座２０を白金により構成した実施例１よりも鉄により構成した実施例２の方が、少し溶接部１０ａの面積が大きく、台座２０にアルミニウムの付着が若干見られることが分かった。これは、鉄の熱伝導率が白金に比べて低いので、溶接部１０ａの温度がより高くなり、溶接部１０ａの面積が大きくなったからであると考えられる。更に、白金よりも鉄の方が融点が低いので、鉄の表面の微小な部分が溶解したからであると考えられる。
【００６８】
これに対して、図１４ないし図１６から分かるように、台座を銅により構成した比較例１では、溶接部１０ａの面積が小さく、溶接強度が小さく、台座にアルミニウムの付着が多く見られた。これは、銅の熱伝導率が大きいために十分にアルミニウム板１１およびニッケル板１２を加熱することができず、また、融点が低いためにアルミニウム板１１と共に台座の一部が溶解してしまうからであると考えられる。ここで、溶接時の設定電圧をより高くすれば、十分に溶接対象物１０を加熱し、強固な溶接をすることができるとも考えられるが、アルミニウム板１１が台座２０に付着し、アルミニウム板１１に穴があいてしまうので、好ましくない。
【００６９】
また、図１７ないし図１９から分かるように、台座をセラミックにより構成した比較例２では、アルミニウム板１１に穴があいてしまい、溶接強度が不十分であり、台座にアルミニウムの一部が付着していた。これは、セラミックなどの絶縁物質の場合、溶接電流が台座を流れないので、溶接電流の大半がアルミニウム板１１およびニッケル板１２に流れてしまい、アルミニウム板とニッケル板との溶接部の温度が上がらないこと、また、台座の熱伝導率が低いので、アルミニウム板が過溶解あるいは沸騰してしまうことによるものと考えられる。
【００７０】
すなわち、溶接対象物１０よりも融点が高く、７００℃における熱伝導率が１０Ｗ／ｍＫ以上であり、かつ１００℃における電気体積抵抗率が３０μΩｃｍ以下の高融点金属により台座２０を構成するようにすれば、材料の異なる２つ以上の溶接対象物１０を強固に電気抵抗溶接できることが分かった。
【００７１】
なお、上記実施例では、台座２０を白金あるいは鉄により構成し、アルミニウム板１１とニッケル板１２とを溶接する場合について具体的に例を挙げて説明したが、上記実施の形態において説明した他の材料により台座２０を構成するようにしても、上記実施例と同様の結果を得ることができる。また、上記実施の形態において説明したように、他の材料の異なる２つ以上の溶接対象物１０を電気抵抗溶接する場合についても、上記実施例と同様の結果を得ることができる。
【００７２】
以上、実施の形態および実施例を挙げて本発明を説明したが、本発明は上記実施の形態および実施例に限定されるものではなく、種々変形可能である。例えば、上記実施の形態では、電池の構成について具体的に例を挙げて説明したが、本発明は、他の構成を有する電池についても同様に適用することができる。例えば、上記実施の形態では、リチウムを電極反応種として用いる電池について具体的に説明したが、他の電極反応種を用いる電池についても同様に適用することができる。また、上記実施の形態では、電解質がゲル状電解質あるいは有機固体電解質よりなる場合について説明したが、液状の電解質である電解液により構成するようにしてもよく、無機材料よりなる無機電解質により構成するようにしてもよい。更に、電池の形状もどのようなものでもよい。
【００７３】
また、上記実施の形態では、本発明の溶接物の製造方法を電池の製造に用いる場合について説明したが、他のものを製造する場合にも同様に適用することができる。特に、本発明は、融点が異なる厚さが薄い溶接対象物を溶接する場合に有効である。
【００７４】
【発明の効果】
以上説明したように請求項１ないし請求項９のいずれか１に記載の溶接物の製造方法によれば、台座を、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、載置部よりも熱伝導率の大きい放熱部とにより構成するようにしたので、または請求項１０ないし請求項１４のいずれか１に記載の台座によれば、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、載置部よりも熱伝導率の大きい放熱部とにより構成するようにしたので、または請求項１５ないし請求項２４のいずれか１に記載の電池の製造方法によれば、台座を、１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属よりなる載置部と、載置部よりも熱伝導率の大きい放熱部とにより構成するようにしたので、材料の異なる溶接対象物を電気抵抗溶接しても、溶接対象物が台座に付着することを防止することができると共に、溶接対象物の過溶解を防止することができ、かつ溶接部に大きな溶接電流を流すことができる。よって、溶接対象物を強固に電気抵抗溶接することができる。また、電気溶接制御装置の設定範囲が広いので、大量に溶接する場合においても溶接強度を安定させることができる。
【００７５】
また、台座の載置部を１００℃における電気体積抵抗率が１３．６μΩ・ｃｍ以上３０．０μΩ・ｃｍ以下の金属により構成するようにしたので、台座にも溶接電流を適度に流すことができ、溶接部の垂直方向に大きな溶接電流を流すことができる。
【００７６】
また、台座を、台座を、載置部と、載置部よりも熱伝導率の大きい放熱部とを有するようにしたので、溶接対象物を適度に加熱しつつ放熱効果をより高めることができると共に、費用を安くでき、再利用も可能とできる。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係る溶接物の製造方法およびそれに用いる溶接装置を表す斜視図である。
【図２】図１に示した溶接装置の変形例を表す斜視図である。
【図３】図２に示した溶接装置の変形例を表す斜視図である。
【図４】図１に示した溶接装置における溶接棒の先端形状を表す正面図である。
【図５】図１に示した溶接物の製造方法を用いた電池の製造方法を表す斜視図である。
【図６】図６に示した電池のＩ−Ｉ線に沿った断面図である。
【図７】図６に示した電池の製造方法の変形例を表す斜視図である。
【図８】本発明の実施例１に係るアルミニウム板の溶接痕を表す光学顕微鏡写真である。
【図９】本発明の実施例１に係る台座の状態を表す光学顕微鏡写真である。
【図１０】本発明の実施例１に係る引き剥がし後の状態を表す光学顕微鏡写真である。
【図１１】本発明の実施例２に係るアルミニウム板の溶接痕を表す光学顕微鏡写真である。
【図１２】本発明の実施例２に係る台座の状態を表す光学顕微鏡写真である。
【図１３】本発明の実施例２に係る引き剥がし後の状態を表す光学顕微鏡写真である。
【図１４】比較例１に係るアルミニウム板の溶接痕を表す光学顕微鏡写真である。
【図１５】比較例１に係る台座の状態を表す光学顕微鏡写真である。
【図１６】比較例１に係る引き剥がし後の状態を表す光学顕微鏡写真である。
【図１７】比較例２に係るアルミニウム板の溶接痕を表す光学顕微鏡写真である。
【図１８】比較例２に係る台座の状態を表す光学顕微鏡写真である。
【図１９】比較例２に係る引き剥がし後の状態を表す光学顕微鏡写真である。
【符号の説明】
１０…溶接対象物、１０ａ…溶接部、１１…アルミニウム板、１２…ニッケル板、２０…台座、２０ａ…載置面、２１…載置部、２２…放熱部、２３…密着層、３０…溶接棒、４１…正極端子板、４１ａ，４２ａ…溝、４２…負極端子板、５０…電池素子、６０…外装部材、７１，７２…配線板。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a welded article in which an object to be welded is placed on a pedestal, and a resistance is welded by pressing a welding rod, a pedestal used therefor, and a method for manufacturing a battery using the same.
[0002]
[Prior art]
In recent years, along with the advancement of electronic technology, a large number of portable electronic devices such as camera-integrated VTRs (video tape recorders), mobile phones, and portable computers have become widespread, and their size and weight have been reduced. Therefore, development of batteries, particularly secondary batteries, is being promoted as portable power sources used for them. In particular, lithium ion secondary batteries are attracting attention as being capable of realizing a high energy density, and in particular, research and development of a thin and high-flexible shape that can be bent is being actively promoted.
[0003]
As such a battery, for example, a solidified electrolyte with no risk of leakage is used, a thin aluminum plate having a thickness of about 0.1 mm is used for the positive electrode terminal plate, and about 0.00 mm is used for the negative electrode terminal plate. One using a thin nickel plate having a thickness of 1 mm is known. This positive terminal plate and A wiring board made of a nickel plate or the like for connection to the outside is welded to the negative terminal plate. This welding, particularly welding of the positive terminal plate and the wiring board, has been conventionally performed by ultrasonic welding. This is because it is technically difficult to perform electrical resistance welding between a thin aluminum plate and a nickel plate.
[0004]
The first reason why electric resistance welding is difficult is the difference in melting point between aluminum and nickel. The melting point of aluminum is 660 ° C., whereas the melting point of nickel is 1455 ° C., and the difference is greatly different from about 800 ° C. In addition, the boiling point of aluminum is 2486 ° C., whereas the boiling point of nickel is 2731 ° C., and the boiling point is also greatly different.
[0005]
The second reason why electric resistance welding is difficult is the presence of an oxide film (aluminum oxide) formed on the surface of the aluminum plate. The melting point of aluminum oxide is as high as 2050 ° C. When electric resistance welding of an aluminum plate and a nickel plate is performed, it is necessary to set the temperature of the welded portion to about 2050 ° C. or higher to dissolve this thin oxide film. Here, the aluminum oxide film on the surface of aluminum is generally called alumina, and the chemical formula is Al. ₂ O ₃ It is.
[0006]
Therefore, if the voltage, current, and time of electric resistance welding are set sufficiently strong, the aluminum plate of the welded part will melt completely and holes will be formed, or the aluminum plate of the welded part will reach the boiling point and the aluminum will evaporate. And violently scatters around. On the contrary, when the electric resistance welding current is weakened, only the aluminum plate is melted and the nickel plate is not melted. Therefore, an alloy layer of aluminum and nickel is not formed, and welding cannot be performed. For this reason, in an actual product mass production process, it is difficult to perform electrical resistance welding between a thin aluminum plate and a nickel plate, and even if electrical resistance welding can be performed, the defect rate is large and reliability is extremely lacking. Moreover, the welding strength was weak.
[0007]
In addition, if the positive electrode terminal plate is made of a nickel plate in the same manner as the negative electrode terminal plate, electric resistance welding can be performed. However, if the positive electrode terminal plate is made of a nickel plate, it electrically reacts and dissolves inside the battery. In some cases, it is not preferable. In addition, it is conceivable to solder the positive electrode terminal plate and the wiring board. However, if the thin aluminum plate constituting the positive electrode terminal plate becomes hot, the inside of the battery also becomes hot and the battery deteriorates. It ’s difficult. That is, conventionally, there was only a method of ultrasonic welding.
[0008]
[Problems to be solved by the invention]
However, ultrasonic welding has the following problems. First, the setting range of vibration intensity and amplitude time of ultrasonic welding is small, and it is difficult to maintain the optimum welding conditions. Second, it is difficult to stabilize the welding strength, and a certain proportion of welding defects may occur in a mass production process in which a large number of products are manufactured. Thirdly, the ultrasonic welding apparatus is more expensive than the resistance welding apparatus, and the equipment cost for mass production becomes high. Fourth, the ultrasonic welding device is larger than the resistance welding device and requires a larger floor space. Thus, development of a technique for welding a thin aluminum plate and a nickel plate by electric resistance welding has been desired.
[0009]
The present invention has been made in view of such problems, and its purpose is as follows. Electric volume resistance value at 100 ° C. is less than 13.6 μΩ · cm It is an object to provide a method for manufacturing a welded product that can easily and highly reliably weld two or more objects to be welded of different materials, a pedestal used therefor, and a method for manufacturing a battery using the same. .
[0010]
[Means for Solving the Problems]
In the method for manufacturing a welded article according to the present invention, two or more welding objects of different materials having an electric volume resistivity of less than 13.6 μΩ · cm at 100 ° C. are placed on a pedestal, and a welding rod is pressed against the electric resistance. When welding, The pedestal is composed of a placing portion made of a metal having an electric volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and a heat radiating portion having a higher thermal conductivity than the placing portion. It is comprised by.
[0011]
The pedestal according to the present invention is: A placement part made of a metal having an electrical volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and a heat dissipation part having a higher thermal conductivity than the placement part, It is comprised by.
[0012]
The method for manufacturing a battery according to the present invention is a method for manufacturing a battery in which a wiring board is welded to an electrode terminal plate, and an electrode terminal plate made of different materials having an electric volume resistivity at 100 ° C. of less than 13.6 μΩ · cm. When placing the wiring board on the pedestal and pressing the welding rod to conduct electrical resistance welding, A pedestal, a mounting portion made of a metal having an electric volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and a heat radiating portion having a higher thermal conductivity than the mounting portion, It is comprised by.
[0013]
In the method of manufacturing a weldment according to the present invention, A pedestal, a mounting portion made of a metal having an electric volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and a heat radiating portion having a higher thermal conductivity than the mounting portion, Therefore, it is possible to prevent the pedestal from being melted together with the welding object at the time of welding, and the welding object from adhering to the pedestal. Moreover, overmelting of the welding object is prevented by the heat dissipation effect of the pedestal. Furthermore, since a welding current flows through the pedestal, a large welding current flows through the welded portion of the welding object.
[0014]
In the pedestal according to the present invention, at least the mounting surface has a melting point. 3407 In addition, since the battery manufacturing method according to the present invention uses the welded product manufacturing method of the present invention, welding is performed in the same manner as the welded product manufacturing method of the present invention. Attachment and overmelting of the object are prevented, and a large welding current flows through the welded portion.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 shows a method for manufacturing a welded product and a welding apparatus used therefor according to an embodiment of the present invention. In the present embodiment, a case where an aluminum plate 11 and a nickel plate 12 of different materials are welded as the welding object 10 will be described. Here, the aluminum plate 11 may be an aluminum-based alloy plate containing aluminum, and the nickel plate 12 may be a nickel-based alloy plate containing nickel.
[0017]
The welding apparatus includes a pedestal 20 on which the welding target object 10 is placed and a pair of welding rods 30 that press against the welding target object 10 and cause a current to flow through the welding target object 10. The welding rod 30 is connected to an electric welding control device (not shown) so that conditions for welding the welding object 10 can be set.
[0018]
In the pedestal 20, it is preferable that at least the mounting surface 20 a of the welding object 10 is made of a refractory metal having a melting point higher than that of the welding object 10. This is because by increasing the melting point, it is possible to prevent the pedestal 20 from being melted together with the welding object 10 during welding and the welding object 10 from adhering to the pedestal 20. Moreover, since the metal has a high thermal conductivity, a heat dissipation effect can be expected, and the aluminum plate 11 can be prevented from over-dissolving and boiling. Furthermore, since the metal has conductivity, a welding current flows through the pedestal 20, and a large welding current can flow through the welded portion 10 a of the welding object 10.
[0019]
In the present embodiment, since the melting point of the aluminum plate 11 that is the welding object 10 is 660 ° C. and the melting point of the nickel plate 12 is 1455 ° C., at least the mounting surface 20 a is higher than the melting point 1455 ° C. of the nickel plate 12. It is preferably composed of a refractory metal having a melting point. Furthermore, it is advantageous that the difference in melting point between the mounting surface 20a and the nickel plate 12 is large.
[0020]
Moreover, it is preferable that at least the mounting surface 20a of the pedestal 20 is made of a metal having a thermal conductivity at 700 ° C. of 10 W / mK or more. This is because if the thermal conductivity is too low, a heat dissipation effect cannot be expected, and overdissolution and boiling of the aluminum plate 11 cannot be effectively prevented. When the electric welding control device is small, at least the mounting surface 20a of the pedestal 20 is preferably made of a metal having a thermal conductivity at 700 ° C. of 200 W / mK or less. When the current / voltage capacity of the electric welding control device is small and the welding maximum current is about 300 A to 800 A or less, if the thermal conductivity is too high, heat is not accumulated in the welding object 10 and welding cannot be performed. Because there are cases. Incidentally, the reason why the heat conductivity at 700 ° C. is defined is that the portion of the mounting surface 20a that directly contacts the welded portion 10a during welding is considered to be heated to about 700 ° C.
[0021]
Furthermore, at least the mounting surface 20a of the pedestal 20 is preferably made of a metal having an electric volume resistivity at 100 ° C. of 30 μΩcm or less. If the electric volume resistivity of the mounting surface 20a is too high, most of the welding current flows through the nickel plate 12 and the aluminum plate 11 in the plane direction, and a large welding current is generated in the vertical direction of the welded portion 10a of the welding object 10. This is because the welded portion 10a cannot be heated sufficiently. Moreover, when the electrical volume resistivity of the mounting surface 20a is too high, about 20 to 70% of the welding current flows in the plane direction connecting the two welded portions 10a of the aluminum plate 11, and the temperature of the aluminum plate 11 is further increased. It is because it becomes high and the welding part 10a of the aluminum plate 11 melt | dissolves too much, and a hole may be formed. That is, it is preferable to reduce the calorific value of the aluminum plate 11. Incidentally, the reason why it is defined by the electric volume resistivity at 100 ° C. is that the vicinity of the welded portion 10 a through which the welding current of the mounting surface 20 a flows at the time of welding is considered to be heated to about 100 ° C.
[0022]
Specifically, as the metal constituting at least the mounting surface 20a, platinum (Pt), iron (Fe), chromium (Cr), zirconium (Zr), titanium (Ti), molybdenum (Mo), palladium (Pd ), Tungsten (W), and iridium (Ir) are preferred. In this specification, a metal is a broad concept including an alloy. These physical properties (melting point, thermal conductivity at 700 ° C. and electric volume resistivity at 100 ° C.) are shown in Table 1.
[0023]
[Table 1]

[0024]
The thickness of the pedestal 20 (thickness in the direction perpendicular to the mounting surface 20a) is preferably set to, for example, 1 mm or more when the entire pedestal 20 is made of the metal as described above. If it is too thin, a sufficient heat dissipation effect cannot be obtained, and the resistance value between the welded portions of the pedestal 20 becomes large, so that a sufficiently large welding current cannot flow, and the pedestal 20 is deformed by the pressure of the welding rod 30. Because it will do.
[0025]
Note that the pedestal 20 may be entirely made of the metal as described above, but as shown in FIG. 2, the mounting portion 21 made of the metal as described above and a heat that is higher than that of the mounting portion 21. You may be comprised so that it may have the thermal radiation part 22 with large conductivity. If the entire pedestal 20 is made of a single metal, it is easy to manufacture. However, if the pedestal 20 is constructed to have the placement portion 21 and the heat dissipation portion 22, welding is performed by the placement portion 21 made of a refractory metal. This is because heat radiation of the welded portion 10a can be promoted by the heat radiating portion 22 while preventing the object 10 from adhering, and overdissolution of the aluminum plate 11 can be more effectively prevented. Moreover, many of the metals as described above are expensive, and if only the mounting portion 21 is made of these metals, there is an advantage that the cost of the base 20 can be reduced. Further, when the mounting portion 21 is uneven or deteriorated by performing electric resistance welding many times, the heat radiating portion 22 can be reused by replacing only the mounting portion 21. Therefore, as shown in FIG. 2, the pedestal 20 having the placement portion 21 and the heat radiating portion 22 is preferable because it can prevent melting of the portion in contact with the welding object 10 and can radiate heat to the maximum.
[0026]
Specifically, the material constituting the heat radiation part 22 is preferably a metal including at least one selected from the group consisting of silver (Ag), copper (Cu), aluminum (Al), and gold (Au). Table 2 shows the thermal conductivity at 100 ° C. The reason why the thermal conductivity at 100 ° C. is shown is that the temperature of the heat radiating portion 22 during welding is considered to be about 100 ° C. The thermal conductivity of platinum at 100 ° C. is 72 W / mK.
[0027]
[Table 2]

[0028]
The thickness of the mounting portion 21 is preferably about 0.5 mm to 2 mm, for example, and more preferably about 1 mm. This is because if the thickness is too thin, the mounting portion 21 is deformed by the pressure of the welding rod 30, or the heat radiation portion 22 is melted and deformed. If it is too thick, the heat radiation effect is reduced and the welding strength is reduced. This is because there is a possibility of a slight decrease, and the cost of the pedestal 20 is also increased. The thickness of the heat dissipation part 22 is preferably 5 mm or more, for example. This is because if the thickness is too thin, a sufficient cooling effect cannot be obtained, and the pedestal 20 itself becomes high temperature and is oxidized and deteriorated.
[0029]
For example, the mounting portion 21 and the heat radiating portion 22 are applied with pressure so that they are mechanically adhered to each other with screws or support brackets arranged vertically, for example, after the joint surface is mirror-finished so that there is no unevenness. Being joined. Note that the placement unit 21 may be merely placed on the heat dissipation unit 22. A force of several kg or more is applied in the direction in which the mounting part 21 and the heat radiating part 22 are brought into close contact with each other during the electric resistance welding, and is thermally coupled. Do Because. Moreover, the mounting part 21 and the heat radiating part 22 may be welded by applying a considerably high pressure of several Mg or more from above and below. However, it is preferable to mechanically join the mounting portion 21 because the replacement of the mounting portion 21 is easy and the stability and adhesion are excellent.
[0030]
When mechanically joining the mounting part 21 and the heat radiating part 22, for example, as shown in FIG. 3, between the mounting part 21 and the heat radiating part 22, a silicon-based adhesive, silicon oil Or you may make it interpose the contact | adherence layer 23 which consists of a heat conductive sheet. This is preferable because the adhesion between the placing portion 21 and the heat radiating portion 22 can be easily maintained and the heat radiating property can be further improved.
[0031]
Moreover, you may make it join the mounting part 21 and the thermal radiation part 22 by brazing. In this way, although it is inferior in convenience when exchanging the mounting portion 21, it is excellent in adhesion between the mounting portion 21 and the heat radiating portion 22, excellent in heat dissipation, and can be easily manufactured. Therefore, it is preferable. Examples of the brazing material include silver-containing silver solder, lead-containing solder, and copper-containing lead-free solder. However, if lead-containing solder is used, the heat dissipation is slightly reduced.
[0032]
The welding rod 30 needs to have high hardness, electrical conductivity, and thermal conductivity, and is made of, for example, a copper alloy such as chromium copper or alumina dispersion strengthened copper. The tip shape of the welding rod 30 is, for example, a hemispherical shape as shown in FIG. 4A, a conical shape as shown in FIG. 4B, a cylindrical shape as shown in FIG. A trapezoidal shape with the tip of the cone cut flat as shown in Fig. 5), a combination of a hemisphere with the tip of the hemisphere cut flat with a flat surface as shown in Fig. 2E, or the shape shown in Fig. 2F. It is preferable to use a polygonal pyramid shape such as a quadrangular pyramid shape (pyramid shape).
[0033]
Among these, the hemispherical shape is the most preferable tip shape of the welding rod 30. According to this shape, when the welding rod 30 is pressed against the object 10 to be welded, a high pressure is applied to the center of the tip of the welding rod 3 and the welding current flows in a concentrated manner. Rises, the welding object 10 is melted, and an alloy layer is easily formed. Further, since the place where the alloy layer is formed is always fixed at the center of the welding rod 30, the distance between the two welded portions 10a through which the welding current flows is fixed, and the welding conditions are stable and preferable. Furthermore, since the pressure when the welding rod 30 is pressed against the welding object 10 becomes weaker from the center of the welding rod 30 toward the periphery, even if the welding object 10 melts at the center of the welding rod 30, It does not melt completely in the periphery, and it is difficult to form a hole in the welding object 10. Here, the welding current becomes weaker from the center of the welding rod 30 toward the periphery in proportion to the pressure.
[0034]
An effective hemispherical tip shape is, for example, a cylinder having a diameter of 0.5 mm to 10 mm and a radius of the tip hemisphere of 0.5 mm to 5 mm. The optimum hemispherical tip shape is that the diameter of the cylinder 10 mm above the tip of the welding rod 30 is 3 mm, the diameter of the cylinder 1 mm above the tip of the welding rod 30 is 1.5 mm, and the radius of the hemisphere at the tip Is 1.5 mm.
[0035]
The conical shape acts in substantially the same manner as the hemispherical shape and is a relatively good tip shape. The tip angle of the cone is preferably an obtuse angle of 140 ° to 175 °, and the diameter of the cylinder is preferably 0.5 mm to 5 mm. The optimum conical tip shape is that the diameter of the cylinder 10 mm above the tip of the welding rod 30 is 3 mm, the diameter of the cylinder 1 mm above the tip of the welding rod 30 is 1.5 mm, and the angle of the tip cone is 1.5 mm. It is 170 degrees. If the angle of the tip is an acute angle of 90 degrees or less, a high pressure is applied to the center, and a hole may be formed in the welding object 10 or the area through which the welding current flows may be reduced. It is not preferable. The polygonal pyramid shape is the same as the conical shape.
[0036]
For example, the cylindrical shape is the most common shape when welding nickel plates, but the current value for welding varies, so the welding strength also tends to vary, and a certain percentage of welding defects occur. There is a possibility that. For example, when the welding rod 30 is pressed against the welding object 10 during electric resistance welding, a high pressure is applied to a smaller portion in the circular shape at the tip of the welding rod 30 and a welding current flows therethrough. Depending on the oxidation state and deterioration state of the tip, the state of the pedestal 20, or the surface state of the object to be welded 10, the location of the welded part is accidentally moved for each welding. Therefore, the distance between the two welds 10a cannot be kept constant, the resistance value and the current value between the two welding rods 30 change, the temperature of the weld 10a changes, and the welding strength Changes, which is not preferable. Furthermore, when the voltage or current at the time of welding is increased, there is a possibility that the welding object 10 is completely melted and a hole is opened. However, since the area of the tip is wider than the hemispherical shape, the alloy layer may be formed with a large area. In addition, there is an advantage that the polishing work after repeated use for welding is extremely simple and the work cost is low.
[0037]
A trapezoidal shape in which the tip of the cone is cut flat, or a shape in which the tip of the semicircle is cut flat also acts in substantially the same manner as the hemispherical shape, and is a relatively good tip shape. Moreover, when the area where a high pressure is applied is compared, there is a possibility that an alloy layer is formed with a larger area than the hemispherical shape. However, if the voltage or current during welding is considerably increased, the welding object 10 may be completely melted and a hole may be formed, which may be undesirable.
[0038]
In the present embodiment, such a welding apparatus is used to weld the aluminum plate 11 and the nickel plate 12 as follows.
[0039]
First, the aluminum plate 11 and the nickel plate 12 are placed on the placement surface 20a of the pedestal 20 so as to overlap each other. At this time, the side of the aluminum plate 11, that is, the side having a lower melting point is defined as the pedestal side. This is to prevent overmelting due to the heat dissipation effect of the pedestal 20. Next, the pair of welding rods 30 are moved downward, and the nickel plate 12 is pressed from above with a preset weight. At this time, the nickel plate 12 and the aluminum plate 11 are brought into close contact with each other by pressure immediately below the tip of the welding rod 30, and the aluminum plate 11 is brought into close contact with the pedestal 20.
[0040]
Subsequently, a voltage is applied to the pair of welding rods 30 with a voltage waveform or a current waveform for a predetermined time by an electric welding control device (not shown). The welding current flows in the order of plus electrode welding rod 30 → nickel plate 12 → aluminum plate 11 → base 20 → aluminum plate 11 → nickel plate 12 → minus electrode welding rod 30 in the order of several tens of ms. Thereby, the junction part of the nickel plate 12 and the aluminum plate 11 in the direct lower part of the welding rod 30, ie, the welding part 10a, melt | dissolves and it melts. When the welding current is stopped by the electric welding control device, the welded portion 10a is rapidly cooled, and an alloy layer is formed and welded.
[0041]
At that time, the surface of the aluminum plate 11 in contact with the pedestal 20 is cooled by the heat dissipation effect of the pedestal 20 and is covered with an oxide film having a high melting point, and therefore does not reach the melting point. Moreover, since at least the mounting surface 20a of the base 20 is made of a refractory metal having a melting point higher than that of the welding object 10, it is not melted. Therefore, the alloy layer between the pedestal 20 and the aluminum plate 11 is not easily formed. Further, the pedestal 20 is prevented from rising due to its heat dissipation effect, and is prevented from being oxidized by a high temperature. In addition, when the pedestal 20 includes the placing portion 21 and the heat radiating portion 22, the heat generated in the welded portion 10 a is radiated more efficiently.
[0042]
The voltage at the time of welding, the voltage application time, and the like may be set to the minimum necessary values for melting the nickel plate 12. For example, the maximum voltage is 0.5 V to 5 V, the maximum current is 100 A to 3000 A, and the voltage application time is 5 ms to 40 ms. As an example, the voltage is about 1.1 V, the current is about 1000 A, and the voltage application time is about 10 ms. The voltage waveform to be applied may be a DC voltage waveform or an AC voltage waveform. However, since the direct current can flow a large current in a shorter time, the temperature of the welded portion 10a can be increased quickly, which is preferable. Therefore, an alloy layer can be formed on the welded portion 10a in a short time during which the aluminum plate 11 can be cooled. The control method may be an applied voltage control method or an applied current control method. The applied voltage control method is preferable because the amount of heat generated in the welded portion 10a is constant, and the applied current control method is preferable because the surface condition or resistance of the mounting surface 20a of the welding object 10, the welding rod 30, and the pedestal 20 is used. Since a constant current flows even if the value changes, the amount of heat generated at the portion where the nickel plate 12 and the aluminum plate 11 are joined becomes constant, which is preferable.
[0043]
The mounting surface 20a of the pedestal 20 is polished with a buff, a grindstone, or a sandpaper coated with an abrasive, and oxides or aluminum deposits on the surface of the mounting surface 20a every hundreds to thousands of times of welding. It is preferable to carry out a cleaning operation to remove the. This is because the resistance value of the mounting surface 20a of the pedestal 20 increases, the welding current hardly flows to the pedestal 20, and the welding strength becomes unstable. Moreover, it is preferable to perform the grinding | polishing operation | work which polishes the front-end | tip of the welding rod 30 for every thousands of welding. For example, if the oxidized or deteriorated layer at the tip is thin, it is polished with sandpaper, and if the oxidized or deteriorated layer is thick, it is cut by about 0.2 mm or more with a cutting machine such as an end mill. Expose part. Furthermore, it is preferable to replace the pedestal 20 or the mounting portion 21 of the pedestal 20 and the welding rod 30 with new ones every tens of thousands of times of welding.
[0044]
Thus, according to the present embodiment, at least the mounting surface 20a of the pedestal 20 is made of a refractory metal having a melting point higher than that of the welding object 10, for example, a refractory metal having a melting point higher than 1455 ° C. Therefore, even if the welding object 10 made of different materials such as the aluminum plate 11 and the nickel plate 12 is subjected to electric resistance welding, the welding object 10 can be prevented from adhering to the base 20 and the welding object 10 can be prevented. Can be prevented, and a large welding current can be passed through the welded portion 10a. Therefore, the welding object 10 can be strongly resistance-welded. Moreover, since the setting range of the electric welding control device is wide, the welding strength can be stabilized even when welding in large quantities. Furthermore, since the aluminum plate 11 is welded while being cooled, the aluminum does not boil and splatters violently, so that the safety of work can be improved and the labor of cleaning can be saved.
[0045]
In particular, if at least the mounting surface 20a of the pedestal 20 is made of a metal having a thermal conductivity at 700 ° C. of 10 W / mK or more, the welding object 10 is heated appropriately and radiated appropriately. Dissolution and boiling can be effectively prevented.
[0046]
Further, if at least the mounting surface 20a of the pedestal 20 is made of a metal having an electric volume resistivity at 100 ° C. of 30 μΩcm or less, a welding current flows appropriately through the pedestal 20 and is large in the vertical direction of the welded portion 10a. A welding current can be flowed, and the welding part 10a can be heated locally enough.
[0047]
Further, if the pedestal 20 is configured to include the placement portion 21 and the heat radiating portion 22, the heat radiation effect can be further enhanced while appropriately heating the welding object 10, the cost can be reduced, and the reuse can also be achieved. It becomes possible. For example, if the pedestal 20 is made of only platinum, if the size of the pedestal 20 is 10 × 10 × 10 mm, it will be about 40,000 yen or more. However, if the mounting portion 21 is made of 10 × 10 × 1 mm platinum and the heat radiating portion 22 is made of 10 × 10 × 9 mm silver, the amount can be reduced to 8,000 yen or less.
[0048]
In addition, the tip shape of the welding rod 30 is a hemispherical shape, a conical shape, a trapezoidal shape obtained by cutting the tip of the cone flat, a shape combining a hemisphere and a flat surface obtained by cutting the tip of the hemisphere flatly, or a polygonal pyramid shape. As a result, the range in which the welding current flows can be made extremely small, and the welded portion 10a can be easily heated. Moreover, since the distance of the two welding parts 10a can be made constant with high precision, welding conditions can be stabilized. In particular, if a hemispherical shape is used, a higher effect can be obtained.
[0049]
In addition, in this Embodiment, although the case where the aluminum plate 11 and the nickel plate 12 were welded as the welding target object 10 was demonstrated, this invention is widely used when welding two or more welding target objects from which materials differ. Can be applied. For example, the same applies to the case where a metal plate (cladding material) obtained by bonding a nickel plate and an iron plate and the aluminum plate 11 are welded instead of the nickel plate 12. In this case, if the part to be welded is the nickel plate part of the metal plate and the aluminum plate 11, the welding object is a nickel plate, and the melting point of the welding object is the melting point of the aluminum plate and the nickel plate. Point to.
[0050]
This welded article manufacturing method can be used, for example, in the following battery manufacturing method.
[0051]
FIG. 5 shows a battery manufacturing method using the welded article manufacturing method according to the present embodiment and the structure of the battery manufactured thereby. FIG. 6 shows a cross-sectional structure along the line II in FIG. In this battery, a battery element 50 to which a positive terminal plate 41 and a negative terminal plate 42 are attached is enclosed in an exterior member 60. The battery element 50 has a configuration in which a positive electrode 51 and a negative electrode 52 are stacked with an electrolyte 53 interposed therebetween.
[0052]
The positive electrode 51 includes, for example, a positive electrode current collector layer 51a and a positive electrode mixture layer 51b, and the positive electrode terminal plate 41 is connected to the positive electrode current collector layer 51a. The positive electrode current collector layer 51a is made of, for example, aluminum foil. The positive electrode mixture layer 51b is made of, for example, a positive electrode material, a conductive agent such as carbon black or graphite, and a binder such as polyvinylidene fluoride. Contains. The positive electrode material is preferably a lithium composite oxide or lithium composite sulfide containing lithium (Li), or a metal sulfide or oxide not containing lithium, or a specific polymer material, depending on the intended use of the battery. Any one or more of them are selected.
[0053]
The negative electrode 52 includes, for example, a negative electrode current collector layer 52a and a negative electrode mixture layer 52b, and the negative electrode terminal plate 42 is connected to the negative electrode current collector layer 52a. The negative electrode current collector layer 52a is made of, for example, copper foil, and the negative electrode mixture layer 52b is made of, for example, a negative electrode material and a binder such as polyvinylidene fluoride. The negative electrode material includes, for example, a material capable of inserting and extracting lithium such as a carbon material or a silicon compound, or a material capable of depositing and dissolving lithium such as lithium metal or a lithium alloy.
[0054]
The electrolyte 53 is configured by what is called a gel electrolyte or an organic solid electrolyte, and includes, for example, a polymer compound, a plasticizer as necessary, and a lithium salt as an electrolyte salt. A separator (not shown) may be disposed between the positive electrode 51 and the negative electrode 52 as necessary.
[0055]
The positive terminal plate 41 is made of, for example, a thin aluminum plate having a thickness of about 0.05 mm to 0.15 mm. The negative electrode terminal plate 42 is made of, for example, a thin nickel plate having a thickness of about 0.05 mm to 0.15 mm. For the positive electrode terminal plate 41 and the negative electrode terminal plate 42, for example,

wiring boards

71 and 72 made of a thin nickel plate having a thickness of about 0.1 mm to 0.2 mm or a metal plate in which a nickel plate and an iron plate are bonded to each other are provided. Are welded.
[0056]
Such a battery can be manufactured as follows.
[0057]
First, the battery element 50 is produced by a predetermined method, the positive electrode terminal plate 41 and the negative electrode terminal plate 42 are connected to the battery element 50, and the battery element 50 is sealed inside the exterior member 60. Subsequently, the wiring board 71 is electrically resistance-welded to the positive terminal plate 41 by the above-described welded manufacturing method. That is, the pedestal 20 made of a refractory metal having a melting point higher than that of the positive electrode terminal plate 41 and the wiring board 71 is used, and the positive terminal plate 41 and the wiring board 71 are placed on the pedestal 20 with the positive electrode terminal plate 41 facing the pedestal 20. Then, a voltage is applied by pressing the welding rod 30 as shown in FIG. Here, since the method described above is used, the positive electrode terminal plate 41 and the wiring board 71 are firmly welded without the positive electrode terminal plate 41 made of an aluminum plate adhering to the base 20.
[0058]
Subsequently, the wiring board 72 is electrically resistance welded to the negative terminal plate 42. At this time, although the method described above may be performed, since both the negative electrode terminal plate 42 and the wiring board 72 are made of nickel plates, the conventional pedestal 80, that is, copper, copper alloy, or nonmetal is used. You may use what was comprised with the bake board and electrically resistance-welded. Thereby, the battery shown in FIG. 5 is completed.
[0059]
Moreover, also when manufacturing a battery as shown in FIG. 7, the manufacturing method of the welded material which concerns on this Embodiment can be used. This battery has the same configuration as the battery shown in FIG. 5 except that

grooves

41 a and 42 a are provided at the tip portions of the positive electrode terminal plate 41 and the negative electrode terminal plate 42.
[0060]
In such a battery, since the groove 41a is provided at the tip of the positive electrode terminal plate 41, the welding current hardly passes through the positive electrode terminal plate 41, and most of the welding current passes through the base 20 or the wiring board 11. become. For this reason, welding strength becomes stronger.
[0061]
Incidentally, if the wiring board 71 is also provided with grooves similar to those of the positive electrode terminal board 41 and the negative electrode terminal board 42, the current flowing from the positive electrode welding rod 30 → the wiring board 71 → the negative electrode welding rod 30 is eliminated. The temperature rise of the welded portion of the wiring board 71 is hindered, and a very good effect cannot be expected. Therefore, it is preferable that the

wiring boards

71 and 72 have no groove.
[0062]
Thus, according to the present embodiment, the positive electrode terminal plate made of a thin aluminum plate and the wiring board made of a nickel plate or the like can be firmly welded by electric resistance welding. By the way, in conventional ultrasonic welding, since the range of setting conditions for strong welding strength is extremely narrow, it is extremely difficult to keep the welding strength strong, and if the attachment shape or positional relationship changes even a little, defective products However, according to the present embodiment, it is easy to keep the welding strength strong because there is a wide range of setting conditions for strong welding strength. The defective product rate can be extremely reduced. In addition, since the electric resistance welding apparatus is less expensive than ultrasonic welding, the equipment cost can be reduced.
[0063]
【Example】
Further, a specific embodiment of the present invention will be described in detail with reference to FIG.
[0064]
(Examples 1 and 2)
As Example 1, the pedestal 20 was made of platinum, and the aluminum plate 11 and the nickel plate 12 were electrically resistance welded as the welding object 10 as described in the above embodiment. At that time, a DC voltage was applied by an applied voltage control method, the maximum voltage was 1.2 V, the maximum current was 1000 A, and the voltage application time was 10 ms. As Example 2, the aluminum plate 11 and the nickel plate 12 were electrically resistance-welded in the same manner as in Example 1 except that the base 20 was made of iron.
[0065]
After that, the state of the welding mark on the side of the aluminum plate 11 and the mounting surface 20a of the pedestal 20 was observed with an optical microscope. Moreover, the welded aluminum plate 11 and the nickel plate 12 were peeled off, and the state of the nickel plate 12 after peeling was observed with an optical microscope. The results are shown in FIGS. 8 is a welding mark of the aluminum plate 11 of the first embodiment, FIG. 9 is a state of the pedestal 20 of the first embodiment, FIG. 10 is a state after peeling of the first embodiment, and FIG. 11 is a view of the aluminum plate 11 of the second embodiment. FIG. 12 shows the welding marks, FIG. 12 shows the state of the pedestal 20 of Example 2, and FIG. 13 shows the state after peeling of Example 2.
[0066]
In addition, as Comparative Examples 1 and 2 for this example, an aluminum plate and a nickel plate were used in the same manner as in this example, except that the base was made of copper (Comparative Example 1) or ceramic (Comparative Example 2). Electrical resistance welded. In Comparative Examples 1 and 2, as in this example, the welding marks on the aluminum plate side, the state of the pedestal, and the state of the nickel plate 12 after peeling were observed with an optical microscope. The results are shown in FIGS. 14 shows the welding marks of the aluminum plate 11 of Comparative Example 1, FIG. 15 shows the state of the pedestal 20 of Comparative Example 1, FIG. 16 shows the state after peeling of Comparative Example 1, and FIG. 17 shows the state of the aluminum plate 11 of Comparative Example 2. FIG. 18 shows the state of the pedestal 20 of Comparative Example 2, and FIG. 19 shows the state after peeling of Comparative Example 2, respectively.
[0067]
As can be seen from FIGS. 8 to 13, according to this embodiment, the pedestal 20 and the aluminum plate 11 are hardly welded or aluminum is not attached to the pedestal 20. The condition was also good. Further, as can be seen from FIG. 10 and FIG. 13, even after seeing the state after peeling, it was confirmed that the welded portion 10 a was firmly welded because the aluminum of the welded portion 10 a adhered to the nickel plate 12. . Moreover, it turned out that the direction of Example 2 comprised with iron rather than Example 1 which comprised the base 20 with platinum was a little larger in the area of the welding part 10a, and aluminum adhesion to the base 20 was seen a little. This is probably because the thermal conductivity of iron is lower than that of platinum, so the temperature of the welded portion 10a is higher and the area of the welded portion 10a is larger. Furthermore, iron has a lower melting point than platinum, so it is considered that a minute portion of the iron surface has dissolved.
[0068]
On the other hand, as can be seen from FIGS. 14 to 16, in Comparative Example 1 in which the pedestal is made of copper, the area of the welded portion 10a is small, the welding strength is small, and a lot of aluminum adheres to the pedestal. This is because the aluminum plate 11 and the nickel plate 12 cannot be heated sufficiently because of the high thermal conductivity of copper, and part of the pedestal is dissolved together with the aluminum plate 11 because the melting point is low. It is thought that. Here, it is considered that if the set voltage at the time of welding is further increased, the object to be welded 10 can be sufficiently heated to perform strong welding, but the aluminum plate 11 adheres to the pedestal 20 and the aluminum plate 11 Since there is a hole, it is not preferable.
[0069]
Further, as can be seen from FIGS. 17 to 19, in Comparative Example 2 in which the pedestal is made of ceramic, the aluminum plate 11 has a hole, the welding strength is insufficient, and a part of aluminum adheres to the pedestal. It was. This is because, in the case of an insulating material such as ceramic, since the welding current does not flow through the pedestal, most of the welding current flows through the aluminum plate 11 and the nickel plate 12, and the temperature of the welded portion between the aluminum plate and the nickel plate increases. In addition, it is considered that the aluminum plate is excessively dissolved or boiled because the thermal conductivity of the pedestal is low.
[0070]
That is, the pedestal 20 is made of a refractory metal having a melting point higher than that of the object 10 to be welded, a thermal conductivity at 700 ° C. of 10 W / mK or more, and an electric volume resistivity at 100 ° C. of 30 μΩcm or less. For example, it has been found that two or more welding objects 10 of different materials can be strongly resistance-welded.
[0071]
In the above embodiment, the case where the pedestal 20 is made of platinum or iron and the aluminum plate 11 and the nickel plate 12 are welded has been described with a specific example, but the other examples described in the above embodiment are used. Even if the pedestal 20 is made of a material, the same result as in the above embodiment can be obtained. Further, as described in the above embodiment, the same result as in the above embodiment can be obtained also in the case where two or more welding objects 10 of different materials are subjected to electric resistance welding.
[0072]
Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the above embodiments and examples, and various modifications can be made. For example, in the above-described embodiment, the configuration of the battery has been described with a specific example, but the present invention can be similarly applied to a battery having another configuration. For example, in the above embodiment, a battery using lithium as an electrode reactive species has been specifically described. However, the present invention can also be applied to a battery using another electrode reactive species. In the above embodiment, the case where the electrolyte is made of a gel electrolyte or an organic solid electrolyte has been described. However, the electrolyte may be made of an electrolytic solution that is a liquid electrolyte, or made of an inorganic electrolyte made of an inorganic material. You may do it. Further, the battery may have any shape.
[0073]
Moreover, although the said embodiment demonstrated the case where the manufacturing method of the welded material of this invention was used for manufacture of a battery, it can apply similarly also when manufacturing another thing. In particular, the present invention is effective when welding thin objects having different melting points.
[0074]
【Effect of the invention】
As described above, claims 1 to Claim 9 According to the method for manufacturing a weldment according to any one of A pedestal, a mounting portion made of a metal having an electric volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and a heat radiating portion having a higher thermal conductivity than the mounting portion, Because it was configured by or Claims 10 to 14 According to the pedestal described in any one of A mounting portion made of a metal having an electrical volume resistivity at 100 ° C. of 13.6 μΩ · cm or more and 30.0 μΩ · cm or less, and a heat dissipation portion having a higher thermal conductivity than the mounting portion, Because it was configured by or Claims 15 to 24 According to any one of the battery manufacturing methods, A pedestal, a mounting portion made of a metal having an electric volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and a heat radiating portion having a higher thermal conductivity than the mounting portion, Therefore, even if welding objects of different materials are subjected to electric resistance welding, it is possible to prevent the welding object from adhering to the pedestal and to prevent overmelting of the welding object. And a large welding current can flow through the weld. Therefore, the object to be welded can be strongly electric resistance welded. Moreover, since the setting range of the electric welding control device is wide, the welding strength can be stabilized even when welding in large quantities.
[0075]
Also, the pedestal Placement part Is made of a metal having an electrical volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, so that a welding current can be appropriately passed through the pedestal, and in the vertical direction of the weld. A large welding current can be passed.
[0076]
Also , Stand Since the seat has a pedestal and a heat radiating part having a larger thermal conductivity than the pedestal, the heat radiation effect can be further enhanced while appropriately heating the welding object, Costs can be reduced and reused.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a method for manufacturing a welded product and a welding apparatus used therefor according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating a modification of the welding apparatus shown in FIG.
FIG. 3 is a perspective view showing a modification of the welding apparatus shown in FIG.
4 is a front view showing a tip shape of a welding rod in the welding apparatus shown in FIG. 1. FIG.
5 is a perspective view showing a battery manufacturing method using the welded article manufacturing method shown in FIG. 1. FIG.
6 is a cross-sectional view taken along line II of the battery shown in FIG.
7 is a perspective view showing a modification of the method for manufacturing the battery shown in FIG. 6. FIG.
FIG. 8 is an optical micrograph showing welding marks on an aluminum plate according to Example 1 of the present invention.
FIG. 9 is an optical micrograph showing the state of a pedestal according to Example 1 of the present invention.
FIG. 10 is an optical micrograph showing a state after peeling according to Example 1 of the present invention.
FIG. 11 is an optical micrograph showing weld marks of an aluminum plate according to Example 2 of the present invention.
FIG. 12 is an optical micrograph showing the state of a pedestal according to Example 2 of the present invention.
FIG. 13 is an optical micrograph showing a state after peeling according to Example 2 of the present invention.
14 is an optical micrograph showing weld marks on an aluminum plate according to Comparative Example 1. FIG.
15 is an optical micrograph showing the state of a pedestal according to Comparative Example 1. FIG.
16 is an optical micrograph showing a state after peeling according to Comparative Example 1. FIG.
17 is an optical micrograph showing welding marks on an aluminum plate according to Comparative Example 2. FIG.
18 is an optical micrograph showing the state of a pedestal according to Comparative Example 2. FIG.
19 is an optical micrograph showing a state after peeling according to Comparative Example 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Welding object, 10a ... Welding part, 11 ... Aluminum plate, 12 ... Nickel plate, 20 ... Base, 20a ... Mounting surface, 21 ... Mounting part, 22 ... Radiation part, 23 ... Adhesion layer, 30 ... Welding Rod, 41 ... Positive electrode terminal plate, 41a, 42a ... Groove, 42 ... Negative electrode terminal plate, 50 ... Battery element, 60 ... Exterior member, 71, 72 ... Wiring board.

Claims

When two or more welding objects of different materials having an electric volume resistivity of less than 13.6 μΩ · cm at 100 ° C. are placed on a pedestal and pressed against a welding rod to perform electric resistance welding, the pedestal is placed at 100 ° C. And a mounting portion made of a metal having an electrical volume resistivity of 13.6 μΩ · cm to 30.0 μΩ · cm and a heat radiating portion having a higher thermal conductivity than the mounting portion.
Manufacturing method of weldments.

The method of manufacturing a welded article according to claim 1, wherein the welding object is an electric resistance welding of a nickel plate, a nickel-based alloy plate or a metal plate obtained by bonding a nickel plate and an iron plate, and an aluminum plate or an aluminum-based alloy plate. .

The manufacturing method of the welded article of Claim 2 which piles up a welding target object by making an aluminum plate or an aluminum-type alloy plate into a base side, and mounts it on a base.

The mounting portion platinum, iron, chromium, zirconium, as well as more configuration metals containing at least one kind selected from the group consisting of titanium and palladium, the heat radiating portion of silver, copper, selected from the group consisting of aluminum and gold The manufacturing method of the welded article of Claim 1 comprised by the metal containing at least 1 sort (s) .

The manufacturing method of the welding thing of Claim 1 which joins a mounting part and a thermal radiation part mechanically.

The method for manufacturing a welded article according to claim 1 , wherein an adhesion layer is interposed between the placing portion and the heat radiating portion.

The manufacturing method of the welding thing of Claim 1 which joins a mounting part and a thermal radiation part by brazing.

The tip shape of the welding rod is a hemispherical shape, a conical shape, a cylindrical shape, a trapezoidal shape obtained by cutting the tip of the cone flat, a shape combining a hemisphere and a flat surface obtained by cutting the tip of the hemisphere flatly, or a polygonal pyramid shape. The manufacturing method of the welding thing of Claim 1.

DC voltage or AC voltage is applied to the welding rod by applied voltage control method or applied current control method, the maximum voltage is 0.5V to 5V, the maximum current is 100A to 3000A, and the voltage application time is 5ms to 40ms. The method for manufacturing a welded article according to claim 1.

A pedestal on which the welding object is placed when welding two or more welding objects of different materials having an electric volume resistivity of less than 13.6 μΩ · cm at 100 ° C., wherein the electric volume resistivity at 100 ° C. Is a pedestal composed of a placing portion made of a metal having a resistance of 13.6 μΩ · cm to 30.0 μΩ · cm and a heat radiating portion having a higher thermal conductivity than the placement portion .

The mounting portion platinum, iron, chromium, zirconium, as well as more configuration metals containing at least one kind selected from the group consisting of titanium and palladium, the heat radiating portion of silver, copper, selected from the group consisting of aluminum and gold The pedestal according to claim 10 , comprising a metal including at least one kind.

The pedestal according to claim 10 , wherein the mounting portion and the heat dissipation portion are mechanically joined.

The pedestal according to claim 10 , wherein an adhesion layer is interposed between the placing portion and the heat radiating portion.

The pedestal according to claim 10 , wherein the mounting portion and the heat radiating portion are joined by brazing.

A method of manufacturing a battery in which a wiring board is welded to an electrode terminal board, wherein an electrode terminal board and a wiring board having different electrical volume resistivity at 100 ° C. of less than 13.6 μΩ · cm are placed on a pedestal, When performing electric resistance welding by pressing a welding rod, the pedestal is mounted with a mounting portion made of a metal having an electric volume resistivity at 100 ° C. of 13.6 μΩ · cm to 30.0 μΩ · cm, and the mounting portion described above. A method for manufacturing a battery comprising a heat radiating part having a high thermal conductivity .

The battery according to claim 15 , wherein an electrode terminal plate made of an aluminum plate or an aluminum-based alloy plate and a wiring plate made of a nickel plate, a nickel-based alloy plate or a metal plate obtained by bonding a nickel plate and an iron plate are electrically resistance-welded. Manufacturing method.

The method of manufacturing a battery according to claim 15 , wherein the electrode terminal plate and the wiring board are overlapped and placed on the pedestal with the electrode terminal plate facing the pedestal side.

The battery manufacturing method according to claim 15 , wherein the mounting portion is made of a refractory metal having a melting point higher than that of the wiring board.

The mounting portion platinum, iron, chromium, zirconium, as well as more configuration metals containing at least one kind selected from the group consisting of titanium and palladium, the heat radiating portion of silver, copper, selected from the group consisting of aluminum and gold The battery manufacturing method according to claim 15 , comprising a metal containing at least one kind.

The method for manufacturing a battery according to claim 15 , wherein the mounting portion and the heat dissipation portion are mechanically joined.

The method for manufacturing a battery according to claim 15 , wherein an adhesion layer is interposed between the placing portion and the heat radiating portion.

The battery manufacturing method according to claim 15 , wherein the mounting portion and the heat radiating portion are joined by brazing.

The tip shape of the welding rod is a hemispherical shape, a conical shape, a cylindrical shape, a trapezoidal shape in which the tip of the cone is cut flat, a shape combining a hemisphere and a flat surface in which the tip of the hemisphere is flattened, or a polygonal pyramid shape. The method for producing a battery according to claim 15 .

DC voltage or AC voltage is applied to the welding rod by applied voltage control method or applied current control method, the maximum voltage is 0.5V to 5V, the maximum current is 100A to 3000A, and the voltage application time is 5ms to 40ms. The method for producing a battery according to claim 15 .