JP3567577B2

JP3567577B2 - Battery can and manufacturing method thereof

Info

Publication number: JP3567577B2
Application number: JP34621695A
Authority: JP
Inventors: 久夫岩本; 均戸田; 幸司山田; 勝宏今津
Original assignee: Toyo Seikan Kaisha Ltd
Current assignee: Toyo Seikan Kaisha Ltd
Priority date: 1995-12-01
Filing date: 1995-12-01
Publication date: 2004-09-22
Anticipated expiration: 2015-12-01
Also published as: JPH09161736A

Description

【０００１】
【発明の属する技術分野】
本発明は、アルカリマンガン電池、ニッケルカドミウム電池、ニッケル電池等の端子兼容器として用いる電池用缶およびその製造方法に関する。
【０００２】
【従来の技術】
アルカルマンガン電池等に用いられる缶はトランスフア絞りにより製造されるため底部の厚さが、側面部より薄いものであったので正極合剤の加圧上、また耐内圧強度上から厚みを必要とする底部の肉厚が側面部の肉厚より大きくし、また正極合剤との接触面積を大きくし接触抵抗を低減するために缶内面の表面粗さを９〜１１μｍの粗面とすることが提案されている。（特公平７−９９６８６号）このような粗さの大きな粗面とすると、接触抵抗は減少するが、他の問題が発生する。
つまり、絞り、しごき加工時に用いた加工油の洗浄が困難となり、残存する油分のためこの缶を用いて電池を組み立てると初期は良好である短絡電流が１ヶ月保存後著しく低下する傾向がみられる。
また正極合剤を充填する場合充填が困難となり、ペレット状の正極合剤が破壊される恐れが大きい。
さらに、電池のかしめ部が粗面であると漏液が発生する危険が大きい。
【０００３】
【発明が解決しようとする課題】
本発明は、保存後の短絡電流の低下を防止し、かしめ部からの漏液を防止し、正極合剤と缶との接触面積を大きくして接触抵抗を減少し、高性能、高安全性の端子を兼ねた電池用缶とその製造方法を提供する。
【０００４】
【課題を解決するための手段】
本発明は、
「１．プレめっき鋼板から成形された、かしめ部と主部からなる有底筒状の電池用缶であって、側壁主部とかしめ部の真円度が０．０７ｍｍ〜０であり、側壁主部の内面の表面粗さＲａが０．１０〜１．９μｍであり、かしめ部内面の表面粗さＲａが１．０〜０．０１μｍであって、開口部内面に丸みを形成したことを特徴とする、電池用缶。
２．電池の内面側のめっき層の表層がＮｉ、Ｎｉ−Ｆｅ合金、Ｎｉ−Ｓｎ合金、
のいずれか一の層であり、中間層が存在しないか存在する場合は
Ｎｉ、Ｎｉ−Ｓｎ−Ｆｅ合金のいずれか一の層であり、下地層は存在しないか存在する場合はＮｉ、またはＮｉ−Ｆｅ合金の層であって、電池の外面側のめっき層の表層がＮｉ、またはＮｉ−Ｆｅ合金の層であり、下地層は存在しないか存在する場合はＮｉ−Ｆｅ合金の層である、請求項１に記載された、電池用缶。
３．プレめっき鋼板が低炭素アルミキルド鋼である、１項または２項に記載された、電池用缶。
４．開口部内面の丸みが０．２〜３．０mmである、１項に記載された、電池用缶。
５．開口部内面の丸みが０．５〜２．０mmである、１項に記載された、電池用缶。
６．側壁主部とかしめ部の真円度が０．０５mm〜０である円筒部で形成された、１項ないし５項のいずれか１項に記載された、電池用缶。
７．側壁の厚みが底部の厚みより薄い、１項ないし６項のいずれか１項に記載された、電池用缶。
８．側壁主部とかしめ部の厚みが異なる、１項ないし７項のいずれか１項に記載された、電池用缶。
９．底部の厚みのばらつきが０．０５mm〜０、側壁主部の厚みのばらつきが０．０４mm〜０、かしめ部の厚みのばらつきが０．０３mm〜０である、１項ないし８項のいずれか１項に記載された、電池用缶。
１０．めっき鋼板より形成したカップを絞り加工と再絞り加工により縮径と増長をおこなって得た有底筒状体を平均しごき率１〜２５％でしごき加工して側壁の肉厚を均一薄肉化した筒状体を側壁先端部近傍を除いて再絞り加工して縮径すると共に表面を
粗面化して側壁主部を形成した後側壁先端部近傍を側壁主部より軽度に再絞り加工して側壁主部より径が大きくかつ粗面化の小さいかしめ部を形成し次いでトリーミングして開口部内面に丸みを形成することを特徴とする電池用缶の製造方法。
１１．絞り加工を第１工程ないし第５工程で行い縮径と同時に側壁先端部にフランジを形成し次の第６工程で平均しごき率１〜２５％でしごき加工を行って表面を平滑化すると共にフランジ直下の側壁先端部近傍の肉厚を側壁部より大とし、第７工程で側壁先端部近傍を除いて再絞り加工を行って内表面を粗面化した側壁主部を形成すると共に側壁主部の先端部近傍に段差を形成し次いで第８工程で段差部分と側壁先端部の間を再絞り加工して径を側壁主部の径より大としてかしめ部を形成し、第９工程でトリミングを行って第８工程で形成したかしめ部先端を側壁側面と平行する方向に切断してかしめ部先端に丸みを配設した、１０項に記載された電池用缶の製造方法。
１２．第６工程のしごき加工で径の異なる２枚のリングを使用して側壁の先端側を厚肉とし底部側をそれより薄肉の二段側壁とする、１１項に記載された電池用缶の製造方法。
１３．第９工程のトリミングで第８工程で形成したかしめ部先端を屈曲部で切断してかしめ部先端に丸みを配設した、１１項に記載された電池用缶の製造方法。
１４．第７工程の側面主部を形成する再絞り加工の再絞り比を、第５工程の径／第７工程の径＝１．０４〜１．２０とし、ダイラジアスを大きくし、クリアランスを側壁の厚みと同一にしてしごき加工により均一化された側壁厚みを変化させないで再絞り加工する、１１項に記載された電池用缶の製造方法。
１５．第６工程のしごき加工をアプローチ部、ランド部、逃げ部を有し、ランド部の長さが０．５〜２mmであり、アプローチ部の中心線に対する角度が４°〜１０°であり、逃げ部の中心線に対する角度が２°〜１０°であるリングを用いて行う、１１項ないし１４項のずれか１項に記載された電池用缶の製造方法。
１６．絞り加工を第１工程ないし第５工程で行い縮径と同時に側壁先端部にフランジを形成し次の第６工程でしごき加工を行って表面を平滑化すると共にフランジ直下の側壁先端部近傍の肉厚を側壁部より大とし、第７工程でフランジ直下の側壁先端部近傍を除いて再絞り加工を行って側壁主部とかしめ部を形成し、第８工程でトリミングを行って第７工程で形成したかしめ部先端を側壁側面と平行する方向に切断してかしめ部先端に丸みを配設した、１１項に記載された電池用缶の製造方法。
１７．第８工程のトリミングで第７工程で形成したかしめ部先端を屈曲部で切断してかしめ部先端に丸みを配設した、１６項に記載された電池用缶の製造方法。」
に関する。
【０００５】
本発明における、缶の側面主部の内面の表面粗さＲａは粗さが０．１０μｍ以下では粗さが小さすぎ、正極合剤との接触抵抗の低減が不充分となるため電池性能が劣る。
また１．９μｍ以上の大きな粗さでは板厚のくびれを伴いやすくピンホールの原因となる危険がある。
【０００６】
かしめ部においては表面粗さＲａは、かしめは縮み加工で表面が粗いと円周方向圧縮応力によるしわが発生し易いのでかしめ加工性とシール性から制限される。Ｒａが１．０μｍ以上ではガスケットとの間に間隙が生じやすくなり電解液の漏液が発生する危険がある。
０．０１μｍ以下にすることは技術的に出来ない。
【０００７】
粗面の粗さを表すパラメーターとして、ＪＩＳＢ０６０１−１９９４には次のように定義されている。
算術平均粗さ（Ｒａ）
最大高さ（Ｒｙ）
十点平均粗さ（Ｒｚ）
凹凸の平均間隔（Ｓｍ）
局部山頂の平均間隔（Ｓ）
負荷長さ率（ｔｐ）
いずれも粗さ曲線から求められる数値であり粗さ曲線には、山、谷などが定義されている。ところで上述のパラメータの内、Ｓｍ、Ｓでは高さ方向の量が入らず、Ｒｙ、Ｒｚ、ｔｐでは微小な凹凸である局部山、局部谷の存在が無視されるので本発明ではＲａで粗さを表すことにした。
なお、Ｒａの測定は東京精密株式会社製、表面粗さ形状測定機５７５Ａ−３ＤＦを用いた。
【０００８】
鋼板材料としては加工によるピンホール、開口端の割れを発生させないようにするため大型介在物の少ない、例えば連続鋳造の低炭素アルミキルド鋼板がよい。
【０００９】
缶開口部内面に丸みを形成すると、かしめ加工に際し、ガスケット挿入時に傷付き、ゆがみがなく組み立てが確実に行われ、さらにかしめの際の円周方向圧縮応力による端面の割れ、しわが発生しないので密封安全性が高い。
開口部内面の丸みは０．２〜３．０ｍｍの範囲が好ましく、０．５〜２．０ｍｍの範囲がより好ましい。
０．２ｍｍ以下であると挿入時にガスケットが傷ついたり、開口部が変形する原因となり、３．０ｍｍを越えるとかしめ時開口端にしわが生じやすくなって好ましくない。丸み部を設けると傷付き、ゆがみがなく組み立てが確実に行われ、さらにかしめの際の円周方向圧縮応力による端面の割れ、しわが発生しないので密封安全性が高い。
【００１０】
主部、かしめ部が真円であると正極合剤との密着が円周方向で均一になり、かしめ強度が周方向で均一になる作用が奏されるので真円に近いことが好ましい。主部、かしめ部の真円度が０．０７ｍｍを越えると、正極合剤との密着に問題が生じて性能が低下したり、かしめ不良が生じて好ましくない。
０．０５ｍｍ〜０がより好ましい。真円度０は真円である。
真円度の測定には、株式会社ミツトヨ製非接触形真円度円筒度測定機ＲＬ−１０１を用いた。
【００１１】
落下、耐内圧等の強度上側壁の必要厚みは底部より薄く済むので缶の軽量化のためには必要な最低限の底板厚を設定しその厚みの原板を使用するとよい。
側壁主部とかしめ部の厚みが異なると例えば側壁主部を薄くして軽量化をはかり、かしめ部を主部より厚くしてかしめのしわを防止する効果が奏される。
【００１２】
底部の厚みのバラつきが０．０５ｍｍを越えると落下した時、局部が凹んだりする欠点が生じ、側壁主部の厚みのバラツキが０．０４ｍｍを越えると正極合剤との密着が不均一になる問題が生じる。かしめ部の厚みのバラツキが０．０３ｍｍを越えると、かしめ不良が生じやすいという問題が生じる。
したがって底部の厚みのばらつきが０．０５ｍｍ〜０、側壁主部の厚みのばらつきが０．０４ｍｍ〜０、かしめ部の厚みのばらつきが０．０３ｍｍ〜０であることが好ましい。
この範囲外では安定した性能が得られなくなる傾向があり好ましくない。
【００１３】
鋼板表面には電池性能上、防錆上、必要なめっきを両面に施す。
缶体のめっき鋼板は鋼板にＮｉをめっきし、場合によりさらにＳｎをめっきした鋼板である。めっき時にＮｉやＳｎの一部が鋼板の表面に分散したり、鋼板のＦｅがめっき層に分散したり、めっきした金属が互いに分散して合金を形成する場合がある。
本発明の缶体のめっき鋼板のめっき層について説明すると、めっき層の内面側は表１の構造となっている。
【００１４】
【表１】

【００１５】
（註）表中−は存在しないことを示す。下地層の次は基体の鋼板である。Ｓｎの存在する場合はＮｉめっき層の上にＳｎめっきをほどこした場合或いはＳｎとＮｉの合金のめっきを施した場合である。
【００１６】
また外面のめっき層は表２に示す通りとなっている。
【００１７】
【表２】

【００１８】
次に製造方法の発明において、絞り加工の次にしごき加工して壁部の肉厚を均一化した後、再絞り加工するのは内面を粗面化して正極合剤との接触面積を大にし、接触抵抗を小とするためである。
側壁主部の再絞り比を１．０４〜１．２０としダイラジアスを大きくして、クリアランスを側壁と同一にし、肉厚の変化を防止することにより、表面粗さＲａは大きくなる。
かしめ部の再絞りは再絞り比は側壁主部の再絞り比より小さいので表面の粗さは小さくなり平滑となる。
トリミングはかしめ部先端の屈曲部を切断することにより開口部には丸みが形成される。
【００１９】
【発明の実施の形態】
発明の実施の態様を図面に基づき製造方法により説明する。
はじめに説明のため図１４に電池を示す。１は正極缶、２は正極合剤、３がセパレータ、４が集電体、５がガスケット、６が負極端子、７が負極活物質である。本発明は正極缶に関する。
【００２０】
図１は、カップ８を絞り加工したところである。９は底部、１０は側壁である。ポンチ等加工具は図示していない。
図２〜図５はいずれも順次再絞り加工した缶を示し、図５で缶体の径はｄ_４となった。
絞りと再絞りの繰り返しで径を小さくするとともに高さを増すが、側壁厚みが絞り作用で開口部程厚くなるのでこれを均一薄肉化するために６工程目でしごきを導入する。
【００２１】
図６はしごき加工した缶体を示す。壁部の肉厚はｔ_１となり、径ｄ_５はｄ_４と同一であり縮径はない。
拡大部から明らかなように側壁部１１の先端部には段差１３を有する側壁先端部１２が形成されている。
均一薄肉化を効果的かつめっき層にダメージを与えることなく行うには１３図のような中心線に対する角度が４°〜１０°であるアプローチ部１７、長さが０．５〜２ｍｍのランド部１８、中心線に対する角度が２°〜１０°である逃げ部１９を有したしごきリング１６を用いることがよく、特にランド部の設定が重要である。
しごきによる板厚の減少率をしごき率と言うが、しごき前の再絞り（２〜５工程）で薄肉化再絞りを導入するとしごき率が小さくなり、しごきによる平滑化は大きくならない。
【００２２】
図７は側壁１１を再絞り加工し側壁主部２０を形成した缶であって径ｄ_６はしごき加工した缶の径ｄ_５より小さくなっている。側壁先端部近傍２１は絞られていないので径はしごき加工した缶と同一である。
再絞り比（ｄ_５／ｄ_６）は比較的小さく（１．０４〜１．２０）し、かつダイラジアスを大きめにし、さらにクリアランスは側壁と同等（ｔ_１）にして均一化された側壁厚み（ｔ_１）を変化させないようにすることがよい。
こうして出来た側壁主部は半径方向の絞り加工により、しごき工程直後と比較して表面粗さＲａが大きくなる。
Ｒａが大きくなると加工油の洗浄が困難になり、残油が充填物に何らかの悪影響を与え、電池性能を低下させる可能性があるので極端に大きく出来ない。また大掛かりな洗浄は衛生上、環境上避けるべきである。
【００２３】
図８は段差部２２と側壁先端部近傍２１を再絞りしかしめ部２３を形成した缶体である。再絞り比は側壁主部より小さいので径ｄ７はしごき加工した缶の径ｄ_５より小さいが、側面主部の径ｄ_６より大となっている。
このように側壁のかしめ部再絞りは側壁主部を形成した後、８工程目に行う。この部分の径ｄ_７はｄ_６よりわずかに大きいが、そのため再絞り比が主部より小さくなり粗さの変化は少なく、従って主部より滑らかである。この場合絞りしごきすればより滑らかなかしめ部が得られる。
この再絞りでもしごきで均一になった厚みを崩さないことが重要である。
このように径はｄ_５＞ｄ_７＞ｄ_６となる。
しごき工程での缶の抜き取りは一般に非常に大きい力を必要とする。そのため開口部にフランジを残しておくことが引っ掛かりを確実にし、円周上の一部に偏った力による缶の変形するを防止することに有利である。また万一、変形が生じた場合も７、８工程はこれを矯正し、真円度を向上させる効果がある。
トリミングはかしめ部先端２４で行われる。この部分は第８工程のダイラジアスをＲとすると、トリミング前にはほぼ半径Ｒ＋ｔ１の屈曲部２５が形成される。この屈曲部の半径はトリミングの加工力で変形し、やや変わる傾向がある。
トリミングのバリはかしめ時の端面の割れ、しわを防止するため極力少なくすることがよい。
【００２４】
トリミングは図９と図１０に示されるようにかしめ部の先端の屈曲部２５切断する。
【００２５】
図１１は拡大部から明らかなように、側壁の先端側に段差部分２７を有する厚肉部２６を配設し、底部側に段差部分２８を有する薄肉部２９が設けられている。これはしごき加工でしごきリングを２枚同心にセットし、最終的に主部に相当する部分をｔ_１、かしめ部に相当する部分をｔ_２（ｔ_２＞ｔ_１）にしておき、８工程でｔ_１に絞りしごきし形成することも出来る。
【００２６】
本発明は図１２に示すように、第７工程でしごき加工後トリミングの位置まで再絞り加工してかしめ部の再絞りを省略し、トリミングにより開口端に丸みをつける方法であり、本発明に包含される。
【００２７】
【実施例】
次に実施例と比較例を示して本発明を具体的に説明する。
【００２８】
実施例１
炭素０．０３％、マンガン０．１８％、リン０．０１２％、硫黄０．００２％の冷延鋼板（厚み０．２５ｍｍ）の両面にニッケルめっき（厚み２ μｍ）した後、熱処理して拡散させ、ニッケル−鉄合金層を形成させた材料を用いた。板の状態で水溶性の加工油（日本工作油製Ｇ２７００ＮＴ）を塗り、直径５１ｍｍに打ち抜き、図１ないし図９の工程にピップ部形成を加えたプロセスで、主部内径１３．４ｍｍ、かしめ部内径１３．７ｍｍ、高さ５０．３ｍｍ、側壁部厚み０．２１ｍｍの缶をプレス成形した。缶を４０℃の湯で６０秒間スプレー洗浄し、乾燥させ電池用缶を得た。
この缶を正極缶として使い以下の手順で単３サイズのアルカリマンガン電池を作成した。二酸化マンガンと黒鉛とを水酸化カリウムで混練し、加圧成形してペレット状にしたものを正極合剤とした。この正極合剤を缶内に挿入した後、セパレータを挿入し、亜鉛粒と酸化亜鉛を飽和させた水酸化カリウムからなる負極活物質をセパレータ内に入れた。かしめ部下部をネックイン加工後、集電体を溶接した負極端子、ガスケットを組み立てたものを挿着し、開口端をかしめて電池とした。
電池を２５℃で１６時間放置した直後のものと６０℃−湿度９５％に４週間保存したものをそれぞれ３０個、短絡電流値、内部抵抗（交流インピーダンス法）を測定した。測定結果の平均値（除漏洩缶）を表３に示す。
【００２９】
【表３】

【００３０】
成形は、第１工程から第５工程まではＲｄ＝３ｍｍ（Ｒｄ…ダイラジアス）、ＣＬ＝０．２５ｍｍ（ＣＬ…クリアランス）の再絞りである。第６工程のしごき加工はＣＬ＝０．２１ｍｍであり、平均しごき率は１６．０％である。第７工程はＲｄ＝３ｍｍＣＬ＝０．２１ｍｍ、第８工程はＲｄ＝１．５ｍｍＣＬ＝０．２１ｍｍである。第９工程のトリミングはトリミング径１４．１２ｍｍである。
【００３１】
実施例２
第５工程をＲｄ＝０．７ｍｍ、ＣＬ＝０．２５ｍｍとした以外は実施例１と同様にして電池用缶とし、実施例１と同様にして電池とした。平均しごき率は１０．６％である。
【００３２】
実施例３
第４工程と第５工程をＲｄ＝０．７ｍｍ、ＣＬ＝０．２５ｍｍとした以外は実施例１と同様にして電池用缶とし、実施例１と同様にして電池とした。平均しごき率は７．５％である。
【００３３】
実施例４
第３工程と第４工程と第５工程をＲｄ＝０．７ｍｍ、ＣＬ＝０．２５ｍｍとした以外は実施例１と同様にして電池用缶とし、実施例１と同様にして電池とした。平均しごき率は４．５％である。
【００３４】
実施例５
第３工程と第４工程をＲｄ＝０．７ｍｍ、ＣＬ＝０．２５ｍｍとし、第５工程をＲｄ＝０．５ｍｍ、ＣＬ＝０．２５ｍｍとした以外は実施例１と同様にして電池用缶とし、実施例１と同様にして電池とした。平均しごき率は１．９％である。
【００３５】
実施例６
第３工程をＲｄ＝０．７ｍｍ、ＣＬ＝０．２５ｍｍとし、第４工程と第５工程をＲｄ＝０．５ｍｍ、ＣＬ＝０．２５ｍｍとし、第８工程をＲｄ＝１．５ｍｍ、ＣＬ＝０．２０７ｍｍとした以外は実施例１と同様にして電池用缶とし、実施例１と同様にして電池とした。平均しごき率は１．４％である。
【００３６】
比較例１
第５工程までＲｄ＝３ｍｍ、ＣＬ＝０．３０ｍｍの再絞りとした以外は実施例１と同様にした。平均しごき率は２８％である。
【００３７】
比較例２
第８工程でかしめ部のしごきをしない以外は実施例６と同様にした。平均しごき率は１．４％である。
【００３８】
比較例３
第３工程ないし第５工程をＲｄ＝０．５ｍｍ、ＣＬ＝０．２５ｍｍとした以外は実施例１と同様にした。平均しごき率は０．９％である。
【００３９】
比較例４
第３工程のＲｄ＝０．５ｍｍ、ＣＬ＝０．２５ｍｍとし、第４工程と第５工程をＲｄ＝０．２ｍｍ、ＣＬ＝０．２５ｍｍとした以外は実施例６と同様にした。平均しごき率は０％である。
【００４０】
比較例５
第４工程までは比較例３と同様にし、第５工程をＲｄ＝０．２ｍｍ、ＣＬ＝０．２５ｍｍとし、第６工程、第７工程、第９工程を実施例６と同様とし、第８工程をＲｄ＝３．５ｍｍ、ＣＬ＝０．２１ｍｍとした。平均しごき率は０．５％である。
【００４１】
総合評価として短絡電流値が保存後も４．０を下回らず、かつ漏洩のないものを○、そうでないものを×とする相対評価を行った。本発明の範囲にあるものはいずれも良好な結果が得られている。
本発明に対し、比較例１のように主部Ｒａが０．１以下では短絡電流が劣る。比較例３のように粗さが１．９を超えると初期の性能はよいが経時で劣化する。この原因は粗さが大きすぎるために谷部に油が残留し、徐々にしみ出し、発電要素と反応していることが予想される。また比較例４のようにＲａが極端に大きくなると初期の性能も悪くなる。この場合主部の粗さが大きすぎるため缶内面と正極合剤との接触が悪化していると考えられる。
比較例２、比較例３、比較例４、比較例５のようにかしめ部のＲａが１．０を超えるとガスケットとの間に間隙が生じやすくなり電解液の漏洩が起こりやすい。
【００４２】
【発明の効果】
本発明は、側壁主部の内面の表面租さＲａを０．１０〜１．９μｍとし、かしめ部内面の表面粗さＲａを１．０〜０．０１μｍとしたことにより正極合剤との接触抵抗が低減し電池性能が非常に向上し、かしめ部の表面粗さＲａを１．０〜０．０１μｍとしたことにより平滑となり漏液の発生がない効果が奏される。
【図面の簡単な説明】
【図１】絞りカップを示す説明図である。
【図２】第１絞り缶を示す説明図である。
【図３】第２絞り缶を示す説明図である。
【図４】第３絞り缶を示す説明図である。
【図５】第４絞り缶を示す説明図である。
【図６】しごき加工した缶を示す説明図である。
【図７】側壁主部を再絞りした缶を示す説明図である。
【図８】かしめ部を再絞りした缶を示す説明図である。
【図９】トリミングした缶を示す説明図である。
【図１０】かしめ部先端の屈曲部を示す説明図である。
【図１１】二枚リングを用いたしごき缶を示す説明図である。
【図１２】側壁主部とかしめ部を同時再絞りした缶を示す説明図である。
【図１３】しごきリングの説明図である。
【図１４】電池の説明図である。
【符号の説明】
１正極缶
２正極合剤
３セパレータ
４集電体
５ガスケット
６負極端子
７負極活物質
８カップ
９底部
１０側壁
１１側壁部
１２側壁先端部
１３段差
１４フランジ
１５トリミング位置
１６しごきリング
１７アプローチ部
１８ランド部
１９逃げ部
２０側壁主部
２１側壁先端部近傍
２２段差部
２３かしめ部
２４かしめ部先端
２５屈曲部
２６厚肉部
２７段差部分
２８段差部分
２９薄肉部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery can used as a terminal / container for an alkaline manganese battery, a nickel cadmium battery, a nickel battery, and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Since the cans used for alkaline manganese batteries are manufactured by transfer drawing, the thickness of the bottom is thinner than that of the side, so the thickness must be increased from the pressure of the positive electrode mixture and the internal pressure resistance. In order to increase the thickness of the bottom part to be greater than the thickness of the side parts, and to increase the contact area with the positive electrode mixture and reduce the contact resistance, the inner surface of the can may have a rough surface of 9 to 11 μm. Proposed. (Japanese Patent Publication No. 7-99686) With such a rough surface, the contact resistance is reduced, but other problems occur.
In other words, it becomes difficult to wash the processing oil used during drawing and ironing, and when a battery is assembled using this can due to the remaining oil, the short-circuit current, which is initially good, tends to be significantly reduced after storage for one month. .
In addition, when the positive electrode mixture is filled, it is difficult to fill the positive electrode mixture, and there is a high possibility that the positive electrode mixture in the form of a pellet is broken.
Furthermore, if the caulked portion of the battery is rough, there is a high risk of liquid leakage.
[0003]
[Problems to be solved by the invention]
The present invention prevents a decrease in short-circuit current after storage, prevents liquid leakage from the caulked portion, increases the contact area between the positive electrode mixture and the can, reduces contact resistance, and provides high performance and high safety. And a method for manufacturing the same.
[0004]
[Means for Solving the Problems]
The present invention
"1. A bottomed tubular battery can formed from a pre-plated steel sheet and formed of a caulked portion and a main portion, wherein the roundness of the side wall main portion and the caulked portion is 0.07 mm to 0, the surface roughness Ra of the inner surface of the main portion is 0.10～1.9Myuemu, the surface roughness Ra of the caulking portion inner surface I 1.0~0.01μm der to form a rounded opening inner surface A can for a battery, characterized in that:
2. The surface layer of the plating layer on the inner surface side of the battery is Ni, Ni-Fe alloy, Ni-Sn alloy,
Any one of the following layers: Ni if the intermediate layer does not exist or is present; Ni or any one of Ni-Sn-Fe alloys; and Ni or Ni if the underlayer does not exist or exists. -A layer of a Fe alloy, wherein the surface layer of the plating layer on the outer surface side of the battery is a layer of Ni or a Ni-Fe alloy, and a base layer is a layer of a Ni-Fe alloy if not present or present. The battery can according to claim 1.
3. 3. The battery can according to item 1 or 2, wherein the pre-plated steel sheet is a low-carbon aluminum killed steel.
4 . The battery can according to claim 1 , wherein the inner surface of the opening has a roundness of 0.2 to 3.0 mm.
5 . 2. The battery can according to claim 1 , wherein the inner surface of the opening has a roundness of 0.5 to 2.0 mm.
6 . Item 6. The battery can according to any one of Items 1 to 5 , wherein the main portion of the side wall and the cylindrical portion having a roundness of the swaged portion of 0.05 mm to 0 are formed.
7 . 7. The battery can according to any one of Items 1 to 6 , wherein the thickness of the side wall is smaller than the thickness of the bottom.
8 ． Item 8. The battery can according to any one of Items 1 to 7 , wherein the thickness of the side wall main portion and the swaged portion is different.
9 . Any one of clauses 1 to 8 , wherein the variation in the thickness of the bottom portion is 0.05 mm to 0, the variation in the thickness of the main portion of the side wall is 0.04 mm to 0, and the variation in the thickness of the caulked portion is 0.03 mm to 0; The battery can described in the paragraph.
10 ． The bottomed cylindrical body obtained by reducing and increasing the diameter of the cup formed from the plated steel sheet by drawing and redrawing was ironed at an average ironing rate of 1 to 25% to make the thickness of the side wall uniform. The cylindrical body is re-drawn and reduced in diameter except for the vicinity of the side wall tip, and the surface is roughened to form a main wall portion. A method for manufacturing a battery can, comprising: forming a caulked portion having a larger diameter than the main portion and having a smaller surface roughness, and then trimming to form a rounded inner surface of the opening.
11 . Draw processing is performed in the first to fifth steps to form a flange at the end of the side wall at the same time as diameter reduction, and in the next sixth step ironing is performed at an average ironing rate of 1 to 25% to smooth the surface and to form a flange. The thickness near the tip of the sidewall immediately below is made larger than that of the sidewall, and in the seventh step, a redrawing process is performed except for the vicinity of the tip of the sidewall to form a sidewall main part whose inner surface is roughened and a sidewall main part. A step is formed in the vicinity of the tip of the step, and then, in the eighth step, a re-drawing process is performed between the step and the tip of the side wall so that the diameter is larger than the diameter of the main part of the side wall to form a swaged part. performed by the caulked tip formed in the eighth step is disposed rounded caulking tip was cut in a direction parallel to the side wall side, process for the preparation of battery can according to 1 0 wherein.
12 . A sixth step using two rings of different diameter ironing of the distal end side of the side walls with thick bottom and two-stage sidewall of thinner than it has been in the battery can according to 1 1, wherein Production method.
13 . Were provided with rounded caulking portion tip caulking tip formed in the eighth step in the trimming step 9 was cut at the bent portion, process for the preparation of battery can according to 1 (1).
14 . The redrawing ratio of the redrawing process for forming the side main portion of the seventh step is set to the diameter of the fifth step / the diameter of the seventh step = 1.04 to 1.20, the radius is increased, and the clearance is set to the thickness of the side wall. re-drawing without changing the uniform sidewall thickness by ironing in the same and, process for the preparation of battery can according to 1 (1).
15 . The ironing process in the sixth step includes an approach portion, a land portion, and a relief portion, the length of the land portion is 0.5 to 2 mm, and the angle of the approach portion to the center line is 4 ° to 10 °. angle relative to the centerline of the part is carried out using a ring is 2 ° to 10 °, process for the preparation of battery can according to the deviation or one of 1 1, wherein to 1 4 Section.
16 . The drawing process is performed in the first to fifth steps to form a flange at the end of the side wall at the same time as the diameter reduction, and in the next step 6, ironing is performed to smooth the surface and to fill the vicinity of the end of the side wall immediately below the flange. The thickness is made larger than that of the side wall portion, and in the seventh step, redrawing is performed except for the vicinity of the tip of the side wall immediately below the flange to form a side wall main portion and a caulked portion. Trimming is performed in the eighth step, and the seventh step is performed. It was provided with rounded caulking tip the formed caulked tip was cut in a direction parallel to the side wall side, process for the preparation of battery can according to 1 (1).
17 . 16. The method for manufacturing a battery can according to item 16 , wherein the end of the caulked portion formed in the seventh step by the trimming in the eighth step is cut at a bent portion and the rounded end is provided. "
About.
[0005]
In the present invention, the surface roughness Ra of the inner surface of the main part of the side surface of the can is too small when the roughness is 0.10 μm or less, and the reduction in contact resistance with the positive electrode mixture becomes insufficient, resulting in poor battery performance. .
Further, when the roughness is 1.9 μm or more, the plate is liable to be constricted, which may cause a pinhole.
[0006]
In the caulked portion, the surface roughness Ra is limited from the caulking workability and the sealing property because if the surface is roughened by shrinking, wrinkles due to circumferential compressive stress are likely to occur. When Ra is 1.0 μm or more, a gap is easily formed between the gasket and the electrolyte, and there is a risk that the electrolyte may leak.
It is technically impossible to reduce the thickness to 0.01 μm or less.
[0007]
JIS B0601-1994 defines the following parameters as parameters representing the roughness of the rough surface.
Arithmetic mean roughness (Ra)
Maximum height (Ry)
Ten point average roughness (Rz)
Average spacing of irregularities (Sm)
Average distance between local peaks (S)
Load length ratio (tp)
Each is a numerical value obtained from the roughness curve, and the roughness curve defines peaks, valleys, and the like. By the way, among the above parameters, Sm and S do not include the amount in the height direction, and Ry, Rz and tp ignore the presence of local peaks and valleys which are minute irregularities. I decided to represent.
Note that Ra was measured using a surface roughness shape measuring instrument 575A-3DF manufactured by Tokyo Seimitsu Co., Ltd.
[0008]
As a steel sheet material, a low-carbon aluminum-killed steel sheet with a large number of large inclusions, for example, a continuous cast is preferable in order to prevent the occurrence of pinholes and cracks at the opening ends due to processing.
[0009]
By forming roundness on the inner surface of the can opening, there is no damage when inserting the gasket during crimping, assembling is surely performed without distortion, and furthermore, there is no cracking or wrinkling of the end face due to circumferential compressive stress at the time of caulking. High sealing safety.
The roundness of the inner surface of the opening is preferably in the range of 0.2 to 3.0 mm, more preferably in the range of 0.5 to 2.0 mm.
If it is less than 0.2 mm, the gasket may be damaged or the opening may be deformed at the time of insertion, and if it exceeds 3.0 mm, wrinkling is likely to occur at the opening end when swaging, which is not preferable. When the rounded portion is provided, the assembly is reliably performed without any damage and distortion, and furthermore, since the end face is not cracked or wrinkled due to the circumferential compressive stress at the time of caulking, the sealing safety is high.
[0010]
If the main portion and the caulked portion are perfect circles, the contact with the positive electrode mixture becomes uniform in the circumferential direction, and the effect of making the caulking strength uniform in the circumferential direction is exerted. If the roundness of the main portion and the caulked portion exceeds 0.07 mm, there is a problem in adhesion to the positive electrode mixture and performance is lowered, or unsatisfactory caulking occurs, which is not preferable.
0.05 mm-0 is more preferable. Roundness 0 is a perfect circle.
For measurement of the roundness, a non-contact roundness cylindricity measuring machine RL-101 manufactured by Mitutoyo Corporation was used.
[0011]
Since the required thickness of the side wall is smaller than that of the bottom part in terms of strength such as dropping and internal pressure resistance, it is preferable to set the minimum necessary bottom plate thickness and use an original plate of that thickness in order to reduce the weight of the can.
If the thickness of the side wall main portion and the caulked portion are different, for example, the thickness of the side wall main portion is reduced to reduce the weight, and the effect of preventing the crimping of the caulked portion by making the caulked portion thicker than the main portion.
[0012]
If the variation in the thickness of the bottom portion exceeds 0.05 mm, there is a defect that the local portion is dented when dropped, and if the variation in the thickness of the main portion of the side wall exceeds 0.04 mm, the adhesion with the positive electrode mixture becomes uneven. Problems arise. If the variation in the thickness of the caulked portion exceeds 0.03 mm, there is a problem that a caulking failure is likely to occur.
Therefore, it is preferable that the variation in the thickness of the bottom portion is 0.05 mm to 0, the variation in the thickness of the main portion of the side wall is 0.04 mm to 0, and the variation in the thickness of the caulked portion is 0.03 mm to 0.
Outside this range, stable performance tends not to be obtained, which is not preferable.
[0013]
The surface of the steel plate is plated on both sides for battery performance, rust prevention and necessary plating.
The plated steel sheet of the can body is a steel sheet obtained by plating a steel sheet with Ni, and optionally further plating Sn. At the time of plating, a part of Ni or Sn may be dispersed on the surface of the steel sheet, Fe of the steel sheet may be dispersed in the plating layer, or the plated metals may be mutually dispersed to form an alloy.
The plating layer of the plated steel sheet of the can of the present invention will be described. The inner surface of the plating layer has the structure shown in Table 1.
[0014]
[Table 1]

[0015]
(Note)-in the table indicates that it does not exist. Next to the underlayer is a base steel plate. The case where Sn is present is the case where Sn plating is applied on the Ni plating layer or the case where plating of an alloy of Sn and Ni is performed.
[0016]
The plating layer on the outer surface is as shown in Table 2.
[0017]
[Table 2]

[0018]
Next, in the invention of the manufacturing method, after the drawing process is performed and then the ironing process is performed to uniform the wall thickness, and then the re-drawing process is performed to roughen the inner surface and increase the contact area with the positive electrode mixture. This is to reduce the contact resistance.
The surface roughness Ra is increased by setting the redrawing ratio of the main portion of the side wall to 1.04 to 1.20, increasing the radius, making the clearance equal to that of the side wall, and preventing a change in wall thickness.
In the redrawing of the caulked portion, the redrawing ratio is smaller than the redrawing ratio of the main portion of the side wall, so that the surface roughness is reduced and the surface becomes smooth.
In the trimming, the opening is rounded by cutting the bent portion at the tip of the caulked portion.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described with reference to the drawings based on a manufacturing method.
First, a battery is shown in FIG. 14 for explanation. 1 is a positive electrode can, 2 is a positive electrode mixture, 3 is a separator, 4 is a current collector, 5 is a gasket, 6 is a negative electrode terminal, and 7 is a negative electrode active material. The present invention relates to a positive electrode can.
[0020]
FIG. 1 shows a state where the cup 8 has been drawn. 9 is a bottom part and 10 is a side wall. Processing tools such as punches are not shown.
Figures 2-5 show the processed cans sequentially redrawing any, the diameter of the can body in FIG. 5 became d _4.
The diameter is reduced and the height is increased by repeating the drawing and re-drawing. However, since the thickness of the side wall becomes larger at the opening due to the drawing action, ironing is introduced in the sixth step to make the thickness uniform and thin.
[0021]
FIG. 6 shows an ironed can body. The thickness of the wall portion t ₁ becomes, the diameter d ₅ and diameter reduction is not the same as d _4.
As is clear from the enlarged portion, a side wall front end portion 12 having a step 13 is formed at the front end portion of the side wall portion 11.
In order to perform uniform thinning effectively and without damaging the plating layer, an approach portion 17 having an angle of 4 ° to 10 ° with respect to a center line as shown in FIG. 13 and a land portion having a length of 0.5 to 2 mm are provided. It is preferable to use an ironing ring 16 having an escape portion 19 whose angle with respect to the center line is 2 ° to 10 °, and the setting of the land portion is particularly important.
The reduction rate of the sheet thickness due to ironing is referred to as the ironing rate. If a thinning redrawing is introduced in the redrawing before the ironing (2 to 5 steps), the ironing rate decreases and the smoothing due to the ironing does not increase.
[0022]
FIG. 7 shows a can in which the side wall 11 is redrawn and the side wall main portion 20 is formed, and the diameter d ₆ is smaller than the diameter d ₅ of the ironed can. Since the vicinity 21 of the side wall tip is not narrowed, the diameter is the same as that of the ironed can.
The redrawing ratio (d ₅ / d ₆ ) is relatively small (1.04 to 1.20), the radius is increased, and the clearance is equal to the side wall (t ₁ ), and the uniformized side wall thickness (t ₁ ) It is preferable not to change t ₁ ).
The main portion of the side wall thus formed has a larger surface roughness Ra than that immediately after the ironing process due to the radial drawing.
When Ra is large, it becomes difficult to wash the processing oil, and the residual oil may have some adverse effect on the filler, thereby deteriorating the battery performance. Extensive cleaning should be avoided for sanitary and environmental reasons.
[0023]
FIG. 8 shows a can body in which a step portion 22 and a portion 21 near the end portion of the side wall are redrawn and a fringe portion 23 is formed. Redrawing ratio diameter d ₅ is smaller than the processed cans-out smaller the diameter d7 ladder than the side wall main section, which is larger than the diameter d ₆ of the side main portion.
The re-drawing of the caulked portion of the side wall is performed in the eighth step after forming the main portion of the side wall. Diameter d ₇ of this portion is slightly greater than d _6, but for redrawing ratio change of less becomes roughness than the main portion is small and is therefore smoother than the main portion. In this case, a smoother caulked portion can be obtained by drawing and ironing.
It is important that this re-drawing does not break the uniform thickness due to ironing.
Thus the diameter becomes _{_{_{d 5> d 7> d 6}}} .
Extraction of cans during the ironing process generally requires very large forces. Therefore, it is advantageous to leave the flange in the opening to secure the hooking and prevent the can from being deformed due to the partial biasing force on the circumference. In the event that deformation occurs, steps 7 and 8 have the effect of correcting the deformation and improving the roundness.
Trimming is performed at the crimping portion tip 24. In this portion, assuming that the radius of the eighth step is R, a bent portion 25 having a radius of approximately R + t1 is formed before trimming. The radius of the bent portion tends to be deformed and slightly changed by the processing force of the trimming.
Trimming burrs are preferably reduced as much as possible to prevent cracking and wrinkling of the end face at the time of caulking.
[0024]
The trimming cuts the bent portion 25 at the tip of the caulked portion as shown in FIGS.
[0025]
In FIG. 11, as is clear from the enlarged portion, a thick portion 26 having a step portion 27 is provided on the tip side of the side wall, and a thin portion 29 having a step portion 28 is provided on the bottom side. In this process, two ironing rings are set concentrically by ironing, and finally a portion corresponding to the main portion is set to t ₁ , and a portion corresponding to the caulked portion is set to t ₂ (t ₂ > t ₁ ). By pressing at a time t ₁ , it is possible to form an iron.
[0026]
As shown in FIG. 12, the present invention is a method of rounding the open end by trimming and omitting the re-drawing of the caulked portion by performing re-drawing to the trimming position after ironing in the seventh step. Included.
[0027]
【Example】
Next, the present invention will be specifically described with reference to examples and comparative examples.
[0028]
Example 1
Nickel plating (2 μm thickness) on both sides of cold-rolled steel sheet (0.25 mm thickness) of 0.03% carbon, 0.18% manganese, 0.012% phosphorus, and 0.002% sulfur, then heat-treated and diffused The material on which the nickel-iron alloy layer was formed was used. A water-soluble processing oil (G2700 NT manufactured by Nippon Kogyo Oil Co., Ltd.) is applied in the state of the plate, punched to a diameter of 51 mm, and a process of adding a pip portion to the steps of FIGS. A can having an inner diameter of 13.7 mm, a height of 50.3 mm and a side wall thickness of 0.21 mm was press-formed. The can was spray-washed with 40 ° C. water for 60 seconds and dried to obtain a battery can.
Using this can as a positive electrode can, an AA size alkaline manganese battery was prepared by the following procedure. Manganese dioxide and graphite were kneaded with potassium hydroxide, pressed and formed into a pellet to form a positive electrode mixture. After inserting this positive electrode mixture into a can, a separator was inserted, and a negative electrode active material composed of zinc hydroxide and potassium hydroxide saturated with zinc oxide was placed in the separator. After necking the lower part of the caulked portion, the assembled negative electrode terminal and gasket to which the current collector was welded were inserted, and the opening end was caulked to obtain a battery.
The short circuit current value and the internal resistance (AC impedance method) of 30 batteries each immediately after being left at 25 ° C. for 16 hours and 30 batteries each stored at 60 ° C.-95% humidity for 4 weeks were measured. Table 3 shows the average value of the measurement results (leak cans).
[0029]
[Table 3]

[0030]
Forming is redrawing of Rd = 3 mm (Rd ... radius) and CL = 0.25 mm (CL ... clearance) from the first step to the fifth step. The ironing in the sixth step is CL = 0.21 mm, and the average ironing rate is 16.0%. In the seventh step, Rd = 3 mm CL = 0.21 mm, and in the eighth step, Rd = 1.5 mm CL = 0.21 mm. The trimming in the ninth step has a trimming diameter of 14.12 mm.
[0031]
Example 2
A battery can was made in the same manner as in Example 1 except that the fifth step was changed to Rd = 0.7 mm and CL = 0.25 mm, and a battery was made in the same manner as in Example 1. The average ironing rate is 10.6%.
[0032]
Example 3
A battery can was made in the same manner as in Example 1 except that Rd = 0.7 mm and CL = 0.25 mm in the fourth and fifth steps. The average ironing rate is 7.5%.
[0033]
Example 4
A battery can was made in the same manner as in Example 1 except that Rd = 0.7 mm and CL = 0.25 mm in the third, fourth, and fifth steps, and a battery was made in the same manner as in Example 1. The average ironing rate is 4.5%.
[0034]
Example 5
Battery can in the same manner as in Example 1 except that Rd = 0.7 mm and CL = 0.25 mm in the third step and the fourth step, and Rd = 0.5 mm and CL = 0.25 mm in the fifth step. In the same manner as in Example 1, a battery was obtained. The average ironing rate is 1.9%.
[0035]
Example 6
The third step is Rd = 0.7 mm, CL = 0.25 mm, the fourth and fifth steps are Rd = 0.5 mm, CL = 0.25 mm, and the eighth step is Rd = 1.5 mm, CL = A battery can was made in the same manner as in Example 1 except that the thickness was 0.207 mm, and a battery was made in the same manner as in Example 1. The average ironing rate is 1.4%.
[0036]
Comparative Example 1
The procedure was the same as in Example 1 except that the redrawing was performed with Rd = 3 mm and CL = 0.30 mm until the fifth step. The average ironing rate is 28%.
[0037]
Comparative Example 2
Example 8 was carried out in the same manner as in Example 6, except that the caulked portion was not ironed in the eighth step. The average ironing rate is 1.4%.
[0038]
Comparative Example 3
Example 3 was the same as Example 1 except that Rd = 0.5 mm and CL = 0.25 mm in the third to fifth steps. The average ironing rate is 0.9%.
[0039]
Comparative Example 4
Example 6 was the same as Example 6 except that Rd = 0.5 mm and CL = 0.25 mm in the third step, and Rd = 0.2 mm and CL = 0.25 mm in the fourth and fifth steps. The average ironing rate is 0%.
[0040]
Comparative Example 5
Up to the fourth step, the same as in Comparative Example 3, the fifth step with Rd = 0.2 mm and CL = 0.25 mm, the sixth, seventh, and ninth steps as in Example 6, The process was performed with Rd = 3.5 mm and CL = 0.21 mm. The average ironing rate is 0.5%.
[0041]
As a comprehensive evaluation, a relative evaluation was performed in which the value of the short-circuit current did not fall below 4.0 even after storage and no leakage was evaluated as good, and that of the other was evaluated as x. Good results have been obtained for any of those within the scope of the present invention.
In contrast to the present invention, when the main portion Ra is 0.1 or less as in Comparative Example 1, the short-circuit current is inferior. When the roughness exceeds 1.9 as in Comparative Example 3, the initial performance is good but deteriorates with time. It is assumed that the cause is that the oil remains in the valley portion because the roughness is too large, gradually exudes, and reacts with the power generating element. Further, when Ra is extremely large as in Comparative Example 4, the initial performance is also deteriorated. In this case, it is considered that the contact between the inner surface of the can and the positive electrode mixture was deteriorated because the roughness of the main portion was too large.
When Ra of the caulked portion exceeds 1.0 as in Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 5, a gap is easily formed between the gasket and leakage of the electrolyte is likely to occur.
[0042]
【The invention's effect】
The present invention provides a contact with the positive electrode mixture by setting the surface roughness Ra of the inner surface of the main portion of the side wall to 0.10 to 1.9 μm and the surface roughness Ra of the inner surface of the caulked portion to 1.0 to 0.01 μm. The resistance is reduced, the battery performance is greatly improved, and the surface roughness Ra of the caulked portion is set to 1.0 to 0.01 μm, whereby an effect is obtained in which the surface becomes smooth and no liquid leakage occurs.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an aperture cup.
FIG. 2 is an explanatory view showing a first drawn can.
FIG. 3 is an explanatory view showing a second drawn can.
FIG. 4 is an explanatory view showing a third drawn can.
FIG. 5 is an explanatory view showing a fourth drawn can.
FIG. 6 is an explanatory view showing an ironed can.
FIG. 7 is an explanatory view showing a can in which a main portion of a side wall is redrawn.
FIG. 8 is an explanatory view showing a can in which a caulked portion is redrawn.
FIG. 9 is an explanatory view showing a trimmed can.
FIG. 10 is an explanatory view showing a bent portion at the tip of a caulked portion.
FIG. 11 is an explanatory view showing a canned ironing can using two rings.
FIG. 12 is an explanatory view showing a can in which a side wall main portion and a caulked portion are simultaneously redrawn.
FIG. 13 is an explanatory view of an ironing ring.
FIG. 14 is an explanatory diagram of a battery.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Positive electrode can 2 Positive electrode mixture 3 Separator 4 Current collector 5 Gasket 6 Negative electrode terminal 7 Negative active material 8 Cup 9 Bottom part 10 Side wall 11 Side wall part 12 Side wall tip part 13 Step 14 Flange 15 Trimming position 16 Ironing ring 17 Approach part 18 Land Part 19 Relief part 20 Side wall main part 21 Near side wall tip part 22 Step part 23 Caulking part 24 Caulking part tip 25 Bent part 26 Thick part 27 Step part 28 Step part 29 Thin part

Claims

A bottomed cylindrical battery can formed from a caulked portion and a main portion formed from a pre-plated steel sheet , wherein the roundness of the side wall main portion and the caulked portion is 0.07 mm to 0, and the side wall main portion has a roundness of 0.07 mm to 0. a surface roughness Ra of the inner surface is 0.10～1.9Myuemu, and wherein a surface roughness Ra of the caulking portion inner surface I 1.0~0.01μm der to form a rounded opening inner surface Battery cans.

The surface layer of the plating layer on the inner surface side of the battery is Ni, Ni-Fe alloy, Ni-Sn alloy,
Any one of the following layers: Ni if the intermediate layer does not exist or is present; Ni or any one of Ni-Sn-Fe alloys; and Ni or Ni if the underlayer does not exist or exists. -A layer of a Fe alloy, wherein the surface layer of the plating layer on the outer surface side of the battery is a layer of Ni or a Ni-Fe alloy, and a base layer is a layer of a Ni-Fe alloy if not present or present. The battery can according to claim 1.

The battery can according to claim 1 or 2, wherein the pre-plated steel sheet is a low carbon aluminum killed steel.

Rounded openings inner surface is 0.2 to 3.0 mm, according to claim 1, the can battery.

Rounded openings inner surface is 0.5 to 2.0 mm, according to claim 1, the can battery.

The battery can according to any one of claims 1 to 5 , wherein the side wall main portion and the caulked portion are formed of a cylindrical portion having a roundness of 0.05 mm to 0.

The battery can according to any one of claims 1 to 6 , wherein the thickness of the side wall is smaller than the thickness of the bottom.

The battery can according to any one of claims 1 to 7 , wherein a thickness of the side wall main portion and a thickness of the caulked portion are different.

Bottom of the variation in thickness is 0.05Mm～0, variation in the thickness of the side wall main portion 0.04Mm～0, a variation in the thickness of the caulking portion is 0.03Mm～0, any one of claims 1 to 8 1 The battery can described in the paragraph.

The bottomed cylindrical body obtained by reducing and increasing the diameter of the cup formed from the plated steel sheet by drawing and redrawing was ironed at an average ironing rate of 1 to 25% to make the thickness of the side wall uniform. The cylindrical body is re-drawn and reduced in diameter except for the vicinity of the side wall tip, and the surface is roughened to form a main wall portion. A method for manufacturing a battery can, comprising: forming a caulked portion having a larger diameter than the main portion and having a smaller surface roughness, and then trimming to form a rounded inner surface of the opening.

Draw processing is performed in the first to fifth steps to form a flange at the end of the side wall at the same time as diameter reduction, and in the next sixth step ironing is performed at an average ironing rate of 1 to 25% to smooth the surface and to form a flange. The thickness near the tip of the sidewall immediately below is made larger than that of the sidewall, and in the seventh step, a redrawing process is performed except for the vicinity of the tip of the sidewall to form a sidewall main part whose inner surface is roughened and a sidewall main part. A step is formed in the vicinity of the tip of the step, and then, in the eighth step, a re-drawing process is performed between the step and the tip of the side wall so that the diameter is larger than the diameter of the main part of the side wall to form a swaged part. performed by the caulking tip formed in the eighth step were provided with rounded caulking tip was cut in a direction parallel to the side wall sides, the manufacturing method of the battery can according to claim 1 0.

The bottom side and thicker the tip side of the side wall using two rings with different diameters in the ironing sixth step and two-step sidewall of thinner than it can for a battery of claim 1 1 Manufacturing method.

Were provided with rounded caulking portion tip caulking tip formed in the eighth step in the trimming step 9 was cut at the bent portion, the manufacturing method of the battery can according to claim 1 1.

The redrawing ratio of the redrawing process for forming the side main portion of the seventh step is set to the diameter of the fifth step / the diameter of the seventh step = 1.04 to 1.20, the radius is increased, and the clearance is set to the thickness of the side wall. re-drawing without changing the uniform sidewall thickness by ironing in the same and method of manufacturing a battery can according to claim 1 1.

The ironing process in the sixth step includes an approach portion, a land portion, and a relief portion, the length of the land portion is 0.5 to 2 mm, and the angle of the approach portion to the center line is 4 ° to 10 °. angle relative to the centerline of the part is carried out using a ring is 2 ° to 10 °, process for the preparation of battery can according to the deviation of the claims 1 1 to 1 4.

The drawing process is performed in the first to fifth steps to form a flange at the end of the side wall at the same time as the diameter reduction, and in the next step 6, ironing is performed to smooth the surface and to fill the vicinity of the end of the side wall immediately below the flange. The thickness is made larger than that of the side wall portion, and in the seventh step, redrawing is performed except for the vicinity of the tip of the side wall immediately below the flange to form a side wall main portion and a caulked portion. Trimming is performed in the eighth step, and the seventh step is performed. were provided with rounded caulking tip the formed caulked tip was cut in a direction parallel to the side wall sides, the manufacturing method of the battery can according to claim 1 1.

The method for manufacturing a battery can according to claim 16 , wherein the tip of the caulked portion formed in the seventh step by the trimming in the eighth step is cut at the bent portion and the tip of the caulked portion is rounded.