JP3661568B2

JP3661568B2 - Manufacturing method of battery separator

Info

Publication number: JP3661568B2
Application number: JP2000172859A
Authority: JP
Inventors: 清英筒井; 道高池田; 秀二村上; 廣彦太田
Original assignee: FDK Corp
Current assignee: FDK Corp
Priority date: 2000-06-09
Filing date: 2000-06-09
Publication date: 2005-06-15
Anticipated expiration: 2020-06-09
Also published as: JP2001351595A

Description

【０００１】
【発明の属する技術分野】
本発明は、筒型アルカリ電池の正極と負極とを電池缶内で隔離するために用いる電池用セパレータの製造方法に関するものである。
【０００２】
【従来の技術】
通常、単３型その他のアルカリ乾電池は、例えば図１に示すように、有底円筒状の正極缶２の内面にカーボン等から成る導電膜（図示せず）が形成され、正極缶２内に円筒状に成形した３個の正極合剤３が収納され、この正極合剤３の内側に有底円筒状のセパレータ４が挿入され、このセパレータ４及び正極合剤３中に電解液が浸潤され、セパレータ４の中空部にゲル状亜鉛負極５が充填されている構成が一般的である。
【０００３】
正極缶２の開口部には、封口体６が装着されている８。即ち、封口体６は、負極端子７の内側中央部に集電子８がスポット溶接などにより固着され、この集電子８にガスケット９がシール剤１０を介在させて嵌入され、封口キャップ１１によって締め付けられて構成されている。そして、集電子８がゲル状亜鉛負極５内に挿入されるとともに、セパレータ４の先端部４Ａがガスケット９により押圧され内側に折曲された状態で、正極缶２の開口部側の端部が内側にかしめられて、ガスケット９の外周部が負極端子７の外周部と正極缶２との間で締め付けられることにより、封口体６により正極缶２の開口部が封止される。
正極缶２の外側には、ラベル１２が巻き付けられ、負極端子７の外側の外周部と上記ラベル１２との間には、環状の負極側ワッシャ１３が介在されている。
【０００４】
さて、従来、上記セパレータは本願出願人による特開平１１−３３９７５３号公報に記載のように種々の製造方法が提案されている。その１例を添付図面の図３に示し、且つ、これを改良した更に別の従来例を図４および図５に示して簡単に説明する。
【０００５】
先ず、図３の製造法では、図３（ａ）に示すように、フープ状の原紙を所定寸法に切断して円筒状に巻回して筒体２２を形成した後で、パーツフィーダなどで筒体２２を底部形成工程に搬送して、図３（ｂ）〜図３（ｅ）に示すように、筒体２２の一端を熱融着して閉塞している。
そして、このときの閉塞性を確保するために、熱融着に先立って筒体２２の折曲加工を行っている。即ち、図３（ｂ）に示すように、筒体２２を心棒２５に嵌着し、筒体２２の上端に刃状金型２４を下向きに押し当てて、図３（ｃ）のように、窪み２２ｂを形成し、その状態で、図３（ｄ）に示すように、筒体２２の上端に熱カール金型２９を押し当てる。すると、図３（ｅ）に示すように、半球面状の底部２２ａが形成され、電池用セパレータ４が完成する、というものである。
【０００６】
しかし、上記の製造方法では次のような問題点があった。第１に、筒体２２をパーツフィーダなどで搬送しなければならないので、機械的要因や自重などで筒体２２の開口端部が変形したり、潰れたりする虞があり、電池用セパレータ４の生産性低下につながる。第２に、筒体２２の上端に窪みを形成するとき、筒体２２の硬さなどの性質によっては窪み２２ｂを付けにくく、従って筒体２２の底部２２ａの閉塞性が不完全となる。この場合、刃状金型２４を押し当てる強さや時間を調節して無理に窪み２２ｂをつけようとすると、筒体２２の破損や生産性の低下を惹起することから、必然的に原紙の材質選択の幅が狭まってしまう。
【０００７】
そこで、上記欠点を解消するものとして、図４と図５に示した方法がある。この方法は、図４（ａ）に示すように、先ず、水溶性バインダー成分を含むフープ状の原紙２１を用意し、この原紙２１の適所（筒体２２の巻終りの上端部、中央部及び下端部の３カ所）にノズル３０で水分を噴射添加する。この際、水分の添加長さは、後述する筒体２２の１周分に相当する長さ以上になるようにする。その後、この原紙２１を所定寸法に切断し、図４（ｂ）に示すように、所定の径のマンドレル３２に円筒状に巻き付けて筒体２２を形成する。このとき、原紙２１の水分添加箇所を熱板の押しつけによって加熱することで水分を蒸発させる。かくて、水溶性バインダー成分が水分の蒸発によって固化し、筒体２２がその円筒形状のまま固定される。次いで、図４（ｃ）に示すように、筒体２２をマンドレル３２から抜き、所定の円筒形治具３３の保持孔３３ａに写して挿通する。この状態で、筒体２２及び円筒形治具３３を底部形成工程に搬送する。
【０００８】
そして、底部成形工程に移行し、筒体２２が円筒形治具３３に挿通されたまま図４（ｄ）に示すように、心棒２５で筒体２２の高さ方向と径方向を指示した上で、筒体２２の一端を熱融着して閉塞する。その方法として、図５（ａ）に示すように、筒体２２の上端に対して棒状治具２７を斜めに押し当てることにより、図５（ｂ）に示すように、筒体２２の上端片側２２ｃに窪ませて直角に畳み込む。この状態で図５（ｃ）に示すように、筒体２２の上端に熱カール金型２９を押し当てて熱融着する。すると、図４（ｄ）に示すように、筒体２２の上端に半球面状の底部２２ａが形成されることとなる。これが前記した特開平１１−３３９７５３号に開示された従来のセパレータの製造方法である。
【０００９】
【発明が解決しようとする課題】
しかしながら、円筒体セパレータを上下方向に移動させ、セパレータの端部を成形金型に押し当てて閉蓋部を設ける方法では、セパレータ端部を屈曲する工程と、閉蓋部を成形する工程の２工程が必要であった。
また、上下方向の応力が加わるため、セパレータに皺、襞、潰れなどが発生し、信頼性（ＯＣＶ：Open Circuit Voltage／開路圧）に関して大いに問題があった。
【００１０】
従って、本発明の目的は、上記従来の欠陥を無くし、改良された電池用セパレータの製造方法を提供することである。
本発明の別の目的は、セパレータの製造工程を簡略化すると共に、セパレータとしての信頼性を向上させ、安全性の高い電池用セパレータを提供することである。
本発明の更に別の目的は、円筒体を回転させると共に一方向に移動させるだけで、屈曲方向にわずかな応力を加えることが可能となり、筒状セパレータ内側に屈曲させることが出来、上下方向からの応力を軽減でき、信頼性の高い電池用セパレータを提供することである。
【００１１】
【課題を解決するための手段】
本発明は、次の構成を有するものである。
即ち、請求項１の発明では、電池用の円筒状セパレータの製造方法において、円筒体の被成形端部を回転させながら、傾斜面を備えた成形金型の上記傾斜面を摺動して上昇させて上記円筒体の端部を半径方向内側に屈曲させ、上記円筒体の端部に閉蓋部を形成することを特徴とする電池用の円筒状セパレータの製造方法である。
【００１２】
また、請求項２の発明では、上記請求項１の発明において、上記成形金型は、上記傾斜面に連接して、上記円筒体の軸芯に対して垂直となる平板面を有しており、上記円筒体の被成形端部を回転させながら上記成形金型の傾斜面を摺動移動させた後で、上記成形金型の平板面に移行させて上記円筒体の端部に閉蓋部を形成するようにしてなる電池用円筒状セパレータの製造方法である。
【００１３】
更に、請求項３の発明では、電池用の円筒状セパレータの製造方法において、傾斜面とそれに連接すると共に円筒状セパレータとなる円筒体の軸芯に垂直な平板面とを備えた成形金型を用い、上記円筒体の被成形端部を回転させながら、上記成形金型の上記傾斜面を摺動して上昇させて上記円筒体の端部を半径方向内側に屈曲させ、引き続き上記成形金型の上記平板面に移行させて上記円筒体の端部に閉蓋部を形成するようにしてなる電池用の円筒状セパレータの製造方法である。
【００１４】
また、請求項４の発明は、前記請求項１乃至３の発明構成において、上記成形金型の上記傾斜面は、およそ５〜２０度の傾斜角度を備えている電池用円筒状セパレータの製造方法である。
【００１５】
更に、請求項５の発明は、傾斜面を有する成形金型により、円筒体の端部を加熱成形して閉蓋部を形成する電池用円筒状セパレータの製造方法において、上記円筒体の被成形端部を上記成形金型の傾斜面に押し当てた状態で、上記円筒体の被成形端部を回転させながら一方向に移動させることにより、上記円筒体の被成形端部を屈曲させて、上記閉蓋部を形成することを特徴とする電池用円筒状セパレータの製造方法である。
【００１６】
また、請求項６の発明は、請求項５の発明において、上記成形金型は、上記傾斜面に連接して、上記円筒体の軸芯に対して垂直となる平板面を有しており、上記円筒体の被成形端部を回転させながら上記成形金型の傾斜面を摺動移動させ、上記円筒体の端部に閉蓋部を形成するようにしてなる電池用円筒状セパレータの製造方法である。
【００１７】
更に、請求項７の発明では、請求項５の発明において、上記成形金型は、上記傾斜面に連接して、上記円筒体の軸芯に対して垂直となる平板面を有しており、上記円筒体の被成形端部を回転させながら上記成形金型の傾斜面を摺動移動させた後で、上記成形金型の平板面に移行させて上記円筒体の端部に閉蓋部を形成するようにしてなる電池用円筒状セパレータの製造方法である。
【００１８】
【作用】
上記構成により、円筒体を回転させて、屈曲方向にわずかな応力を加えることでセパレータ内側に屈曲することが出来、上下方向からの応力が軽減され、信頼性の高い電池用セパレータを製造することができる。
【００１９】
更に、従来成型時に発生していた閉蓋部近傍での皺や襞の発生を抑制出きるために、上記皺は襞の発生に起因する負極ゲルのこぼれや、集電子挿入時における上記皺や襞部の潰れによる負極ゲルのはみ出しをなくすことができる。
また、単純構造の成形金型を備えることで達成出きるので製造コスト的にも有利なセパレータの製造が達成できる。
【００２０】
【発明の実施の形態】
本発明の電池用セパレータの製造方法について、好ましい実施例を説明する。先ず、図２（ａ）に示すように、水溶性バインダー成分を含むフープ状の原紙２１を準備し、この原紙２１の適所（例えば、筒体２２の巻終わりの上端部、中央部及び下端部の位置に相当する３カ所）にノズル（図示せず）で水分を噴射添加する。この際、水分には必要に応じて少量の水溶性バインダーを加えても良い。
【００２１】
その後、上記原紙２１を所定寸法に切断し、所定径のマンドレル（図示せず）に円筒状に巻き付けて筒体２２を形成する（図２（ｂ）参照）。このとき、原紙２１の水分添加箇所を熱板を押しつけて加熱することで水分を蒸発できる。すると、原紙２１に含まれる水溶性バインダー成分が水分の蒸発によって固化することとなり、筒体２２がその円筒形状を保持したまま固定される。ここまでは、従来の製造工程と大同小異である。
本発明は次の工程より特徴がある。
【００２２】
即ち、図２（ｃ）において、円筒状セパレータ２２に回転型治具３５を緊着させて回転させると共に、セパレータの有底部となる下端部を成形金型４０の傾斜面４１に軽く押しつけながら肉厚方向（図の矢印方向）に移動させることでセパレータ底部を内側、即ち径方向の内側に屈曲させ、次いで、図２（ｄ）に示すように、成形金型の平板面４２に移動した後も所定の時間回転を継続させて円滑な底面２２ａを形成する。
【００２３】
図示のように、上記成形金型４０は、上記傾斜面４１に連接して、上記円筒体２２の軸芯（即ち、回転型治具３５の回転軸）
に対して垂直となる平板面４２を有する構成となっており、上記円筒体２２の被成形端部を回転させながら上記成形金型４０の傾斜面４１を摺動移動させた後で、引き続き上記成形金型の平板面４２に移行させて上記円筒体の端部に閉蓋部を形成する。この場合、傾斜面上の移行だけで所望の閉蓋部が形成されれば、敢えて平板面に移行することなく形成工程を終了することも可能である。
このようにして形成したセパレータ用筒体２２が図２（ｅ）に示した構造となる。
【００２４】
なお、上記傾斜面４１を備えた成形金型４０の傾斜角度は、実験によればおよそ５〜２０度、更に好ましくは７〜１０度とした例が好結果を見た。また、セパレータの回転速度と一方向への進行速度は、特に限定的なものとする必要がないことが判明したが、それぞれ６００回転／分、６ｍ／分程度が望ましい。
【００２５】
この結果、本願出願人による前記図５において説明した製造方法もそれ以前の製法（例えば図３の従来製法）に対する大きな改善を示したが、本願発明のよる製造方法によれば更に飛躍的な改善となったものである。即ち、図５の製法を従来例とするならば、従来例と本発明による製造方法によってそれぞれＬＲ６電池を製造した結果、従来例の場合には１０，０００個に対して１個の割合でＯＣＶ（開路電圧）不良が発生したのに対して、本発明の製法によれば上記ＯＣＶ不良発生率は従来例のおよそ１／４に止まっていた。そして、ＯＣＶ不良発生の原因を調査してみたところ、セパレータ潰れによるもの、及びそれに関連する負極ゲルこぼれや外部ショートに起因するものであることが知得された。
【００２６】
ここで、セパレータの潰れや負極ゲルのこぼれは、セパレータの成型時に閉蓋部付近に皺や襞が発生し、これが電解注入時に引き延ばされ、負極ゲルを注入した後で注入ポンプのノズルにセパレータの端部が接触し、それによって負極ゲルが正極合剤上端面にこぼれたり、集電子の挿入時に潰す結果となり、負極ゲルがはみ出す、というものである。
【００２７】
従って、セパレータの製造を本発明の製造方法に基づくものとすることにより、電池全体の特性及び性能を飛躍的に改善させることが出来たことが判明した。
【００２８】
以上、本発明の好適な実施例について説明したが、本発明はこれらの実施例に限定されるものではなく、種々変更が可能である。
例えば、成形金型４０に関して、図示例では傾斜面４１とそれに連接して傾斜面の上端に、回転する円筒体２２の軸芯に対して垂直の平板面４２を備えた構造であるが、この構造に加えて、上記傾斜面４１の一側側部に湾曲面を備えた壁部（図示せず）を形成して、傾斜面４１と上記壁部の湾曲面との協働と円筒体の回転と一方向の移動との相互関係により、閉蓋部を形成することも可能である。
【００２９】
【発明の効果】
以上のように、本発明によれば、従来技術に見られる種々の欠陥を払拭でき、信頼性および安全性に優れると共に、生産性および性能的にも優れた電池を提供できる優れた電池用セパレータを提供することができる。
更に、製造方法自体、回転させながら同時に一方向に移動させるだけで良いので、単一工程で製造可能であり、工程そのものが簡便であり、効率的な生産に寄与することができる。
また、製造設備的にも、傾斜面を備えた単純な成形金型を備えただけで達成できるので製造コスト上も有利である。
【００３０】
【図面の簡単な説明】
【図１】本発明の電池用セパレータを採用する電池の構成例を示す断面図である。
【図２】本発明の電池用セパレータの製造工程を示す説明図である。
【図３】従来の電池用セパレータの製造方法の例を示す図である。
【図４】従来の電池用セパレータの別の製造方法の工程を示す図である。
【図５】図４に示す電池用セパレータの製造工程の閉蓋部形成工程を示す説明図である。
【符号の説明】
２１原紙
２２筒体
３５回転型治具
４０成型金型
４１傾斜面
４４平板面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a battery separator used for isolating a positive electrode and a negative electrode of a cylindrical alkaline battery in a battery can.
[0002]
[Prior art]
In general, AA type other alkaline batteries have a conductive film (not shown) made of carbon or the like formed on the inner surface of a bottomed cylindrical positive electrode can 2 as shown in FIG. Three positive electrode mixtures 3 formed into a cylindrical shape are accommodated, and a cylindrical separator 4 with a bottom is inserted inside the positive electrode mixture 3, and an electrolyte is infiltrated into the separator 4 and the positive electrode mixture 3. The structure in which the hollow portion of the separator 4 is filled with the gelled zinc negative electrode 5 is common.
[0003]
A sealing body 6 is attached to the opening of the positive electrode can 2 8. That is, the sealing body 6 has a current collector 8 fixed to the inner central portion of the negative electrode terminal 7 by spot welding or the like, and a gasket 9 is inserted into the current collector 8 with a sealant 10 interposed therebetween and is tightened by a sealing cap 11. Configured. Then, the current collector 8 is inserted into the gelled zinc negative electrode 5, and the end of the positive electrode can 2 on the opening side is pressed in a state where the tip 4 </ b> A of the separator 4 is pressed by the gasket 9 and bent inward. The opening of the positive electrode can 2 is sealed by the sealing body 6 by crimping the outer periphery of the gasket 9 between the outer periphery of the negative electrode terminal 7 and the positive electrode can 2.
A label 12 is wound around the outside of the positive electrode can 2, and an annular negative electrode washer 13 is interposed between the outer peripheral portion of the negative electrode terminal 7 and the label 12.
[0004]
Conventionally, various manufacturing methods have been proposed for the separator as described in Japanese Patent Application Laid-Open No. 11-39753 by the applicant of the present application. One example thereof is shown in FIG. 3 of the accompanying drawings, and a further conventional example improved from this is shown in FIGS. 4 and 5 and will be briefly described.
[0005]
First, in the manufacturing method of FIG. 3, as shown in FIG. 3A , a hoop-shaped base paper is cut into a predetermined size and wound into a cylindrical shape to form a cylindrical body 22. conveying the body 22 to the bottom forming process, as shown in FIG. 3 (b) ~ FIG 3 (e), it is closed by heat sealing one end of the cylindrical body 22.
And in order to ensure the obstruction | occlusion property at this time, the bending process of the cylinder 22 is performed prior to heat sealing | fusion. That is, as shown in FIG. 3 (b), the cylindrical member 22 fitted to the mandrel 25, the blade-like mold 24 to the upper end of the cylindrical body 22 by pressing downwardly, as shown in FIG. 3 (c), the the recess 22b is formed, in this state, as shown in FIG. 3 (d), pressing a hot curling die 29 to the upper end of the cylindrical body 22. Then, as shown in FIG. 3E , a hemispherical bottom 22a is formed, and the battery separator 4 is completed.
[0006]
However, the above manufacturing method has the following problems. First, since the cylindrical body 22 must be transported by a parts feeder or the like, there is a possibility that the opening end of the cylindrical body 22 may be deformed or crushed due to mechanical factors or its own weight. This leads to a decrease in productivity. Secondly, when forming a dent at the upper end of the cylindrical body 22, depending on the properties such as the hardness of the cylindrical body 22, it is difficult to attach the dent 22b, so that the bottom 22a of the cylindrical body 22 is not completely closed. In this case, adjusting the strength and time of pressing the blade-shaped mold 24 and forcibly attaching the recess 22b causes damage to the cylindrical body 22 and a decrease in productivity. The range of selection is narrowed.
[0007]
Therefore, there are methods shown in FIG. 4 and FIG. This method, as shown in FIG. 4 (a), First, a hoop-shaped base paper 21 comprising a water-soluble binder component, the upper end portion of the winding end of the place (the tubular body 22 of the base paper 21, the central portion and Water is sprayed and added to the lower end (three locations) with a nozzle 30. At this time, the addition length of the water is set to be equal to or longer than a length corresponding to one round of the cylindrical body 22 described later. Thereafter, the base paper 21 is cut into a predetermined dimension, and as shown in FIG. 4B , a cylindrical body 22 is formed by winding it around a mandrel 32 having a predetermined diameter. At this time, moisture is evaporated by heating the moisture added portion of the base paper 21 by pressing the hot plate. Thus, the water-soluble binder component is solidified by evaporation of moisture, and the cylinder 22 is fixed in its cylindrical shape. Then, as shown in FIG. 4 (c), disconnect the tubular body 22 from the mandrel 32, is inserted in duplicate in the holding hole 33a of a predetermined cylindrical jig 33. In this state, the cylindrical body 22 and the cylindrical jig 33 are transported to the bottom forming process.
[0008]
Then, the process proceeds to the bottom forming step, and the height direction and the radial direction of the cylindrical body 22 are indicated by the mandrel 25 as shown in FIG. 4 (d) while the cylindrical body 22 is inserted into the cylindrical jig 33 . Thus, one end of the cylindrical body 22 is thermally fused and closed. As the method, as shown in FIG. 5 (a), by pressing the rod-shaped jig 27 obliquely to the upper end of the cylindrical body 22, as shown in FIG. 5 (b), the upper end side of the tubular body 22 It dents into 22c and folds it at a right angle. As shown in FIG. 5 (c) in this state, heat sealing by pressing a hot curling die 29 to the upper end of the cylindrical body 22. Then, as shown in FIG. 4D , a hemispherical bottom 22a is formed at the upper end of the cylindrical body 22. This is the conventional separator manufacturing method disclosed in Japanese Patent Application Laid-Open No. 11-339975.
[0009]
[Problems to be solved by the invention]
However, in the method in which the cylindrical separator is moved in the vertical direction and the end of the separator is pressed against the molding die to provide the closing cover, the process of bending the separator end and the process of forming the closing cover are two. A process was required.
Further, since stress in the vertical direction is applied, wrinkles, wrinkles, crushing, etc. occur in the separator, and there is a great problem regarding reliability (OCV: Open Circuit Voltage).
[0010]
Accordingly, an object of the present invention is to provide an improved battery separator manufacturing method that eliminates the conventional defects.
Another object of the present invention is to simplify the manufacturing process of the separator, improve the reliability as the separator, and provide a battery separator with high safety.
Still another object of the present invention is to be able to apply a slight stress in the bending direction only by rotating and moving the cylindrical body in one direction, and can be bent inside the cylindrical separator. It is an object to provide a battery separator that can reduce the stress of the battery and has high reliability.
[0011]
[Means for Solving the Problems]
The present invention has the following configuration.
That is, according to the first aspect of the present invention, in the method for manufacturing a cylindrical separator for a battery, the rotating end of the cylindrical body is rotated and the inclined surface of the molding die having the inclined surface is slid and raised. Then, the end of the cylindrical body is bent inward in the radial direction, and a closed lid is formed at the end of the cylindrical body.
[0012]
According to a second aspect of the present invention, in the first aspect of the invention, the molding die has a flat plate surface connected to the inclined surface and perpendicular to the axis of the cylindrical body. , Sliding the inclined surface of the molding die while rotating the molding end of the cylindrical body, and then moving to the flat plate surface of the molding die and closing the lid at the end of the cylindrical body Is a method for producing a cylindrical separator for a battery.
[0013]
According to a third aspect of the present invention, in the method for manufacturing a cylindrical separator for a battery, a molding die having an inclined surface and a flat plate surface connected to the inclined surface and perpendicular to the axis of the cylindrical body that becomes the cylindrical separator is provided. The cylindrical mold body is rotated while the molded end portion is rotated, and the inclined surface of the molding die is slid and raised to bend the end portion of the cylindrical body inward in the radial direction. This is a method for producing a cylindrical separator for a battery, wherein the lid is formed on the end of the cylindrical body by shifting to the flat plate surface.
[0014]
According to a fourth aspect of the present invention, there is provided a method for producing a cylindrical separator for a battery according to the first to third aspects of the invention, wherein the inclined surface of the molding die has an inclination angle of about 5 to 20 degrees. It is.
[0015]
Furthermore, the invention of claim 5 is a method for manufacturing a cylindrical separator for a battery, in which a closed end is formed by thermoforming an end portion of a cylindrical body with a molding die having an inclined surface. With the end pressed against the inclined surface of the molding die, the molded end of the cylindrical body is bent by moving it in one direction while rotating the molded end of the cylindrical body, A method of manufacturing a cylindrical separator for a battery, wherein the lid portion is formed.
[0016]
The invention of claim 6 is the invention of claim 5, wherein the molding die has a flat plate surface connected to the inclined surface and perpendicular to the axis of the cylindrical body, A method for producing a cylindrical separator for a battery, wherein an inclined surface of the molding die is slid and moved while rotating a molded end of the cylindrical body to form a closed lid at the end of the cylindrical body. It is.
[0017]
Further, in the invention of claim 7, in the invention of claim 5, the molding die has a flat plate surface connected to the inclined surface and perpendicular to the axis of the cylindrical body, After sliding the inclined surface of the molding die while rotating the molding end of the cylindrical body, the cylindrical body is moved to the flat plate surface of the molding die, and a closing portion is attached to the end of the cylindrical body. It is a manufacturing method of the cylindrical separator for batteries formed.
[0018]
[Action]
With the above configuration, the cylindrical body can be rotated to bend the inside of the separator by applying a slight stress in the bending direction, and the stress from the vertical direction is reduced, and a highly reliable battery separator is manufactured. Can do.
[0019]
Furthermore, in order to suppress the generation of wrinkles and wrinkles in the vicinity of the closed lid portion that has occurred in the conventional molding, the wrinkles are spilled negative electrode gel due to the generation of wrinkles, and the wrinkles and The protrusion of the negative electrode gel due to the crushing of the buttocks can be eliminated.
Moreover, since it can be achieved by providing a molding die having a simple structure, it is possible to achieve the manufacture of a separator that is advantageous in terms of manufacturing cost.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
A preferable example is described about the manufacturing method of the separator for batteries of the present invention. First, as shown in FIG. 2 (a), a hoop-like base paper 21 containing a water-soluble binder component is prepared, and appropriate positions (for example, an upper end portion, a central portion, and a lower end portion at the end of winding of the cylindrical body 22). Water is sprayed and added to the three locations corresponding to the position of (1) with a nozzle (not shown). At this time, a small amount of a water-soluble binder may be added to the moisture as necessary.
[0021]
Thereafter, the base paper 21 is cut into a predetermined size and wound around a mandrel (not shown) having a predetermined diameter in a cylindrical shape to form a cylindrical body 22 (see FIG. 2B). At this time, moisture can be evaporated by heating the moisture added portion of the base paper 21 by pressing the hot plate. Then, the water-soluble binder component contained in the base paper 21 is solidified by evaporation of moisture, and the cylindrical body 22 is fixed while maintaining its cylindrical shape. Up to this point, it is almost the same as the conventional manufacturing process.
The present invention is characterized by the following steps.
[0022]
That is, in FIG. 2C, the rotating jig 35 is attached to the cylindrical separator 22 and rotated, and the lower end portion of the separator having the bottom is lightly pressed against the inclined surface 41 of the molding die 40 while the meat is pressed. After the separator bottom is bent inward, that is, radially inward by moving in the thickness direction (arrow direction in the figure), and then moved to the flat plate surface 42 of the molding die as shown in FIG. In addition, the smooth bottom surface 22a is formed by continuing the rotation for a predetermined time.
[0023]
As shown in the figure, the molding die 40 is connected to the inclined surface 41, and the axial center of the cylindrical body 22 (that is, the rotational axis of the rotary jig 35).
After the inclined surface 41 of the molding die 40 is slid and moved while rotating the molding end of the cylindrical body 22, the above-described configuration is continued. The lid is formed at the end of the cylindrical body by shifting to the flat plate surface 42 of the molding die. In this case, if a desired lid part is formed only by the transition on the inclined surface, it is possible to end the formation process without shifting to the flat surface.
The separator cylinder 22 thus formed has the structure shown in FIG.
[0024]
In addition, according to an experiment, the example in which the inclination angle of the molding die 40 provided with the inclined surface 41 is about 5 to 20 degrees, more preferably 7 to 10 degrees has been seen as a good result. Further, it has been found that the rotational speed of the separator and the traveling speed in one direction do not need to be particularly limited, but are preferably about 600 rotations / minute and 6 m / minute, respectively.
[0025]
As a result, the manufacturing method described in FIG. 5 by the applicant of the present application also showed a significant improvement over the previous manufacturing method (for example, the conventional manufacturing method of FIG. 3). However, according to the manufacturing method according to the present invention, a further dramatic improvement is achieved. It has become. That is, if the manufacturing method of FIG. 5 is a conventional example, the LR6 battery is manufactured by the manufacturing method according to the conventional example and the present invention, respectively. Whereas (open circuit voltage) failure occurred, according to the manufacturing method of the present invention, the OCV failure occurrence rate was about ¼ that of the conventional example. Then, as a result of investigating the cause of the occurrence of OCV failure, it was found that it was caused by separator crushing, and negative gel spillage or external shorting associated therewith.
[0026]
Here, the collapse of the separator and spilling of the negative electrode gel generate wrinkles and wrinkles in the vicinity of the closed lid when the separator is molded, and this is stretched during the electrolytic injection, and after the negative electrode gel is injected, The end part of the separator comes into contact, whereby the negative electrode gel is spilled on the upper end surface of the positive electrode mixture or crushed when the current collector is inserted, and the negative electrode gel protrudes.
[0027]
Therefore, it was found that the characteristics and performance of the entire battery could be dramatically improved by making the separator production based on the production method of the present invention.
[0028]
As mentioned above, although the suitable Example of this invention was described, this invention is not limited to these Examples, A various change is possible.
For example, with respect to the molding die 40, in the illustrated example, the inclined surface 41 is connected to the upper end of the inclined surface, and a flat plate surface 42 perpendicular to the axis of the rotating cylindrical body 22 is provided. In addition to the structure, a wall portion (not shown) having a curved surface is formed on one side of the inclined surface 41, and the cooperation between the inclined surface 41 and the curved surface of the wall portion and the cylindrical body It is also possible to form a lid by the mutual relationship between rotation and movement in one direction.
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to eliminate various defects found in the prior art, and it is excellent in reliability and safety, and can provide a battery excellent in productivity and performance. Can be provided.
Furthermore, since the manufacturing method itself only needs to be moved in one direction at the same time while being rotated, it can be manufactured in a single process, the process itself is simple, and can contribute to efficient production.
Also, in terms of manufacturing equipment, this can be achieved simply by providing a simple mold having an inclined surface, which is advantageous in terms of manufacturing cost.
[0030]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structural example of a battery employing a battery separator of the present invention.
FIG. 2 is an explanatory view showing a production process of the battery separator of the present invention.
FIG. 3 is a diagram showing an example of a conventional method for producing a battery separator.
FIG. 4 is a diagram showing a process of another method for manufacturing a conventional battery separator.
5 is an explanatory view showing a closing lid forming step in the manufacturing process of the battery separator shown in FIG. 4. FIG.
[Explanation of symbols]
21 Base Paper 22 Tube 35 Rotating Die 40 Molding Mold 41 Inclined Surface 44 Flat Plate Surface

Claims

In the method of manufacturing a cylindrical separator for a battery, the end of the cylindrical body is moved by sliding and raising the inclined surface of the molding die having the inclined surface while rotating the molded end of the cylindrical body. A method for producing a cylindrical separator for a battery, wherein the battery is bent inward in a radial direction, and a closed lid is formed at an end of the cylindrical body.

The molding die has a flat plate surface that is connected to the inclined surface and is perpendicular to the axis of the cylindrical body, and the molding die is rotated while rotating the molding end of the cylindrical body. 2. The cylindrical shape for a battery according to claim 1, wherein after the slanted surface is slid and moved, it is shifted to the flat plate surface of the molding die to form a closed lid at the end of the cylindrical body. Separator manufacturing method.

In a method for manufacturing a cylindrical separator for a battery, a molding die having an inclined surface and a flat plate surface connected to the inclined surface and perpendicular to the axis of the cylindrical body serving as the cylindrical separator is used. While rotating the part, the inclined surface of the molding die is slid and raised to bend the end portion of the cylindrical body inward in the radial direction, and subsequently transferred to the flat plate surface of the molding die. A method for producing a cylindrical separator for a battery, wherein a closed lid is formed at an end of a cylindrical body.

The method for producing a cylindrical separator for a battery according to claim 1 or 3, wherein the inclined surface of the molding die has an inclination angle of about 5 to 20 degrees.

In a method for manufacturing a cylindrical separator for a battery , in which an end portion of a cylindrical body is formed by thermoforming an end portion of the cylindrical body by using a molding die having an inclined surface, the molded end portion of the cylindrical body is inclined to the molding die. Forming the closed lid portion by bending the molded end portion of the cylindrical body by rotating the molded end portion of the cylindrical body in one direction while being pressed against the surface. A method for producing a cylindrical separator for a battery .

The molding die has a flat plate surface that is connected to the inclined surface and is perpendicular to the axis of the cylindrical body, and the molding die is rotated while rotating the molding end of the cylindrical body. 6. A method for producing a cylindrical separator for a battery according to claim 5, wherein the inclined surface is slid and moved to form a closed lid at the end of the cylindrical body.

The molding die has a flat plate surface that is connected to the inclined surface and is perpendicular to the axis of the cylindrical body, and the molding die is rotated while rotating the molding end of the cylindrical body. 6. The cylindrical shape for a battery according to claim 5, wherein the inclined surface is slid and moved to a flat plate surface of the molding die to form a closed portion at an end of the cylindrical body. Separator manufacturing method.