JP4975901B2

JP4975901B2 - Battery electrode plate and battery

Info

Publication number: JP4975901B2
Application number: JP2000328932A
Authority: JP
Inventors: 健一大嶋; 安弘荒瀧; 秀幸小林; 彰井口; 頼人大花; 征吾井崎
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-10-27
Filing date: 2000-10-27
Publication date: 2012-07-11
Anticipated expiration: 2020-10-27
Also published as: JP2002134102A

Description

【０００１】
【発明の属する技術分野】
本発明は、主としてリチウムイオン二次電池などの非水電解液二次電池の発電要素として用いられる電池用電極板とその製造方法及びその電極板を用いて構成された電池に関するものである。
【０００２】
【従来の技術】
近年、民生用電子機器のポータブル化、コードレス化が急速に促進されている。これらの電子機器の駆動用電源としては、従来はニッケルカドミウム電池やニッケル水素電池、或いは密閉型鉛蓄電池が主に用いられていたが、電子機器のポータブル化やコードレス化が進展して定着するに従って、駆動用電源となる二次電池の高エネルギー密度化や小型軽量化の要望がますます強くなっている。
【０００３】
また、近年では、ＡＶ機器、ノート型パソコン、或いは携帯型通信機器などのポータブル化やコードレス化も急速に促進されていることから、これらの駆動用電源として、効率充放電が可能な電池の出現が要望されている。
【０００４】
このような状況から、近年では効率充放電特性を示すリチウムコバルト複合酸化物、例えばＬｉＣｏＯ₂を正極活物質に用いてリチウムイオンの挿入、離脱を利用したリチウムイオン二次電池に代表される非水電解液（有機溶媒系電解液）二次電池が主流になりつつある。
【０００５】
リチウムイオン二次電池は、小型・軽量でありながら急速充電が可能で、高エネルギー密度を有するという極めて顕著な特徴を有するものである。このような非水電解液二次電池では、効率充放電を可能にするため、正極側電極板及び負極側電極板をこれらの間にセパレータを介在して積層した状態で渦巻き状に巻回して電極群を構成することにより、電池ケース内において化学反応に寄与する電極板の面積を可及的に大きくする工夫がなされている。
【０００６】
ところで、電池用電極板の製造に際しては、図３に示すように、アルミニウム箔や銅箔からなる帯状の集電用芯材１をＡ矢印方向に移送しながら、この集電用芯材１の一面１ａにペースト状活物質を間欠的に塗布し、この活物質を乾燥して固化させることによって電極合剤部２を形成し、一面１ａに対する電極合剤部２の形成が終了したのちに、集電用芯材１をＢ矢印方向に移送しながら、この集電用芯材１の他面１ｂにペースト状活物質を間欠的に塗布し、この活物質を乾燥して固化させることによって電極合剤部２を形成し、続いて集電用芯材１の両面に形成された電極合剤部２、２を加圧圧延して所定厚みにし、その後所定の寸法に裁断するという工程で製造されている。
【０００７】
また、上述の集電用芯材１にペースト状活物質を塗布するに際しては、巻き取り機から繰り出した集電用芯材１を、ドラム状のバックアップロールの外周の一部に巻き付けた状態で移送しながら、バックアップロールに対して所定の間隙をあけて対向されたダイノズルからペースト状活物質を集電用芯材１に向けて吐出させることで、間欠塗布を連続的に行うようにしている。
【０００８】
そして、集電用芯材１に対してペースト状活物質の未塗布部を形成する際には、切替え弁の作動によりペースト状活物質の吐出を停止するとともにダイの上側に設置されている内のピストンを後退させることによって行い、塗布を開始又は再開する際には、切替え弁の作動と同時にピストンに瞬時に所定の圧力を付与してノズルからペースト状活物質を吐出している。
【０００９】
また、一面１ａの電極合剤部２の形成が終了した集電用芯材１は一旦巻き取り機に巻き取られ、この巻き取り機を繰り出し側に移して設置し、この巻き取り機から集電用芯材１を繰り出しながら他面１ｂへのペースト状活物質の塗布が行われる。従って、他面１ｂへのペースト状活物質の間欠塗布時には、集電用芯材１を一面１ａへの塗布時とは逆方向に移送しながら、一面１ａの塗布終端部２ｂに合わせて塗布を開始するとともに、一面１ａの電極合剤部２の塗布開始部２ａに合わせて塗布を停止している。
【００１０】
【発明が解決しようとする課題】
しかしながら、上記従来の電極板の製造方法では、一面、他面の塗布開始時にはダイ内部の圧力が高くなっているため、一面１ａ、他面１ｂにおける塗布開始端部２ａに比較的大きな盛り上がり部２ｃ、２ｄができてしまう。また、特に他面１ｂの塗布始端部２ａは、一面１ａの塗布終端部２ｂは塗布厚みが他の箇所よりも薄くなっているので、この塗布始端部２ａとダイのスリットノズルとの間隔が、一面１ａの塗布終端部２ｂの厚みが薄くなっている分広がった状態になるために、さらに大きな盛り上がり部２ｄができてしまう。
【００１１】
この盛り上がり部２ｃ、２ｄは、電極合剤部２の形成後の加圧圧延時や、正負の電極板をこれらの間にセパレータを介在して渦巻き状に巻回する際に、集電用芯材１の塗布始端部２ａ及び塗布終端部２ｂと未塗布部との境界部に曲げ力と引張力を発生させて集電用芯材１にストレスがかかり、加工硬化して集電用芯材１が破断することがあり、これらが電池用電極板の歩留り低下の一因になっているという問題があった。
【００１２】
本発明は、上記従来の問題点に鑑み、電極合剤部の塗布始端部と未塗布部の境界部での集電用芯材の切断防止を図れる電池用電極板とその製造方法及びをそれを用いた電池を提供することを目的としている。
【００１４】
【課題を解決するための手段】
また、本発明の電池用電極板は、塗布方向を相互に反対向きにして集電用芯材の両面に活物質を間欠的に塗布して乾燥固化して成る電極合剤部を有する電池用電極板において、前記電極合剤部の塗布始端部は盛り上がり部を有し、集電用芯材の他面に、塗布開始位置を一面における電極合剤部の塗布終端部から塗布開始部寄りに１〜５ｍｍ離れた位置に、塗布終端位置を一面における電極合剤部の塗布始端部から未塗布側に１〜５ｍｍ離れた位置に設定したことにより、一面と他面の何れか一方の面の前記電極合剤部の有する塗布始端部と未塗布部の境界部が反対側の面における電極合剤部の塗布終端部に対向するものである。
【００１５】
この電池用電極板によれば、一面と他面の何れか一方の面の合剤塗布部の塗布始端と未塗布部の境界の反対側の面には合剤塗布部の塗布終端部が存在し、この塗布終端部で集電用芯材がバックアップされているので、圧延時に合剤塗布部の始端部にその突出部により大きな負荷が作用しても、始端と未塗布部の境界で集電用芯材にかかる曲げ力を抑制することができ、加圧圧延時やセパレータを介して渦巻き状に巻回する時に集電用芯材が切断するのを防止でき、電池用電極を歩留り良く生産することができる。
【００１６】
また、本発明の電池は、上記配置構成を有し、その電極合剤がリチウムを可逆的に吸蔵・放出可能な材料を含む活物質から成る正極側電極板と、負極側電極板とがそれらの間にセパレータを介在した状態で渦巻き状に巻回された電極群と、この電極群を収容した電池ケースと、電池ケース内に注液された電解液と、電池ケースの開口部を封口する封口板とを備えたものであり、正極側電極板の芯材に切れや亀裂が生じることがなく、その電極板の電気抵抗が常に安定した状態を保持することから、電池内部抵抗の増大による不具合が発生せず、高い電池性能を得ることができる。
【００１７】
【発明の実施の形態】
以下、本発明の電池用電極板とその製造方法及びそれを用いた電池の一実施形態について、図１、図２を参照して説明する。
【００１８】
なお、図１において、図３で説明した従来例と同一又は同様の構成要素については同一参照符号を付してその説明を省略する。
【００１９】
図１は、帯状の集電用芯材１の両面にそれぞれ電極合剤部２を間欠的に形成する工程を経た状態であって、圧延して個々の電池用電極板に切断位置で裁断する以前の状態を示す。
【００２０】
集電用芯材１の一面１ａには、図３の従来例と同様の間欠的な配置で電極合剤部２が形成されているが、集電用芯材１の他面１ｂの電極合剤部２は、塗布始端部２ａが一面１ａの塗布終端部２ｂから塗布始端部２ａ寄りにｄ＝１ｍｍ〜５ｍｍ程度離れた位置に設定されるとともに、塗布終端部２ｂが一面１ａの塗布始端部２ａから未塗布側に同様にｄ＝１ｍｍ〜５ｍｍ程度離れた位置に設定されて形成されている。
【００２１】
次に、この電池用電極板を正極用電極板に適用した円筒型リチウムイオン二次電池について図２を参照して説明する。
【００２２】
図２において、１２は正極側電極板で、例えばアルミニウム箔からなる集電用芯材１の両面にペースト状活物質を図１に示すように間欠塗布して乾燥した後所定の厚みに圧延することによって電極合剤部２を設け、これを所定の長さのシート状に裁断することによって製作されている。この正極側電極板１２の一端部の電極合剤部２が形成されていないリード取付部に、例えばアルミニウムからなる正極リード１７が溶接により取付けられている。１３は負極側電極板であり、例えば帯状の銅箔からなる集電用芯材の両面にペースト状活物質を間欠塗布して乾燥した後に所定の厚みに圧延することによって電極合剤部を設け、これを所定長さのシート状に裁断することによって製作されている。この負極側電極板１３の端部の電極合剤部が形成されていないリード取付部に負極リード１８が溶接により取付けられている。
【００２３】
これら正極側電極板１２及び負極側電極板１３をそれらの間に例えばポリエチレン製のセパレータ１４を介在して積層した状態で渦巻き状に巻回して電極群１１が構成され、この電極群１１が、耐有機電解液性のステンレス鋼板を加工して形成された電池ケース１９内に収容され、正極リード１７の他端部が封口板２０にスポット溶接によって接続されるとともに、負極リード１８の一端部がスポット溶接により電池ケース１９の底部に接続されている。なお、電極群１１の上下部にはそれぞれ絶縁板２１、２２が配設されている。
【００２４】
さらに電池ケース１９内には、炭酸エチレンと炭酸ジエキル等の等容積混合溶媒に六フッ化リン酸リチウム１モル／ｌの割合で溶解してなる非水電解液が注液され、続いて安全弁２３を設けた封口板２０が絶縁パッキン２４を介在して電池ケース１９の開口部にかしめ込まれた後に、電池ケース１９の開口部の周縁部を内方にかしめ加工することにより、開口部が密閉されている。
【００２５】
次に、上記正極側電極板１２の実施例について、詳細を説明する。
【００２６】
正極活物質は、コバルト酸リチウムを１００重量部に対して、導電剤としてアセチレンブラックを３重量部、結着剤としてＰＴＦＥとＦＥＰを混合したディスパージョンを固形分で４重量部とカルボキシメチルセルロースを０．８重量部を加え、水を溶媒として混練してペースト状とした。この混練したペースト状活物質を、厚さ１５μｍの帯状の圧延アルミ箔からなる集電用芯材１の一面１ａに塗工部長さが４４６．５ｍｍで非塗工部長さが６．５ｍｍ（したがって、電極板のピッチが４４６．５ｍｍ＋６．５ｍｍ＝４５３ｍｍ）の配置で連続的に間欠塗布を行い、その後に乾燥して固化させることにより、電極合剤部２を形成した。
【００２７】
次に、集電用芯材１の他面１ｂにも、同様にペースト状活物質を間欠塗布した。この他面１ｂに間欠塗布を行う際の間欠塗布開始位置を、一面１ａの塗布終端部２ｂから塗布始端部２ａ寄りに２ｍｍ離れた位置に設定して、塗工部長さが４４６．５ｍｍで非塗工部長さが６．５ｍｍの配置で連続的に間欠塗工を行い、その後に乾燥して固化させることにより電極合剤部２を形成し、これを第１の電池用電極板とした。
【００２８】
これとは別に、他面１ｂに間欠塗布を行う際に間欠塗布開始位置を、一面１ａの塗布終端部２ｂから塗布始端部２ａ寄りに１ｍｍ離れた位置に設定して、塗工長さが４４６．５ｍｍで、非塗工部の長さが６．５ｍｍの配置で連続的に間欠塗布を行い、その後に乾燥して固化させることにより電極合剤部２を形成し、これを第２の電池用電極板とした。
【００２９】
また、上記実施例とは別に、それと比較するために、集電用芯材１の他面１ｂに間欠的に塗布を行う際の間欠塗布開始位置を、一面１ａの塗布終端部２ｂから塗布始端部２ａ寄りに２ｍｍ離れた位置に設定して、塗工長さが４４４．５ｍｍで非塗工部長さが８．５ｍｍの配置で、一面１ａの電極合剤部２の塗布開始位置２ａに合わせて塗布を停止するように連続的に間欠塗布を行い、その後乾燥して固化させることにより電極合剤部２を形成し、これを第３の電池用電極板とした。
【００３０】
さらに、別の比較例として、集電用芯材１の他面１ｂに間欠的に塗布を行う際の間欠塗布開始位置を、図３に示す従来の電極板と同様に、一面１ａの塗布終端部２ｂに一致する位置に設定して、塗工長さが４４６．５ｍｍで、非塗工部長さが６．５ｍｍの配置で、一面１ａの電極合剤部２の塗布開始位置２ａに合わせて塗布を停止するように連続的に間欠塗布を行い、その後に乾燥して固化させることにより電極合剤部２を形成し、これを第４の電池用電極板とした。
【００３１】
上記４種の電極板は以下のように統一した。すなわち、集電用芯材１の他面１ｂの極板ピッチは、全て一面１ａの極板ピッチである４５３ｍｍに合わせて、ペースト状活物質の乾燥後の塗布重量を集電用芯材１の一面１ａまたは他面１ｂ当たり２．４１ｇ／１００²（集電用芯材１の重量を除く）とした。また、各電極板におけるペースト状活物質の長手方向塗布長さは４４６．５ｍｍで、乾燥後の電極板における集電用芯材１を含む厚みは０．２４０ｍｍとした。このようにしてペースト状活物質を乾燥した後、これをロールプレス機によって所定の厚みになるまで圧縮成型を施して、全体の厚みを０．１４７ｍｍとした。圧延は、定圧圧延方式で行い、加圧力は線圧１７００ｋｇ／ｃｍで４回圧延を行った。
【００３２】
以上のように製作した４種の電極板における集電用芯材１の他面１ｂと電極合剤部２の塗布始端部２ａの境界部の圧延時の芯材切断率を測定したところ、第３の電極板が７％、第４の電極板が３２％であったのに対し、第１及び第２の電極板では集電用芯材１の切断は全く発生しなかった。
【００３３】
以上の試験結果から、集電用芯材１の他面１ｂへのペースト状活物質の間欠塗布開始位置を、一面１ａの電極合剤部２における塗布終端部２ｂから塗布始端部２ａ寄りに１ｍｍまたは２ｍｍ離れた位置に設定し、かつ塗布終端部２ｂを一面１ａの電極合剤部２の塗布始端部２ａから未塗布側に１ｍｍまたは２ｍｍ離れた位置にすることにより、電極合剤部２の塗布始端部２ａと未塗布部の境界部が反対側の面における電極合剤部２の塗布終端部２ｂに対向することから、圧延時の合剤塗布部と未塗布部の境界部の芯材にかかる曲げ力を抑制できることが判明した。
【００３４】
これに対し、集電用芯材１の他面１ｂのペースト状活物質の間欠塗布開始位置を、一面１ａの電極合材部２における塗布終端部２ｂに一致する位置に設定し、かつ間欠塗布終了位置２ｂを一面１ａの電極合剤部２の塗布始端部２ａに一致する位置に設定すると、特に他面１ｂの塗布始端部２ａの盛り上がり量が増大してしまい、圧延時の合剤塗布部と未塗布部の境界部の芯材にかかる曲げ力が増大し、圧延時の芯材の切断が多発してしまう。
【００３５】
以上の実施例の説明では、集電用芯材１の他面１ｂへのペースト状活物質の塗布開始位置を、一面１ａの電極合剤部２における塗布終端部２ｂから塗布始端部２ａ寄りに１ｍｍ又は２ｍｍ離れた位置に設定し、かつ塗布終端部２ｂを一面１ａにおける電極合剤部２の塗布始端部２ａから未塗布側に１ｍｍまたは２ｍｍ離れた位置に設定した例を示したが、これらを１ｍｍ〜５ｍｍの範囲とすることによって、電極合剤部２の塗布始端部２ａと未塗布部の境界部が反対側の面における電極合剤部２の塗布終端部２ｂに対向することから、圧延時の合剤塗布部と未塗布部の境界部の芯材にかかる曲げ力を抑制できることが判明している。
【００３６】
かくして、以上の正極側電極板１２を用いたリチウムイオン二次電池では、正極側電極板１２に芯剤の切れなどが生じないので、高い電池性能を得ることができる。なお、負極側電極板１３にも本発明を適用することができる。
【００３７】
【発明の効果】
本発明の電池用電極板及びその製造方法によれば、以上のように集電用芯材の一面に、活物質を間欠的に塗着し、乾燥固化させて電極合剤部を形成し、集電用芯材の他面に、塗布開始位置を一面における電極合剤部の塗布終端部から塗布開始部寄りに１〜５ｍｍ離れた位置に、塗布終端位置を一面における電極合剤部の塗布始端部から未塗布側に１〜５ｍｍ離れた位置に設定した状態で活物質を間欠的に塗着し、乾燥固化させて電極合剤部を形成したので、一面と他面の何れか一方の面の合剤塗布部の始端と未塗布部の境界の反対側の面には合剤塗布部の終端部が存在し、この合剤塗布終端部で集電用芯材がバックアップされ、圧延時に合剤塗布部の始端部にその突出部により大きな負荷が作用しても、始端と未塗布部の境界で集電用芯材にかかる曲げ力を抑制することができ、加圧圧延時やセパレータを介して渦巻き状に巻回する時に集電用芯材が切断するのを防止でき、電池用電極を歩留り良く生産することができる。
【００３８】
また、本発明の電池によれば、電極合剤がリチウムを可逆的に吸蔵・放出可能な材料を含む活物質から成る上記の正極側電極板と、負極側電極板とがそれらの間にセパレータを介在した状態で渦巻き状に巻回された電極群と、この電極群を収容した電池ケースと、電池ケース内に注液された電解液と、電池ケースの開口部を封口する封口板とを備えているので、正極側電極板の芯材に切れや亀裂が生じることがなく、その電極板の電気抵抗が常に安定した状態を保持することから、電池内部抵抗の増大による不具合が発生せず、高い電池性能を得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態の電池用電極板の製造過程における電池用電極板の縦断面図である。
【図２】同実施形態にかかる電池の構成を示す縦断面図である。
【図３】従来例の電池用電極板の製造過程における電池用電極板の縦断面図である。
【符号の説明】
１集電用芯材
１ａ一面
１ｂ他面
２電極合剤部
２ａ塗布始端部
２ｂ塗布終端部
１１電極群
１２正極側電極板
１３負極側電極板
１４セパレータ
１９電池ケース
２０封口板[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a battery electrode plate used as a power generation element of a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, a manufacturing method thereof, and a battery configured using the electrode plate.
[0002]
[Prior art]
In recent years, portable electronic devices and cordless devices have been rapidly promoted. Conventionally, nickel cadmium batteries, nickel metal hydride batteries, or sealed lead-acid batteries have been mainly used as power sources for driving these electronic devices. However, as electronic devices become more portable and cordless, they become established. The demand for higher energy density and smaller and lighter secondary batteries that serve as driving power sources is increasing.
[0003]
Also, in recent years, portable devices and cordless devices such as AV devices, notebook personal computers, and portable communication devices have been rapidly promoted. As a power source for driving these devices, batteries capable of efficient charging / discharging have emerged. Is desired.
[0004]
Under these circumstances, in recent years, lithium cobalt composite oxides exhibiting efficient charge / discharge characteristics, for example, LiCoO ₂ is used as a positive electrode active material, and lithium ion secondary batteries using lithium ion insertion and detachment utilizing lithium ion secondary batteries are used. Electrolytic solution (organic solvent-based electrolytic solution) secondary batteries are becoming mainstream.
[0005]
Lithium ion secondary batteries have extremely remarkable characteristics that they can be rapidly charged while being small and light and have a high energy density. In such a non-aqueous electrolyte secondary battery, in order to enable efficient charge / discharge, the positive electrode plate and the negative electrode plate are wound in a spiral shape with a separator interposed therebetween. By configuring the electrode group, a device has been devised to make the area of the electrode plate contributing to the chemical reaction as large as possible in the battery case.
[0006]
By the way, in manufacturing the battery electrode plate, as shown in FIG. 3, while the strip-shaped current collecting core 1 made of aluminum foil or copper foil is transferred in the direction of the arrow A, After the pasty active material is intermittently applied to the one surface 1a, the active material is dried and solidified to form the electrode mixture portion 2, and after the formation of the electrode mixture portion 2 for the one surface 1a is completed, An electrode is obtained by intermittently applying a pasty active material to the other surface 1b of the current collecting core 1 while transporting the current collecting core 1 in the direction of arrow B, and drying and solidifying the active material. Manufactured in the process of forming the mixture part 2 and subsequently pressing and rolling the electrode mixture parts 2 and 2 formed on both surfaces of the current collecting core 1 to a predetermined thickness and then cutting to a predetermined dimension. Has been.
[0007]
Further, when applying the paste-like active material to the current collecting core 1, the current collecting core 1 fed out from the winder is wound around a part of the outer periphery of the drum-shaped backup roll. While being transferred, the paste-like active material is ejected from the die nozzle facing the backup roll with a predetermined gap toward the current collecting core material 1, thereby performing intermittent application continuously. .
[0008]
And when forming the non-application part of a paste-form active material with respect to the core material 1 for current collection, while the discharge of a paste-form active material is stopped by the action | operation of a switching valve, it is installed in the upper side of die | dye When the application is started or restarted by retreating the piston, a predetermined pressure is instantaneously applied to the piston simultaneously with the operation of the switching valve, and the pasty active material is discharged from the nozzle.
[0009]
Further, the current collecting core material 1 on which the formation of the electrode mixture portion 2 on the one surface 1a has been completed is once taken up by a winder, and this winder is moved to the feeding side and installed, and collected from this winder. The paste-like active material is applied to the other surface 1b while the electric core material 1 is fed out. Therefore, at the time of intermittent application of the paste-like active material to the other surface 1b, while applying the current collecting core 1 in the opposite direction to the application to the one surface 1a, the application is performed in accordance with the application terminal portion 2b of the one surface 1a. While starting, application | coating is stopped according to the application | coating start part 2a of the electrode mixture part 2 of the one surface 1a.
[0010]
[Problems to be solved by the invention]
However, in the above conventional electrode plate manufacturing method, since the pressure inside the die is high at the start of coating on one surface and the other surface, a relatively large raised portion 2c is formed on the coating start end portion 2a on the one surface 1a and the other surface 1b. 2d is made. In particular, the coating start end portion 2a of the other surface 1b is thinner than the other portion of the coating end portion 2b of the one surface 1a, so that the distance between the coating start end portion 2a and the slit nozzle of the die is Since the coating end portion 2b of the one surface 1a is widened as the thickness is reduced, a larger bulge portion 2d is formed.
[0011]
The raised portions 2c and 2d are used for the current collecting core during pressure rolling after the electrode mixture portion 2 is formed or when the positive and negative electrode plates are spirally wound with a separator between them. A bending force and a tensile force are generated at the boundary between the coating start end portion 2a and the coating end portion 2b of the material 1 and the uncoated portion, so that the current collecting core material 1 is stressed, work-hardened, and the current collecting core material. 1 sometimes breaks, which causes a problem that the yield of the battery electrode plate is reduced.
[0012]
In view of the above-described conventional problems, the present invention provides a battery electrode plate capable of preventing cutting of a current collecting core material at the boundary between an application start end of an electrode mixture portion and an unapplied portion, and a method for manufacturing the same. It aims at providing the battery using this.
[0014]
[Means for Solving the Problems]
Moreover, the battery electrode plate of the present invention is for a battery having an electrode mixture portion formed by intermittently applying an active material on both surfaces of a current collecting core with the application directions opposite to each other and drying and solidifying the active material. In the electrode plate, the application start end portion of the electrode mixture portion has a bulging portion, and the application start position on the other surface of the current collecting core is closer to the application start portion from the application end portion of the electrode mixture portion on one surface. By setting the application end position at a position 1-5 mm away from the application start end of the electrode mixture part on one side to the non-application side at a position 1-5 mm away, one of the other side and the other side The boundary between the coating start end portion and the uncoated portion of the electrode mixture portion faces the coating end portion of the electrode mixture portion on the opposite surface.
[0015]
According to this battery electrode plate, there is an application termination portion of the mixture application portion on the surface opposite to the boundary between the application start end of the mixture application portion and the unapplied portion on one surface or the other surface. However, since the current collecting core is backed up at the coating end portion, even if a large load acts on the starting end portion of the mixture application portion during rolling, the current is collected at the boundary between the starting end and the uncoated portion. Bending force applied to the electrical core can be suppressed, and the current collector core can be prevented from being cut during pressure rolling or when it is wound in a spiral shape via a separator. Can be produced.
[0016]
The battery of the present invention, has an upper Symbol arrangement, the positive electrode side electrode plate that electrode mixture is made of lithium active material containing reversibly occluding and releasing material capable, and the negative side electrode plate An electrode group wound in a spiral shape with a separator interposed therebetween, a battery case containing the electrode group, an electrolyte solution injected into the battery case, and an opening of the battery case are sealed The inner plate of the positive electrode plate is not cut or cracked, and the electric resistance of the electrode plate is always kept stable, increasing the internal resistance of the battery. Therefore, high battery performance can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a battery electrode plate of the present invention, a method for producing the same, and a battery using the same will be described with reference to FIGS. 1 and 2.
[0018]
In FIG. 1, the same or similar components as those in the conventional example described in FIG.
[0019]
FIG. 1 shows a state in which an electrode mixture portion 2 is intermittently formed on both surfaces of a strip-shaped current collecting core material 1 and is rolled and cut into individual battery electrode plates at a cutting position. Indicates the previous state.
[0020]
An electrode mixture portion 2 is formed on one surface 1a of the current collecting core 1 in an intermittent arrangement similar to the conventional example of FIG. The agent part 2 is set at a position where the application start end 2a is separated from the application end part 2b of the one surface 1a toward the application start end part 2a by d = 1 mm to 5 mm, and the application end part 2b is the application start end part of the one surface 1a. Similarly, it is set to a position away from d by about 1 mm to 5 mm on the uncoated side from 2a.
[0021]
Next, a cylindrical lithium ion secondary battery in which this battery electrode plate is applied to a positive electrode plate will be described with reference to FIG.
[0022]
In FIG. 2, reference numeral 12 denotes a positive electrode plate, for example, a paste-like active material is intermittently applied on both surfaces of a current collecting core 1 made of aluminum foil and dried to a predetermined thickness as shown in FIG. Thus, the electrode mixture portion 2 is provided, and the electrode mixture portion 2 is cut into a sheet having a predetermined length. A positive electrode lead 17 made of, for example, aluminum is attached to a lead attachment portion where the electrode mixture portion 2 at one end of the positive electrode plate 12 is not formed by welding. Reference numeral 13 denotes a negative electrode plate. For example, an electrode mixture portion is provided by intermittently applying and drying a paste-like active material on both sides of a current collecting core made of a strip-shaped copper foil and rolling it to a predetermined thickness. This is manufactured by cutting the sheet into a sheet having a predetermined length. A negative electrode lead 18 is attached by welding to a lead attachment portion where the electrode mixture portion at the end of the negative electrode plate 13 is not formed.
[0023]
The electrode group 11 is configured by winding the positive electrode plate 12 and the negative electrode plate 13 in a spiral state in a state where, for example, a polyethylene separator 14 is interposed between the positive electrode plate 12 and the negative electrode plate 13. It is housed in a battery case 19 formed by processing a stainless steel plate resistant to organic electrolyte, the other end of the positive electrode lead 17 is connected to the sealing plate 20 by spot welding, and one end of the negative electrode lead 18 is It is connected to the bottom of the battery case 19 by spot welding. Insulating plates 21 and 22 are disposed above and below the electrode group 11, respectively.
[0024]
Further, in the battery case 19, a non-aqueous electrolyte solution dissolved in an equal volume mixed solvent such as ethylene carbonate and diethyl carbonate at a ratio of 1 mol / l lithium hexafluorophosphate is injected, and then the safety valve 23 After the sealing plate 20 provided with a gap is caulked into the opening of the battery case 19 via the insulating packing 24, the opening is sealed by caulking the peripheral edge of the opening of the battery case 19 inward. Has been.
[0025]
Next, details of the embodiment of the positive electrode plate 12 will be described.
[0026]
The positive electrode active material is composed of 3 parts by weight of acetylene black as a conductive agent, 100 parts by weight of lithium cobaltate, 4 parts by weight of a solid mixture of PTFE and FEP as a binder, and 0% of carboxymethylcellulose. .8 parts by weight was added, and water was used as a solvent to make a paste. The kneaded paste-like active material is coated on the surface 1a of the current collecting core 1 made of a strip-shaped rolled aluminum foil having a thickness of 15 μm with a coated part length of 446.5 mm and a non-coated part length of 6.5 mm (accordingly, The electrode mixture part 2 was formed by performing intermittent application continuously in an arrangement with an electrode plate pitch of 446.5 mm + 6.5 mm = 453 mm, followed by drying and solidification.
[0027]
Next, the pasty active material was also intermittently applied to the other surface 1b of the current collecting core 1 in the same manner. The intermittent application start position when intermittent application is performed on the other surface 1b is set at a position 2 mm away from the application end portion 2b of the one surface 1a toward the application start end portion 2a, and the coating portion length is 446.5 mm and non-applicable. The electrode mixture part 2 was formed by carrying out intermittent application continuously in an arrangement with a coating part length of 6.5 mm, and then drying and solidifying it, and this was used as the first electrode plate for a battery.
[0028]
Separately from this, when intermittent coating is performed on the other surface 1b, the intermittent coating start position is set to a position 1 mm away from the coating end portion 2b of the one surface 1a toward the coating start end portion 2a, and the coating length is 446. The electrode mixture portion 2 is formed by continuously applying intermittently in an arrangement of 0.5 mm and the length of the non-coated portion being 6.5 mm, and then drying and solidifying it. This is the second battery. An electrode plate was obtained.
[0029]
In addition to the above-described embodiment, in order to compare with that, the intermittent application start position for intermittent application to the other surface 1b of the current collecting core 1 is determined from the application end portion 2b of the one surface 1a to the application start end. Set at a position 2 mm away from the portion 2a, with a coating length of 444.5mm and a non-coated portion length of 8.5mm, according to the application start position 2a of the electrode mixture portion 2 on the entire surface 1a The electrode mixture part 2 was formed by continuously applying intermittently so as to stop the application, and then drying and solidifying it, and this was used as a third battery electrode plate.
[0030]
Furthermore, as another comparative example, the intermittent application start position when intermittently applying to the other surface 1b of the current collecting core 1 is the same as that of the conventional electrode plate shown in FIG. Set to a position that coincides with the part 2b, with a coating length of 446.5 mm and a non-coated part length of 6.5 mm, according to the application start position 2a of the electrode mixture part 2 on the one surface 1a The electrode mixture part 2 was formed by performing intermittent application continuously so as to stop the application, then drying and solidifying, and this was used as a fourth battery electrode plate.
[0031]
The above four types of electrode plates were unified as follows. That is, the electrode plate pitch of the other surface 1b of the current collecting core material 1 is set to 453 mm, which is the electrode plate pitch of the entire surface 1a, and the coating weight of the pasty active material after drying is set to that of the current collecting core material 1. The amount was 2.41 g / 100 ² (excluding the weight of the current collecting core 1) per side 1a or other side 1b. In addition, the length of the paste-like active material applied in the longitudinal direction on each electrode plate was 446.5 mm, and the thickness of the dried electrode plate including the current collecting core 1 was 0.240 mm. After the pasty active material was dried in this way, it was compression-molded to a predetermined thickness using a roll press machine, so that the total thickness was 0.147 mm. The rolling was performed by a constant pressure rolling method, and the pressing force was 4 times with a linear pressure of 1700 kg / cm.
[0032]
When the core material cutting rate at the time of rolling at the boundary between the other surface 1b of the current collecting core material 1 and the coating start end portion 2a of the electrode mixture part 2 in the four types of electrode plates manufactured as described above was measured, The third electrode plate was 7% and the fourth electrode plate was 32%, whereas the first and second electrode plates were not cut at all in the current collecting core 1.
[0033]
From the above test results, the intermittent application start position of the paste-like active material on the other surface 1b of the current collecting core 1 is 1 mm from the application terminal portion 2b in the electrode mixture portion 2 of the one surface 1a toward the application start end portion 2a. Alternatively, by setting the coating end portion 2b away from the coating start end portion 2a of the electrode mixture portion 2 on the surface 1a by 1 mm or 2 mm away from the coating start end portion 2a, the position of the electrode mixture portion 2 is set. Since the boundary portion between the coating start end portion 2a and the uncoated portion faces the coating end portion 2b of the electrode mixture portion 2 on the opposite surface, the core material of the boundary portion between the mixture coated portion and the uncoated portion during rolling It has been found that the bending force applied to can be suppressed.
[0034]
On the other hand, the intermittent application start position of the paste-like active material on the other surface 1b of the current collecting core 1 is set to a position that coincides with the application terminal portion 2b in the electrode mixture portion 2 on the one surface 1a, and is intermittently applied. When the end position 2b is set to a position that coincides with the application start end 2a of the electrode mixture portion 2 on the one surface 1a, the amount of swell of the application start end 2a on the other surface 1b increases, and the mixture application portion during rolling is increased. As a result, the bending force applied to the core material at the boundary between the uncoated portions increases, and the core material is frequently cut during rolling.
[0035]
In the description of the above embodiment, the application start position of the paste-like active material on the other surface 1b of the current collecting core 1 is closer to the application start end portion 2a from the application end portion 2b in the electrode mixture portion 2 on the first surface 1a. Examples are shown in which 1 mm or 2 mm apart is set, and the coating end part 2 b is set to a position 1 mm or 2 mm away from the coating start end 2 a of the electrode mixture part 2 on the one surface 1 a on the non-coating side. Since the boundary between the application start end 2a of the electrode mixture part 2 and the unapplied part is opposed to the application end part 2b of the electrode mixture part 2 on the opposite surface, by setting the range of 1 mm to 5 mm, It has been found that the bending force applied to the core material at the boundary between the mixture-applied portion and the uncoated portion during rolling can be suppressed.
[0036]
Thus, in the lithium ion secondary battery using the positive electrode side electrode plate 12 described above, since the core agent is not cut off in the positive electrode side electrode plate 12, high battery performance can be obtained. The present invention can also be applied to the negative electrode plate 13.
[0037]
【Effect of the invention】
According to the battery electrode plate of the present invention and the manufacturing method thereof, the active material is intermittently applied to one surface of the current collecting core as described above, and dried and solidified to form an electrode mixture part. On the other side of the current collecting core, the application start position is 1-5 mm away from the application termination part of the electrode mixture part on one side and closer to the application start part, and the electrode termination part is applied on the other side. Since the active material was intermittently applied in a state set at a position 1 to 5 mm away from the start end to the non-application side, and dried and solidified to form the electrode mixture part, either one side or the other side The end of the mixture application part exists on the surface opposite to the boundary between the starting end of the mixture application part and the unapplied part of the surface, and the current collecting core is backed up at this mixture application end part, Even if a large load acts on the starting end of the mixture application part due to the protruding part, it will be applied to the current collector core at the boundary between the starting end and the uncoated part The bending force can be suppressed, the core material for current collection can be prevented from being cut during pressure rolling or when spirally wound via a separator, and battery electrodes can be produced with high yield. .
[0038]
Further, according to the battery of the present invention, the positive electrode plate and the negative electrode plate made of an active material containing a material in which the electrode mixture is capable of reversibly occluding and releasing lithium, and the negative electrode plate are interposed between them. An electrode group wound in a spiral shape with the electrode interposed therebetween, a battery case containing the electrode group, an electrolyte injected into the battery case, and a sealing plate for sealing the opening of the battery case Because it is equipped, the core material of the positive electrode plate will not be cut or cracked, and the electric resistance of the electrode plate will always remain stable, so there will be no problems due to increased battery internal resistance. High battery performance can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a battery electrode plate in the process of manufacturing a battery electrode plate according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing the configuration of the battery according to the embodiment.
FIG. 3 is a longitudinal sectional view of a battery electrode plate in the process of manufacturing a conventional battery electrode plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Core material for current collection 1a One surface 1b Other surface 2 Electrode mixture part 2a Application | coating start end part 2b Application | coating end part 11 Electrode group 12 Positive electrode plate 13 Negative electrode plate 14 Separator 19 Battery case 20 Sealing plate

Claims

塗布方向を相互に反対向きにして集電用芯材の両面に活物質を間欠的に塗布して乾燥固化して成る電極合剤部を有する電池用電極板において、
前記電極合剤部の塗布始端部は盛り上がり部を有し、集電用芯材の他面に、塗布開始位置を一面における電極合剤部の塗布終端部から塗布開始部寄りに１〜５ｍｍ離れた位置に、塗布終端位置を一面における電極合剤部の塗布始端部から未塗布側に１〜５ｍｍ離れた位置に設定したことにより、
一面と他面の何れか一方の面の前記電極合剤部の有する塗布始端部と未塗布部の境界部が反対側の面における電極合剤部の塗布終端部に対向していることを特徴とする電池用電極板。In the battery electrode plate having an electrode mixture portion formed by applying the active material intermittently on both sides of the current collecting core with the application directions opposite to each other and drying and solidifying the active material,
The application start end portion of the electrode mixture portion has a raised portion, and the application start position is separated from the application end portion of the electrode mixture portion on one surface by 1-5 mm closer to the application start portion on the other surface of the current collecting core. By setting the application end position at a position 1 to 5 mm away from the application start end of the electrode mixture part on one side to the non-application side,
The boundary between the coating start end portion and the uncoated portion of the electrode mixture portion on one of the one surface and the other surface is opposed to the coating end portion of the electrode mixture portion on the opposite surface. A battery electrode plate.

請求項１記載の配置構成を有し、その電極合剤がリチウムを可逆的に吸蔵・放出可能な材料を含む活物質から成る正極側電極板と、負極側電極板とがそれらの間にセパレータを介在した状態で渦巻き状に巻回された電極群と、この電極群を収容した電池ケースと、電池ケース内に注液された電解液と、電池ケースの開口部を封口する封口板とを備えたことを特徴とする電池。 A positive electrode plate having an arrangement according to claim 1, wherein the electrode mixture is made of an active material containing a material capable of reversibly occluding and releasing lithium, and a negative electrode plate between them. An electrode group wound in a spiral shape with the electrode interposed therebetween, a battery case containing the electrode group, an electrolyte injected into the battery case, and a sealing plate for sealing the opening of the battery case A battery characterized by comprising.