JP4266546B2

JP4266546B2 - Cylindrical battery

Info

Publication number: JP4266546B2
Application number: JP2001275795A
Authority: JP
Inventors: 一成大北; 秀雄萩野; 淳浩船橋; 俊之能間; 育郎米津
Original assignee: Sanyo Electric Co Ltd
Current assignee: Sanyo Electric Co Ltd
Priority date: 2001-09-11
Filing date: 2001-09-11
Publication date: 2009-05-20
Anticipated expiration: 2021-09-11
Also published as: JP2003086165A

Description

【０００１】
【発明の属する技術分野】
本発明は、電池缶内に発電要素となる電極体が収容されて、該電極体が発生する電力を外部へ取り出すことが可能な筒型電池に関するものである。
【０００２】
【従来の技術】
近年、電気自動車等の電源として、大きなエネルギー密度を有する筒型電池が使用されている。
該筒型電池は、例えば図４に示す如く、筒体(11)の両端部に蓋体(12)(12)を溶接固定してなる円筒状の電池缶(１)の内部に巻き取り電極体(９)を収容して構成されている。両蓋体(12)(12)には、正負一対の電極端子機構(80)(81)が取り付けられており、巻き取り電極体(９)と各電極端子機構(80)(81)とが、複数本の集電タブ(３)を介して互いに接続され、巻き取り電極体(９)が発生する電力を一対の電極端子機構(80)(81)から外部に取り出すことが可能となっている。電池缶(１)内の巻き取り電極体(９)は、電解質を溶媒に溶解してなる電解液に浸漬されている。又、各蓋体(12)には圧力開閉式のガス排出弁(83)が取り付けられている。
【０００３】
巻き取り電極体(９)は、図５に示す様に、それぞれ帯状の正極(91)と負極(93)の間に帯状のセパレータ(92)を介在させて、これらを渦巻状に巻回して構成されている。正極(91)は、アルミニウム箔からなる帯状芯体の両面にリチウム複合酸化物からなる正極活物質(94)を塗布して構成され、負極(93)は、銅箔からなる帯状芯体の両面に炭素材料を含む負極活物質(95)を塗布して構成されている。
又、正極(91)には、正極活物質(94)の塗布されていない非塗工部(96)が形成され、該非塗工部(96)に、複数本の集電タブ(３)の基端部が溶接されている。同様に負極(93)には、負極活物質(95)の塗布されていない非塗工部(97)が形成され、該非塗工部(97)に、複数本の集電タブ(３)の基端部が溶接されている。
【０００４】
【発明が解決しようとする課題】
ところで、電気自動車用の電池においては、車載時の振動による電池特性の低下を抑えることが必要である。
しかし、図４に示す様な従来の筒型電池においては、外部からの振動を受けて集電タブ(３)が振動するために、集電タブ(３)の基端部に、集電タブ(３)を巻き取り電極体(９)から引き抜く方向の力が作用することになる。又、集電タブ(３)の振動が大きい場合には、その振動によって、集電タブ(３)どうしが干渉して、互いに力を及ぼし合う場合があり、これによって、集電タブ(３)の基端部に引き抜き力が作用することになる。
集電タブ(３)の基端部は、前記引き抜き力によって巻き取り電極体(９)の電極から剥離する虞があり、集電タブ(３)の基端部が巻き取り電極体(９)の電極から剥離すると、該電極と電極端子機構の間の電流経路の断面積が小さくなって、電池の内部抵抗が増大し、電池特性が低下する問題があった。
【０００５】
本発明の目的は、振動を受けても特性が低下することのない筒型電池を提供することである。
【０００６】
【課題を解決する為の手段】
本発明に係る筒型電池においては、電池缶の内部に収容された巻き取り電極体の正極及び負極から夫々複数本の集電タブが引き出されており、該巻き取り電極体が発生する電力を、前記複数本の集電タブを介して一対の電極端子部から外部へ取り出すことが出来る。
前記巻き取り電極体の巻き取り中心には軸部材が配備され、該軸部材の少なくとも一方の端部は巻き取り電極体から突出しており、該端部には絶縁材料からなるタブ保持板が相対回転不能に取り付けられ、該タブ保持板は前記巻き取り電極体から離れた位置に支持されている。該タブ保持板には、それぞれ１本の集電タブが貫通可能な複数の貫通孔が開設されており、各集電タブは、前記巻き取り電極体に接続された基端部から前記タブ保持板に向かって伸び、更に前記タブ保持板の異なる貫通孔を貫通して伸び、その先端部が一方の電極端子部に連結され、各集電タブは、前記基端部と先端部の中間位置で前記タブ保持板の貫通孔の内壁によって拘束されている。
【０００７】
上記本発明の筒型電池においては、各集電タブが、タブ保持板に開設されている貫通孔の内壁によって拘束されているので、電池が振動を受けた場合に、集電タブが大きく振動することはない。従って、集電タブの基端部には、大きな引き抜き力は作用せず、集電タブの基端部が、巻き取り電極体の電極から剥離することはない。
【０００８】
本発明の具体的構成において、前記タブ保持板に開設されている貫通孔の数は、極性が同じ集電タブの本数よりも多い。
該具体的構成によれば、タブ保持板に開設された貫通孔に集電タブの先端部を挿入する工程にて、複数の貫通孔の内、集電タブの先端部の挿入が容易な貫通孔を任意に選択することが出来る。これにより、集電タブを貫通孔に通過せしめる作業が容易となる。
【０００９】
他の具体的構成において、前記タブ保持板には、少なくとも１つの液孔が開設されている。
該具体的構成によれば、電池缶内に電解液を注入する工程にて、電解液は前記液孔を通過して、巻き取り電極体の収容空間に流入する。従って、タブ保持板が筒体の内径と同じ外径であっても、電解液が該タブ保持板によってせき止められることはない。この結果、電池缶内の巻き取り電極体には、充分に電解液が浸透することになる。
【００１０】
更に他の具体的構成において、前記軸部材は、フッ素樹脂、ポリエチレン、ポリプロピレン、及びセラミックの中から選択される１つの材質を用いて形成され、前記タブ保持板は、フッ素樹脂、ポリエチレン、ポリプロピレン、及びセラミックの中から選択される１つの材質を用いて形成されている。
該具体的構成によれば、フッ素樹脂、ポリエチレン、ポリプロピレン、及びセラミックは絶縁材料であるので、軸部材及びタブ保持板が正負極間を短絡させることはない。
【００１１】
更に他の具体的構成において、前記一方の電極端子部は、蓋体を貫通して取り付けられている端子部材と、該端子部材の基端部に螺合している挟圧部材とを具え、該挟圧部材は、前記軸部材の端部に相対回転不能に係合し、該挟圧部材と前記端子部材とによって複数本の集電タブの先端部が挟持されている。
該具体的構成においては、該挟圧部材が前記軸部材の端部に相対回転不能に係合しているので、該挟圧部材と前記端子部材とによって複数本の集電タブの先端部を挟持する工程において、前記端子部材の基端部を該挟圧部材にねじ込む過程で、該挟圧部材が前記端子部材と伴回りすることはない。従って、前記端子部材の基端部を該挟圧部材にねじ込むときに、該挟圧部材を直接に保持する必要がない。
【００１２】
【発明の効果】
本発明の筒型電池によれば、外部から振動を受けても、集電タブの基端部が巻き取り電極体の電極から剥離する虞がないので、電極と電極端子機構の間の電流経路の断面積が小さくなって電池の内部抵抗が増大することはなく、これによって電池特性の低下が防止される。
【００１３】
【発明の実施の形態】
以下、本発明をリチウム二次電池に実施した形態につき、図面に沿って具体的に説明する。
本実施例のリチウム二次電池は、図１に示す如く、筒体(11)の両端部に蓋体(12)(12)を溶接固定してなる円筒状の電池缶(１)の内部に、巻き取り電極体(２)を収容して構成されている。
【００１４】
一方の蓋体(12)には正極端子機構(５)が取り付けられており、巻き取り電極体(２)の正極から伸びる複数本のリード(３)が正極端子機構(５)に接続されている。他方の蓋体(12)には負極端子機構(６)が取り付けられており、巻き取り電極体(２)の負極から伸びる複数本のリード(３)が負極端子機構(６)に接続されている。これによって、巻き取り電極体(２)が発生する電力を一対の電極端子機構(５)(６)から外部に取り出すことが可能となっている。
巻き取り電極体(２)の巻き取り中心にはフッ素樹脂製の中空の軸部材(４)が配備されており、巻き取り電極体(２)の両端からは該軸部材(４)の端部(41)(41)が突出している。又、該軸部材(４)の両端部(41)(41)には、タブ保持板(７)(７)が取り付けられている。各蓋体(12)には圧力開閉式のガス排出弁(15)(15)が取り付けられている。
【００１５】
巻き取り電極体(２)は、図２に示す様に、それぞれ帯状の正極(21)と負極(23)の間に帯状のセパレータ(22)を介在させ、これらを前記軸部材(４)の周囲に渦巻状に巻回して構成されている。正極(21)は、アルミニウム箔からなる帯状芯体の両面にリチウム複合酸化物からなる正極活物質(24)を塗布して構成され、負極(23)は、銅箔からなる帯状芯体の両面に炭素材料を含む負極活物質(25)を塗布して構成されている。又、正極(21)には、正極活物質(24)の塗布されていない非塗工部(26)が形成され、該非塗工部(26)に、各集電タブ(３)の基端部が溶接されている。同様に負極(23)には、負極活物質(25)の塗布されていない非塗工部(27)が形成され、該非塗工部(27)に、各集電タブ(３)の基端部が溶接されている。
前記軸部材(４)の各端部(41)は、その外周面及び内周面がそれぞれ六角柱面に形成されている。
【００１６】
図３に示すタブ保持板(７)は、ポリエチレン製の円板からなり、電池缶の筒体の内径よりも僅かに小さな外径に形成されている。タブ保持板(７)には、断面六角形の中央孔(73)と、各極の集電タブ(３)の本数よりも多い複数の貫通孔(71)と、複数の液孔(72)とが開設されている。各貫通孔(71)は、その断面形状がタブ保持板(７)の中心と同心の円弧状を呈し、１本の集電タブが貫通可能な大きさを有している。
図１に示す様に、正極の複数本の集電タブ(３)は、それぞれタブ保持板(７)の各貫通孔(71)を通過して、各集電タブ(３)の先端部が正極端子機構(５)に接続されている。負極の集電タブ(３)も正極の集電タブ(３)と同様にして、負極端子機構(６)に接続されている。
軸部材(４)の端部(41)(41)には、タブ保持板(７)(７)の断面六角形の中央孔が嵌合している。これによって、軸部材(４)の端部(41)(41)の六角柱面の外周面とタブ保持板(７)(７)の断面六角形の中央孔の内壁とが係合し、軸部材(４)とタブ保持板(７)(７)は互いに相対回転不能に連結されている。
【００１７】
正極端子機構(５)は、電池缶(１)の蓋体(12)を貫通して取り付けられたネジ部材からなる正極端子部材(50)と、該正極端子部材(50)に螺合している挟圧部材(56)とを具えている。
該正極端子部材(50)の基端部には鍔部(52)が形成されており、鍔部(52)の表面には、正極端子部材(50)の軸方向にねじ穴(51)が凹設されている。蓋体(12)の貫通孔には、樹脂製の絶縁部材(53)が装着され、蓋体(12)と正極端子部材(50)の間の電気的絶縁性とシール性が保たれている。又、蓋体(12)にはＯリング(44)が装着され、蓋体(12)と絶縁部材(53)の間のシール性を確実なものとしている。又、絶縁部材(53)にはＯリング(45)が装着され、絶縁部材(53)と正極端子部材(50)の鍔部(52)の間のシール性を確実なものとしている。正極端子部材(50)には、電池缶(１)の外側からワッシャ(54)が嵌められると共に、ナット(55)が螺合している。そして、該ナット(55)を締め付けて、正極端子部材(50)の鍔部(52)とワッシャ(54)によって絶縁部材(53)を狭圧することにより、シール性を高めている。
【００１８】
挟圧部材(56)は、平板部(57)と、該平板部(57)の表面に突設されたねじ軸(58)と、該平板部(57)の裏面に突設された差込軸(59)とから構成されている。該ねじ軸(58)は、正極端子部材(50)のねじ穴(51)にねじ込まれている。これによって、複数本の集電タブ(３)の先端部が、正極端子部材(50)の鍔部(52)の裏面と挟圧部材(56)の平板部(57)の表面との間に挟持されている。
該平板部(57)の裏面に突設された差込軸(59)は、前記軸部材(４)の端部(41)の中空部に差し込まれている。これによって、該平板部(57)の差込軸の六角柱面の外周面と前記軸部材(４)の端部(41)の六角柱面の内周面とが係合し、挟圧部材(56)と軸部材(４)は互いに相対回転不能に連結されている。但し、挟圧部材(57)は軸部材(４)の軸方向に移動可能である。これによって、電池を組み立てるときの各部材の位置調整が可能となっている。負極端子機構(６)も、正極端子機構(５)と同様に構成されている。
【００１９】
次に、上記リチウム二次電池の製造方法について説明する。
正極の作製
先ず、コバルト酸リチウム(ＬｉＣｏＯ_２)粉末と、炭素粉末からなる導電剤と、ポリフッ化ビニリデン(ＰＶｄＦ)からなる結着剤とを、重量比で９０：５：５の割合によって混合して、正極合剤を作製する。次に、この正極合剤にＮ−メチル−２−ピロリドンを加えてスラリー状とし、これをアルミニウム箔に塗布し、１５０℃で２時間の真空乾燥を施して、図２に示す如き正極(21)を作製する。又、非塗工部(26)には、複数本のアルミニウム製の集電タブ(３)を溶接する。
負極の作製
先ず、天然の黒鉛粉末と、ポリフッ化ビニリデン(ＰＶｄＦ)からなる結着剤とを、重量比で９０：１０の割合に混合して、負極合剤を作製する。次に、この負極合剤にＮ−メチル−２−ピロリドンを加えてスラリー状とし、これを銅箔に塗布し、１５０℃で２時間の真空乾燥を施して、図２に示す如き負極(23)を作製する。又、非塗工部(27)には、複数本のニッケル製の集電タブ(３)を溶接する。
【００２０】
巻き取り電極体の作製
前記正極の作製工程によって得られた正極(21)と、前記負極の作製工程によって得られた負極(23)との間に、ポリエチレン製の微多孔性薄膜からなるセパレータ(22)を挟んで、これらを互いに重ね合わせる。但し、正極(21)と負極(23)は、夫々から突出する極性の異なる集電タブ(３)が逆向きとなる姿勢に配置する。
重ね合わされた正極(21)とセパレータ(22)と負極(23)とを、軸部材(４)を巻き取り軸として渦巻き状に巻き取り、巻き取り電極体(２)を作製する。
電解液の調製
エチレンカーボネートとジエチルカーボネートとを体積比で１：１の割合に混合して混合溶媒を作製する。この混合溶媒に六フッ化リン酸リチウムを１モル／リットルの割合で溶解して電解液を調製する。
【００２１】
タブ保持板の作製
図３に示す如く、ポリエチレン製の円板に、断面六角形の中央孔(73)と、複数の貫通孔(71)と、複数の液穴(72)とを開設して、タブ保持板(７)を作製する。
電池の組立
先ず、図１に示す如く、巻き取り電極体(２)の正極から伸びている各集電タブ(３)の先端部を異なる貫通孔(71)に挿入し、貫通孔(71)から突出せしめる。ここで、複数の貫通孔(71)の数は、各極の複数本の集電タブ(３)の本数よりも多いので、集電タブ(３)の挿入が容易な貫通孔(71)を選択することが出来る。その後、タブ保持板(７)の中央孔を軸部材(４)の端部(41)に嵌合せしめる。
次に、挟圧部材(56)の差込軸(59)を軸部材(４)の端部(41)の中空部に差し込む。その後、各集電タブ(３)の先端部を挟圧部材(56)の平板部(57)の表面に配置し、正極端子部材(50)のねじ穴(51)を挟圧部材(56)のねじ軸(58)に螺合せしめる。これによって、挟圧部材(56)の平板部(57)と、正極端子部材(50)の鍔部(52)との間に複数の集電タブ(３)の先端部を挟持する。負極の各集電タブ(３)は、上述の正極の各集電タブ(３)と同様にして、挟圧部材(66)の平板部と負極端子部材(60)の鍔部との間に挟持する。
続いて、筒体(11)の内部に巻き取り電極体(２)を収容し、一方の蓋体(12)の貫通孔に絶縁部材(53)を取り付け、絶縁部材(53)の貫通孔に正極端子部材(50)を挿入し、正極端子部材(50)にワッシャ(54)を嵌めると共に、ナット(55)を螺合せしめる。この様にして正極端子機構(５)を組み立てる。又、負極端子機構(６)を正極端子機構(５)と同様にして組み立てる。その後、筒体(11)の各開口部に各蓋体(12)を溶接固定し、一方の蓋体(12)のガス排出弁取付孔にガス排出弁(15)を取り付け、他方の蓋体(12)のガス排出弁取付孔から電池缶(１)内に電解液を注入する。最後に、該ガス排出弁取付孔にガス排出弁(15)を取り付けて本実施例のリチウム二次電池を完成する。
【００２２】
上記実施例のリチウム二次電池においては、各集電タブ(３)が、タブ保持板(７)の貫通孔(71)の内壁によって拘束されているので、該二次電池が振動を受けたとき、各集電タブ(３)は僅かに振動するに過ぎない。これによって、集電タブ(３)の基端部に作用する引き抜き力は、従来の筒型電池の集電タブが振動したときの引き抜き力よりも、充分に小さくなる。
又、各集電タブ(３)の振動は僅かであるので、集電タブ(３)どうしが干渉して力を及ぼしあうことがない。従って、集電タブ(３)の基端部には、集電タブ(３)どうしの干渉による引き抜き力が生じない。
この結果、集電タブ(３)の基端部は、巻き取り電極体(２)の電極から剥離する虞がない。これによって、巻き取り電極体(４)と各極端子機構(５)(６)の間の電流経路の断面積は維持されるので、電池の内部抵抗が増大することはなく、電池性能の低下が防止される。
【００２３】
又、電池缶(１)内に注入された電解液は、タブ保持板(７)に開設されている複数の液孔(72)を通過する。従って、電解液は、タブ保持板(７)によってせき止められることなく、巻き取り電極体(２)に浸透する。
更に、各極の端子部材(50)(60)のねじ穴(51)(61)を各極の挟圧部材(56)(66)のねじ軸(58)(68)に螺合せしめて、各極の端子部材(50)(60)の鍔部(52)(62)と挟圧部材(56)(66)の平板部(57)(67)との間に各極の複数本の集電タブ(３)の先端部を挟持する工程において、挟圧部材(56)(66)が軸部材(４)の各端部(41)に相対回転不能に係合しているので、各極の端子部材(50)(60)のねじ穴(51)(61)を各極の挟圧部材(56)(66)のねじ軸(58)(68)にねじ込む過程で、挟圧部材(56)(66)が端子部材(50)(60)と伴回りすることはない。従って、各極の端子部材(50)(60)のねじ穴(51)(61)を各極の挟圧部材(56)(66)のねじ軸(58)(68)にねじ込むときに、挟圧部材(56)(66)を保持する必要はない。
更に、電極端子機構(５)(６)を構成する挟圧部材(56)(66)の差込軸(59)(69)を軸部材(４)の端部(41)(41)の中空部に差し込むことによって、該軸部材(４)は、軸方向と直交する向きの動きが拘束される。これによって、巻き取り電極体(２)の前記軸方向と直交する向きの動きも拘束される。この結果、巻き取り電極体(２)の前記軸方向と直交する向きの振動が抑制される。
【００２４】
以下、本発明に係るリチウム二次電池の効果を確認するために行なった実験の内容及びその結果について説明する。
［実験］
以下に述べる発明電池１、発明電池２、比較電池１、及び比較電池２を作製し、各電池について内部抵抗を測定した後、振動試験を行なって、振動試験後の内部抵抗を測定した。内部抵抗の測定周波数を、１ｋＨｚとした。
振動試験は、包装貨物−振動試験方法(ＪＩＳＺ０２３２)に準じて行なった。試験条件は、ピーク加速度を±０.７５Ｇ、加振時間を２０分間、振動数の範囲を５Ｈｚ〜５０Ｈｚ、振動方向を上下に設定した。
【００２５】
発明電池１は、上記実施例と同様にして作製した。発明電池２は、上記実施例と同様に作製したが、タブ保持板をセラミック製とし、軸部材をポリエチレン製とした。比較電池１は、タブ保持板を取り付けなかったこと以外は、上記実施例と同様に作製した。比較電池２は、図４に示す従来の筒型電池と同じ構成とした。
各電池の内部抵抗の測定結果を表１に示す。
【００２６】
【表１】

【００２７】
表１に示す結果から明らかな様に、発明電池１及び発明電池２は、振動試験前後の内部抵抗が同じであった。一方、比較電池１及び比較電池２は、振動試験前よりも振動試験後の内部抵抗が大きくなった。
この結果より、本発明に係る筒型電池においては、振動を受けても、集電タブの基端部が巻き取り電極体の電極から剥離することはなく、巻き取り電極体と各極端子機構の間の電流経路の断面積が維持されるので、電池の内部抵抗は増大しないことが確認された。
【００２８】
尚、本発明の各部構成は上記実施の形態に限らず、特許請求の範囲に記載の技術的範囲内で種々の変形が可能である。例えば、上記実施例においては、軸部材を巻き取り軸として巻き取り電極体を作製したが、従来の巻き取り軸を用いて巻き取り電極体を作製し、該巻き取り軸を巻き取り電極体から抜き取った後、巻き取り電極体の中心部に形成された空間に本発明に係る軸部材を挿入する工程を採用することも可能である。
【図面の簡単な説明】
【図１】本発明に係るリチウム二次電池の断面図である。
【図２】該二次電池に用いられる巻き取り電極体の一部展開斜視図である。
【図３】該二次電池に用いられるタブ保持板を示す平面図である。
【図４】従来のリチウム二次電池の断面図である。
【図５】該二次電池に用いられる巻き取り電極体の一部展開斜視図である。
【符号の説明】
(１) 電池缶
(２) 巻き取り電極体
(３) 集電タブ
(４) 軸部材
(５) 正極端子機構
(50) 正極端子部材
(56) 挟圧部材
(６) 負極端子機構
(７) タブ保持板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical battery in which an electrode body serving as a power generation element is accommodated in a battery can, and electric power generated by the electrode body can be taken out to the outside.
[0002]
[Prior art]
In recent years, cylindrical batteries having a large energy density have been used as power sources for electric vehicles and the like.
For example, as shown in FIG. 4, the cylindrical battery has a cylindrical battery can (1) in which both ends of a cylindrical body (11) are welded and fixed. It is configured to accommodate the body (9). A pair of positive and negative electrode terminal mechanisms (80), (81) is attached to the lids (12), (12), and the take-up electrode body (9) and the electrode terminal mechanisms (80), (81) include The power generated by the take-up electrode body (9) connected to each other via the plurality of current collecting tabs (3) can be taken out from the pair of electrode terminal mechanisms (80) (81). Yes. The winding electrode body (9) in the battery can (1) is immersed in an electrolytic solution obtained by dissolving an electrolyte in a solvent. Each lid (12) is provided with a pressure open / close gas discharge valve (83).
[0003]
As shown in FIG. 5, the take-up electrode body (9) is formed by interposing a strip-shaped separator (92) between a strip-shaped positive electrode (91) and a negative electrode (93), and winding them in a spiral shape. It is configured. The positive electrode (91) is configured by applying a positive electrode active material (94) made of a lithium composite oxide to both surfaces of a strip-shaped core made of aluminum foil, and the negative electrode (93) is formed on both surfaces of the strip-shaped core made of copper foil. A negative electrode active material (95) containing a carbon material is applied to the substrate.
The positive electrode (91) is formed with a non-coated portion (96) to which the positive electrode active material (94) is not applied, and a plurality of current collecting tabs (3) are formed on the non-coated portion (96). The proximal end is welded. Similarly, the non-coated portion (97) to which the negative electrode active material (95) is not applied is formed on the negative electrode (93), and a plurality of current collecting tabs (3) are formed on the non-coated portion (97). The proximal end is welded.
[0004]
[Problems to be solved by the invention]
By the way, in a battery for an electric vehicle, it is necessary to suppress a decrease in battery characteristics due to vibration in the vehicle.
However, in the conventional cylindrical battery as shown in FIG. 4, since the current collecting tab (3) vibrates due to external vibration, the current collecting tab (3) has a current collecting tab. A force in the direction of pulling out (3) from the take-up electrode body (9) acts. In addition, when the vibration of the current collecting tab (3) is large, the current collecting tabs (3) may interfere with each other due to the vibration, and force may be exerted on each other. A pulling-out force acts on the base end portion.
The proximal end of the current collecting tab (3) may be peeled off from the electrode of the take-up electrode body (9) by the pulling force, and the proximal end of the current collecting tab (3) is taken up by the take-up electrode body (9). When peeled from the electrode, there is a problem that the cross-sectional area of the current path between the electrode and the electrode terminal mechanism is reduced, the internal resistance of the battery is increased, and the battery characteristics are deteriorated.
[0005]
An object of the present invention is to provide a cylindrical battery whose characteristics do not deteriorate even when subjected to vibration.
[0006]
[Means for solving the problems]
In the cylindrical battery according to the present invention, a plurality of current collecting tabs are drawn out from the positive electrode and the negative electrode of the winding electrode body housed inside the battery can, and the electric power generated by the winding electrode body is generated. The plurality of current collecting tabs can be taken out from a pair of electrode terminal portions.
A shaft member is provided at the winding center of the winding electrode body, and at least one end portion of the shaft member protrudes from the winding electrode body, and a tab holding plate made of an insulating material is relatively opposed to the end portion. The tab holding plate is mounted so as not to rotate , and is supported at a position away from the winding electrode body. The tab holding plate is provided with a plurality of through holes through which one current collecting tab can pass, and each current collecting tab is held by the tab from the base end connected to the winding electrode body. extends towards the plate, extends through the further the tub holding plate of different holes, its distal end is connected to one electrode terminal portion, an intermediate position of each current collecting tabs, the proximal end and a distal end And is restrained by the inner wall of the through hole of the tab holding plate .
[0007]
In the cylindrical battery according to the present invention, each current collecting tab is constrained by the inner wall of the through hole formed in the tab holding plate, so that when the battery is vibrated, the current collecting tab greatly vibrates. Never do. Therefore, a large pulling force does not act on the proximal end portion of the current collecting tab, and the proximal end portion of the current collecting tab does not peel from the electrode of the winding electrode body.
[0008]
In the specific configuration of the present invention, the number of through holes provided in the tab holding plate is larger than the number of current collecting tabs having the same polarity.
According to the specific configuration, in the step of inserting the tip end portion of the current collecting tab into the through hole formed in the tab holding plate, the through end that is easy to insert the tip end portion of the current collecting tab among the plurality of through holes is provided. A hole can be arbitrarily selected. Thereby, the operation | work which allows a current collection tab to pass through a through-hole becomes easy.
[0009]
In another specific configuration, at least one liquid hole is formed in the tab holding plate.
According to this specific configuration, in the step of injecting the electrolytic solution into the battery can, the electrolytic solution passes through the liquid hole and flows into the accommodating space of the winding electrode body. Therefore, even if the tab holding plate has the same outer diameter as the inner diameter of the cylindrical body, the electrolytic solution is not blocked by the tab holding plate. As a result, the electrolytic solution sufficiently permeates the winding electrode body in the battery can.
[0010]
In still another specific configuration, the shaft member is formed using one material selected from fluororesin, polyethylene, polypropylene, and ceramic, and the tab holding plate is made of fluororesin, polyethylene, polypropylene, And one material selected from ceramics.
According to this specific configuration, since the fluororesin, polyethylene, polypropylene, and ceramic are insulating materials, the shaft member and the tab holding plate do not short-circuit between the positive and negative electrodes.
[0011]
In still another specific configuration, the one electrode terminal portion includes a terminal member attached through the lid, and a pinching member screwed into a base end portion of the terminal member, The pinching member is engaged with the end portion of the shaft member so as not to be relatively rotatable, and the tip portions of a plurality of current collecting tabs are pinched by the pinching member and the terminal member.
In the specific configuration, since the pinching member is engaged with the end portion of the shaft member so as not to be relatively rotatable, the tip portions of a plurality of current collecting tabs are formed by the pinching member and the terminal member. In the clamping step, the clamping member is not accompanied with the terminal member in the process of screwing the proximal end portion of the terminal member into the clamping member. Therefore, when the base end portion of the terminal member is screwed into the pinching member, it is not necessary to hold the pinching member directly.
[0012]
【The invention's effect】
According to the cylindrical battery of the present invention, there is no possibility that the base end portion of the current collecting tab peels off from the electrode of the take-up electrode body even when subjected to vibration from outside, so that the current path between the electrode and the electrode terminal mechanism The cross-sectional area of the battery does not decrease and the internal resistance of the battery does not increase, thereby preventing deterioration of battery characteristics.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention applied to a lithium secondary battery will be described in detail with reference to the drawings.
As shown in FIG. 1, the lithium secondary battery of the present embodiment has a cylindrical battery can (1) formed by welding and fixing lids (12) and (12) to both ends of the cylinder (11). The winding electrode body (2) is accommodated.
[0014]
A positive electrode terminal mechanism (5) is attached to one lid (12), and a plurality of leads (3) extending from the positive electrode of the winding electrode body (2) are connected to the positive electrode terminal mechanism (5). Yes. A negative electrode terminal mechanism (6) is attached to the other lid (12), and a plurality of leads (3) extending from the negative electrode of the winding electrode body (2) are connected to the negative electrode terminal mechanism (6). Yes. As a result, the electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (5) and (6).
A hollow shaft member (4) made of a fluororesin is disposed at the winding center of the winding electrode body (2), and ends of the shaft member (4) from both ends of the winding electrode body (2). (41) (41) protrudes. Tab holding plates (7) and (7) are attached to both end portions (41) and (41) of the shaft member (4). Each lid (12) is provided with a pressure open / close type gas discharge valve (15) (15).
[0015]
As shown in FIG. 2, the take-up electrode body (2) has a belt-like separator (22) interposed between the belt-like positive electrode (21) and the negative electrode (23), respectively, and these are attached to the shaft member (4). It is configured to be wound around in a spiral. The positive electrode (21) is configured by applying a positive electrode active material (24) made of a lithium composite oxide on both surfaces of a strip-shaped core made of aluminum foil, and the negative electrode (23) is formed on both surfaces of the strip-shaped core made of copper foil. A negative electrode active material (25) containing a carbon material is applied to the substrate. Further, the positive electrode (21) is formed with an uncoated portion (26) to which the positive electrode active material (24) is not applied, and the non-coated portion (26) has a base end of each current collecting tab (3). The parts are welded. Similarly, the negative electrode (23) is formed with a non-coated portion (27) to which the negative electrode active material (25) is not applied, and the base end of each current collecting tab (3) is formed on the non-coated portion (27). The parts are welded.
Each end portion (41) of the shaft member (4) has an outer peripheral surface and an inner peripheral surface formed as hexagonal column surfaces.
[0016]
The tab holding plate (7) shown in FIG. 3 is made of a polyethylene disc and has an outer diameter slightly smaller than the inner diameter of the cylindrical body of the battery can. The tab holding plate (7) includes a central hole (73) having a hexagonal cross section, a plurality of through holes (71) larger than the number of current collecting tabs (3) of each pole, and a plurality of liquid holes (72). And have been established. Each through-hole (71) has a cross-sectional shape that is concentric with the center of the tab holding plate (7) and has a size through which one current collecting tab can pass.
As shown in FIG. 1, the current collecting tabs (3) of the positive electrode respectively pass through the through holes (71) of the tab holding plate (7), and the tip portions of the current collecting tabs (3) Connected to the positive terminal mechanism (5). The negative current collecting tab (3) is connected to the negative electrode terminal mechanism (6) in the same manner as the positive current collecting tab (3).
A center hole having a hexagonal cross section of the tab holding plates (7) and (7) is fitted into the end portions (41) and (41) of the shaft member (4). As a result, the outer peripheral surfaces of the hexagonal column surfaces of the end portions (41) and (41) of the shaft member (4) engage with the inner walls of the central hole having a hexagonal cross section of the tab holding plates (7) and (7). The member (4) and the tab holding plate (7) (7) are connected to each other so as not to rotate relative to each other.
[0017]
The positive electrode terminal mechanism (5) is screwed into the positive electrode terminal member (50) and the positive electrode terminal member (50) which is a screw member attached through the lid (12) of the battery can (1). A clamping member (56).
A flange portion (52) is formed at the base end portion of the positive electrode terminal member (50), and a screw hole (51) is formed on the surface of the flange portion (52) in the axial direction of the positive electrode terminal member (50). It is recessed. A resin insulating member (53) is attached to the through-hole of the lid (12), and electrical insulation and sealing between the lid (12) and the positive terminal member (50) are maintained. . In addition, an O-ring (44) is attached to the lid (12) to ensure a sealing property between the lid (12) and the insulating member (53). In addition, an O-ring (45) is attached to the insulating member (53) to ensure a sealing property between the insulating member (53) and the flange portion (52) of the positive electrode terminal member (50). A washer (54) is fitted to the positive terminal member (50) from the outside of the battery can (1), and a nut (55) is screwed. The nut (55) is tightened, and the insulating member (53) is narrowed by the flange portion (52) and the washer (54) of the positive electrode terminal member (50), thereby improving the sealing performance.
[0018]
The clamping member (56) includes a flat plate portion (57), a screw shaft (58) protruding from the surface of the flat plate portion (57), and a plug protruding from the back surface of the flat plate portion (57). It consists of a shaft (59). The screw shaft (58) is screwed into the screw hole (51) of the positive electrode terminal member (50). As a result, the front ends of the current collecting tabs (3) are located between the back surface of the flange portion (52) of the positive electrode terminal member (50) and the surface of the flat plate portion (57) of the pinching member (56). It is pinched.
The insertion shaft (59) protruding from the back surface of the flat plate portion (57) is inserted into the hollow portion of the end portion (41) of the shaft member (4). Thereby, the outer peripheral surface of the hexagonal column surface of the insertion shaft of the flat plate portion (57) and the inner peripheral surface of the hexagonal column surface of the end portion (41) of the shaft member (4) are engaged, and the clamping member (56) and the shaft member (4) are connected to each other such that they cannot rotate relative to each other. However, the pinching member (57) is movable in the axial direction of the shaft member (4). Thereby, position adjustment of each member when assembling a battery is possible. The negative electrode terminal mechanism (6) is configured similarly to the positive electrode terminal mechanism (5).
[0019]
Next, a method for manufacturing the lithium secondary battery will be described.
Preparation of positive electrode <br/> First, lithium cobaltate (LiCoO ₂₎ powder, a conductive agent consisting of carbon powder, and a binder consisting of polyvinylidene fluoride (PVdF), a weight ratio of 90: 5: 5 A positive electrode mixture is prepared by mixing at a ratio. Next, N-methyl-2-pyrrolidone is added to the positive electrode mixture to form a slurry, which is applied to an aluminum foil and vacuum-dried at 150 ° C. for 2 hours to obtain a positive electrode as shown in FIG. ). A plurality of aluminum current collecting tabs (3) are welded to the non-coated portion (26).
Production of negative electrode First, a natural graphite powder and a binder made of polyvinylidene fluoride (PVdF) are mixed at a weight ratio of 90:10 to produce a negative electrode mixture. Next, N-methyl-2-pyrrolidone was added to the negative electrode mixture to form a slurry, which was applied to a copper foil and vacuum-dried at 150 ° C. for 2 hours to obtain a negative electrode as shown in FIG. ). A plurality of nickel current collecting tabs (3) are welded to the non-coated portion (27).
[0020]
Production of wound electrode body Between the positive electrode (21) obtained by the production process of the positive electrode and the negative electrode (23) obtained by the production process of the negative electrode, a microporous thin film made of polyethylene These are superposed on each other with a separator (22) made of However, the positive electrode (21) and the negative electrode (23) are arranged in such a posture that the current collecting tabs (3) projecting from each of them have different polarities.
The superimposed positive electrode (21), separator (22), and negative electrode (23) are wound up in a spiral shape with the shaft member (4) as a winding shaft to produce a wound electrode body (2).
Preparation of electrolyte solution A mixed solvent is prepared by mixing ethylene carbonate and diethyl carbonate in a volume ratio of 1: 1. An electrolytic solution is prepared by dissolving lithium hexafluorophosphate in this mixed solvent at a rate of 1 mol / liter.
[0021]
3. Production of tab holding plate As shown in FIG. 3, a polyethylene disc has a hexagonal cross section (73), a plurality of through holes (71), and a plurality of liquid holes (72). And a tab holding plate (7) is produced.
Assembling the battery First, as shown in FIG. 1, the tip of each current collecting tab (3) extending from the positive electrode of the take-up electrode body (2) is inserted into a different through hole (71) to penetrate the battery. Project from hole (71). Here, since the number of the plurality of through holes (71) is larger than the number of the plurality of current collecting tabs (3) of each pole, the through holes (71) in which the current collecting tabs (3) can be easily inserted are provided. You can choose. Thereafter, the center hole of the tab holding plate (7) is fitted into the end (41) of the shaft member (4).
Next, the insertion shaft (59) of the pinching member (56) is inserted into the hollow portion of the end portion (41) of the shaft member (4). Then, the front-end | tip part of each current collection tab (3) is arrange | positioned on the surface of the flat plate part (57) of a clamping member (56), and the screw hole (51) of a positive electrode terminal member (50) is arrange | positioned in a clamping member (56). Screwed onto the screw shaft (58). Thereby, the front-end | tip part of several current collection tab (3) is clamped between the flat plate part (57) of a clamping member (56), and the collar part (52) of a positive electrode terminal member (50). Each of the negative electrode current collecting tabs (3) is disposed between the flat plate portion of the pinching member (66) and the flange portion of the negative electrode terminal member (60) in the same manner as each of the current collecting tabs (3) of the positive electrode. Hold it.
Subsequently, the winding electrode body (2) is accommodated in the cylindrical body (11), an insulating member (53) is attached to the through hole of one lid body (12), and the through hole of the insulating member (53) is attached. The positive terminal member (50) is inserted, the washer (54) is fitted into the positive terminal member (50), and the nut (55) is screwed together. In this way, the positive electrode terminal mechanism (5) is assembled. Further, the negative electrode terminal mechanism (6) is assembled in the same manner as the positive electrode terminal mechanism (5). Thereafter, each lid (12) is welded and fixed to each opening of the cylinder (11), the gas exhaust valve (15) is attached to the gas exhaust valve mounting hole of one lid (12), and the other lid The electrolyte is injected into the battery can (1) from the gas discharge valve mounting hole of (12). Finally, the gas discharge valve (15) is attached to the gas discharge valve mounting hole to complete the lithium secondary battery of this example.
[0022]
In the lithium secondary battery of the above embodiment, each current collecting tab (3) is restrained by the inner wall of the through hole (71) of the tab holding plate (7), so that the secondary battery is subjected to vibration. Sometimes each current collecting tab (3) only vibrates slightly. Accordingly, the pulling force acting on the proximal end portion of the current collecting tab (3) is sufficiently smaller than the pulling force when the current collecting tab of the conventional cylindrical battery vibrates.
Further, since the vibrations of the current collecting tabs (3) are slight, the current collecting tabs (3) do not interfere with each other and exert force. Therefore, the pulling-out force due to the interference between the current collecting tabs (3) does not occur at the base end portion of the current collecting tab (3).
As a result, the base end portion of the current collecting tab (3) is not likely to be peeled off from the electrode of the winding electrode body (2). As a result, the cross-sectional area of the current path between the winding electrode body (4) and each of the electrode terminal mechanisms (5) and (6) is maintained, so that the internal resistance of the battery does not increase and the battery performance deteriorates. Is prevented.
[0023]
The electrolyte injected into the battery can (1) passes through the plurality of liquid holes (72) provided in the tab holding plate (7). Therefore, the electrolytic solution penetrates into the winding electrode body (2) without being blocked by the tab holding plate (7).
Further, the screw holes (51) (61) of the terminal members (50), (60) of the respective poles are screwed into the screw shafts (58), (68) of the pinching members (56), (66) of the respective poles. A plurality of current collectors for each pole are provided between the flange portions (52) (62) of the electrode terminal members (50) and (60) and the flat plate portions (57) and (67) of the pinching members (56) and (66). In the step of clamping the tip portion of the tab (3), the clamping members (56) and (66) are engaged with the respective end portions (41) of the shaft member (4) in a relatively non-rotatable manner. In the process of screwing the screw holes (51) and (61) of the terminal members (50) and (60) into the screw shafts (58) and (68) of the pinching members (56) and (66) of each pole, the pinching member (56) (66) is not accompanied by the terminal members (50) and (60). Therefore, when screwing the screw holes (51) (61) of the terminal members (50), (60) of each pole into the screw shafts (58), (68) of the pinching members (56), (66) of each pole, It is not necessary to hold the pressure members (56) and (66).
Further, the insertion shafts (59) and (69) of the clamping members (56) and (66) constituting the electrode terminal mechanism (5) and (6) are made hollow in the end portions (41) and (41) of the shaft member (4). The shaft member (4) is restrained from moving in a direction perpendicular to the axial direction by being inserted into the portion. Thereby, the movement of the winding electrode body (2) in the direction orthogonal to the axial direction is also restrained. As a result, the vibration of the winding electrode body (2) in the direction orthogonal to the axial direction is suppressed.
[0024]
Hereinafter, the content of the experiment conducted in order to confirm the effect of the lithium secondary battery which concerns on this invention, and its result are demonstrated.
[Experiment]
Inventive battery 1, inventive battery 2, comparative battery 1 and comparative battery 2 described below were prepared, and after measuring the internal resistance of each battery, a vibration test was performed to measure the internal resistance after the vibration test. The measurement frequency of the internal resistance was 1 kHz.
The vibration test was performed according to the packaged cargo-vibration test method (JIS Z 0232). The test conditions were set such that the peak acceleration was ± 0.75 G, the excitation time was 20 minutes, the frequency range was 5 Hz to 50 Hz, and the vibration direction was up and down.
[0025]
Inventive battery 1 was prepared in the same manner as in the above example. Invention battery 2 was produced in the same manner as in the above example, but the tab holding plate was made of ceramic and the shaft member was made of polyethylene. Comparative battery 1 was produced in the same manner as in the above example except that the tab holding plate was not attached. The comparative battery 2 has the same configuration as the conventional cylindrical battery shown in FIG.
Table 1 shows the measurement results of the internal resistance of each battery.
[0026]
[Table 1]

[0027]
As is apparent from the results shown in Table 1, the inventive battery 1 and the inventive battery 2 had the same internal resistance before and after the vibration test. On the other hand, Comparative Battery 1 and Comparative Battery 2 had higher internal resistance after the vibration test than before the vibration test.
As a result, in the cylindrical battery according to the present invention, the base end portion of the current collecting tab does not peel from the electrode of the winding electrode body even when receiving vibration, and the winding electrode body and each electrode terminal mechanism It was confirmed that the internal resistance of the battery did not increase because the cross-sectional area of the current path between the two was maintained.
[0028]
In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, in the above embodiment, a winding electrode body is manufactured using the shaft member as a winding shaft, but a winding electrode body is manufactured using a conventional winding shaft, and the winding shaft is removed from the winding electrode body. It is also possible to employ a step of inserting the shaft member according to the present invention into the space formed in the center portion of the winding electrode body after the extraction.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a lithium secondary battery according to the present invention.
FIG. 2 is a partially developed perspective view of a wound electrode body used in the secondary battery.
FIG. 3 is a plan view showing a tab holding plate used in the secondary battery.
FIG. 4 is a cross-sectional view of a conventional lithium secondary battery.
FIG. 5 is a partially developed perspective view of a winding electrode body used in the secondary battery.
[Explanation of symbols]
(1) Battery can
(2) Winding electrode body
(3) Current collection tab
(4) Shaft member
(5) Positive terminal mechanism
(50) Positive terminal member
(56) Clamping member
(6) Negative terminal mechanism
(7) Tab holding plate

Claims

A plurality of current collecting tabs are drawn from the positive electrode and the negative electrode of the winding electrode body housed inside the battery can, respectively, and the electric power generated by the winding electrode body is passed through the plurality of current collecting tabs. In the cylindrical battery that can be taken out from the pair of electrode terminal portions, a shaft member is provided at the winding center of the winding electrode body, and at least one end of the shaft member is formed from the winding electrode body. The tab holding plate made of an insulating material is attached to the end portion so as not to be relatively rotatable, and the tab holding plate is supported at a position away from the winding electrode body. A plurality of through-holes through which one current collecting tab can penetrate each, and each current collecting tab extends from the base end connected to the winding electrode body toward the tab holding plate, Furthermore different penetration of the tabs holding plate Extend through, are connected the tip to one electrode terminal portion, the electrode tabs are restrained by the inner wall of the through hole of the tab holding plate at an intermediate position of the proximal end and a distal end A cylindrical battery characterized by that.

The cylindrical battery according to claim 1, wherein the number of through holes provided in the tab holding plate is greater than the number of current collecting tabs having the same polarity.

The cylindrical battery according to claim 1 or 2, wherein at least one liquid hole is formed in the tab holding plate.

The shaft member is formed using one material selected from fluororesin, polyethylene, polypropylene, and ceramic, and the tab holding plate is selected from fluororesin, polyethylene, polypropylene, and ceramic. The cylindrical battery according to any one of claims 1 to 3, wherein the cylindrical battery is formed using one material.

The shaft member is hollow and has an open end portion, and the one electrode terminal portion is screwed into a terminal member that is attached through the lid and a base end portion of the terminal member. A pinching member, the pinching member engaging with an end of the shaft member in a relatively non-rotatable manner, and having an insertion shaft inserted into an opening end of the shaft member , the pinching member The cylindrical battery according to any one of claims 1 to 4, wherein tip ends of a plurality of current collecting tabs are sandwiched between the terminal member and the terminal member.