JP4248849B2

JP4248849B2 - Square battery

Info

Publication number: JP4248849B2
Application number: JP2002328976A
Authority: JP
Inventors: 俊治北川; 真介福田; 幸司齋藤
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-11-13
Filing date: 2002-11-13
Publication date: 2009-04-02
Anticipated expiration: 2022-11-13
Also published as: JP2004164980A

Description

【０００１】
【発明の属する技術分野】
本発明は、半殻体に形成された本体ケースの開口部が蓋板によって封口された電池ケース内に発電要素を収容した扁平形状の角形電池に関するものである。
【０００２】
【従来の技術】
携帯電話機やＰＤＡなどの携帯電子機器は、高機能化と共に小型化、薄型化の進展が著しく、それに適用する電池に小型、薄型にして高エネルギー密度であることが要求され、これに対応する電池として扁平角形のリチウムイオン二次電池が広く用いられている。この扁平角形の電池に適用される電池ケースは、深絞り加工によって有底角筒形状に形成された電池缶と、その開口端を閉じる封口板とによって構成され、電池ケース内に極板群および電解液からなる発電要素が収容されている。
【０００３】
電池の薄型化を達成するためには、前記電池缶をより狭い幅の角筒に深絞りする必要があるが、加工方向の深さに対して開口面積が小さくなるほどに加工が困難となり、深絞り加工による電池缶の薄型化には限度がある。また、幅が狭く深い筒状に形成された電池缶に極板群を挿入することも、薄型化して開口面積が小さくなるほどに困難になる。
【０００４】
従って、薄型化に限度がある角形電池の更なる薄型化を図るためには、電池ケースの構造を変える必要があり、半殻体に形成された本体ケースと、この本体ケースの開口部を閉じる平板もしくは半殻体に形成された蓋板とによって電池ケースを形成した電池が開発されている。
【０００５】
例えば、図１０に示すように、上カップ１内に極板群３を収容し、その開口部を下カップ２によって封口した角形電池が知られている（特許文献１参照）。この電池ケース構造では、浅い絞り加工によって発電要素を収容する凹部を形成することができるので、電池ケースの製造は容易である。
【０００６】
また、図１１（ａ）に示すように、凹部の周囲に鍔部４ａ，５ａを形成した一対のケース部材４，５の凹部４ａ，５ａ内に極板群８を収容して鍔部４ｂ，５ｂ間で接合した角形電池が知られている（特許文献２参照）。この角形電池では、一方のケース部材４に設けられた正極外部接続端子６及び負極外部接続端子７と極板群８との間を接続するために、図１１（ｂ）に示すように、極板群８に設けられた正極リード６ａ及び負極リード７ａと前記正極外部接続端子６及び負極外部接続端子７との間が正極接続リード６ｂ及び負極接続リード７ｂで接続するように構成されている。
【０００７】
【特許文献１】
特開２００１−２５０５１７号公報（第２〜４頁、図１）
【０００８】
【特許文献２】
特開２００１−１６７７４４号公報（第４〜７頁、図１）
【０００９】
【発明が解決しようとする課題】
小型化、薄型化した角形電池は狭い空間に極板群が収容されるため、極板群を構成する正極板及び負極板と正負それぞれの外部接続端子への接続を容易に行い得るように構成することが要求される。しかし、上記従来例構成では、極板群の正極板及び負極板と正負それぞれの外部接続端子との間の接続構造が限られた空間内を占める体積が大きく、接続構造が複雑になる課題があった。
【００１０】
また、狭い空間に極板群が収容されるため、正極板又は負極板が金属製であり正極又は負極の端子となる電池ケースに接触しないように絶縁を図る必要がある。しかし、接触の恐れがある部位に絶縁テープや絶縁板等の絶縁手段を配置すると、製造工数の増加や生産性を低下させる課題があった。
【００１１】
本発明が目的とするところは、半殻体ケースを蓋板で閉じる構造の電池ケースを用いた角形電池に適した接続構造及び絶縁構造を備えた角形電池を提供することにある。
【００１２】
【課題を解決するための手段】
上記目的を達成するための本発明に係る角形電池は、正極板と負極板とをセパレータを介して扁平に巻回し、巻き終わり端から正極リードおよび負極リードが巻回方向に群体から突出するようにして極板群が形成され、四角形半殻体に形成された凹部深さを一辺側で部分的に浅くした段差部に正負の各外部接続端子が設けられた本体ケース内に、前記極板群が前記正極リードおよび負極リードがそれぞれ前記段差部上の正極外部接続端子及び負極外部接続端子上に位置するように収容され、正極外部接続端子に正極リード、負極外部接続端子に負極リードを接合した後、前記本体ケースの開口部が蓋板によって封口されてなる角形電池であって、正極板及び負極板、セパレータの極板群巻回方向と直交する方向の幅は、正極板及び負極板は凹部内幅寸法より小さく、セパレータは凹部内幅寸法より大きく形成されてなることを特徴とする。
【００１３】
上記構成によれば、段差部を形成した凹部内に極板群を収納すると、極板群から引き出された正極リード及び負極リードはそれぞれ段差部上に設けられた正極外部接続端子及び負極外部接続端子上に位置するので、狭いケース内にリードを引き回すことなく本体ケースに大きく開口する開口部から正極リード及び負極リードを容易に接合することができる。また、リードを引き回すためのスペースが不要であるため、ケース内のスペースが有効に利用できるサイズに極板群を形成して電池容量の増加を図ることができる。また、正極板及び負極板、セパレータの極板群巻回方向と直交する方向の幅は、正極板及び負極板は凹部内幅寸法より小さく、セパレータは凹部内幅寸法より大きく形成しているので、極板群を凹部内に押し込むと、セパレータの端辺は折れ曲がって正極板及び負極板の端を被覆する結果、絶縁部材を設けることなく極板群とケースとの絶縁を図ることができる。
【００１４】
上記構成において、正極リード及び負極リードは、極板の巻き終わり端から所定長さに延出させた部位の所定位置を所定幅に形成することにより、極板端部の外部接続端子延長線上をリード幅にして正極及び負極リードとすることができるので、極板群にリード形成したことによる厚さ増加がなく、角形電池の薄型化に有効となる。
【００１６】
【発明の実施の形態】
以下、添付図面を参照して本発明の実施形態について説明し、本発明の理解に供する。尚、以下に示す実施形態は本発明を具体化した一例であって、本発明の技術的範囲を限定するものではない。
【００１７】
図１は、本実施形態に係る角形電池の外観形状を示すもので、リチウムイオン二次電池として構成されたものである。この角形電池は、図２に示す電池本体２０と、それを被覆する外装体３０とによって構成されている。
【００１８】
電池本体２０は、図３に各構成要素に分解して示すように、半殻体に形成された本体ケース１１と、その開放部を閉じる蓋板１２とにより電池ケース１０が構成されており、本体ケース１１の凹部１５内に極板群１４を収容し、本体ケース１１に形成されたフランジ部１３に蓋板１２の周囲を溶接して本体ケース１１の開口部を蓋体１２で封止するように構成されている。
【００１９】
前記本体ケース１１は、ステンレス鋼あるいは冷間圧延鋼板等の鉄系板材をプレス加工して一端側に絞り深さを小さくした段差部１６を設けて凹部１５を形成すると共に、凹部１５の周囲にフランジ部１３を設けて形成される。前記段差部１６は正極及び負極の外部接続端子を形成する部位で、ここでは段差部１６に形成された端子孔１７に下ガスケット１８で本体ケース２と絶縁すると共に気密性を確保してリベット１９によりＰＴＣユニット２６を段差部１６の外面上に固定している。
【００２０】
前記ＰＴＣユニット２６は、図８に示すように、ＰＴＣ導電性ポリマ３３ａの両面に上電極３３ｂと下電極３３ｃとを接合したＰＴＣ素子３３をＰＴＣホルダ３４内に収容し、上ガスケット３５によって段差部１６と絶縁してワッシャ３７を介して前記リベット１９を締結することにより段差部１６上に固定され、前記ＰＴＣホルダ３４の開口部にホルダプレート３６を溶接したものである。ホルダプレート３６は、ここでは正極外部接続端子を構成する。尚、ＰＴＣ（Positive Temperature Coefficient）素子３３は、過電流や過熱により温度上昇して素子温度が所定温度に達すると急激に抵抗値が上昇するデバイスであり、平常時は僅少な抵抗値で通電回路の電力損失は低く抑えられ、所定温度に達したときには抵抗値が１０の４乗から６乗にも急上昇するので、外部短絡が生じたときに温度上昇して短絡電流を抑え、電池を外部短絡から保護する。
【００２１】
前記本体ケース１１の凹部１５内には、正極板４７と負極板４８とをセパレータ４９を介して扁平に巻回された極板群１４が収容される。極板群１４は、図４に示すように、最外周が負極板４８となるように巻回され、その巻回方向は、段差部１６からその対向辺に向く方向であり、巻き終わり端が段差部１６側になるようにして、正極板４７及び負極板４８それぞれの巻き終わり端から正極リード２１、負極リード２２が引き出される。正極リード２１は、正極板４７の巻き終わり端からの延長部を、段差部１６上に取り付けられたリベット１９の延長線上となる位置にリードとして適切な幅で、極板群１４を凹部１５ないに収納したときに先端部がリベット１９上に位置する長さになるように切断加工して形成される。また、負極リード２２は、負極板４８の巻き終わり端からの延長部を、段差部１６上のリベット１９等の部材が存在しない任意位置の延長線上となる位置にリードとして適切な幅で、極板群１４を凹部１５内に収納したときに先端部が段差部１６上に位置する長さになるように切断加工して形成される。また、セパレータ４９は、図５に示すように、巻回方向と直交する方向の幅が、正極板４７及び負極板４８の幅より大きく、凹部１５の幅寸法より大きく形成されている。
【００２２】
上記構成になる極板群１４は、図６に示すように、本体ケース１１の凹部１６内に正極リード２１及び負極リード２２が引き出された側を前記段差部１６側にすると共に、巻き終わり端が外方になるようにして収納する。このとき、極板群１４の巻回方向と直交する方向の側面から出ているセパレータ４９の端辺は、図７に示すように、極板群１４の凹部１５内への押し込み方向の下流側に折り曲げられるので、折り曲げられたセパレータ４９は正極板４７が負極電位となる本体ケース１１に接触するのを防止する絶縁手段となる。
【００２３】
また、極板群１４を凹部１５内に収納すると、巻き終わり端が外方になるようにすると、段差部１６よりやや高い高さ位置で、正極リード２１の先端部は前記リベット１９上に位置し、負極リード２２の先端部分は段差部１６上に位置するので、リードを引き回すことなく、正極リード２１はリベット１９に、負極リード２２は段差部１６にそれぞれ接合することができる。
【００２４】
極板群１４が収容された本体ケース１１の開口部は、フランジ部１３上に蓋板１２を載置し、フランジ部１３と蓋板１２とをそれぞれの外縁端が一致するように位置決めして、蓋板１２の周辺部とフランジ部１３との間を溶接することにより封口される。
【００２５】
蓋板１２は本体ケース１１に用いる金属板材の厚さより薄い金属板材が適用され、図示するように中央部に浅い窪み２３を形成して、極板群４の膨張、あるいは内圧の上昇により電池ケース５０に膨らみが生じたとき、膨らみを窪み２３の形成深さ内で吸収して、角形電池としての全体厚さに変化が生じないようにしている。
【００２６】
封止された凹部１５内には、段差部１６に形成された電解液注入口２８から所定量の電解液が注入され、注入完了後に電解液注入口２８には封栓２９が挿入され、段差部１６に封栓２９を溶接することにより凹部１５内は密封される。
【００２７】
上記のように形成された電池本体２０には、図９に示すように、樹脂成形によって形成された樹脂カバー２５が被せられ、樹脂フィルム３８を巻着することにより、図１に示した角形電池に形成される。前記樹脂カバー２５には、段差部１６の外面上に固定されたＰＴＣユニット２６のホルダプレート３６上に開口する正極端子窓３１と、本体ケース１１底面の段差部１６が形成されていない部位上に開口する負極端子窓３２とが形成され、正極端子窓３１及び負極端子窓３２の部分には、前記樹脂フィルム３８が巻着されないように切り欠きが形成されているので、正極端子窓３１から正極外部接続端子となるホルダプレート３６が外部露出し、負極端子窓３２から負極外部接続端子となる本体ケース１１が外部露出するので、外部接続の用に供することができる。
【００２８】
上記構成になる角形電池は、極板の膨張や通常使用における内圧上昇が生じたとき、板厚が本体ケース１１より薄く形成された蓋板１２に膨らみが生じるが、蓋板１２に窪み２３が形成されていることにより、膨らみを窪み２３の形成深さ内で吸収して、角形電池全体の厚さに変化が生じないようにする。
【００２９】
【発明の効果】
以上の説明の通り本発明によれば、半殻体に形成された本体ケースの凹部内に極板群を収納したとき、凹部の端部に設けられた段差部上に配設された外部接続端子上に正極及び負極の各リードが位置するので、リードを引き回すことなくリード接続が可能となる。また、極板群を凹部内に押し入れることにより、正負極板より幅を大きく形成したセパレータが折れ曲がって正負極板の端部を被覆するので、別途に絶縁手段を設けることなく内部短絡を防止する絶縁手段が構成される。
【図面の簡単な説明】
【図１】実施形態に係る角形電池の外観形状を示す斜視図。
【図２】同上角形電池を構成する電池本体の外観形状を示す斜視図。
【図３】電池本体の構成を示す分解斜視図。
【図４】リードの引き出し構造を示す斜視図。
【図５】極板群の構成を示す部分断面図。
【図６】本体ケース内への極板群の収納状態を示す平面図。
【図７】角形電池の部分断面図。
【図８】ＰＴＣユニットの構成を示す断面図。
【図９】電池本体に対する外装体の形成を示す斜視図。
【図１０】従来技術に係る角形電池の構成を示す分解斜視図。
【図１１】従来技術に係る角形電池の構成を示す（ａ）は斜視図、（ｂ）は平面図。
【符号の説明】
１０電池ケース
１１本体ケース
１２蓋板
１３フランジ部
１４極板群
１５凹部
１６段差部
１９リベット（外部接続端子）
２１正極リード
２２負極リード
４７正極板
４８負極板
４９セパレータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flat prismatic battery in which a power generation element is accommodated in a battery case in which an opening of a main body case formed in a half-shell is sealed by a cover plate.
[0002]
[Prior art]
Portable electronic devices such as mobile phones and PDAs are becoming increasingly smaller and thinner with higher functionality, and the batteries applied to them are required to be smaller and thinner and have a higher energy density. A flat rectangular lithium ion secondary battery is widely used. The battery case applied to the flat rectangular battery is composed of a battery can formed into a bottomed rectangular tube shape by deep drawing and a sealing plate that closes the open end thereof. A power generation element made of an electrolytic solution is accommodated.
[0003]
In order to achieve thinning of the battery, it is necessary to deeply draw the battery can into a narrower rectangular tube. However, as the opening area becomes smaller with respect to the depth in the processing direction, the processing becomes more difficult, There is a limit to reducing the thickness of battery cans by drawing. It is also difficult to insert the electrode plate group into the battery can formed in a narrow and deep cylindrical shape as the opening area is reduced by reducing the thickness.
[0004]
Therefore, in order to further reduce the thickness of a prismatic battery that is limited in thickness, it is necessary to change the structure of the battery case. The main body case formed in the half-shell and the opening of the main body case are closed. A battery in which a battery case is formed by a lid plate formed on a flat plate or a half shell has been developed.
[0005]
For example, as shown in FIG. 10, a rectangular battery in which an electrode plate group 3 is accommodated in an upper cup 1 and an opening thereof is sealed by a lower cup 2 is known (see Patent Document 1). In this battery case structure, since the recess for accommodating the power generation element can be formed by shallow drawing, the battery case can be easily manufactured.
[0006]
Further, as shown in FIG. 11A, the electrode plate group 8 is accommodated in the recesses 4a and 5a of the pair of case members 4 and 5 in which the flanges 4a and 5a are formed around the recesses. A prismatic battery joined between 5b is known (see Patent Document 2). In this square battery, in order to connect between the positive electrode external connection terminal 6 and the negative electrode external connection terminal 7 provided on one case member 4 and the electrode plate group 8, as shown in FIG. The positive electrode lead 6a and the negative electrode lead 7a provided in the plate group 8 and the positive electrode external connection terminal 6 and the negative electrode external connection terminal 7 are connected by the positive electrode connection lead 6b and the negative electrode connection lead 7b.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-250517 (pages 2 to 4, FIG. 1)
[0008]
[Patent Document 2]
Japanese Patent Laid-Open No. 2001-167744 (pages 4-7, FIG. 1)
[0009]
[Problems to be solved by the invention]
The small and thin prismatic battery is configured so that the electrode plate group is accommodated in a narrow space, so that the positive electrode plate and the negative electrode plate constituting the electrode plate group can be easily connected to the positive and negative external connection terminals. It is required to do. However, in the above conventional configuration, the connection structure between the positive and negative electrode plates of the electrode plate group and the positive and negative external connection terminals occupies a large volume in a limited space, and the connection structure is complicated. there were.
[0010]
Further, since the electrode plate group is accommodated in a narrow space, it is necessary to insulate the positive electrode plate or the negative electrode plate so that the positive electrode plate or the negative electrode plate does not come into contact with the battery case serving as the positive electrode or negative electrode terminal. However, when an insulating means such as an insulating tape or an insulating plate is disposed at a site where there is a risk of contact, there are problems in that the number of manufacturing steps is increased and the productivity is lowered.
[0011]
An object of the present invention is to provide a prismatic battery having a connection structure and an insulating structure suitable for a prismatic battery using a battery case having a structure in which a half-shell case is closed with a cover plate.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a prismatic battery according to the present invention winds a positive electrode plate and a negative electrode plate flatly via a separator so that the positive electrode lead and the negative electrode lead protrude from the group body in the winding direction from the winding end. The electrode plate is formed in a body case in which positive and negative external connection terminals are provided in a stepped portion in which a concave portion formed in a square half-shell is partially shallowed on one side. The group is accommodated such that the positive electrode lead and the negative electrode lead are respectively positioned on the positive electrode external connection terminal and the negative electrode external connection terminal on the stepped portion, and the positive electrode lead is connected to the positive electrode external connection terminal and the negative electrode lead is bonded to the negative electrode external connection terminal Then, the opening of the main body case is a rectangular battery that is sealed with a cover plate , and the width in the direction orthogonal to the positive electrode plate and negative electrode plate and the electrode plate group winding direction of the separator is positive electrode plate and negative electrode plate Is concave Smaller than the inner width, the separator is characterized by comprising formed larger than the recess width.
[0013]
According to the above configuration, when the electrode plate group is housed in the concave portion in which the step portion is formed, the positive electrode lead and the negative electrode lead drawn from the electrode plate group are respectively connected to the positive electrode external connection terminal and the negative electrode external connection provided on the step portion. Since it is located on the terminal, it is possible to easily join the positive electrode lead and the negative electrode lead from the opening that opens largely to the main body case without drawing the lead in the narrow case. In addition, since a space for routing the leads is unnecessary, the electrode plate group can be formed in a size that can effectively use the space in the case, thereby increasing the battery capacity. In addition, the width of the positive electrode plate, the negative electrode plate, and the separator in the direction orthogonal to the electrode plate group winding direction is smaller than the inner width dimension of the concave portion of the positive electrode plate and the negative electrode plate, and larger than the inner width dimension of the concave portion. When the electrode plate group is pushed into the recess, the edge of the separator is bent to cover the ends of the positive electrode plate and the negative electrode plate, so that the electrode plate group and the case can be insulated without providing an insulating member.
[0014]
In the above configuration, the positive electrode lead and the negative electrode lead are formed on the external connection terminal extension line at the end portion of the electrode plate by forming a predetermined position of the portion extended from the end of winding of the electrode plate to a predetermined length with a predetermined width. Since the lead width can be used as a positive electrode and a negative electrode lead, there is no increase in thickness due to the formation of the leads on the electrode plate group, which is effective in reducing the thickness of the prismatic battery.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
[0017]
FIG. 1 shows the external shape of a prismatic battery according to this embodiment, which is configured as a lithium ion secondary battery. This rectangular battery is composed of a battery main body 20 shown in FIG. 2 and an exterior body 30 covering the battery main body 20.
[0018]
As shown in FIG. 3 in which the battery body 20 is disassembled into components, a battery case 10 is constituted by a body case 11 formed in a half-shell and a lid plate 12 that closes an open portion thereof. The electrode plate group 14 is accommodated in the recess 15 of the main body case 11, and the periphery of the cover plate 12 is welded to the flange portion 13 formed in the main body case 11 to seal the opening of the main body case 11 with the cover body 12. It is configured as follows.
[0019]
The main body case 11 is formed by pressing a ferrous plate material such as stainless steel or cold-rolled steel plate to provide a step portion 16 having a reduced drawing depth on one end side to form a concave portion 15, and around the concave portion 15. A flange portion 13 is provided and formed. The step portion 16 is a portion for forming positive and negative external connection terminals. Here, a terminal hole 17 formed in the step portion 16 is insulated from the main body case 2 by a lower gasket 18, and airtightness is secured, thereby providing a rivet 19. Thus, the PTC unit 26 is fixed on the outer surface of the step portion 16.
[0020]
As shown in FIG. 8, the PTC unit 26 accommodates a PTC element 33 in which an upper electrode 33b and a lower electrode 33c are joined to both surfaces of a PTC conductive polymer 33a in a PTC holder 34, and a step portion is formed by an upper gasket 35. The rivet 19 is fastened with a washer 37 insulatively and is fixed on the stepped portion 16, and a holder plate 36 is welded to the opening of the PTC holder 34. Here, the holder plate 36 constitutes a positive external connection terminal. The PTC (Positive Temperature Coefficient) element 33 is a device whose temperature rises due to overcurrent or overheating and the resistance value suddenly rises when the element temperature reaches a predetermined temperature. Power loss is kept low, and when the temperature reaches a predetermined temperature, the resistance value rises rapidly from the fourth power to the sixth power, so when an external short circuit occurs, the temperature rises and the short circuit current is suppressed, and the battery is shorted externally. Protect from.
[0021]
The electrode plate group 14 in which the positive electrode plate 47 and the negative electrode plate 48 are wound flatly via a separator 49 is accommodated in the recess 15 of the main body case 11. As shown in FIG. 4, the electrode plate group 14 is wound so that the outermost periphery is the negative electrode plate 48, and the winding direction is a direction from the stepped portion 16 toward the opposite side, and the winding end end is The positive electrode lead 21 and the negative electrode lead 22 are drawn out from the winding end ends of the positive electrode plate 47 and the negative electrode plate 48 so as to be on the stepped portion 16 side. The positive electrode lead 21 has an appropriate width as a lead extending from the winding end of the positive electrode plate 47 on the extended line of the rivet 19 attached on the stepped portion 16, and the electrode plate group 14 does not have the concave portion 15. It is formed by cutting so that the tip end portion has a length located on the rivet 19 when stored in the container. Also, the negative electrode lead 22 has an appropriate width as a lead with an extension portion from the winding end of the negative electrode plate 48 at a position on the extension line at an arbitrary position where no member such as the rivet 19 on the step portion 16 exists. When the plate group 14 is housed in the recess 15, it is formed by cutting so that the tip portion has a length located on the step portion 16. Further, as shown in FIG. 5, the separator 49 is formed such that the width in the direction orthogonal to the winding direction is larger than the width of the positive electrode plate 47 and the negative electrode plate 48 and larger than the width dimension of the recess 15.
[0022]
As shown in FIG. 6, the electrode plate group 14 having the above configuration has the side where the positive electrode lead 21 and the negative electrode lead 22 are drawn into the concave portion 16 of the main body case 11 as the stepped portion 16 side, and the winding end end. Store so that is on the outside. At this time, the end side of the separator 49 protruding from the side surface in the direction orthogonal to the winding direction of the electrode plate group 14 is downstream in the pushing direction of the electrode group 14 into the recess 15 as shown in FIG. Therefore, the folded separator 49 serves as an insulating means for preventing the positive electrode plate 47 from coming into contact with the main body case 11 having a negative electrode potential.
[0023]
Further, when the electrode plate group 14 is housed in the recess 15, the end of the positive electrode lead 21 is positioned on the rivet 19 at a slightly higher height than the stepped portion 16 when the winding end is outward. Since the tip portion of the negative electrode lead 22 is located on the step portion 16, the positive electrode lead 21 can be joined to the rivet 19 and the negative electrode lead 22 can be joined to the step portion 16 without routing the lead.
[0024]
The opening of the main body case 11 in which the electrode plate group 14 is accommodated is such that the cover plate 12 is placed on the flange portion 13 and the flange portion 13 and the cover plate 12 are positioned so that their outer edge ends coincide. It is sealed by welding between the peripheral part of the cover plate 12 and the flange part 13.
[0025]
A metal plate material thinner than the metal plate material used for the main body case 11 is applied to the cover plate 12, and a shallow recess 23 is formed in the center as shown in the figure, and the battery case is formed by expansion of the electrode plate group 4 or increase in internal pressure. When a bulge occurs in 50, the bulge is absorbed within the formation depth of the recess 23 so that the overall thickness of the rectangular battery does not change.
[0026]
A predetermined amount of electrolyte is injected into the sealed recess 15 from an electrolyte injection port 28 formed in the stepped portion 16, and a sealing plug 29 is inserted into the electrolyte injection port 28 after the injection is completed. The inside of the recess 15 is sealed by welding a plug 29 to the portion 16.
[0027]
The battery body 20 formed as described above is covered with a resin cover 25 formed by resin molding, as shown in FIG. 9, and a rectangular film shown in FIG. Formed. The resin cover 25 has a positive terminal window 31 that opens on the holder plate 36 of the PTC unit 26 fixed on the outer surface of the step portion 16 and a portion on the bottom surface of the main body case 11 where the step portion 16 is not formed. A negative electrode terminal window 32 is formed, and notches are formed in the positive electrode terminal window 31 and the negative electrode terminal window 32 so that the resin film 38 is not wound around. Since the holder plate 36 serving as an external connection terminal is exposed to the outside and the main body case 11 serving as the negative electrode external connection terminal is exposed from the negative electrode terminal window 32, it can be used for external connection.
[0028]
In the prismatic battery having the above configuration, when the electrode plate expands or the internal pressure increases during normal use, the cover plate 12 formed with a plate thickness thinner than that of the main body case 11 swells, but the cover plate 12 has a recess 23. By being formed, the bulge is absorbed within the formation depth of the recess 23 so that the thickness of the entire rectangular battery does not change.
[0029]
【The invention's effect】
As described above, according to the present invention, when the electrode plate group is stored in the recess of the main body case formed in the half-shell, the external connection disposed on the stepped portion provided at the end of the recess. Since the positive and negative leads are located on the terminal, lead connection is possible without drawing the lead. In addition, by pushing the electrode plate group into the recess, the separator formed wider than the positive and negative electrode plates bends to cover the ends of the positive and negative electrode plates, preventing internal short circuit without providing separate insulation means Insulating means are configured.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external shape of a prismatic battery according to an embodiment.
FIG. 2 is a perspective view showing an external shape of a battery main body constituting the same rectangular battery.
FIG. 3 is an exploded perspective view showing a configuration of a battery main body.
FIG. 4 is a perspective view showing a lead drawing structure.
FIG. 5 is a partial cross-sectional view showing a configuration of an electrode plate group.
FIG. 6 is a plan view showing a state in which the electrode plate group is stored in the main body case.
FIG. 7 is a partial cross-sectional view of a prismatic battery.
FIG. 8 is a cross-sectional view showing a configuration of a PTC unit.
FIG. 9 is a perspective view showing the formation of an exterior body on the battery body.
FIG. 10 is an exploded perspective view showing a configuration of a prismatic battery according to the prior art.
11A is a perspective view, and FIG. 11B is a plan view showing the configuration of a prismatic battery according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Battery case 11 Main body case 12 Cover plate 13 Flange part 14 Electrode board group 15 Recessed part 16 Step part 19 Rivet (external connection terminal)
21 Positive electrode lead 22 Negative electrode lead 47 Positive electrode plate 48 Negative electrode plate 49 Separator

Claims

A positive electrode plate and a negative electrode plate are wound flatly through a separator, and a positive electrode group and a negative electrode lead are formed at the end of the winding so that the positive electrode lead and the negative electrode lead protrude from the group in the winding direction. In the main body case in which the positive and negative external connection terminals are provided in the stepped portion in which the depth of the recessed portion is partially shallowed on one side, the positive electrode group and the negative electrode lead are respectively on the stepped portion. The positive electrode external connection terminal and the negative electrode external connection terminal are accommodated so as to be positioned. After the positive electrode lead is connected to the positive electrode external connection terminal and the negative electrode lead is bonded to the negative electrode external connection terminal, the opening of the main body case is sealed with a lid plate. a rectangular battery comprising Te, the positive electrode plate and negative electrode plate, width in the direction perpendicular to the electrode plate group winding direction of the separator, the positive electrode plate and the negative electrode plate is smaller than the recess width dimension, the separator from the recess within the width dimension Prismatic battery characterized by comprising been listening formed.

2. The prismatic battery according to claim 1, wherein the positive electrode lead and the negative electrode lead are formed in a predetermined width at a predetermined position in a portion extended from the winding end of the electrode plate to a predetermined length.