JP3691268B2

JP3691268B2 - Sealed battery

Info

Publication number: JP3691268B2
Application number: JP00410799A
Authority: JP
Inventors: 修渡辺; 佳明泉
Original assignee: Hitachi Maxell Energy Ltd
Current assignee: Hitachi Maxell Energy Ltd
Priority date: 1999-01-11
Filing date: 1999-01-11
Publication date: 2005-09-07
Anticipated expiration: 2019-01-11
Also published as: JP2000208130A

Description

【０００１】
【発明の属する技術分野】
この発明は、電池ケースが密封してある密閉型の電池に関する。
【０００２】
【従来の技術】
密閉型の電池においては、電池ケースの開口を蓋で密封する。蓋には、負極端子（出力端子）がプラスチック製のガスケットを介して、蓋壁を内外に貫通する状態で固定してある。ガスケットは負極端子と蓋との直接接触を避ける絶縁体を兼ねている。多くの場合、負極端子はガスケットの外面に露出する頭部と、ガスケットに内嵌する軸部とを有し、軸部の下端をかしめ処理することによって、ガスケットと一体化され、蓋に対して抜け外れ不能に固定してある。
【０００３】
【発明が解決しようとする課題】
上記のように、負極端子をガスケットに対してかしめ固定する密閉型電池においては、軸部の下端をかしめ処理する際に軸部が僅かに膨張変形し、ガスケットに設けた軸挿通穴と密着して、軸部とガスケットとの間の隙間を封止する。同時に、軸部に外嵌するガスケットのボス部が膨張変形して、蓋に通設した取付穴に密着し、ガスケットと蓋との間の隙間を封止する。
【０００４】
しかし、軸部や軸挿通穴および取付穴の仕上り寸法のばらつきや、かしめ処理時の軸部の変形量のばらつき等によって、軸部と軸挿通穴、あるいはボス部と取付穴との密着度合が不足してシール不良を生じ、液漏れの原因になることがあった。とくに、電池ケースに内圧が作用する電池の場合には液漏れを生じやすい。
【０００５】
かしめ処理した後に負極端子とガスケットのシール状態を確認することは不可能ではないが、その分だけ電池の製造コストが高く付く。例えば、ねじを用いて、軸部と軸挿通穴の密着度を向上することも考えられるが、部品数の増加と、組み立て工数とが増えるのを避けられず、この場合にも製造コストが増加する。
【０００６】
この発明の目的は、従来と同様に出力端子をかしめ処理して蓋に固定する構造を採りながら、ガスケットと出力端子および蓋との密着度を向上し、以て軸部のシール不良に基づく液漏れを一掃し、密閉型電池の信頼性を向上することにある。
この発明の他の目的は、出力端子およびガスケットの一部を変更することにより、ガスケットまわりのシール不良を一掃でき、従って液漏れのない信頼性に優れた密閉型の電池を、より低コストで提供することにある。
【０００７】
【課題を解決するための手段】
この発明の電池は、電池ケース１の開口を塞ぐ蓋６に、一方の出力端子９がガスケット８を介してかしめ固定してある密閉型の電池を前提とする。出力端子９は、ガスケット８の外面に露出する頭部２０と、頭部２０の下面に突設される軸部２１と、軸部２１の下端に形成されたかしめ軸部２２とを備えている。ガスケット８は、頭部２０と蓋６とで挟持されるフランジ部２３と、蓋６に通設した取付穴１２に内嵌するボス部２４とを有し、ボス部２４に軸部２１と嵌合する軸挿通穴２５が上下貫通状に通設されている。軸部２１の突出基端には、ボス部２４を拡径状に変形させる封止部１９が下すぼまり状に形成される。以て、出力端子９をガスケット８にかしめ固定した状態において、ガスケット８の軸挿通穴２５を軸部２１に密着させ、同時にボス部２４を取付穴１２に密着させる。
【０００８】
具体的には、封止部１９を下すぼまり状のテーパー面で形成し、ガスケット８の軸挿通穴２５の上端に、封止部１９に対応する下すぼまりテーパー状のシール面２７を形成する。
【０００９】
軸挿通穴２５の下端に、軸部２１より小径のシール穴２８を周回状に形成し、出力端子９をガスケット８に組み付けた状態において、シール穴２８が軸部２１で拡径変形されるようにする。
【００１０】
【作用】
軸部２１の突出基端に封止部１９を設け、出力端子９をガスケット８に組み付けた状態において、軸挿通穴２５の上部を封止部１９で拡形状に変形させ、同時にボス部２４を上下方向で挟圧変形させるので軸部２１をガスケット８に密着させると同時に、ボス部２４を取付穴１２に密着させるので、ガスケット８と出力端子９および蓋６との間の隙間を確実に封止して、ガスケットまわりのシール不良を解消できる。下すぼまり状に形成した封止部１９は、くさび作用を発揮して、出力端子９のかしめ力が小さい場合にも、ボス部２４を確実に拡径変形するのに役立つ。出力端子９に下すぼまり状の封止部１９を付加することにより、ガスケット８と出力端子９および蓋６との間の隙間を封止するので、部品点数や組み立て工数の増加を伴うことなく、液漏れのない密閉型の電池を構成できる。
【００１１】
封止部１９を下すぼまり状のテーパー面で形成し、さらに軸挿通穴２５の上端に下すぼまりテーパー状のシール面２７を形成したシール構造によれば、かしめ処理後のボス部２４の変形量を正確に設定でき、ガスケット８の締め付け力を過不足なく適正化できる。
【００１２】
ガスケット８の軸挿通穴２５の下端に軸部２１より小径のシール穴２８を設け、出力端子９をガスケット８に組み付けた状態において、シール穴２８を軸部２１で強制的に拡径変形させるので、軸部２１や軸挿通穴２５の仕上り寸法にばらつきがあったとしても、軸部２１とシール穴２８を確実に密着させて、両者２１・２８間の隙間を確実に封止できる。
【００１３】
【実施例】
図１ないし図４は、この発明を角形のリチウムイオン二次電池に適用した実施例を示す。図２において、電池は上面が開口する縦長角箱状の電池ケース１と、電池ケース１内に装填される電極体２および電解液と、電池ケース１の開口を塞ぐ封口構造などで構成する。電池ケース１はニッケル板を深絞り加工して形成してあり、正極側の出力端子を兼ねている。その底壁の下面には正極端子板３が溶接してある。電極体２はＬｉＣｏＯ₂ を活物質とするシート状の正極と、黒鉛を活物質とするシート状の負極とを、セパレータを間にして渦巻状に巻回した後、全体を電池ケース１の断面形状に合致して断面四角形状に押し潰し変形して形成してあり、その正極シートおよび負極シートのそれぞれから導電タブ４・５を上向きに導出してある。符号１７は電極体２の下端周面に巻装した絶縁テープである。
【００１４】
封口構造は、電池ケース１の上面開口を塞ぐ蓋６と、蓋６の内側に配置されるプラスチック製のインシュレータ７と、蓋６に対してガスケット８を介してかしめ固定される負極端子（出力端子）９と、負極端子９と同時にかしめ固定される押え板１０と、負極用の絶縁板１１などで構成する。
【００１５】
蓋６はアルミニウム合金板材を素材にしたプレス成形品からなり、その板面中央にガスケット８用の取付穴１２を長円状に通設し、取付穴１２の一側板面に防爆用の開裂ベント１３を設け、他側板面に電解液用の注入穴１４を通設してなる。取付穴１２の上面側の開口周縁壁には、ガスケット８用の受座１５が凹み形成してある。開裂ベント１３は、断続的に周回する切溝で囲まれていて、ケース内圧が一定値を越えると、切溝が破断してガスを放出する。注入穴１４は電解液を注入したのちプラグ１６で閉止され、プラグ１６を蓋６に対して溶接することにより密封される。
【００１６】
図４において、負極端子９は頭部２０と、頭部２０の下面に突設した軸部２１と、軸部２１の下端に形成したかしめ軸部２２とを有するアルミニウム製の軸体からなる。かしめ軸部２２は下向きに開口する筒軸からなり、この筒壁の下半側を拡形し反転状にかしめ変形する。頭部２０は、平面視が長円状の端子部２０ａと、端子部２０ａの下面に突設した断面円径の首部２０ｂとからなり、首部２０ｂの下面に軸部２１を突設してある。これらの首部２０ｂと軸部２１との間に、ガスケット８のボス部２４を拡径状に変形させる封止部１９を設ける。封止部１９は下すぼまり状のテーパー面に形成し、テーパー面の傾き角度を４５度に設定した。
【００１７】
ガスケット８は、長円状のフランジ部２３と、フランジ部２３の下面に突設した丸軸状のボス部２４とを一体に形成したプラスチック成形品からなり、ボス部２４の中央に軸部２１と嵌合する軸挿通穴２５を上下貫通状に通設し、フランジ部２３の上面中央に、出力端子９の頭部２０を受け入れる凹部２６を凹み形成する。軸挿通穴２５の上端隅部には、先の封止部１９に対応して下すぼまりテーパー状のシール面２７を形成する。さらに、軸挿通穴２５の下端には、軸部２１より小径のシール穴２８を周回状に形成する。
【００１８】
封口構造の組み付けは次の手順で行う。まずインシュレータ７を電池ケース１に内嵌装着した後、ガスケット８のボス部２４を蓋６の取付穴１２に挿嵌し、さらに負極端子９を軸挿通穴２５に挿嵌する。このとき軸部２１はシール穴２８を拡径状に変形させるので、両者２１・２８は隙間なく密着する。この後、軸部２１に負極用の絶縁板１１を介して押え板１０を外嵌し、この状態でかしめ軸部２２をかしめ処理することにより、ガスケット８のボス部２４が首部２０ｂとかしめ軸部２２とで上下に挟持され、拡径状に変形し、同時に上下の挟圧されて圧縮変形する。さらに封止部１９がシール面２７を介して軸挿通穴２５の上部周壁を拡径状に変形させる。加えて、かしめ処理時に軸部２１の下部が自由状態時よりも拡径変形して、ボス部２４の下部を拡径させる。従って、ボス部２４の周面は蓋６の取付穴１２に密着して、両者１２・２４間の隙間を完全に封止できる。
【００１９】
上記の組立体の押え板１０に負極側の導電タブ５を溶接し、正極側の導電タブ４を蓋６の内面に溶接する。この後、蓋６を電池ケース１に内嵌したうえで、蓋６と電池ケース１との嵌合面を溶接して封止する。最後に注入穴１４から電解液をケース内へ注入したうえで、注入穴１４にプラグ１６を内嵌し溶接して、注入穴１４を封止し電池を完成する。
【００２０】
軸部２１と軸挿通穴２５、およびシール穴２８の直径寸法は、それぞれを次のように設定する。軸部２１の直径は軸挿通穴２５の直径寸法と同じか、前者直径が後者直径より僅かに小さくなるようにする。シール穴２８の直径寸法は、軸挿通穴２５の直径寸法より小さく、さらに軸部２１の直径寸法より小さく設定する。より具体的には、軸部２１の直径寸法の0.７〜0.９倍の値をシール穴２８の直径値とする。
【００２１】
上記の実施例では、出力端子９が負極側の端子である場合について説明したがその必要はなく、正極側の端子であってもよい。シール穴２８は軸挿通穴２５の任意位置に形成でき、必要があれば複数個所に形成することができる。封止部１９はテーパー面で形成する以外に、突弧面や凹弧面を縦軸まわりに回転して得られる下すぼまり状の回転面で形成することができる。シール面２７の面取り寸法は封止部１９の上下寸法と一致させるのが好ましいが、面取り寸法を封止部１９の上下寸法より小さく設定することができる。場合によっては、シール面２７を省略して、軸挿通穴２５の上端開口縁を封止部１９で拡径変形してもよい。首部２０ｂを省略して、頭部２０の下面に軸部２１を突設することができる。
【００２２】
【発明の効果】
この発明では、出力端子９の軸部２１の突出基端に下すぼまり状の封止部１９を設け、出力端子９をガスケット８にかしめ固定した状態において、ボス部２４を封止部１９で拡径方向と圧縮方向へ同時に変形させ、ボス部２４と軸部２１および取付穴１２とをそれぞれ密着させ、ガスケット８と出力端子９および蓋６との間の隙間を確実に封止できるようにした。従って、従前同様に出力端子９をかしめ固定する構造を採りながら、ガスケット８と出力端子９および蓋６との間を確実に封止して、ガスケットまわりのシール不良に基づく液漏れを一掃でき、その分だけ密閉型電池の信頼性を向上できる。出力端子９およびガスケット８の一部を変更して、ガスケットまわりのシール不良を回避するので、部品数の増加等のコスト増を伴うことなくシール作用を強化できる点で有利であり、液漏れのない密閉型の電池をより低コストで提供できる。
【図面の簡単な説明】
【図１】図２におけるＡ−Ａ線断面図である。
【図２】電池の縦断正面図である。
【図３】電池の平面図である。
【図４】出力端子とガスケットを分離した状態の断面図である。
【符号の説明】
１電池ケース
６蓋
９出力端子（負極端子）
１９封止部
２０頭部
２１軸部
２２かしめ軸部
２３フランジ部
２４ボス部
２５軸挿通穴
２７シール面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed battery in which a battery case is sealed.
[0002]
[Prior art]
In a sealed battery, the opening of the battery case is sealed with a lid. A negative electrode terminal (output terminal) is fixed to the lid through a plastic gasket so as to penetrate the lid wall inward and outward. The gasket also serves as an insulator that avoids direct contact between the negative electrode terminal and the lid. In many cases, the negative electrode terminal has a head portion exposed on the outer surface of the gasket and a shaft portion fitted into the gasket, and is integrated with the gasket by caulking the lower end of the shaft portion, and is attached to the lid. It is fixed so that it cannot be removed.
[0003]
[Problems to be solved by the invention]
As described above, in a sealed battery in which the negative electrode terminal is caulked and fixed to the gasket, when the lower end of the shaft portion is caulked, the shaft portion is slightly expanded and deformed, and is in close contact with the shaft insertion hole provided in the gasket. Then, the gap between the shaft portion and the gasket is sealed. At the same time, the boss portion of the gasket that is externally fitted to the shaft portion is expanded and deformed, and is closely attached to the mounting hole provided in the lid, thereby sealing the gap between the gasket and the lid.
[0004]
However, the degree of close contact between the shaft part and the shaft insertion hole or the boss part and the mounting hole may vary depending on variations in the finished dimensions of the shaft part, shaft insertion hole, and mounting hole, and variations in the deformation amount of the shaft part during caulking. Insufficient sealing could result in liquid leakage. In particular, in the case of a battery in which internal pressure acts on the battery case, liquid leakage tends to occur.
[0005]
Although it is not impossible to confirm the sealing state of the negative electrode terminal and the gasket after the caulking process, the manufacturing cost of the battery increases accordingly. For example, it is possible to improve the adhesion between the shaft part and the shaft insertion hole using screws, but it is inevitable that the number of parts and assembly man-hours will increase, and in this case also the manufacturing cost will increase. To do.
[0006]
The object of the present invention is to improve the adhesion between the gasket, the output terminal and the lid while adopting a structure in which the output terminal is caulked and fixed to the lid as in the prior art. The purpose is to eliminate leakage and improve the reliability of the sealed battery.
Another object of the present invention is to change the output terminal and a part of the gasket so that the sealing failure around the gasket can be eliminated. Therefore, a sealed battery having excellent reliability with no liquid leakage can be obtained at a lower cost. It is to provide.
[0007]
[Means for Solving the Problems]
The battery of the present invention is premised on a sealed battery in which one output terminal 9 is caulked and fixed to a lid 6 that closes the opening of the battery case 1 via a gasket 8. The output terminal 9 includes a head portion 20 exposed on the outer surface of the gasket 8, a shaft portion 21 protruding from the lower surface of the head portion 20, and a caulking shaft portion 22 formed at the lower end of the shaft portion 21. . The gasket 8 has a flange portion 23 sandwiched between the head portion 20 and the lid 6, and a boss portion 24 that fits inside the mounting hole 12 that is passed through the lid 6, and the shaft portion 21 is fitted to the boss portion 24. A matching shaft insertion hole 25 is vertically penetrated. A sealing portion 19 that deforms the boss portion 24 into a diameter-expanded shape is formed at the protruding base end of the shaft portion 21 in a constricted shape. Thus, in a state where the output terminal 9 is caulked and fixed to the gasket 8, the shaft insertion hole 25 of the gasket 8 is brought into close contact with the shaft portion 21, and at the same time, the boss portion 24 is brought into close contact with the mounting hole 12.
[0008]
More specifically, the sealing portion 19 is formed with a tapered surface with a lower concavity, and a lower concavity taper-shaped sealing surface 27 corresponding to the sealing portion 19 is formed at the upper end of the shaft insertion hole 25 of the gasket 8. To do.
[0009]
A seal hole 28 having a diameter smaller than that of the shaft portion 21 is formed at the lower end of the shaft insertion hole 25 so that the diameter of the seal hole 28 is increased and deformed by the shaft portion 21 when the output terminal 9 is assembled to the gasket 8. To.
[0010]
[Action]
In the state where the sealing portion 19 is provided at the projecting proximal end of the shaft portion 21 and the output terminal 9 is assembled to the gasket 8, the upper portion of the shaft insertion hole 25 is deformed into an enlarged shape by the sealing portion 19, and at the same time, the boss portion 24 is Since the shaft portion 21 is pressed and deformed in the vertical direction, the shaft portion 21 is brought into close contact with the gasket 8 and at the same time the boss portion 24 is brought into close contact with the mounting hole 12, so that the gap between the gasket 8 and the output terminal 9 and the lid 6 is securely sealed. The seal failure around the gasket can be eliminated. The sealing portion 19 formed in a lower constricted shape exhibits a wedge action, and helps to reliably expand and deform the boss portion 24 even when the caulking force of the output terminal 9 is small. Since the gap between the gasket 8 and the output terminal 9 and the lid 6 is sealed by adding the constricted sealing portion 19 to the output terminal 9, there is no increase in the number of parts and assembly man-hours. A sealed battery without liquid leakage can be configured.
[0011]
According to the sealing structure in which the sealing portion 19 is formed with a tapered surface having a lower concavity and the constricted taper-shaped sealing surface 27 is formed at the upper end of the shaft insertion hole 25, the boss portion 24 after the caulking process is formed. The amount of deformation can be set accurately, and the tightening force of the gasket 8 can be optimized without excess or deficiency.
[0012]
Since the seal hole 28 having a smaller diameter than the shaft portion 21 is provided at the lower end of the shaft insertion hole 25 of the gasket 8 and the output terminal 9 is assembled to the gasket 8, the seal hole 28 is forcibly expanded and deformed by the shaft portion 21. Even if the finished dimensions of the shaft portion 21 and the shaft insertion hole 25 vary, the shaft portion 21 and the seal hole 28 can be securely brought into close contact with each other, and the gap between the two can be reliably sealed.
[0013]
【Example】
1 to 4 show an embodiment in which the present invention is applied to a prismatic lithium ion secondary battery. In FIG. 2, the battery is configured by a vertically long rectangular box-shaped battery case 1 whose upper surface is open, an electrode body 2 and an electrolytic solution loaded in the battery case 1, a sealing structure that closes the opening of the battery case 1, and the like. The battery case 1 is formed by deep drawing a nickel plate, and also serves as an output terminal on the positive electrode side. A positive terminal plate 3 is welded to the lower surface of the bottom wall. The electrode body 2 is formed by winding a sheet-like positive electrode having LiCoO ₂ as an active material and a sheet-like negative electrode having graphite as an active material in a spiral shape with a separator interposed therebetween, and then the entire cross section of the battery case 1. It conforms to the shape and is formed by being crushed and deformed into a square cross section, and the conductive tabs 4 and 5 are led upward from the positive electrode sheet and the negative electrode sheet, respectively. Reference numeral 17 denotes an insulating tape wound around the lower peripheral surface of the electrode body 2.
[0014]
The sealing structure includes a lid 6 that closes the upper surface opening of the battery case 1, a plastic insulator 7 that is disposed inside the lid 6, and a negative terminal (output terminal) that is caulked and fixed to the lid 6 via a gasket 8. ) 9, a holding plate 10 that is caulked and fixed simultaneously with the negative electrode terminal 9, an insulating plate 11 for the negative electrode, and the like.
[0015]
The lid 6 is made of a press-molded product made of an aluminum alloy plate material. An attachment hole 12 for the gasket 8 is formed in an oval shape in the center of the plate surface, and an explosion-proof cleavage vent is provided on one side plate surface of the attachment hole 12. 13 and an electrolyte solution injection hole 14 is provided on the other side plate surface. A seat 15 for the gasket 8 is recessed in the opening peripheral wall on the upper surface side of the mounting hole 12. The cleavage vent 13 is surrounded by a cut groove that circulates intermittently. When the internal pressure of the case exceeds a certain value, the cut groove breaks and releases gas. The injection hole 14 is closed by a plug 16 after injecting an electrolytic solution, and is sealed by welding the plug 16 to the lid 6.
[0016]
In FIG. 4, the negative electrode terminal 9 is made of an aluminum shaft body having a head portion 20, a shaft portion 21 protruding from the lower surface of the head portion 20, and a caulking shaft portion 22 formed at the lower end of the shaft portion 21. The caulking shaft portion 22 has a cylindrical shaft that opens downward, and the lower half side of the cylindrical wall is enlarged and caulked and deformed in an inverted manner. The head 20 includes a terminal portion 20a having an oval shape in plan view and a neck portion 20b having a cross-sectional diameter projecting from the lower surface of the terminal portion 20a, and a shaft portion 21 projecting from the lower surface of the neck portion 20b. . A sealing portion 19 is provided between the neck portion 20b and the shaft portion 21 to deform the boss portion 24 of the gasket 8 into an expanded diameter. The sealing portion 19 was formed on a tapered surface having a lower conical shape, and the inclination angle of the tapered surface was set to 45 degrees.
[0017]
The gasket 8 is made of a plastic molded product in which an oval flange portion 23 and a round shaft-shaped boss portion 24 projecting from the lower surface of the flange portion 23 are integrally formed, and the shaft portion 21 is formed at the center of the boss portion 24. A shaft insertion hole 25 that fits in the vertical direction is formed in a vertically penetrating manner, and a recess 26 that receives the head 20 of the output terminal 9 is formed in the center of the upper surface of the flange 23. In the upper end corner portion of the shaft insertion hole 25, a tapered surface 27 having a tapered shape corresponding to the previous sealing portion 19 is formed. Furthermore, a seal hole 28 having a smaller diameter than the shaft portion 21 is formed in a circular shape at the lower end of the shaft insertion hole 25.
[0018]
The sealing structure is assembled in the following procedure. First, after the insulator 7 is fitted into the battery case 1, the boss portion 24 of the gasket 8 is inserted into the mounting hole 12 of the lid 6, and the negative electrode terminal 9 is further inserted into the shaft insertion hole 25. At this time, the shaft portion 21 deforms the seal hole 28 in a diameter-enlarged shape, so that both 21 and 28 are in close contact with each other without a gap. Thereafter, the presser plate 10 is externally fitted to the shaft portion 21 via the negative electrode insulating plate 11, and the crimping shaft portion 22 is caulked in this state, whereby the boss portion 24 of the gasket 8 is crimped to the neck portion 20b. It is clamped up and down by the part 22 and deformed into a diameter-expanded shape, and at the same time, it is compressed by being vertically clamped. Further, the sealing portion 19 deforms the upper peripheral wall of the shaft insertion hole 25 through the seal surface 27 so as to expand in diameter. In addition, the lower portion of the shaft portion 21 is deformed larger than that in the free state during the caulking process, and the lower portion of the boss portion 24 is expanded. Therefore, the peripheral surface of the boss portion 24 is in close contact with the mounting hole 12 of the lid 6, and the gap between the both 12 and 24 can be completely sealed.
[0019]
The conductive tab 5 on the negative electrode side is welded to the holding plate 10 of the assembly, and the conductive tab 4 on the positive electrode side is welded to the inner surface of the lid 6. Thereafter, the lid 6 is fitted into the battery case 1, and the fitting surface between the lid 6 and the battery case 1 is welded and sealed. Finally, after injecting the electrolyte into the case from the injection hole 14, a plug 16 is fitted into the injection hole 14 and welded, and the injection hole 14 is sealed to complete the battery.
[0020]
The diameters of the shaft portion 21, the shaft insertion hole 25, and the seal hole 28 are set as follows. The diameter of the shaft portion 21 is the same as the diameter dimension of the shaft insertion hole 25, or the former diameter is made slightly smaller than the latter diameter. The diameter dimension of the seal hole 28 is set smaller than the diameter dimension of the shaft insertion hole 25 and further smaller than the diameter dimension of the shaft portion 21. More specifically, the value of 0.7 to 0.9 times the diameter dimension of the shaft portion 21 is set as the diameter value of the seal hole 28.
[0021]
In the above embodiment, the case where the output terminal 9 is a negative terminal is described, but this is not necessary, and it may be a positive terminal. The seal hole 28 can be formed at an arbitrary position of the shaft insertion hole 25 and can be formed at a plurality of locations if necessary. In addition to forming the sealing portion 19 with a tapered surface, the sealing portion 19 can be formed with a lower concavity-shaped rotating surface obtained by rotating a projecting arc surface or a concave arc surface about the vertical axis. The chamfer dimension of the seal surface 27 is preferably matched with the vertical dimension of the sealing part 19, but the chamfer dimension can be set smaller than the vertical dimension of the sealing part 19. In some cases, the sealing surface 27 may be omitted, and the upper end opening edge of the shaft insertion hole 25 may be expanded and deformed by the sealing portion 19. It is possible to omit the neck portion 20 b and project the shaft portion 21 on the lower surface of the head portion 20.
[0022]
【The invention's effect】
In the present invention, a sealing portion 19 having a constricted shape is provided at the protruding base end of the shaft portion 21 of the output terminal 9, and the boss portion 24 is fixed by the sealing portion 19 in a state where the output terminal 9 is caulked and fixed to the gasket 8. Simultaneously deforming in the expanding direction and the compressing direction so that the boss portion 24, the shaft portion 21 and the mounting hole 12 are brought into close contact with each other so that the gap between the gasket 8, the output terminal 9 and the lid 6 can be reliably sealed. did. Therefore, while adopting a structure in which the output terminal 9 is caulked and fixed as before, the gap between the gasket 8 and the output terminal 9 and the lid 6 can be reliably sealed, and liquid leakage due to poor sealing around the gasket can be eliminated. The reliability of the sealed battery can be improved accordingly. Since a part of the output terminal 9 and the gasket 8 are changed to avoid a sealing failure around the gasket, it is advantageous in that the sealing action can be strengthened without increasing the cost such as an increase in the number of parts. A sealed battery that does not contain the battery can be provided at a lower cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along line AA in FIG.
FIG. 2 is a longitudinal front view of a battery.
FIG. 3 is a plan view of a battery.
FIG. 4 is a cross-sectional view showing a state where an output terminal and a gasket are separated.
[Explanation of symbols]
1 Battery Case 6 Lid 9 Output Terminal (Negative Terminal)
19 Sealing portion 20 Head portion 21 Shaft portion 22 Caulking shaft portion 23 Flange portion 24 Boss portion 25 Shaft insertion hole 27 Seal surface

Claims

A sealed battery in which one output terminal (9) is caulked and fixed via a gasket (8) to a lid (6) that closes the opening of the battery case (1),
The output terminal (9) has a head portion (20) exposed on the outer surface of the gasket (8), a shaft portion (21) protruding from the lower surface of the head portion (20), and a lower end of the shaft portion (21). A caulking shaft portion (22) that is formed and is a cylindrical shaft that opens downward ;
The gasket (8) includes a flange portion (23) sandwiched between the head portion (20) and the lid (6), and a boss portion (24) fitted in a mounting hole (12) provided in the lid (6). The shaft insertion hole (25) that fits the shaft portion (21) is passed through the boss portion (24) in a vertically penetrating manner,
A sealing portion (19) for deforming the boss portion (24) into a diameter-enlarging shape is formed in a constricted shape at the protruding proximal end of the shaft portion (21),
A seal hole (28) smaller in diameter than the shaft (21) of the output terminal (9) is formed in a circular shape at the lower end of the shaft insertion hole (25), and the output terminal (9) is assembled to the gasket (8). In this state, the seal hole (28) is deformed to expand in diameter at the shaft portion (21),
By caulking the caulking shaft portion (22) of the output terminal (9) , the shaft insertion hole (25) of the gasket (8) is brought into close contact with the shaft portion 21 of the output terminal (9), and the boss of the gasket (8). A sealed battery in which the portion (24) is in close contact with the mounting hole (12) of the lid (6) .

The sealing part (19) is formed with a downwardly tapered surface, and at the upper end of the shaft insertion hole (25) of the gasket (8), a downwardly tapered taper shape corresponding to the sealing part (19) is formed. The sealed battery according to claim 1, wherein a sealing surface (27) is formed .