JP3607179B2 - Sealing plate safety valve device and manufacturing method of sealing plate safety valve - Google Patents

Sealing plate safety valve device and manufacturing method of sealing plate safety valve Download PDF

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JP3607179B2
JP3607179B2 JP2000247392A JP2000247392A JP3607179B2 JP 3607179 B2 JP3607179 B2 JP 3607179B2 JP 2000247392 A JP2000247392 A JP 2000247392A JP 2000247392 A JP2000247392 A JP 2000247392A JP 3607179 B2 JP3607179 B2 JP 3607179B2
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safety valve
sealing plate
rubber
plate safety
gas
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JP2002063885A (en
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和広 在里
昌明 小峪
但 国政
理 大久保
澄雄 前川
明 垣内
忠孝 山崎
明治 佐々木
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大東ポリマー工業株式会社
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description

【０００１】
【発明の属する技術分野】
本発明は、密閉型二次電池に用いられる封口板安全弁装置と封口板安全弁の製造方法に関するものである。
【０００２】
【従来の技術】
この種の密閉型二次電池は、充放電を繰り返して使用されるものであるが、使用の際あるいは使用後に急激な過電流が流れると発熱し、電池内部の電解液の温度上昇により電池内部にガスが発生する。異常にガスが発生した場合は、発生したガスが高圧となり電解液漏れを生じる場合がある。これを防止し、また急激な昇圧を防止する目的で、二次電池の外装缶の開口部に封口板安全弁装置を設けることが従来より行われている。
【０００３】
この封口板安全弁装置は、ガス抜き孔を有する封口板と、ガス抜き孔からガスが抜けるときの圧力方向に１対の平行面を有し、その片面でガス抜き孔を塞ぐゴム弾性を有する高分子材料からなる安全弁と、この安全弁を覆うと共にガス抜きされたガスを排出する排出孔を有するキャップとからなり、前記安全弁を、キャップと封口板との間に形成された空間内にキャップと封口板との間で圧縮されるようにして収容している。安全弁は、金型によって加工された成形体が使用されている。
【０００４】
安全弁の基本機能を本実施形態を示す図１と図２を参酌して説明すれば、電池内部で異常なガスが発生すると、キャップ８内に圧縮状態で収容された安全弁６は、ガス発生による圧力上昇に応動して上方に圧縮変形してガス抜き孔５を開き、破線矢印で示すように、ガス７をガス抜き孔５からキャップ８の排出口８ａを通じて外部に排出させる。ガス７が抜けるときの圧力（作動圧）は、安全弁６の弾性係数と厚み（作動圧がかかる方向の厚み）寸法精度に左右される。
【０００５】
【発明が解決しようとする課題】
しかしながら、従来の封口板安全弁装置は、安全弁を成形する高分子材料がたとえ高い精度の弾性係数のものであっても、それを成形体に加工した場合に、成形体の厚み寸法のばらつきが大きく寸法選別をしない限り安定した作動圧が得られないという課題があった。
【０００６】
【課題を解決するための手段】
本発明の封口板安全弁の製造方法は、上記課題を達成するために、ゴム弾性を有する高分子材料からなり、所定の厚みに成形された円筒状体を、円筒外形を有するマンドレルに拡径状態で装着し、前記円筒状体の外面を回転砥石で前記円筒状体が設定された厚みになるまで円筒研磨し、次いで円筒研磨後の円筒状体をカットして帯状シート体になるように展開した後、この帯状シート体からカッティングまたは打ち抜きにより所定形状の封口板安全弁を多数得ることを特徴とする。また本発明の封口板安全弁装置は上記課題を達成するために、ガス抜き孔を有する封口板と、ガス抜き孔からガスが抜けるときの圧力方向に１対の平行面を有し、その片面でガス抜き孔を塞ぐゴム弾性を有する高分子材料からなる安全弁と、この安全弁を覆うと共にガス抜きされたガスを排出する排出孔を有するキャップとからなり、前記安全弁を、キャップと封口板内との間に形成された空間内にキャップと封口板との間で圧縮されるようにして収容した封口板安全弁装置において、安全弁として上記封口板安全弁の製造方法で得られた封口板安全弁を用い、安全弁の前記１対の平行面の少なくとも１面を、研磨加工面としたことを特徴とする。
【０００７】
上記発明によれば、安全弁の１対の平行面のうち少なくとも１面を研磨加工面としているので、封口板のガス抜き孔からガスが抜けるときの作動圧方向における厚みの寸法精度が向上し、極めて安定した高精度の作動圧を示すことができる。そして上記封口板安全弁装置を用いて密閉型二次電池を構成すると、高い安全性、信頼性を得ることができる。
【０００８】
【発明の実施の形態】
本発明の封口板安全弁装置は、封口板と安全弁とキャップとが合体して高精度な作動圧を示すことができ、その作動圧方向の一対の平行面の１面となる研磨加工面は、１面の場合よりも平行面両方２面の場合がまた、研磨は１回より２回以上の方がより高精度の寸法精度を得ることができる。
【０００９】
ゴム弾性を有する高分子材料としては、天然ゴム、イソプレンゴム、ブタジエンゴム、スチレン−ブタジエンゴム、ニトリルゴム、ブチルゴム、アクリルゴム、フッ素ゴム、エチレン−プロピレンゴム、エピクロルヒドリンゴム、ウレタンゴム等および、これらの内２種類以上のポリマーをブレンドした加硫ゴムを用いることができる。また架橋剤の添加を必要としないポリオレフィン系、ポリスチレン系、ポリブタジエン系、ポリウレタン系、ポリエステル系、ポリアミド系、フッ素系等の熱可塑性エラストマーを用いることもできる。さらに前記加硫ゴムと熱可塑性エラストマーにブレンドする樹脂としてポリオレフィン、ポリウレタン、ポリスチレン等を用いることもできる。
【００１０】
本発明が適用される密閉型二次電池は、上記各封口板安全弁装置を用いてなるニッケル水素電池、ニッケルカドミウム電池等の二次電池であり、高い安全性を得ることができる。
【００１１】
【実施例】
以下、本発明の実施例について図１〜図４を用いて詳細に説明する。
【００１２】
本発明の実施例に用いる封口板安全弁装置２は図１に示すように、密閉型二次電池１の外装缶３の開口部に絶縁ガスケット４を介して気密にカシメ固定されており、円板状で中央部にガス抜き孔５ａを有する封口板５と、直方体でガス抜き孔５ａからガスが抜けるときの作動圧方向に１対の平行面６ａを有し、その片面でガス抜き孔５ａを塞ぐ弾性ゴムからなる安全弁６と、この安全弁６を皿型の安全弁収容部８ｂで覆うと共に外周縁を封口板５に溶着し、側壁にガス７（図２に破線矢印で示す。）を排出する排出孔８ａを有するキャップ８とから構成される。安全弁６は、キャップ８と封口板５との間に形成された空間つまり前記安全弁収容部８ｂ内にキャップ８と封口板５との間で圧縮されるようにして収容されている。
【００１３】
封口板安全弁装置２の基本機能を図２を参照して説明すれば、二次電池１の内部で異常なガスが発生すると、キャップ８内に圧縮状態で収容された安全弁６は、ガス発生による圧力上昇に応動して上方に圧縮変形してガス抜き孔５を開き、破線矢印で示すように、ガス７をガス抜き孔５からキャップ８の排出口８ａを通じて外部に排出させる。ガス７が抜けるときの作動圧は、安全弁６の弾性係数と厚み（作動圧がかかる方向の厚み）寸法精度に左右される。本実施例では１対の平行面６ａの少なくとも１面を、研磨加工面６ｂとすることにより寸法精度を向上させている。
【００１４】
以下実施例と参考例において、安全弁６を成形する高分子材料や製造方法の異なる２つの例で説明する。
【００１５】
（実施例）
上記封口板安全弁装置２を構成する安全弁６の製造方法について、図３に示す実施例に基づき説明する。この安全弁６に用いる高分子材料としての加硫ゴムは、天然ゴム１００重量部、カーボンブラック５０重量部、石油系プロセスオイル１０重量部、フェニル−α−ナフチルアミン２重量部、ステアリン酸１重量部、ジクミルパーオキサイド５重量部をオープンロールで混練しゴム組成物を得た。
【００１６】
次に金型に充填し１６０℃×１０分で成形加硫を行い、図３（ａ）に示すように中心径Ｄ1 が１００ｍｍ、厚みＴ1 が４ｍｍ、長さが１００ｍｍ、硬さが６０度（ＪＩＳスプリング式硬度計）の円筒状のゴム加硫体９を作成した。次に図３（ｂ）に示すように、ゴム加硫体９を拡径して外径Ｄ2 が１０８ｍｍのマンドレル１２に装着し、円筒外面を回転砥石で厚みを３．８ｍｍまで研磨し、研磨加工面６ｂを形成した。尚、ゴム加硫体９を裏返して両面を研磨することも可能であるし、研磨を２回以上行っても良い。
【００１７】
そして研磨されたゴム加硫体９を長手方向にカットし、図３（ｃ）に示す厚みＴ2 が３．８ｍｍの帯状のシート１０を作成した。このシート１０を切断刃を用いて縦横２方向より図３（ｄ）に示すように順次カットし、図３（ｅ）に示すように長さが４ｍｍ、巾が４ｍｍ、厚みＴ2 が３．８ｍｍで、上面に研磨加工面６ｂが形成された直方体を多数作成した。尚、前記厚みＴ2 は直方体が封口板安全弁装置２の安全弁６を構成したとき、作動圧方向の厚みとなる。個々の直方体において前記厚み寸法精度を測定した結果、下記の表１に示すように厚みムラ（最大値と最小値との寸法差）が片面研磨では０．０２ｍｍ以下、両面研磨では０．０１ｍｍ以下の精度を得た。
【００１８】
【表１】

Figure 0003607179
【００１９】
（参考例）
前記安全弁６の製造方法について、図４に示す参考例に基づき説明する。この安全弁６に用いる高分子材料としてのゴム−樹脂組成物は、スチレン−ブタジエンゴム１００重量部、ポリスチレン２０重量部、ステアリン酸１重量部、カーボンブラック４０重量部、石油系プロセスオイル１５重量部、フェニル−α−ナフチルアミン２重量部、ジクミルパーオキサイド５重量部を熱オープンロールで加熱混練し、ゴム−樹脂組成物を得た。
【００２０】
次に金型に充填し１６０℃×１０分で成形加硫を行い、図４（ａ）に示すように長さが１００ｍｍ、巾が３００ｍｍ、厚みＴ1 が４ｍｍ、硬さ６０度のゴム−樹脂組成物のシート１１を作成した。次にこのシート１１を図示しない平面板用の研磨機で厚みＴ2 が３．８ｍｍまで高精度研磨を行い、研磨加工面６ｂを形成した（図４（ｂ））。尚、シート１１を裏返して両面を研磨することも可能であるし、同じ面に２回研磨を行っても良い。
【００２１】
そして研磨されたシート１１を、切断刃を用いて縦横２方向より図４（ｃ）に示すように順次カットし、図４（ｄ）に示すように長さが４ｍｍ、巾が４ｍｍ、厚みＴ2 が３．８ｍｍで１面に研磨加工面６ｂが形成された実施例と同様の直方体（安全弁６）を多数作成した。個々の直方体において厚み寸法精度を測定した結果、上記表１に示すように厚みムラが片面研磨では０．０３ｍｍ以下、両面研磨では０．０２ｍｍ以下の精度を得た。
【００２２】
以上のように実施例は安全弁６のゴム加硫物の円筒研磨の例であり、参考例はゴム−樹脂組成物の平面研磨の例である。これら実施例、参考例と従来製法における厚み寸法精度の結果を示す上記表１により比較すると、シート１０、１１の片面ないし両面を研磨することにより高精度の厚み寸法を得ることができ、また側面を研磨することによりカット巾方向での寸法精度も向上する。
【００２３】
上記実施例によって作成された直方体により構成された安全弁６は、研磨加工面６ｂが形成されているので作動圧方向の厚み寸法精度が向上し、その安全弁６を組込んだ封口板安全弁装置２における作動圧を著しく高精度化することができる。この封口板安全弁装置２における作動圧の安定性を、従来品との比較した実験例によれば、従来品では±２０％の作動圧ばらつきがあったのに対し、本実施例の研磨品は±５％の作動圧ばらつきに改善することが可能になった。尚、試料は長さが４ｍｍ、巾が４ｍｍ、厚みが３．８ｍｍの直方体を用い、作動圧の測定方法は試料を圧縮し、二次電池内部の下方向からガスを昇圧させながら（図２参照）、試料に圧力をかけ、ガスが外部に排出され内圧が下がったときの圧力の値を作動圧とした。
【００２４】
本発明は上記実施例に示すほか種々の態様に構成することができ、例えば、安全弁を成形する高分子材料は上記実施例以外に、他の一般ゴム、熱可塑性エラストマー、異種ポリマーをブレンドした加硫ゴムを材料として用いることができる。また、安全弁の形状は前記厚み方向の１対の平行面を有し、その少なくとも１面が研磨されている限り、上記実施例に示す形状に限定されず、またその製造方法もカッティングの他、打ち抜きを採用しても良い。
【００２５】
【発明の効果】
本発明によれば、以上説明したように封口板安全弁装置を構成する安全弁に研磨加工面を設けることにより、ガスの作動圧方向における厚みの寸法精度が向上し、極めて安定した高精度の作動圧を示すことができ、この封口板安全弁装置を用いて密閉型二次電池を構成すると、高い安全性、信頼性を得ることができる。
【図面の簡単な説明】
【図１】本発明の実施例における密閉型二次電池を示し、（ａ）はその縦断側面図、（ｂ）はその平面図。
【図２】本発明の実施例における封口板安全弁装置の基本機能図。
【図３】本発明の実施例における安全弁の製造方法を示す概略図。
【図４】参考例における安全弁の製造方法を示す概略図。
【符号の説明】
１ 密閉型二次電池
２ 封口板安全弁装置
５ 封口板
５ａ ガス抜き孔
６ 安全弁
６ａ 平行面
６ｂ 研磨加工面
７ ガス
８ キャップ
８ａ 排出孔
８ｂ 安全弁収容部
９ ゴム加硫体（加硫ゴム）
１１ シート（ゴム−樹脂組成物）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method of the sealing plate safety valve device and the sealing plate a safety valve used in the sealed secondary batteries.
[0002]
[Prior art]
This type of sealed secondary battery is used by repeatedly charging and discharging, but generates heat when a sudden overcurrent flows during or after use, and the internal temperature of the battery rises due to a rise in the electrolyte temperature inside the battery. Gas is generated. When the gas is abnormally generated, the generated gas may become high pressure and electrolyte leakage may occur. In order to prevent this, and to prevent sudden pressure increase, it has been conventionally practiced to provide a sealing plate safety valve device at the opening of the outer can of the secondary battery.
[0003]
This sealing plate safety valve device has a sealing plate having a gas venting hole, a pair of parallel surfaces in the pressure direction when gas escapes from the gas venting hole, and has a rubber elasticity that closes the gas venting hole on one side. A safety valve made of a molecular material and a cap that covers the safety valve and has a discharge hole for discharging the degassed gas. The safety valve is placed in a space formed between the cap and the sealing plate. It is accommodated by being compressed between the plates. As the safety valve, a molded body processed by a mold is used.
[0004]
The basic function of the safety valve will be described with reference to FIGS. 1 and 2 showing the present embodiment. When an abnormal gas is generated inside the battery, the safety valve 6 accommodated in a compressed state in the cap 8 In response to the pressure increase, the gas is compressed and deformed upward to open the gas vent hole 5, and the gas 7 is discharged from the gas vent hole 5 to the outside through the discharge port 8 a of the cap 8 as indicated by the broken line arrow. The pressure (working pressure) when the gas 7 is released depends on the elastic coefficient and thickness (thickness in the direction in which the working pressure is applied) of the safety valve 6 and the dimensional accuracy.
[0005]
[Problems to be solved by the invention]
However, in the conventional sealing plate safety valve device, even if the polymer material forming the safety valve is a highly accurate elastic coefficient, when the molded material is processed into a molded product, the thickness dimension of the molded product varies greatly. There is a problem that a stable operating pressure cannot be obtained unless dimension selection is performed.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the manufacturing method of the sealing plate safety valve of the present invention is a state in which a cylindrical body made of a polymer material having rubber elasticity and having a predetermined thickness is expanded to a mandrel having a cylindrical outer shape. The cylindrical body is cylindrically polished with a rotating grindstone until the cylindrical body reaches the set thickness, and then the cylindrical body after the cylindrical polishing is cut to develop a belt-like sheet body. After that, a large number of sealing plate safety valves having a predetermined shape are obtained from the belt-like sheet body by cutting or punching. Moreover, the sealing plate safety valve device of the present invention has a sealing plate having a gas vent hole and a pair of parallel surfaces in the pressure direction when the gas escapes from the gas vent hole in order to achieve the above-mentioned problem. A safety valve made of a polymer material having rubber elasticity that closes the gas vent hole, and a cap that covers the safety valve and has a discharge hole that exhausts the degassed gas, and the safety valve is disposed between the cap and the sealing plate. In a sealing plate safety valve device accommodated in a space formed between the cap and the sealing plate so as to be compressed, the sealing plate safety valve obtained by the manufacturing method of the sealing plate safety valve is used as a safety valve. At least one of the pair of parallel surfaces is a polished surface.
[0007]
According to the above invention, since at least one of the pair of parallel surfaces of the safety valve is a polished surface, the dimensional accuracy of the thickness in the operating pressure direction when the gas escapes from the vent hole of the sealing plate is improved. An extremely stable and highly accurate operating pressure can be shown. When a sealed secondary battery is configured using the sealing plate safety valve device, high safety and reliability can be obtained.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the sealing plate safety valve device of the present invention, the sealing plate, the safety valve, and the cap can be combined to show a high-accuracy operating pressure, and the polished surface that becomes one of a pair of parallel surfaces in the operating pressure direction is In the case of both two parallel surfaces than in the case of one surface, the polishing can be performed more than twice, so that higher dimensional accuracy can be obtained.
[0009]
The polymeric material having a rubber elasticity, natural rubber, isoprene rubber, butadiene rubber, styrene - butadiene rubber, nitrile rubber, butyl rubber, acrylic rubber, fluorine rubber, ethylene - propylene rubber, epichlorohydrin rubber, urethane rubber and, of these Vulcanized rubber obtained by blending two or more of these polymers can be used . In addition, thermoplastic elastomers such as polyolefin-based, polystyrene-based, polybutadiene-based, polyurethane-based, polyester-based, polyamide-based, and fluorine-based which do not require the addition of a crosslinking agent can also be used. Further, polyolefin, polyurethane, polystyrene or the like can be used as a resin blended with the vulcanized rubber and the thermoplastic elastomer.
[0010]
The sealed secondary battery to which the present invention is applied is a secondary battery such as a nickel metal hydride battery or a nickel cadmium battery using the respective sealing plate safety valve devices, and can provide high safety.
[0011]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
[0012]
As shown in FIG. 1, a sealing plate safety valve device 2 used in an embodiment of the present invention is airtightly fixed to an opening of an outer can 3 of a sealed secondary battery 1 via an insulating gasket 4, And a sealing plate 5 having a gas vent hole 5a at the center and a pair of parallel surfaces 6a in the operating pressure direction when gas escapes from the gas vent hole 5a in a rectangular parallelepiped, and the gas vent hole 5a is formed on one side thereof. The safety valve 6 made of elastic rubber to be closed, the safety valve 6 is covered with a dish-shaped safety valve housing 8b, the outer peripheral edge is welded to the sealing plate 5, and the gas 7 (indicated by a broken line arrow in FIG. 2) is discharged to the side wall. And a cap 8 having a discharge hole 8a. The safety valve 6 is accommodated in a space formed between the cap 8 and the sealing plate 5, that is, in the safety valve accommodating portion 8b so as to be compressed between the cap 8 and the sealing plate 5.
[0013]
If the basic function of the sealing plate safety valve device 2 is described with reference to FIG. 2, when abnormal gas is generated inside the secondary battery 1, the safety valve 6 accommodated in a compressed state in the cap 8 is caused by gas generation. In response to the pressure increase, the gas is compressed and deformed upward to open the gas vent hole 5, and the gas 7 is discharged from the gas vent hole 5 to the outside through the discharge port 8 a of the cap 8 as indicated by the broken line arrow. The operating pressure when the gas 7 is released depends on the elastic coefficient and thickness of the safety valve 6 (thickness in the direction in which the operating pressure is applied) dimensional accuracy. In this embodiment, the dimensional accuracy is improved by making at least one of the pair of parallel surfaces 6a a polished surface 6b.
[0014]
In the following examples and reference examples , two examples of different polymeric materials for molding the safety valve 6 and different manufacturing methods will be described.
[0015]
( Example )
A method for manufacturing the safety valve 6 constituting the sealing plate safety valve device 2 will be described based on the embodiment shown in FIG. The vulcanized rubber as the polymer material used for the safety valve 6 is 100 parts by weight of natural rubber, 50 parts by weight of carbon black, 10 parts by weight of petroleum-based process oil, 2 parts by weight of phenyl-α-naphthylamine, 1 part by weight of stearic acid, A rubber composition was obtained by kneading 5 parts by weight of dicumyl peroxide with an open roll.
[0016]
Next, the mold is filled and molded and vulcanized at 160 ° C. for 10 minutes. As shown in FIG. 3A, the center diameter D 1 is 100 mm, the thickness T 1 is 4 mm, the length is 100 mm, and the hardness is 60. A cylindrical rubber vulcanizate 9 having a degree (JIS spring type hardness tester) was prepared. Next, as shown in FIG. 3 (b), the outer diameter D 2 and expanded rubber vulcanizates 9 is mounted on a mandrel 12 of 108 mm, polished thickness to 3.8mm cylindrical outer surface with grinding wheel, A polished surface 6b was formed. It is possible to turn the rubber vulcanized body 9 upside down and polish both sides, or the polishing may be performed twice or more.
[0017]
Then, the polished rubber vulcanized body 9 was cut in the longitudinal direction, and a belt-like sheet 10 having a thickness T 2 of 3.8 mm shown in FIG. This sheet 10 is sequentially cut from two directions, as shown in FIG. 3D, using a cutting blade, as shown in FIG. 3E, and has a length of 4 mm, a width of 4 mm, and a thickness T 2 of 3. A large number of rectangular parallelepipeds having an upper surface and a polished surface 6b of 8 mm were formed. The thickness T 2 is the thickness in the operating pressure direction when the rectangular parallelepiped forms the safety valve 6 of the sealing plate safety valve device 2. As a result of measuring the thickness dimensional accuracy in each rectangular parallelepiped, as shown in Table 1 below, the thickness unevenness (dimensional difference between the maximum value and the minimum value) is 0.02 mm or less for single-side polishing, and 0.01 mm or less for double-side polishing. Obtained accuracy.
[0018]
[Table 1]
Figure 0003607179
[0019]
( Reference example )
A method of manufacturing the safety valve 6 will be described based on a reference example shown in FIG. The rubber-resin composition as a polymer material used for the safety valve 6 is 100 parts by weight of styrene-butadiene rubber, 20 parts by weight of polystyrene, 1 part by weight of stearic acid, 40 parts by weight of carbon black, 15 parts by weight of petroleum-based process oil, 2 parts by weight of phenyl-α-naphthylamine and 5 parts by weight of dicumyl peroxide were heat-kneaded with a hot open roll to obtain a rubber-resin composition.
[0020]
Next, the mold is filled and molded and vulcanized at 160 ° C. for 10 minutes. As shown in FIG. 4A, a rubber having a length of 100 mm, a width of 300 mm, a thickness T 1 of 4 mm, and a hardness of 60 degrees A resin composition sheet 11 was prepared. Next, the sheet 11 was polished with high precision to a thickness T 2 of 3.8 mm using a flat plate polishing machine (not shown) to form a polished surface 6b (FIG. 4B). It is possible to turn the sheet 11 upside down and polish both sides, or the same side may be polished twice.
[0021]
Then, the polished sheet 11 is sequentially cut from two directions, as shown in FIG. 4C, using a cutting blade, as shown in FIG. 4D, and has a length of 4 mm, a width of 4 mm, and a thickness T as shown in FIG. A large number of rectangular parallelepipeds (safety valves 6) similar to the example in which 2 is 3.8 mm and the polished surface 6b is formed on one surface were prepared. As a result of measuring the thickness dimension accuracy in each rectangular parallelepiped, as shown in Table 1 above, the thickness unevenness was 0.03 mm or less in single-side polishing and 0.02 mm or less in double-side polishing.
[0022]
As described above, the examples are examples of cylindrical polishing of a rubber vulcanizate of the safety valve 6, and the reference example is an example of flat polishing of a rubber-resin composition. Comparing these Examples, Reference Examples and Table 1 showing the results of the thickness dimensional accuracy in the conventional manufacturing method, it is possible to obtain a highly accurate thickness dimension by polishing one or both sides of the sheets 10 and 11. The dimensional accuracy in the cut width direction is also improved by polishing.
[0023]
Safety valve 6 constituted by a rectangular parallelepiped created by the above embodiments, the polishing surface so 6b is formed to improve operating pressure direction thickness dimensional precision, sealing plate safety valve device 2 incorporating the safety valve 6 The operating pressure can be remarkably improved. According to the experimental example in which the stability of the operating pressure in the sealing plate safety valve device 2 is compared with the conventional product, the operating product has a variation of ± 20% in the conventional product, whereas the polished product of the present example is It became possible to improve the operating pressure variation of ± 5%. Note that the sample is a rectangular parallelepiped having a length of 4 mm, a width of 4 mm, and a thickness of 3.8 mm. The method for measuring the operating pressure is to compress the sample and increase the gas from below in the secondary battery (FIG. 2). Reference), pressure was applied to the sample, the value of the pressure when the gas was discharged to the outside and the internal pressure decreased was taken as the operating pressure.
[0024]
The present invention can be configured in various modes in addition to those shown in the above examples. For example, the polymer material for molding the safety valve is not limited to the above examples, but is a blend of other general rubber, thermoplastic elastomer, and different polymers. Sulfur rubber can be used as a material. The shape of the safety valve has a pair of parallel surfaces in the thickness direction, and is not limited to the shape shown in the above embodiment as long as at least one surface is polished. Punching may be used.
[0025]
【The invention's effect】
According to the present invention, as described above, by providing a polished surface on the safety valve constituting the sealing plate safety valve device, the dimensional accuracy of the thickness in the gas operating pressure direction is improved, and the highly stable operating pressure is extremely stable. When a sealed secondary battery is configured using this sealing plate safety valve device, high safety and reliability can be obtained.
[Brief description of the drawings]
FIG. 1 shows a sealed secondary battery according to an embodiment of the present invention, in which (a) is a longitudinal side view thereof and (b) is a plan view thereof.
FIG. 2 is a basic functional diagram of a sealing plate safety valve device according to an embodiment of the present invention.
FIG. 3 is a schematic diagram showing a method for manufacturing a safety valve in an embodiment of the present invention.
FIG. 4 is a schematic view showing a method for manufacturing a safety valve in a reference example .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sealed type secondary battery 2 Sealing plate safety valve device 5 Sealing plate 5a Gas vent hole 6 Safety valve 6a Parallel surface 6b Polishing surface 7 Gas 8 Cap 8a Discharge hole 8b Safety valve housing part 9 Rubber vulcanizate (vulcanized rubber)
11 Sheet (Rubber-resin composition)

Claims (3)

ゴム弾性を有する高分子材料からなり、所定の厚みに成形された円筒状体を、円筒外形を有するマンドレルに拡径状態で装着し、前記円筒状体の外面を回転砥石で前記円筒状体が設定された厚みになるまで円筒研磨し、次いで円筒研磨後の円筒状体をカットして帯状シート体になるように展開した後、この帯状シート体からカッティングまたは打ち抜きにより所定形状の封口板安全弁を多数得ることを特徴とする封口板安全弁の製造方法。A cylindrical body made of a polymer material having rubber elasticity and having a predetermined thickness is attached to a mandrel having a cylindrical outer shape in an expanded state, and the outer surface of the cylindrical body is a rotating grindstone, and the cylindrical body is After cylindrical polishing until the set thickness is achieved, then the cylindrical body after cylindrical polishing is cut and developed to form a belt-like sheet body, and then a sealing plate safety valve of a predetermined shape is formed by cutting or punching from the belt-like sheet body A method for manufacturing a sealing plate safety valve, characterized in that a large number are obtained. ガス抜き孔を有する封口板と、ガス抜き孔からガスが抜けるときの圧力方向に１対の平行面を有し、その片面でガス抜き孔を塞ぐゴム弾性を有する高分子材料からなる安全弁と、この安全弁を覆うと共にガス抜きされたガスを排出する排出孔を有するキャップとからなり、前記安全弁を、キャップと封口板との間に形成された空間内にキャップと封口板との間で圧縮されるようにして収容した封口板安全弁装置において、安全弁として請求項１記載の封口板安全弁の製造方法で得られた封口板安全弁を用い、安全弁の前記１対の平行面の少なくとも１面を、研磨加工面としたことを特徴とする封口板安全弁装置。A sealing plate having a vent hole, a safety valve made of a polymer material having rubber elasticity having a pair of parallel surfaces in the pressure direction when gas escapes from the vent hole and closing the vent hole on one side thereof, The safety valve is covered with a cap having a discharge hole for discharging the degassed gas, and the safety valve is compressed between the cap and the sealing plate in a space formed between the cap and the sealing plate. In the sealing plate safety valve device accommodated as described above, the sealing plate safety valve obtained by the manufacturing method of the sealing plate safety valve according to claim 1 is used as a safety valve, and at least one of the pair of parallel surfaces of the safety valve is polished. A sealing plate safety valve device characterized by having a machined surface. 高分子材料は、加硫ゴム、熱可塑性エラストマー、ゴム−樹脂組成物を含むものである請求項２記載の封口板安全弁装置。The sealing plate safety valve device according to claim 2, wherein the polymer material includes vulcanized rubber, thermoplastic elastomer, and rubber-resin composition.
JP2000247392A 2000-08-17 2000-08-17 Sealing plate safety valve device and manufacturing method of sealing plate safety valve Expired - Fee Related JP3607179B2 (en)

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JP2006135070A (en) * 2004-11-05 2006-05-25 Nichicon Corp Aperture sealing plate having a pressure valve and electronic component using the same
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