JP4701636B2 - Sealed storage battery exhaust valve, sealed storage battery using the same, sealed nickel metal hydride storage battery - Google Patents

Sealed storage battery exhaust valve, sealed storage battery using the same, sealed nickel metal hydride storage battery Download PDF

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JP4701636B2
JP4701636B2 JP2004166314A JP2004166314A JP4701636B2 JP 4701636 B2 JP4701636 B2 JP 4701636B2 JP 2004166314 A JP2004166314 A JP 2004166314A JP 2004166314 A JP2004166314 A JP 2004166314A JP 4701636 B2 JP4701636 B2 JP 4701636B2
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storage battery
valve
rubber elastic
elastic body
sealed
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JP2005347130A5 (en
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実 黒葛原
香織 初代
充浩 児玉
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GS Yuasa International Ltd
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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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    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Description

本発明は、密閉形蓄電池用排気弁およびそれを用いた密閉形蓄電池に関するもので、充電済みの蓄電池を外部短絡させるあるいは密閉形蓄電池を急速充電して蓄電池が異常な高温になったり、誤って蓄電池を落下させてキャップが変形してしまうような蓄電池が回復不能となる状況下においても機能する密閉形蓄電池用排気弁および該排気弁を適用した密閉形蓄電池、とりわけ水素吸蔵合金電極を負極に用いた密閉形ニッケル水素蓄電池に関するものであって、前記状況下においても破裂する虞のない密閉形蓄電池の提供を可能とする密閉形蓄電池用排気弁および密閉形蓄電池、特に密閉形ニッケル水素蓄電池に関するものである。   The present invention relates to an exhaust valve for a sealed storage battery and a sealed storage battery using the same, and externally short-circuits a charged storage battery or rapidly charges the sealed storage battery to cause the storage battery to reach an abnormally high temperature. An exhaust valve for a sealed storage battery that functions even in a situation where the storage battery cannot be recovered by dropping the storage battery and the cap is deformed, and a sealed storage battery to which the exhaust valve is applied, particularly a hydrogen storage alloy electrode as a negative electrode The present invention relates to a sealed nickel-metal hydride storage battery, and relates to a sealed storage battery exhaust valve and a sealed storage battery, particularly a sealed nickel-metal hydride storage battery that can provide a sealed storage battery that does not rupture even under the above circumstances. Is.

従来の密閉形ニッケル水素電池やニッケルカドミウム電池においては、有底筒状電槽缶の開放端にキャップを固着した封口板を配置し、ガスケットを介して前記電槽缶の開放端部をかしめることによって電槽缶の上部を閉鎖している。前記封口板の中央部に排気用の透孔を設け、常時は前記封口板とキャップで囲まれた弁室に圧縮状態で装備したゴム製弁体によって排気孔を気密に封止し、蓄電池内部のガス圧が上昇したときには排気孔を開口させることによって、内部に蓄積したガスを排出する圧力調整機構を採っている。   In a conventional sealed nickel-metal hydride battery or nickel cadmium battery, a sealing plate with a cap secured to the open end of a bottomed cylindrical battery case can be disposed, and the open end of the battery case can be caulked through a gasket. This closes the top of the battery case. An exhaust through hole is provided in the central portion of the sealing plate, and the exhaust hole is hermetically sealed by a rubber valve body that is normally provided in a compressed state in a valve chamber surrounded by the sealing plate and a cap. When the gas pressure rises, a pressure adjusting mechanism is employed to discharge the gas accumulated inside by opening an exhaust hole.

以前より、充電済みの蓄電池を誤って外部短絡させたり、１００℃を超えるような高温下に曝した場合にも破裂の虞の無い密閉形蓄電池実現の要望があるが、蓄電池の温度が１００℃を超えるような異常な高温になった場合には、ゴム製の弁体が膨張したり、弾性率が変化するためか圧力調整弁が動作せずに破裂に至る虞があり、前記要望に応えることは難しかった。
特に水素吸蔵合金電極を負極に用いたニッケル水素蓄電池の場合、温度が上昇すると水素を吸蔵させた水素吸蔵電極の平衡圧が増大するためか蓄電池内部の圧力が急激に上昇するために排気弁の機能が追いつかずに破裂に至る虞があった。 There has been a demand for realization of a sealed storage battery that has no risk of rupture even when a charged storage battery is accidentally short-circuited externally or exposed to a high temperature exceeding 100 ° C., but the temperature of the storage battery is 100 ° C. When the temperature becomes abnormally high, the rubber valve element may expand or the elastic modulus may change, causing the pressure regulating valve to not operate and rupture. That was difficult.
In particular, in the case of a nickel metal hydride storage battery that uses a hydrogen storage alloy electrode for the negative electrode, the exhaust valve's internal pressure increases because the equilibrium pressure of the hydrogen storage electrode that stores hydrogen increases or the pressure inside the storage battery suddenly increases. There was a risk that the function would not catch up and could rupture.

また、蓄電池を高温下に曝す以外に、蓄電池を落下させるなどしてキャップに衝撃が加わり、キャップが変形した場合（キャップが潰れた状態）にもゴム製弁体の圧縮率が高まり圧縮応力が増大するためか、前記排気弁が動作しない虞があった。   In addition to exposing the storage battery to high temperatures, the impact is applied to the cap by dropping the storage battery, etc., and the compression rate of the rubber valve body increases when the cap is deformed (when the cap is crushed). There is a possibility that the exhaust valve does not operate because of an increase.

さらに、近年蓄電池の充電時間を短縮したいとの要望に応えるために、３０分間以内、とりわけ約１５分間で充電を完了させるという従来のアルカリ蓄電池では行われていなかった急速充電に対応できる密閉形アルカリ蓄電池が提案されている。例えば密閉形のアルカリ蓄電池を前記急速充電しようとすると、多量のガスが発生して蓄電池内部の圧力が増大したり、蓄電知の温度が上昇して蓄電池の特性劣化を招く虞があった。このように急速な充電に対応する出来るようにするため、前記提案に係る密閉形蓄電池は、正極板と正極の外部端子（キャップ）を結ぶ回路に、充電中において蓄電池の内部圧力が所定値を超えたときに前記回路をオンからオフに切り替えて充電を停止し、蓄電池の内部圧力が所定値以下になったとき前記回路をオフからオンに切り替えて充電を再開する圧力スイッチ機構を内蔵させた密閉形蓄電池である。（例えば特許文献１参照）   Furthermore, in order to meet the demand for shortening the charging time of the storage battery in recent years, a sealed alkaline solution that can cope with rapid charging, which has not been performed in the conventional alkaline storage battery, in which charging is completed within 30 minutes, particularly about 15 minutes. Storage batteries have been proposed. For example, when trying to quickly charge a sealed alkaline storage battery, a large amount of gas may be generated to increase the pressure inside the storage battery, or the temperature of the storage battery may rise to cause deterioration of the storage battery characteristics. In order to cope with such rapid charging, the sealed storage battery according to the above proposal has a circuit connecting the positive electrode plate and the external terminal (cap) of the positive electrode, and the internal pressure of the storage battery has a predetermined value during charging. Built-in pressure switch mechanism that switches the circuit from on to off when it exceeds, stops charging, and switches the circuit from off to on when the internal pressure of the storage battery falls below a predetermined value. It is a sealed storage battery. (For example, see Patent Document 1)

US2002/0119364 A1公報 該密閉形蓄電池を前記従来行われなかった急速充電にて充電しても充電中の蓄電池内部の圧力上昇、蓄電池の温度上昇が抑制できるとされる。しかし、該蓄電池においても万一圧力スイッチ機構に故障が生じ、該スイッチが動作不能に至った場合には充電中に蓄電池内部の圧力が異常に上昇し破裂に至る虞を無くすことができないという課題があった。US2002 / 0119364 A1 publication It is said that even if the sealed storage battery is charged by the rapid charging which has not been performed in the past, an increase in pressure inside the storage battery during charging and an increase in the temperature of the storage battery can be suppressed. However, in the case of the storage battery, if the pressure switch mechanism fails and the switch becomes inoperable, the problem that the internal pressure of the storage battery rises abnormally during charging and cannot be destroyed is not eliminated. was there.

前記従来の密閉形蓄電池の欠点を改良するため、前記ゴム製弁体とキャップの間に軟化温度が１００〜１５０℃の熱軟化性樹脂の平板を配置し、蓄電池の温度が異常に上昇したときに熱軟化性樹脂板を変形させることによってゴム製弁体の弾性率の変化による圧縮応力の増大を吸収し、排気弁を動作させる方法が提案さている。（例えば特許文献２参照）
また、ゴム製弁体をオレフィン系樹脂等の樹脂成分とエチレンプロピレンゴム等のゴム成分からなる混合体とすることによって、高温になったときの変形能を高める方法が提案されている。（例えば特許文献３参照） In order to improve the drawbacks of the conventional sealed storage battery, a heat softening resin flat plate having a softening temperature of 100 to 150 ° C. is disposed between the rubber valve body and the cap, and the temperature of the storage battery rises abnormally. A method of operating the exhaust valve by absorbing the increase in compressive stress due to the change in the elastic modulus of the rubber valve body by deforming the thermosoftening resin plate is proposed. (For example, see Patent Document 2)
In addition, a method has been proposed in which the rubber valve body is a mixture composed of a resin component such as an olefin resin and a rubber component such as ethylene propylene rubber, thereby increasing the deformability when the temperature becomes high. (For example, see Patent Document 3)

特開平６−３２５７４２号公報JP-A-6-325742 特開平９−２３７６２０号公報 しかしながら、引用文献２に記載の排気弁は、熱軟化性樹脂製の平板の厚さが小さい（０．２〜０．４ｍｍ）ためか昇温時に確実に排気弁を機能させる点においてその効果は十分ではなく、蓄電池を落下させるとキャップが変形し、排気弁の機能に支障が生じる虞があった。引用文献２に記載の排気弁は、昇温時における排気弁の機能に優れるものの、蓄電池を落下させたときのキャップの変形（キャップが潰れる）が大きく弁体の圧縮率が増大するためか、蓄電池を落下させた後で蓄電池を高温下に曝したり急速充電を行うと、排気弁が動作しない虞があった。However, in the exhaust valve described in the cited reference 2, the thickness of the heat softening resin flat plate is small (0.2 to 0.4 mm). The effect is not sufficient in terms of functioning, and if the storage battery is dropped, the cap may be deformed, and the function of the exhaust valve may be hindered. Although the exhaust valve described in the cited document 2 is excellent in the function of the exhaust valve at the time of temperature rise, the deformation of the cap when the storage battery is dropped (the cap is crushed) is largely because the compressibility of the valve body increases. If the storage battery is exposed to a high temperature or rapidly charged after dropping the storage battery, the exhaust valve may not operate.

本発明は、蓄電池が回復不能となる状況下、具体的には蓄電池を外部短絡させて蓄電池の温度が異常に上昇したり、蓄電池を落下させて後１００℃を超えるような高温の雰囲気下に曝したり、あるいは、前記圧力スイッチ内蔵形の密閉形蓄電池に於いて圧力スイッチが機能しない状況において１５分間充電を行うといった状況下においても蓄電池内部の圧力を調整する排気弁が確実に動作し、破裂に至る虞のない密閉形蓄電池を実現するための密閉形蓄電池用排気弁および密閉形蓄電池、特に密閉形ニッケル水素蓄電池を提供しようとするものである。   In the situation where the storage battery becomes unrecoverable, specifically, the storage battery is externally short-circuited, and the temperature of the storage battery rises abnormally, or the storage battery is dropped and dropped in a high temperature atmosphere exceeding 100 ° C. The exhaust valve that adjusts the internal pressure of the storage battery operates reliably even if it is exposed to or is charged for 15 minutes in a situation where the pressure switch does not function in the sealed storage battery with a built-in pressure switch. It is an object of the present invention to provide a sealed storage battery exhaust valve and a sealed storage battery, in particular, a sealed nickel-metal hydride storage battery, for realizing a sealed storage battery that does not have a risk of reaching the above.

本発明は、蓄電池の排気弁の構成を以下の構成とすることによって前記課題を解決するものである。
本発明に係る密閉形蓄電池は、中央部分に透孔を設けた封口板と該封口板の一方の面に固着されたキャップとで囲まれた弁室内に、圧縮されたゴム製弾性体と融点が１００〜２００℃の熱可塑性樹脂成形体を積層させた弁体を配置し、前記ゴム製弾性体で前記透孔を気密に封止してなる密閉形蓄電池用排気弁を備えた密閉形蓄電池であって、前記排気弁の圧縮されたゴム製弾性体の弁体に対する厚さの比を０．３〜０．７とし、前記弁室内に空き空間を設け、該空き空間の弁室に対する容積の比を０．２〜０．４とした密閉形蓄電池である。
なお、ここでいう融点とは示差熱（ＤＴＡ）法で求めた値であって、融解ピーク温度をいう。
また、ここでいうゴム弾性体の弁体の厚さに対する比率とは、ゴム製弾性体を含む弁体の厚さを１としたときにゴム製弾性体の厚さが弁体の厚さに占める比をいい、空き空間の弁室に対する容積の比率とは、弁室の容積を１としたときの弁室内の空き空間の大きさをいう。
本発明に係る密閉形蓄電池は、前記排気弁の熱可塑性樹脂成形体の厚さを０．６〜１．４ｍｍとし、該熱可塑性樹脂成形体をキャップの上壁とゴム製弾性体の間に配置したものであることが好ましい。
本発明に係る密閉形蓄電池は、周囲温度２５℃における排気弁の弁作動圧の大きさを１００％としたときに、周囲温度１００℃における排気弁の弁作動圧の大きさが７０％以下であることが好ましい。
本発明に係る密閉形蓄電池は、周囲温度２５℃における排気弁の弁作動圧の大きさを１００％としたときに、周囲温度１５０℃における排気弁の弁作動圧の大きさが４０％以下であることが好ましい。
なお、上記で定める周囲温度が２５℃、１００℃、１５０℃における排気弁の弁作動圧とは、密閉形蓄電池をそれぞれ前記所定の温度に設定した恒温槽内に配置し、蓄電池表面の温度が前記恒温層内の雰囲気温度と等しい状態で１ＩｔＡの電流で充電したときに、排気弁が開弁したときの蓄電池内部の圧力をいう。 This invention solves the said subject by making the structure of the exhaust valve of a storage battery into the following structures.
Sealed electrical storage cell according to the present invention, the valve chamber surrounded by a cap which is fixed to one surface of the sealing plate and the encapsulating port plate provided with through holes in the central portion, and a compressed rubber elastic body Sealed type equipped with an exhaust valve for a sealed storage battery in which a valve body in which a thermoplastic resin molded body having a melting point of 100 to 200 ° C. is laminated is disposed and the through hole is hermetically sealed with the rubber elastic body. A storage battery , wherein the ratio of the thickness of the compressed rubber elastic body of the exhaust valve to the valve body is 0.3 to 0.7, an empty space is provided in the valve chamber, and the empty space with respect to the valve chamber the ratio of the volume which is sealed electric storage batteries which was 0.2 to 0.4.
The melting point here is a value obtained by a differential heat (DTA) method and means a melting peak temperature.
Further, the ratio of the rubber elastic body to the thickness of the valve body here means that the thickness of the rubber elastic body is the thickness of the valve body when the thickness of the valve body including the rubber elastic body is 1. The ratio of the volume of the vacant space to the valve chamber means the size of the vacant space in the valve chamber when the volume of the valve chamber is 1.
Sealed electrical storage cell according to the present invention, between the thickness of the thermoplastic resin molded article of the exhaust valve and 0.6～1.4Mm, thermoplastic resin molded article on the cap wall and the rubber elastic body It is preferable that they are arranged in the above .
Sealed electrical storage cell according to the present invention, when the size of the valve operating pressure of the exhaust valve at an ambient temperature of 25 ° C. to 100%, 70% or less the size of the valve operating pressure of the exhaust valve at ambient temperature 100 ° C. It is preferable that
Sealed electrical storage cell according to the present invention, when the size of the valve operating pressure of the exhaust valve at an ambient temperature of 25 ° C. to 100%, the size of the valve operating pressure of the exhaust valve at ambient temperature 0.99 ° C. 40% or less It is preferable that
Note that the ambient temperature is 25 ° C. as defined hereinbefore, 100 ° C., and the valve operating pressure of the exhaust valves that put the 0.99 ° C., to place the hermetically sealed battery each in a thermostatic chamber set to the predetermined temperature, the battery surface It means the pressure inside the storage battery when the exhaust valve is opened when charged with a current of 1 ItA in a state where the temperature is equal to the atmospheric temperature in the constant temperature layer.

本発明の密閉形蓄電池によれば、蓄電池の温度が上昇したり、キャップが変形した場合においても排気弁の動作の信頼性が高く、蓄電池の温度が上昇したり、蓄電池を落下させ、キャップに押圧が加わった後でも破裂する虞のない密閉形蓄電池を提供することができる。
本発明の密閉形蓄電池では、熱可塑性樹脂成形体の厚さを０．６〜１．４ｍｍとし、該熱可塑性樹脂成形体をキャップの上壁とゴム製弾性体の間に配置する構成とすることによって、蓄電池を落下させるなど、蓄電池に衝撃が加わったときにキャップの変形を抑制することができる。
本発明の密閉形蓄電池では、周囲温度２５℃における排気弁の弁作動圧の大きさを１００％としたときに、周囲温度１００℃における排気弁の弁作動圧の大きさを７０％以下とすることによって、圧力スイッチ内蔵形の密閉形蓄電池を約１５分間で充電を完了させるという急速充電（以下１５分間充電という）を行ったときに、前記圧力スイッチが機能しない場合においても排気弁を機能させ、蓄電池内部の圧力上昇を抑制することにより蓄電池が破裂（ここではクリンプシールなど蓄電池のシールが破壊される状況を破裂という）に至るのを防ぐことができる。
本発明の密閉形蓄電池では、周囲温度２５℃における排気弁の弁作動圧の大きさを１００％としたときに、周囲温度１５０℃における排気弁の弁作動圧の大きさを４０％以下とすることによって、蓄電池を外部短絡させるなどして蓄電池の温度が異常に上昇した場合において、排気弁の動作の機能を維持することができる。
本発明の密閉形蓄電池によれば、蓄電池の温度が異常に昇温したときやキャップに押圧力が加わった後も排気弁の機能が失われない密閉形蓄電池を提供することができ、誤って蓄電池を短絡させたとき、圧力スイッチが故障して機能しない状況で蓄電池を１５分間充電しても破裂する虞のない密閉形蓄電池を提供することができる。 According to the sealed storage battery of the present invention, even when the temperature of the storage battery rises or the cap is deformed, the operation of the exhaust valve is highly reliable, the temperature of the storage battery rises, the storage battery drops, it is possible to provide a sealed electric storage batteries with no risk of rupture even after pressing is applied.
In the sealed storage battery of the present invention, the thickness of the thermoplastic resin molded body is set to 0.6 to 1.4 mm, and the thermoplastic resin molded body is disposed between the upper wall of the cap and the rubber elastic body. Thus , deformation of the cap can be suppressed when an impact is applied to the storage battery, such as dropping the storage battery.
In the sealed storage battery of the present invention, when the magnitude of the valve operating pressure of the exhaust valve at an ambient temperature of 25 ° C. is 100%, the magnitude of the valve operating pressure of the exhaust valve at an ambient temperature of 100 ° C. is 70% or less. Therefore, when a quick charge (hereinafter referred to as 15-minute charge) is performed to complete the charge of a sealed storage battery with a built- in pressure switch in about 15 minutes, the exhaust valve functions even when the pressure switch does not function. By suppressing the pressure increase inside the storage battery, it is possible to prevent the storage battery from rupturing (herein, the situation where the seal of the storage battery such as a crimp seal is broken is called rupture).
In the sealed storage battery of the present invention, when the magnitude of the exhaust valve operating pressure at an ambient temperature of 25 ° C. is 100%, the magnitude of the exhaust valve operating pressure at an ambient temperature of 150 ° C. is 40% or less. Thus, when the temperature of the storage battery rises abnormally, for example, by short-circuiting the storage battery, the function of the operation of the exhaust valve can be maintained.
According to the sealed storage battery of the present invention, it is possible to provide a sealed storage battery in which the function of the exhaust valve is not lost even when the temperature of the storage battery is abnormally increased or the pressing force is applied to the cap. when short circuit the battery, it is possible to provide a sealed electric storage batteries with no risk of rupture even when charging the battery for 15 minutes in a situation where the pressure switch does not work failed.

以下に、実施形態に基づいて本発明を説明する。図１は、本発明に係る円筒形の密閉形蓄電池の断面構造を示す図である。図１において、５は、捲回式電極群（図示せず）を収納した金属製電槽缶であって、その上部開放端にはポリアミド樹脂やポリオレフィン樹脂の成型体からなるガスケット６を介して金属製封口板１が配置されている。封口板１の外面には正極端子を兼ねるキャップ２のフランジ部が接合されている。前記封口板１とキャップ２で囲まれた弁室内には、圧縮状態にあるゴム製弾性体４と融点が１００〜２００℃の熱可塑性樹脂成形体８を積層させた弁体が配置され、常時は前記封口板１の中央部に設けた透孔１０が、前記ゴム製弾性体４によって気密に封止されている。蓄電池内部にガスが蓄積し、蓄電池内部の圧力が高まると透孔１０が開口し、蓄積したガスは透孔１０およびキャップ２に設けた排気孔３を通って外部に排出される。   Below, this invention is demonstrated based on embodiment. FIG. 1 is a diagram showing a cross-sectional structure of a cylindrical sealed storage battery according to the present invention. In FIG. 1, reference numeral 5 denotes a metal battery case that houses a wound electrode group (not shown), and an upper open end thereof is provided with a gasket 6 made of a molded body of polyamide resin or polyolefin resin. A metal sealing plate 1 is arranged. A flange portion of a cap 2 that also serves as a positive electrode terminal is joined to the outer surface of the sealing plate 1. In the valve chamber surrounded by the sealing plate 1 and the cap 2, there is disposed a valve body in which a rubber elastic body 4 in a compressed state and a thermoplastic resin molded body 8 having a melting point of 100 to 200 ° C. are laminated. In the sealing plate 1, a through hole 10 provided in the center is hermetically sealed by the rubber elastic body 4. When gas accumulates inside the storage battery and the pressure inside the storage battery increases, the through hole 10 opens, and the accumulated gas is discharged to the outside through the through hole 10 and the exhaust hole 3 provided in the cap 2.

図２は、従来の密閉形蓄電池の１例を示す断面図である。該密閉形蓄電池においては弁体がゴム弾性体４のみで構成されている。該従来の密閉形蓄電池おいて、蓄電池の温度が通常では起きない１００℃を超える温度に上昇した場合、前記ゴム弾性体４が膨張して圧縮応力が増大するためか、排気弁が作動しない虞がある。特に水素吸蔵合金電極を負極に適用した密閉形ニッケル水素蓄電池においては、蓄電池の温度上昇と共に蓄電池内部でのガス発生量が急激に増大して排気弁の機能が追いつかないためか、蓄電池内部の圧力が増大して破裂に至る虞が高い。また、キャップに押圧力が加わってキャップが変形（潰れる）した場合にもゴム製弾性体の圧縮応力が増大して排気弁が作動しない虞がある。   FIG. 2 is a cross-sectional view showing an example of a conventional sealed storage battery. In the sealed storage battery, the valve body is composed only of the rubber elastic body 4. In the conventional sealed storage battery, when the temperature of the storage battery rises to a temperature exceeding 100 ° C., which does not normally occur, the rubber elastic body 4 expands and the compression stress increases, or the exhaust valve may not operate. There is. Especially in a sealed nickel-metal hydride storage battery in which a hydrogen storage alloy electrode is applied to the negative electrode, the amount of gas generated inside the storage battery suddenly increases with the temperature rise of the storage battery, and the exhaust valve function cannot catch up. There is a high possibility that it will increase and rupture. Further, even when a pressing force is applied to the cap and the cap is deformed (collapsed), there is a possibility that the compression stress of the rubber elastic body increases and the exhaust valve does not operate.

本発明に係る密閉形蓄電池においては、図１に示すように、弁体を熱可塑性樹脂成形体８とゴム製弾性体４の積層体で構成している。前記熱可塑性樹脂成形体８は、常温においてゴム生弾性体４に比べて高い硬度を有するが、温度が上昇すると軟化し、蓄電池の温度が例えば１００℃を超えて上昇したときに、軟化した前記熱可塑性樹脂成形体８がゴム製弾性体４の押圧力によって塑性変形し、その一部が前記弁室内に設けた空き空間９へ移動する。該空き空間９は、塑性変形した熱可塑性樹脂成形体を収容するのに十分な容積を有し、移動する熱可塑性樹脂成形体８の収容空間となる。該空き空間９を弁体側面の周辺に設けることにより、ゴム製弾性体４と積層していた熱可塑性樹脂成形体８が空き空間９に移動すると、ゴム製弾性体４の圧縮率が低減し、圧縮応力が低下するので、蓄電池の温度が上昇した場合にも排気弁が機能する。   In the sealed storage battery according to the present invention, as shown in FIG. 1, the valve body is composed of a laminate of a thermoplastic resin molded body 8 and a rubber elastic body 4. The thermoplastic resin molded body 8 has a hardness higher than that of the rubber raw elastic body 4 at room temperature, but softens when the temperature rises, and softens when the temperature of the storage battery rises above, for example, 100 ° C. The thermoplastic resin molded body 8 is plastically deformed by the pressing force of the rubber elastic body 4, and a part thereof moves to the empty space 9 provided in the valve chamber. The empty space 9 has a volume sufficient to accommodate a plastically deformed thermoplastic resin molded body, and serves as a storage space for the moving thermoplastic resin molded body 8. By providing the empty space 9 around the side surface of the valve body, when the thermoplastic resin molded body 8 laminated with the rubber elastic body 4 moves to the empty space 9, the compression rate of the rubber elastic body 4 is reduced. Since the compressive stress decreases, the exhaust valve functions even when the temperature of the storage battery rises.

本発明においては、前記熱可塑性樹脂成形体に融点が２００℃以下、好ましくは１８０℃以下の樹脂の成形体を適用する。該成形体の融点が２００℃を超えると蓄電池温度が１００℃以上に上昇したときに熱可塑性樹脂成形体が塑性変形しないために排気弁が有効に動作しない虞がある。該成形体の融点が１００℃未満では、蓄電池が正しく取り扱われ、蓄電池の温度が正常な温度であってもゴム製弾性体の押圧力によって熱可塑性樹脂成形体が変形してしまい排気弁の弁作動圧が低下するために、蓄電池内部の圧力が異常に上昇していないにも拘わらず排気弁が開き漏液する虞がある。   In the present invention, a resin molded body having a melting point of 200 ° C. or lower, preferably 180 ° C. or lower is applied to the thermoplastic resin molded body. If the melting point of the molded body exceeds 200 ° C, the exhaust valve may not operate effectively because the thermoplastic resin molded body does not plastically deform when the storage battery temperature rises to 100 ° C or higher. When the melting point of the molded body is less than 100 ° C., the storage battery is handled correctly, and even if the temperature of the storage battery is normal, the thermoplastic resin molded body is deformed by the pressing force of the rubber elastic body, and the valve of the exhaust valve Since the operating pressure decreases, there is a risk that the exhaust valve opens and the liquid leaks even though the pressure inside the storage battery has not increased abnormally.

本発明においては、前記融点が１００〜２００℃の熱可塑性樹脂成形体８の材質は特に限定されるものではなく、例えば高密度、低密度等の各種ポリエチレン樹脂、ポリプロピレン樹脂、ポリ塩化ビニリデン樹脂、ポリフッ化ビニリデン樹脂、ポリアセタール樹脂等が適用でき、中でも熱分解しても有害なガスが発生しないポリエチレン樹脂やポリプロピレン樹脂を適用することが好ましい。ポリエチレンとポリプロピレンの中でも脆化し難く温度が上昇したときに変形し易いポリプロピレンや低密度ポリエチレンが特に好ましい。   In the present invention, the material of the thermoplastic resin molded body 8 having a melting point of 100 to 200 ° C. is not particularly limited, and various polyethylene resins such as high density and low density, polypropylene resin, polyvinylidene chloride resin, Polyvinylidene fluoride resin, polyacetal resin, and the like can be applied, and among them, it is preferable to apply polyethylene resin or polypropylene resin that does not generate harmful gas even when thermally decomposed. Among polyethylene and polypropylene, polypropylene and low density polyethylene that are not easily embrittled and easily deform when the temperature rises are particularly preferable.

前記ゴム性弾性体の材質は、特に限定されるものではなく、ブチルゴム、イソプレンゴム、クロロプレンゴム、スチレンゴム、ニトリルゴムやエチレンプロピレンゴムなどの合成ゴムの他天然ゴムを適用できる。なかでも、常温での圧縮弾性率が高く高温になると圧縮弾性率が顕著に低下し、高温において排気弁の動作圧力を低下させることができるところからエチレンプロピレンゴム約９０重量部にポリプロピレンを約１０重量部混合し架橋させたものが好ましい。   The material of the rubber elastic body is not particularly limited, and natural rubber as well as synthetic rubber such as butyl rubber, isoprene rubber, chloroprene rubber, styrene rubber, nitrile rubber and ethylene propylene rubber can be applied. Among them, the compression elastic modulus at normal temperature is high and the compression elastic modulus is remarkably lowered at high temperatures, and the operating pressure of the exhaust valve can be lowered at high temperatures. Therefore, about 10 parts of polypropylene is added to about 90 parts by weight of ethylene propylene rubber. Those mixed by weight and cross-linked are preferred.

例えば、円筒形のニッケル水素蓄電池やニッケルカドミウム電池などの密閉形アルカリ蓄電池においては、通常排気弁の弁作動圧を１〜３．５ＭＰａに設定する。１ＩｔＡ以下の通常のレートで充電する蓄電池に対しては弁作動圧を１〜２ＭＰａに設定することが多く、１ＩｔＡを超える急速充電を行う密閉形蓄電池においては弁作動圧を２．５〜３．５ＭＰａに設定する。該作動圧を達成するために前記ゴム弾性体の圧縮率を２０〜６０％に設定する。本発明においては、前記のように蓄電池の温度が上昇したときに、弁体を構成する熱可塑性樹脂成形体を塑性変形させて前記明き空間内に移動させることによってゴム製弾性体の圧縮率を低減し圧縮応力を低下させる。このような熱可塑性樹脂成形体を塑性変形させてゴム製弾性体の圧縮応力を低下させる方式の場合、前記ゴム製弾性体と熱可塑性樹脂成形体を積層させた弁体においてゴム弾性体の厚さの、弁体の厚さに対する比率を０．３〜０．７に設定すると、ゴム製弾性体に熱膨張が生じても該熱膨張を吸収してゴム弾性体の圧縮応力を低下させることができる。ゴム製弾性体の熱膨張を吸収してゴム製弾性体の圧縮応力を確実に低下させるためには該比率を０．３〜０．５に設定することがさらに好ましい。   For example, in a sealed alkaline storage battery such as a cylindrical nickel-metal hydride storage battery or a nickel cadmium battery, the valve operating pressure of the exhaust valve is normally set to 1 to 3.5 MPa. For storage batteries that are charged at a normal rate of 1 ItA or less, the valve operating pressure is often set to 1 to 2 MPa. In a sealed storage battery that performs rapid charging exceeding 1 ItA, the valve operating pressure is set to 2.5 to 3. Set to 5 MPa. In order to achieve the operating pressure, the compression rate of the rubber elastic body is set to 20 to 60%. In the present invention, when the temperature of the storage battery rises as described above, the compression rate of the rubber elastic body is obtained by plastically deforming and moving the thermoplastic resin molded body constituting the valve body into the clear space. To reduce the compressive stress. In the case of a method in which the thermoplastic resin molded body is plastically deformed to reduce the compressive stress of the rubber elastic body, the thickness of the rubber elastic body in the valve body in which the rubber elastic body and the thermoplastic resin molded body are laminated. When the ratio of the thickness of the valve body to 0.3 to 0.7 is set, even if thermal expansion occurs in the rubber elastic body, the thermal expansion is absorbed and the compression stress of the rubber elastic body is reduced. Can do. In order to absorb the thermal expansion of the rubber elastic body and reliably reduce the compressive stress of the rubber elastic body, the ratio is more preferably set to 0.3 to 0.5.

本発明においては、前記熱可塑性樹脂成形体８をキャップ２の上面とゴム製弁体４の間に配置する。熱可塑性樹脂成形体８は、ゴム製弾性体４に比べて常温における硬度が高いので、キャップを内側から支え、キャップに押圧力が加わったときにキャップが変形（潰れる）のを抑制する効果がある。該効果を発揮するには、前記熱可塑性樹脂成形体８の厚さを０．６〜１．４ｍｍにすることが好ましく、該効果を維持しながら弁体の占有体積を小さく出来るところから前記熱可塑性樹脂成形体８の厚さを０．６〜１．０ｍｍにすることがさらに好ましい。熱可塑性樹脂成形体の厚さが０．４ｍｍ以下では熱可塑性樹脂成形体の腰の強さが弱く耐曲げ強度が不足するためかキャップの変形を抑制する効果が得られ難い。熱可塑性樹脂成形体の厚さが１．４ｍｍを超えると弁体の厚さが大きくなって極板群を収納する空間容積が小さくなり、容量の低下を招く虞があるり、また、熱可塑性樹脂のクリープ変形が大きいためにゴム製弾性体の圧縮率が低下し、蓄電池の気密性が損なわれる虞がある。   In the present invention, the thermoplastic resin molded body 8 is disposed between the upper surface of the cap 2 and the rubber valve body 4. Since the thermoplastic resin molded body 8 has a higher hardness at room temperature than the rubber elastic body 4, it has an effect of supporting the cap from the inside and suppressing deformation (crushed) of the cap when a pressing force is applied to the cap. is there. In order to exhibit this effect, it is preferable to set the thickness of the thermoplastic resin molded body 8 to 0.6 to 1.4 mm, and from the point that the volume occupied by the valve body can be reduced while maintaining the effect. More preferably, the thickness of the plastic resin molded body 8 is 0.6 to 1.0 mm. When the thickness of the thermoplastic resin molded body is 0.4 mm or less, it is difficult to obtain the effect of suppressing deformation of the cap because the strength of the waist of the thermoplastic resin molded body is weak and the bending strength is insufficient. If the thickness of the thermoplastic resin molded body exceeds 1.4 mm, the thickness of the valve body increases and the space volume for housing the electrode plate group decreases, which may lead to a decrease in capacity, and the thermoplasticity. Since the creep deformation of the resin is large, the compression rate of the rubber elastic body is lowered, and the airtightness of the storage battery may be impaired.

以下に、１実施例により本発明の詳細を説明するが、本発明は、ゴム製弾性体の圧縮応力に基づく押圧力によって封止部材に設けた排気孔を気密に封止してなる排気弁を備えた密閉形電池であれば如何なる構成の密閉形蓄電池にも適用できるものであって、以下に記載の実施例に限定されるものではない。
（実施例１）
硝酸ニッケル９４重量部に硝酸コバルト１重量部と硝酸亜鉛５重量部とを加え、これを溶解させた水溶液に硫酸アンモニウムと水酸化ナトリウム水溶液を滴下してpHを１１〜１２の範囲に保ちながら撹拌し、CoとZnが固溶した水酸化ニッケル粒子を析出させた。これを水洗し、乾燥して水酸化ニッケル粉末とした。次いで、水酸化ニッケル粉末を硫酸アンモニウムと水酸化ナトリウムからなる水溶液中に投入し、これに硫酸コバルトおよび水酸化ナトリウム水溶液を撹拌しながら、且つpH８〜１３に制御しながら滴下した。所定のpHにて１時間保持した後、これを水洗し、乾燥して水酸化物コバルトで被覆された水酸化ニッケル粉末を得た。こうして得られた水酸化ニッケル粉末中の水酸化コバルトの含有量は６％であった。さらに、この水酸化ニッケル粉末を１４モル／立方デシメートル（Ｍ／ｄｍ3）に調整した温度５０℃のNaOH中に、この水酸化コバルトで被覆された水酸化ニッケル粒子を投入して撹拌した後、水酸化ニッケルの酸化値が２．１０となるようにK2S2O8量を変化させて投入した。K2S2O8投入から２時間後、これを水洗し、乾燥して得た粉末９８重量部に酸化イッテルビウム２重量部を混合し、さらに増粘剤を溶解した水溶液を加えてペースト状にしたものをニッケル多孔体基板に充填した後、所定の厚みにプレスして正極板とした。 Hereinafter, the present invention will be described in detail with reference to one embodiment. The present invention is an exhaust valve in which an exhaust hole provided in a sealing member is hermetically sealed by a pressing force based on a compressive stress of a rubber elastic body. The battery can be applied to any type of sealed battery as long as the battery is a sealed battery, and is not limited to the examples described below.
Example 1
To 94 parts by weight of nickel nitrate, 1 part by weight of cobalt nitrate and 5 parts by weight of zinc nitrate are added. Ammonium sulfate and aqueous sodium hydroxide solution are added dropwise to an aqueous solution in which this is dissolved, and the pH is kept in the range of 11-12. Then, nickel hydroxide particles in which Co and Zn were dissolved were precipitated. This was washed with water and dried to obtain nickel hydroxide powder. Next, nickel hydroxide powder was put into an aqueous solution composed of ammonium sulfate and sodium hydroxide, and cobalt sulfate and sodium hydroxide aqueous solution were added dropwise thereto while stirring and controlling to pH 8-13. After maintaining at a predetermined pH for 1 hour, this was washed with water and dried to obtain nickel hydroxide powder coated with cobalt hydroxide. The content of cobalt hydroxide in the nickel hydroxide powder thus obtained was 6%. Further, the nickel hydroxide particles coated with cobalt hydroxide were put into NaOH at 50 ° C. adjusted to 14 mol / cubic decimeter (M / dm 3 ) and stirred. The amount of K 2 S 2 O 8 was changed so that the oxidation value of nickel hydroxide was 2.10. Two hours after the addition of K 2 S 2 O 8 , this was washed with water and dried, and then 98 parts by weight of the powder was mixed with 2 parts by weight of ytterbium oxide. Further, an aqueous solution in which a thickener was dissolved was added to form a paste. After filling the resulting porous nickel substrate, it was pressed to a predetermined thickness to obtain a positive electrode plate.

MmNi3.8Al0.3Co0.7Mn0.2（Mmはミッシュメタルであり、La30%、Ce50%、Pr5%、Nd15%からなる混合物である。）の組成となるように各金属を秤量し、不活性雰囲気下、高周波誘導溶解炉で合金インゴットを作製し、１０００℃で熱処理した。これを７５μｍ以下の大きさに粉砕して水素吸蔵合金粉末とした。次いで、この水素吸蔵合金粉末９９．５重量部に酸化イッテルビウム０．５重量部を混合し、さらに増粘剤を溶解した水溶液を加え、ポロテトラフルオロエチレンを結着剤としてペースト状にしたものをパンチングメタルの両面に塗布して乾燥した後、所定の厚さにプレスして負極板とした。 MmNi 3.8 Al 0.3 Co 0.7 Mn 0.2 (Mm is misch metal, a mixture of La30%, Ce50%, Pr5%, Nd15%) Weigh each metal so that it has an inert atmosphere. Then, an alloy ingot was prepared in a high frequency induction melting furnace and heat-treated at 1000 ° C. This was pulverized to a size of 75 μm or less to obtain a hydrogen storage alloy powder. Next, 99.5 parts by weight of this hydrogen storage alloy powder was mixed with 0.5 part by weight of ytterbium oxide, an aqueous solution in which a thickener was dissolved was further added, and what was made into a paste using polytetrafluoroethylene as a binder was obtained. After applying to both sides of the punching metal and drying, it was pressed to a predetermined thickness to obtain a negative electrode plate.

ポリプロピレンとエチレン−ビニルアルコール共重合体との重量比が５０：５０で、それぞれが繊維断面において交互に隣接されるように複合紡糸された繊度３デニールの分割性複合繊維６０重量とポリプロピレンを芯成分、ポリエチレンを鞘成分とする繊度２デニールの芯鞘複合繊維４０重量部とを用いて目付４５ｇ／ｍ2になるように湿式抄紙した後、これに高圧水流を噴射して繊維を交絡させると同時に分割性複合繊維を分割し、分割後の繊度が０．２デニールの不織布を得た。これを０．１２ｍｍに厚さ調整してセパレータとした。 The weight ratio of polypropylene to ethylene-vinyl alcohol copolymer is 50:50, and 60 wt. Of splittable composite fiber having a fineness of 3 deniers and a polypropylene, each of which is alternately adjacent to each other in the fiber cross section, and polypropylene as a core component. In addition, 40 parts by weight of core-sheath composite fiber having a denier of 2 denier having polyethylene as a sheath component was used to wet papermaking so as to have a basis weight of 45 g / m 2. The splittable conjugate fiber was split to obtain a nonwoven fabric having a fineness of 0.2 denier after splitting. The thickness was adjusted to 0.12 mm to obtain a separator.

正極板と正極容量に対して１．２倍の容量を有する前記負極板とを準備し、この間に前記セパレータを介し、渦巻き状に捲回して電極群を作製した。この電極群を、円筒状金属缶に収納し、７ＮのＫＯＨと１ＮのＬｉＯＨからなる電解液を、正極容量１Ａｈ当たり１．１６ｍｌ注液した後、図１に示す蓋体を備えた蓋体でクリンプシールにより封口してＡＡサイズで２０００ｍＡｈの円筒形ニッケル−水素蓄電池を作製した。   A positive electrode plate and the negative electrode plate having a capacity 1.2 times larger than the positive electrode capacity were prepared, and the electrode group was produced by winding in a spiral manner with the separator interposed therebetween. This electrode group is housed in a cylindrical metal can, and 1.16 ml of an electrolyte consisting of 7N KOH and 1N LiOH is injected per 1Ah of the positive electrode capacity, and then the lid provided with the lid shown in FIG. A cylindrical nickel-hydrogen storage battery having an AA size of 2000 mAh was produced by sealing with a crimp seal.

（排気弁用弁体）
エチレンプロピレンゴム（ＥＰＤＭ）９０重量部とポリプロピレン１０重量部を混合・架橋したゴムからなり直径が２ｍｍ、非圧縮状態における厚さが１．０ｍｍのゴム製弾性体と融点が１７０℃のポリプロピレン樹脂からなり、直径が２．８ｍｍ、厚さが１．４ｍｍのポリプロピレン樹脂成形体を積層させた。 (Valve for exhaust valve)
Made of rubber obtained by mixing and crosslinking 90 parts by weight of ethylene propylene rubber (EPDM) and 10 parts by weight of polypropylene, a rubber elastic body having a diameter of 2 mm and a thickness of 1.0 mm in an uncompressed state, and a polypropylene resin having a melting point of 170 ° C. Thus, a polypropylene resin molded body having a diameter of 2.8 mm and a thickness of 1.4 mm was laminated.

（排気弁）
ニッケルメッキを施した厚さ０．２５ｍｍの鋼板製であって図１にキャップ２として示した断面構造を有するキャップであって、筒状部分の高さ（内法）が２．０ｍｍ、直径（内法）が３．２ｍｍのキャップを用意し、該筒状部分内に前記弁体を熱可塑性樹脂成形体が上側に来るように挿入した。また、ニッケルメッキを施した鋼板製であって、直径１３．５ｍｍ、厚さ０．４ｍｍ、中央に直径０．７ｍｍの透孔を有する封口板を用意し、該封口板外面の中央に前記キャップを載置し、キャップのフランジ部を前記封口板の抵抗溶接によって接合した。ゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．３であった。 (Exhaust valve)
A cap made of a nickel-plated steel plate having a thickness of 0.25 mm and having a cross-sectional structure shown as a cap 2 in FIG. 1, the height (inner method) of the cylindrical portion is 2.0 mm, the diameter ( A cap having an inner method of 3.2 mm was prepared, and the valve body was inserted into the cylindrical portion so that the thermoplastic resin molded body was on the upper side. Also, a sealing plate made of a nickel-plated steel plate having a diameter of 13.5 mm, a thickness of 0.4 mm, and a through hole having a diameter of 0.7 mm is prepared, and the cap is formed at the center of the outer surface of the sealing plate. The flange part of the cap was joined by resistance welding of the sealing plate. The compression rate of the rubber elastic body was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.3.

（初期化成および化成後の充電）
作製した蓄電池を周囲温度２５℃において初期化成を行った後、充電した。作製した電池を０．０２ＩｔＡにて５０時間充電後０．１ＩｔＡにて１０時間充電した。該充電後０．１ＩｔＡにてカット電圧を１．０Ｖとして放電した。次いで、０．２ＩｔＡにて８時間充電し、０．２ＩｔＡにてカット電圧を１．０Ｖとして放電した。該充放電操作をさらに８回繰り返し行い、所定の放電容量が得られることを確認し初期化成を終了した。化成を終えた蓄電池を０．２ＩｔＡにて８時間充電した。 (Initialization and charging after formation)
The produced storage battery was initialized at an ambient temperature of 25 ° C. and then charged. The produced battery was charged at 0.02 ItA for 50 hours and then charged at 0.1 ItA for 10 hours. After the charge, the battery was discharged at 0.1 ItA with a cut voltage of 1.0V. Next, the battery was charged with 0.2 ItA for 8 hours, and discharged with a cut voltage of 1.0 V at 0.2 ItA. The charging / discharging operation was further repeated 8 times, and it was confirmed that a predetermined discharge capacity was obtained. The storage battery that had been formed was charged at 0.2 ItA for 8 hours.

（実施例２）
前記実施例１において、非圧縮状態におけるゴム弾性体の厚さを１．７ｍｍ、直径を２ｍｍとし、プロピレン樹脂成形体の厚さを１ｍｍ、直径を３ｍｍとした以外は実施例１と同じ構成とした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．３であった。該例を実施例２とする。
（実施例３）
前記実施例１において、非圧縮状態におけるゴム弾性体の厚さを２．３ｍｍ、直径を２ｍｍとし、プロピレン樹脂成形体の厚さを０．６ｍｍ、直径を３ｍｍとした以外は実施例１と同じ構成とした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．４であった。該例を実施例３とする。 (Example 2)
In Example 1, the rubber elastic body in the uncompressed state has a thickness of 1.7 mm and a diameter of 2 mm, and the propylene resin molded body has a thickness of 1 mm and a diameter of 3 mm. did. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.3. This example is referred to as Example 2.
(Example 3)
Example 1 is the same as Example 1 except that the rubber elastic body in the uncompressed state has a thickness of 2.3 mm and a diameter of 2 mm, and the propylene resin molded body has a thickness of 0.6 mm and a diameter of 3 mm. The configuration. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.4. This example is referred to as Example 3.

（比較例１）
前記実施例１において、非圧縮状態におけるゴム弾性体の厚さを０．５ｍｍ、特恵を２ｍｍとし、ポリプロピレン樹脂成形体の厚さを１．７ｍｍ、直径を２．６ｍｍとした以外は実施例１と同じ構成とした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．４であった。該例を比較例１とする。
（比較例２）
前記実施例１において、非圧縮状態におけるゴム弾性体の厚さを２．７ｍｍ、直径を２ｍｍとし、ポリプロピレン樹脂成形体の厚さを０．４ｍｍ、直径を３ｍｍとした以外は実施例１と同じ構成とした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．５であった。該例を比較例２とする。
（比較例３）
前記実施例１において、弁体をゴム弾性体のみで構成し、非圧縮状態におけるゴム弾性体の厚さを３．３ｍｍ、直径を２．４ｍｍとした以外は実施例１と同じ構成とした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．４であった。該例を比較例３とする。 (Comparative Example 1)
Example 1 except that the thickness of the rubber elastic body in the uncompressed state is 0.5 mm, the preferentialness is 2 mm, the thickness of the polypropylene resin molded body is 1.7 mm, and the diameter is 2.6 mm. It was the same composition as. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.4. This example is referred to as Comparative Example 1.
(Comparative Example 2)
Example 1 is the same as Example 1 except that the rubber elastic body in the uncompressed state has a thickness of 2.7 mm and a diameter of 2 mm, and the polypropylene resin molded body has a thickness of 0.4 mm and a diameter of 3 mm. The configuration. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.5. This example is referred to as Comparative Example 2.
(Comparative Example 3)
In Example 1, the same configuration as that of Example 1 was adopted except that the valve body was composed only of a rubber elastic body, the thickness of the rubber elastic body in an uncompressed state was 3.3 mm, and the diameter was 2.4 mm. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.4. This example is referred to as Comparative Example 3.

（各温度における排気弁の弁作動圧の調査）
実施例１〜３、比較例２、比較例３に係る蓄電池を各々３ケづつに蓄電池の内部圧力を測定するための圧力センサーを取り付け、周囲温度２５℃、５０℃、７５℃、１００℃、１２５℃、１５０℃、１７５℃、２００℃に於いて、充電電流１ＩｔＡにて排気弁が作動するまで充電を行った。２５℃における排気弁の弁作動圧の大きさを１００（％）として、各温度における弁作動圧の大きさを評価した。なお、蓄電池の表面に温度センサーを取り付け、充電中の電池表面温度が周囲温度とほぼ等しい温度であることを確認した。 (Investigation of valve operating pressure of exhaust valve at each temperature)
A pressure sensor for measuring the internal pressure of each of the storage batteries according to Examples 1 to 3, Comparative Example 2 and Comparative Example 3 was attached to each of the three storage batteries, and the ambient temperature was 25 ° C, 50 ° C, 75 ° C, 100 ° C, Charging was performed at 125 ° C., 150 ° C., 175 ° C., and 200 ° C. with a charging current of 1 ItA until the exhaust valve was activated. The magnitude of the valve operating pressure of the exhaust valve at 25 ° C. was set to 100 (%), and the magnitude of the valve operating pressure at each temperature was evaluated. In addition, a temperature sensor was attached to the surface of the storage battery, and it was confirmed that the battery surface temperature during charging was almost equal to the ambient temperature.

（落下試験）
コンクリート製の床面上に、長さ１０２ｃｍ、内径１６ｍｍの半透明塩化ビニル製のパイプを直立させ、該パイプの上側開放端内に、前記化成後の充電を終えた実施例１〜３、比較例１〜３に係る密閉形蓄電池をキャップを下側に、キャップの下端とコンクリートの床面の距離が１００ｃｍとなるように配置し、該高さから蓄電池をパイプ内を通過させてコンクリート上に落下させた。該操作を１〜５回行った。 (Drop test)
Examples 1 to 3 in which a pipe made of translucent vinyl chloride having a length of 102 cm and an inner diameter of 16 mm was made upright on a concrete floor, and charging after the chemical conversion was finished in the upper open end of the pipe, comparison The sealed storage battery according to Examples 1 to 3 is placed with the cap on the lower side and the distance between the lower end of the cap and the floor of the concrete being 100 cm, and the storage battery is passed through the pipe from the height onto the concrete. I dropped it. This operation was performed 1 to 5 times.

（落下試験後の排気弁の弁作動圧の調査）
実施例１、３、比較例１〜３に係る蓄電池各々３ケづつを落下回数１〜５回の落下試験に供した後、害蓄電池に蓄電池の内部圧力を測定するための圧力センサーを取り付け、周囲温度２５℃において、充電電流１ＩｔＡにて排気弁が動作するまで充電を行った。なお充電に際してはクリンプシール部分を金型で押さえ込みクリンプシールが破壊されないようにした。落下試験を行っていない蓄電池の、排気弁の弁作動圧の大きさを１００（％）として、各落下回数毎に排気弁の動作圧力の大きさを評価した。 (Investigation of valve operating pressure of exhaust valve after drop test)
After each of the storage batteries according to Examples 1 and 3 and Comparative Examples 1 to 3 was subjected to a drop test with 1 to 5 drops, a pressure sensor for measuring the internal pressure of the storage battery was attached to the harmful storage battery, Charging was performed at an ambient temperature of 25 ° C. with a charging current of 1 ItA until the exhaust valve operated. During charging, the crimp seal portion was pressed with a mold so that the crimp seal was not broken. The magnitude of the operating pressure of the exhaust valve was evaluated for each number of drops, assuming that the valve operating pressure of the exhaust valve of the storage battery that was not subjected to the drop test was 100 (%).

（充電試験１：１５分間充電）
前記実施例１〜３、比較例２、比較例３に係り、化成後５回の落下試験を行った蓄電池をそれぞれ２０ケづつ用意し、周囲温度２５℃において１．６２Ｖの定電圧を印加して１５分間充電し、破裂発生の有無を調べた。なお、該充電試験に先だって蓄電池それぞれ３ケづつ蓄電池外側面の正極端子（キャップ）側の端部に温度センサーを取り付け、該部分の温度をモニターした。詳細は省くが、該充電は、充電中の充電電流の大きさを平均すると約４ＩｔＡ（１５分間で充電を完了できるレートに相当）での定電流での充電に相当する急速充電である。該試験は、本来圧力スイッチ内蔵形の蓄電池を対象とした試験であるが、圧力スイッチが機能しなくなった状況を想定し、該状況下で破裂を防ぐことが出来るか否かを評価するために、圧力スイッチを配置していない蓄電池を用いて試験を行った。 (Charge test 1: 15 minute charge)
In accordance with Examples 1 to 3, Comparative Example 2, and Comparative Example 3, 20 storage batteries each subjected to a drop test 5 times after preparation were prepared, and a constant voltage of 1.62 V was applied at an ambient temperature of 25 ° C. The battery was charged for 15 minutes and examined for the presence of rupture. Prior to the charging test, a temperature sensor was attached to the positive electrode terminal (cap) side end of the outer side surface of each of the three storage batteries, and the temperature of the part was monitored. Although not described in detail, the charging is rapid charging corresponding to charging at a constant current of about 4 ItA (corresponding to a rate at which charging can be completed in 15 minutes) on average when the magnitude of the charging current during charging is averaged. This test is originally intended for a storage battery with a built-in pressure switch. In order to evaluate whether the pressure switch can no longer function and evaluate whether or not explosion can be prevented under this condition. The test was conducted using a storage battery in which no pressure switch was arranged.

（短絡試験）
化成後の充電を終えた蓄電池であって、落下試験に供してない蓄電池および落下回数５回の落下試験を行った蓄電池をそれぞれ２０ケづつ用意し、周囲温度２５℃において正極と負極をリード線で結び短絡させ、６０分間短絡状態を保ち、蓄電池に破裂が発生するか否かを調べた。なお、短絡試験に先だって、落下試験に供してない蓄電池および落下試験に供した蓄電池それぞれ３ケづつ蓄電池外側面の正極端子（キャップ）側の端部に温度センサーを取り付け、該部分の温度をモニターした。 (Short-circuit test)
A storage battery that has been charged after the formation and that has not been subjected to a drop test and a storage battery that has been subjected to a drop test with 5 drops are prepared for each of the 20 batteries. Lead wires are connected to the positive electrode and the negative electrode at an ambient temperature of 25 ° C. The battery was short-circuited and kept short-circuited for 60 minutes, and it was examined whether or not a rupture occurred in the storage battery. Prior to the short-circuit test, a temperature sensor is attached to the positive terminal (cap) side end of the storage battery outer surface for each of the storage battery not subjected to the drop test and the storage battery subjected to the drop test, and the temperature of the part is monitored. did.

（充電試験２）
化成及び初期充電を終えた後、直後および３ヶ月放置後の蓄電池をそれぞれ２０ケづつ用意し、周囲温度２５℃において１ＩｔＡの電流で１．５時間充電し、キャップに設けた排気孔からの漏液発生の有無を調べた。 (Charge test 2)
After completion of chemical conversion and initial charging, prepare 20 batteries each immediately after and after standing for 3 months, charge for 1.5 hours at a current of 1 ItA at an ambient temperature of 25 ° C, and leak from the exhaust hole provided in the cap. The presence or absence of liquid generation was examined.

図３は、実施例１〜３、比較例２〜３の各周囲温度における排気弁の弁作動圧（３ヶの平均値）を示した図である。図３に示したように排気弁の開弁圧は何れも周囲温度が上昇するに連れて低下する傾向にあるが、実施例においては弁作動圧低下の度合いが大きく、実施例１〜３の温度１００℃における弁作動圧は、２５℃弁作動圧の７０％であり、温度１５０℃においてはそれぞれ２５℃の２６％、３２％、４０％である。これに対して比較例の場合温度１００℃においては２５℃に比べて比較例２が７８％、比較例３が８５％であり、温度１５０℃においては比較例２が５５％、比較例３が６９％である。実施例１〜３においては図１においてポリプロピレン樹脂成形体が塑性変形し、ゴム弾性体４の圧縮率が低下したために弁作動圧が大きく低下したものと考えられる。比較例３の場合は、弁体がゴム製弾性体のみで構成したので、温度が上昇しても弁作動圧の低下が小さく、比較例２の場合は、実施例同様ゴム製弾性体とポリプロピレン樹脂成形体の積層体からなる弁体を使用しているがゴム製弾性体の厚さの比を大きく、ポリプロピレン樹脂成形体の厚さの比を小さくしたために実施例に比べて１００℃と１５０℃における弁作動圧が大きくなったものと考えられる。   FIG. 3 is a view showing the valve operating pressures (average value of three) of the exhaust valves at each ambient temperature in Examples 1 to 3 and Comparative Examples 2 to 3. As shown in FIG. 3, the exhaust valve opening pressure tends to decrease as the ambient temperature rises. However, in the embodiment, the degree of decrease in the valve operating pressure is large. The valve operating pressure at a temperature of 100 ° C. is 70% of the 25 ° C. valve operating pressure, and at a temperature of 150 ° C., they are 26%, 32%, and 40% of 25 ° C., respectively. On the other hand, in the case of the comparative example, at a temperature of 100 ° C., the comparative example 2 is 78% and the comparative example 3 is 85% compared to 25 ° C., and at the temperature of 150 ° C., the comparative example 2 is 55% 69%. In Examples 1 to 3, it is considered that the valve operating pressure was greatly reduced because the polypropylene resin molded body was plastically deformed in FIG. 1 and the compression rate of the rubber elastic body 4 was lowered. In the case of Comparative Example 3, since the valve body is composed only of a rubber elastic body, the decrease in valve operating pressure is small even when the temperature rises. In the case of Comparative Example 2, the rubber elastic body and polypropylene are the same as in the embodiment. Although a valve body made of a laminate of resin molded bodies is used, the ratio of the thickness of the rubber elastic body is increased, and the ratio of the thickness of the polypropylene resin molded body is decreased. It is thought that the valve operating pressure at ℃ increased.

図４に実施例１、３および比較例１〜３の、落下回数毎に排気弁の弁作動圧を調べた結果を示す。落下試験を行っていない蓄電池の弁作動圧と落下回数５回後の蓄電池の弁作動圧を比較すると、落下試験を行っていない蓄電池の弁作動圧を１００％とした場合、実施例１、２においては、落下試験を行った後では１２０％、比較例１の場合１３０％と増大の程度が小さいのに対して、比較例２、比較例３の場合にはそれぞれ１８０％、２００％と大幅に増大している。落下試験によって排気弁の弁作動圧が増大するのは、キャップが変形して弁室の高さが小さくなり、ゴム製弾性体の圧縮率が増大するためである。実施例１、３、比較例１においては落下試験におけるキャップの変形の度合いが小さかったのに比べて、比較例２、比較例３においてはキャップが顕著に変形していた。実施例１、３、比較例１においては常温においてゴム製弾性体に比べて硬度の高いポリプロピレン樹脂成形体をゴム製弾性体とキャップの上壁の間に配置することによってキャップの変形を抑制できたので弁作動圧の増大を抑制することができたものと考えられる。なお、比較例１は、実施例１、３同様落下によるキャップの変形が小さいが、実施例１、３に比べてゴム製弾性体の厚さが小さいので、落下後によるゴム製弾性体の圧縮率の増大幅が大きく、実施例１、３に比べて若干弁作動圧が大きくなったものと考えられる。   FIG. 4 shows the results of examining the valve operating pressure of the exhaust valve for each number of drops in Examples 1 and 3 and Comparative Examples 1 to 3. Comparing the valve operating pressure of the storage battery not subjected to the drop test and the valve operating pressure of the storage battery after the number of drops of 5 times, when the valve operating pressure of the storage battery not subjected to the drop test is assumed to be 100%, Examples 1 and 2 In Comparative Example 2 and Comparative Example 3, the degree of increase was small, 120% after the drop test, and 130% in Comparative Example 1, whereas the increase was 180% and 200%, respectively. Has increased. The reason why the valve operating pressure of the exhaust valve is increased by the drop test is that the cap is deformed to reduce the height of the valve chamber, and the compression rate of the rubber elastic body is increased. In Examples 1 and 3 and Comparative Example 1, the degree of deformation of the cap in the drop test was small, and in Comparative Examples 2 and 3, the cap was significantly deformed. In Examples 1 and 3 and Comparative Example 1, deformation of the cap can be suppressed by disposing a polypropylene resin molded body having a higher hardness than that of the rubber elastic body at room temperature between the rubber elastic body and the upper wall of the cap. Therefore, it is considered that the increase in valve operating pressure could be suppressed. In Comparative Example 1, the deformation of the cap due to dropping is small as in Examples 1 and 3, but the thickness of the rubber elastic body is smaller than that in Examples 1 and 3, so the compression of the rubber elastic body after dropping is small. It is considered that the rate of increase in the rate was large, and the valve operating pressure was slightly increased as compared with Examples 1 and 3.

表１に、実施例１〜３、比較例２、比較例３を充電試験１（１５分間充電）に供した試験結果を示す。

Figure 0004701636
充電試験１において、充電の末期には蓄電池の充電温度が約１００℃にまで昇温した。表１に示したとおり実施例１〜３においては充電中に破裂する蓄電池が認められなかったのに対して、比較例２および比較例３においては破裂する電池の発生が認められた。表１に示した結果から、圧力スイッチが動作しない状態において充電試験１のような急速充電を行っても電池が破裂に至らないようにするためには、実施例１〜３のように、弁体をゴム製弾性体と熱可塑性樹脂成形体の積層体とし、かつ、弁体に占めるゴム弾性体の厚さの比を０．３〜０．７にするのが良い。また、表１に示した結果では実施例２と実施例３の間に試験結果に差がないが、弁体に占めるゴム製弾性体の比を小さくすることが良い結果が得られるところから、弁体に占めるゴム弾性体の厚さの比を０．３〜０．５にするのが好ましい。 Table 1 shows the test results obtained by subjecting Examples 1 to 3, Comparative Example 2, and Comparative Example 3 to charge test 1 (charge for 15 minutes).
Figure 0004701636
 In charging test 1, the charging temperature of the storage battery was raised to about 100 ° C. at the end of charging. As shown in Table 1, in Examples 1 to 3, no storage battery bursting during charging was observed, whereas in Comparative Example 2 and Comparative Example 3, the generation of bursting batteries was observed. From the results shown in Table 1, in order to prevent the battery from rupturing even when rapid charging as in charging test 1 is performed in a state where the pressure switch does not operate, The body is preferably a laminate of a rubber elastic body and a thermoplastic resin molded body, and the ratio of the thickness of the rubber elastic body in the valve body is preferably 0.3 to 0.7. Moreover, in the results shown in Table 1, there is no difference in the test results between Example 2 and Example 3, from which good results can be obtained by reducing the ratio of the rubber elastic body to the valve body, It is preferable to set the ratio of the thickness of the rubber elastic body in the valve body to 0.3 to 0.5.

充電試験１のような急速充電を行うと、蓄電池の温度が上昇することに伴い蓄電池内のガス発生量が急激に増大するが、前記図３に示した如く比較例２及び比較例３においては温度１００℃近傍における排気弁の弁作動圧が高いために排気弁が機能し難く、蓄電池内部の圧力が上昇して破裂に至る蓄電池が発生したものと考えられる。中でも比較例３は、図４に示した如く蓄電池を落下させると、排気弁の弁作動圧が大きくなったために排気弁が機能し難くなったものと考えられる。これに対して実施例１〜３は、図３に示す如く１００℃近傍における排気弁の弁作動圧が低く、且つ、図４に示したように実施例１、実施例３の場合、蓄電池を落下させても排気弁の弁作動圧の上昇が抑制されたために排気弁が機能し、破裂に至らなかったものと考えられる。急激なガス発生に伴う蓄電池内部の圧力増大による破裂を防ぐには、弁作動圧を低くするのが有効であって、表１、図３に示した結果から、圧力スイッチが機能しない密閉形蓄電池を１５分間充電したときに蓄電池が破裂に至らないようにするためには、温度１００℃における弁作動圧が２５℃の弁作動圧の７０％以下であることが好ましい。   When rapid charging as in charging test 1 is performed, the amount of gas generated in the storage battery increases rapidly as the temperature of the storage battery rises. In Comparative Example 2 and Comparative Example 3, as shown in FIG. The exhaust valve is difficult to function due to the high valve operating pressure of the exhaust valve in the vicinity of a temperature of 100 ° C., and it is considered that a storage battery is generated in which the internal pressure of the storage battery rises and ruptures. In particular, in Comparative Example 3, when the storage battery was dropped as shown in FIG. 4, it was considered that the exhaust valve became difficult to function because the valve operating pressure of the exhaust valve increased. In contrast, in Examples 1 to 3, the valve operating pressure of the exhaust valve in the vicinity of 100 ° C. is low as shown in FIG. 3, and in the case of Example 1 and Example 3 as shown in FIG. Even if it is dropped, it is considered that the exhaust valve functioned because the increase in the valve operating pressure of the exhaust valve was suppressed, and the explosion did not occur. In order to prevent explosion due to an increase in pressure inside the storage battery due to sudden gas generation, it is effective to lower the valve operating pressure. From the results shown in Table 1 and FIG. 3, a sealed storage battery in which the pressure switch does not function. In order to prevent the storage battery from bursting when charged for 15 minutes, the valve operating pressure at a temperature of 100 ° C. is preferably 70% or less of the valve operating pressure at 25 ° C.

実施例１〜３、比較例１〜３の短絡試験結果を表２に示す。なお、短絡試験においては蓄電池表面の温度が１５０℃以上に達した。

Figure 0004701636
表２に示したように、ゴム製弾性体の厚さと弁体の厚さの比が０．３〜０．７である実施例１〜３およびゴム製弾性体の厚さと弁体の厚さの比が０．１５である比較例１においては落下試験に供していないもの、落下試験に供したもの何れも短絡試験において排気弁が作動し、破裂に至らないことが確認された。これに対してゴム製弾性体の厚さと弁体の厚さの比が０．８である比較例２および弁体がゴム製弾性体のみからなる比較例３においては、短絡試験において排気弁が機能せずに破裂に至る蓄電池の発生が認められた。
短絡試験において比較例２、３に破裂発生が認められたのは、蓄電池の温度が上昇するにつれ、蓄電池内部でのガス発生速度が急激に増大するのに対して、排気弁の弁作動圧が高く排気弁が機能し難いために排気弁の機能が追いつかずに蓄電池内部の圧力が上昇して破裂に至ったものと考えられる。実施例１〜３、比較例１の場合、弁体に占めるゴム製弾性体の厚さの比率を０．７以下にしているので短絡試験において蓄電池温度が上昇したときにポリプロピレン成形体が塑性変形してゴム製弾性体の圧縮率が低下したために排気弁が機能し、蓄電池が破裂に至るのを回避できたものと考えられる。一方比較例３の場合は弁体がゴム製弾性体のみからなり、比較例２の場合は弁体がポリプロピレン樹脂成形体とゴム製弾性体の積層体からなるもののゴム製弾性体の弁体に占める厚さの比が大きいために蓄電池の温度が上昇したときに排気弁の弁作動圧が高く排気弁が機能し難かったために破裂に至る蓄電池が発生したものと考えられる。また、表２に示した評価結果では実施例２と実施例３の評価結果に差が認められなかったが、誤って外部短絡させたときに起きる蓄電池温度が異常に昇温した状況化に於いて排気板を確実に動作させるためには、実施例１、実施例２のようにゴム製弾性体の弁体に占める比を０．３〜０．５にすることが好ましい。 Table 2 shows the short-circuit test results of Examples 1 to 3 and Comparative Examples 1 to 3. In the short circuit test, the temperature of the storage battery surface reached 150 ° C. or higher.
Figure 0004701636
 As shown in Table 2, Examples 1 to 3 in which the ratio of the thickness of the rubber elastic body to the thickness of the valve body is 0.3 to 0.7, and the thickness of the rubber elastic body and the thickness of the valve body In Comparative Example 1 in which the ratio of 0.15 was 0.15, it was confirmed that the exhaust valve operated in the short-circuit test and not ruptured in any of those not subjected to the drop test and those subjected to the drop test. On the other hand, in Comparative Example 2 in which the ratio of the thickness of the rubber elastic body to the thickness of the valve body is 0.8 and in Comparative Example 3 in which the valve body is made only of the rubber elastic body, the exhaust valve is not used in the short-circuit test. The generation of storage batteries that did not function and led to rupture was observed.
In the short-circuit test, the occurrence of rupture was observed in Comparative Examples 2 and 3 because the gas generation rate inside the storage battery increased rapidly as the temperature of the storage battery increased, whereas the valve operating pressure of the exhaust valve increased. It is considered that the exhaust valve did not catch up because the exhaust valve was too high to function and the internal pressure of the storage battery increased, leading to rupture. In the case of Examples 1 to 3 and Comparative Example 1, since the ratio of the thickness of the rubber elastic body in the valve body is 0.7 or less, the polypropylene molded body undergoes plastic deformation when the storage battery temperature rises in the short-circuit test. It is thought that the exhaust valve functioned because the compression rate of the rubber elastic body was lowered, and the storage battery could be prevented from rupturing. On the other hand, in the case of Comparative Example 3, the valve body is composed only of a rubber elastic body. In the case of Comparative Example 2, the valve body is composed of a laminate of a polypropylene resin molded body and a rubber elastic body. Since the ratio of the thickness occupied is large, it is considered that when the temperature of the storage battery rose, the valve operating pressure of the exhaust valve was high and the exhaust valve was difficult to function. In addition, in the evaluation results shown in Table 2, there was no difference between the evaluation results of Example 2 and Example 3, but in the situation where the storage battery temperature that occurred when the external short circuit was mistakenly caused was abnormally increased. In order to operate the exhaust plate reliably, the ratio of the rubber elastic body to the valve body is preferably 0.3 to 0.5 as in the first and second embodiments.

因みに、図３に示したように、比較例２、３においては蓄電池を短絡させたときの蓄電池温度（１５０℃）における排気弁の弁作動圧がそれぞれ２５℃の５５％、６９％であり。これに対して実施例１〜３の場合は、図３に示したように１５０℃における排気弁の弁作動圧が２５℃の４０％以下と低いために排気弁が良好に機能し、破裂が回避できたものと考えられる。このことから温度１５０℃における弁作動圧を２５℃における弁作動圧の４０％以下にすることが好ましい。
また、破裂に至った蓄電池においては、蓄電池の温度が１００℃を超える付近から電槽缶のシール部分に変形が生じ始めることが分かった。このことから、蓄電池を誤って外部短絡させた場合にもシール破壊の発生を防ぐには、温度１５０℃における排気弁の弁作動圧が２５℃における弁作動圧の４０％以下であることに加え、１００℃における排気弁の動作圧力を２５℃の弁作動圧の７０％以下にすることがより好ましい。 Incidentally, as shown in FIG. 3, in Comparative Examples 2 and 3, the valve operating pressure of the exhaust valve at the storage battery temperature (150 ° C.) when the storage battery is short-circuited is 55% and 69% of 25 ° C., respectively. On the other hand, in the case of Examples 1 to 3, since the valve operating pressure of the exhaust valve at 150 ° C. is as low as 40% or less of 25 ° C. as shown in FIG. It is thought that it was avoided. Therefore, it is preferable to set the valve operating pressure at a temperature of 150 ° C. to 40% or less of the valve operating pressure at 25 ° C.
Moreover, in the storage battery which reached the rupture, it turned out that a deformation | transformation begins to arise in the seal | sticker part of a battery case can from the vicinity where the temperature of a storage battery exceeds 100 degreeC. Therefore, in order to prevent the occurrence of seal destruction even when the storage battery is accidentally short-circuited, the valve operating pressure of the exhaust valve at a temperature of 150 ° C. is 40% or less of the valve operating pressure at 25 ° C. The operating pressure of the exhaust valve at 100 ° C. is more preferably 70% or less of the valve operating pressure at 25 ° C.

また、表２に示したように、比較例２、３において短絡試験に先だって落下試験に供した蓄電池において破裂する電池が多く発生した。図２の試験結果に示したように、比較例２、３の場合、蓄電池を誤って落下させると排気弁の弁作動圧が大きく増大する。落下試験に供した蓄電池にはキャップが変形して（潰れて）弁室の高さが低くなったため、ゴム性弁体の圧縮率が増大し、排気弁が作動し難くなったものと考えられる。とりわけ比較例３においてはキャップの変形が顕著であったためにゴム製弾性体の圧縮率が大幅に増大し、そのために排気弁の弁作動圧が大きく増大し、破裂に至ったものと考えられる。これに対して実施例１、３は蓄電池を落下させても弁作動圧の増大が抑制され、排気弁が機能したために破裂が回避できたものと考えられる。比較例１の場合、実施例１、３に比べて落下による排気弁の弁作動圧の増大幅が少し大きいが、弁体に占めるゴム弾性体の厚さの比が小さいために蓄電池の温度が上昇してポリプロピレン成形体が塑性変形したときにゴム弾性体の圧縮率が大きく低下し、排気弁の弁作動圧が低下したために排気弁が機能し、蓄電池が破裂に至るのを回避できたものと考えられる。   Further, as shown in Table 2, in Comparative Examples 2 and 3, many batteries that burst in the storage batteries subjected to the drop test prior to the short circuit test occurred. As shown in the test results of FIG. 2, in the case of Comparative Examples 2 and 3, when the storage battery is accidentally dropped, the valve operating pressure of the exhaust valve greatly increases. The storage battery used for the drop test was deformed (collapsed) and the height of the valve chamber was lowered, so that the compression rate of the rubber valve increased and the exhaust valve became difficult to operate. . In particular, in Comparative Example 3, since the cap was significantly deformed, the compression rate of the rubber elastic body was greatly increased, and as a result, the valve operating pressure of the exhaust valve was greatly increased, leading to rupture. On the other hand, in Examples 1 and 3, even if the storage battery was dropped, the increase in the valve operating pressure was suppressed, and it is considered that explosion was avoided because the exhaust valve functioned. In the case of the comparative example 1, although the increase width of the valve operating pressure of the exhaust valve due to the drop is slightly larger than in the first and third embodiments, the ratio of the thickness of the rubber elastic body to the valve body is small, so the temperature of the storage battery is When the polypropylene molded body is plastically deformed, the compression rate of the rubber elastic body is greatly reduced, and the exhaust valve functioning due to the decrease in the valve operating pressure of the exhaust valve prevents the storage battery from bursting. it is conceivable that.

図２の試験結果に示したように、比較例１、３の場合、蓄電池を誤って落下させると排気弁の動作圧力が大きく増大し、過充電などによって蓄電池内部の圧力が上昇したときに排気弁が動作せずに破裂する虞があるのに対して、実施例１、３の場合はその虞がない。このことからも、ゴム製弾性体の弁体に対する厚さの比を０．３〜０．７とすることが良い。   As shown in the test results of FIG. 2, in the case of Comparative Examples 1 and 3, if the storage battery is accidentally dropped, the operating pressure of the exhaust valve greatly increases, and the exhaust gas is exhausted when the internal pressure of the storage battery rises due to overcharge or the like. In contrast to the case where the valve does not operate and bursts, there is no such a possibility in the first and third embodiments. Also from this, the ratio of the thickness of the rubber elastic body to the valve body is preferably 0.3 to 0.7.

実施例１〜３、比較例１〜３の充電試験２の試験結果を表３に示す。

Figure 0004701636
表３に示したように、実施例１〜３、比較例２、３においては充電試験において電解液が排気弁を通って漏液したものは認められなかった。これに対して比較例１においては電解液が排気弁を通って漏液したものが認められた。実施例１〜３、比較例２、３の何れもゴム製弾性体の圧縮率は４０％であるが、圧縮されたゴム製弾性体の縮み代が実施例１においては０．４ｍｍ、実施例３においては０．９ｍｍであるのに対して比較例１の場合はゴム製弾性体の縮み代が０．２ｍｍと小さいので弁室の高さ、熱可塑性樹脂成形体の厚さの僅かな狂いによってもゴム製弾性体の圧縮率が変動し、中にゴム製弾性体の圧縮率の小さい電池ができ弁体が蓋の透孔を抑える押圧力が小さいために排気弁を通って漏液したものと考えられる。さらに、３ヶ月簡放置する間に熱可塑性樹脂がクリープ変形し、厚さが減少したためにゴム製弾性体の圧縮率が低下し、直後から漏液する虞のあった比較例１において、直後に比べてさらに多くの漏液が発生したものと考えられる。このことから、弁体に占めるゴム弾性体の厚さの比を０．３以上にするのが良い。
以上表２と表３に示した結果を総合すると、圧縮された状態のゴム製弾性体の弁体に対する厚さの比を０．３〜０．７とすることが良いことが分かる。 Table 3 shows the test results of the charge test 2 of Examples 1 to 3 and Comparative Examples 1 to 3.
Figure 0004701636
 As shown in Table 3, in Examples 1 to 3 and Comparative Examples 2 and 3, no electrolyte solution leaked through the exhaust valve in the charge test. On the other hand, in Comparative Example 1, the electrolyte solution leaked through the exhaust valve. In each of Examples 1 to 3 and Comparative Examples 2 and 3, the compression rate of the rubber elastic body is 40%. However, in Example 1, the compression allowance of the compressed rubber elastic body is 0.4 mm. 3 is 0.9 mm, but in the case of Comparative Example 1, since the shrinkage allowance of the rubber elastic body is as small as 0.2 mm, the height of the valve chamber and the thickness of the thermoplastic resin molded body are slightly deviated. Also, the compression rate of the rubber elastic body fluctuated, and a battery with a small compression rate of the rubber elastic body could be formed, and the valve body leaked through the exhaust valve because of the small pressing force that restrains the through hole of the lid. It is considered a thing. Furthermore, in the comparative example 1 in which the compression rate of the rubber elastic body is reduced due to creep deformation of the thermoplastic resin and the thickness is reduced during the simple standing for 3 months, and there is a risk of liquid leakage from immediately after, It is thought that more liquid leakage occurred than that. Therefore, the ratio of the thickness of the rubber elastic body in the valve body is preferably set to 0.3 or more.
When the results shown in Table 2 and Table 3 are combined, it is understood that the ratio of the thickness of the compressed rubber elastic body to the valve body is preferably 0.3 to 0.7.

（実施例４）
前記実施例２において、弁体を構成するゴム製弾性体の非圧縮状態における直径を２．４ｍｍとし、それ以外は実施例２と同じ構成とした。該例を実施例５とする。該実施例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．２であった。該例を実施例４とする。
（実施例５）
前記実施例２において、弁体を構成するゴム製弾性体の非圧縮状態における直径を１．２ｍｍとし、それ以外は実施例２と同じ構成とした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．４であった。該例を実施例５とする。 Example 4
In Example 2, the diameter of the rubber elastic body constituting the valve body in the non-compressed state was 2.4 mm, and other than that, the configuration was the same as Example 2. This example is referred to as Example 5. The compression rate of the rubber elastic body of this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.2. This example is referred to as Example 4.
(Example 5)
In Example 2, the diameter of the rubber elastic body constituting the valve body in the non-compressed state was 1.2 mm, and the other configuration was the same as Example 2. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.4. This example is referred to as Example 5.

（比較例４）
前記実施例２において、弁体を構成するゴム製弾性体の非圧縮状態における直径を２．９ｍｍとし、それ以外は実施例３と同じ構成とした。該実例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．１であった。該例を比較例４とする。
（比較例５）
前記実施例２において、弁体を構成するゴム製弾性体の非圧縮状態における直径を１．４ｍｍとし、それ以外は実施例２と同じ構成とした。該実例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．５であった。該例を比較例５とする。 (Comparative Example 4)
In Example 2, the diameter of the rubber elastic body constituting the valve body in the non-compressed state was set to 2.9 mm, and the other configuration was the same as Example 3. The compression rate of the rubber elastic body of this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.1. This example is referred to as Comparative Example 4.
(Comparative Example 5)
In Example 2, the diameter of the rubber elastic body constituting the valve body in the non-compressed state was 1.4 mm, and the other configuration was the same as Example 2. The compression rate of the rubber elastic body of this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.5. This example is referred to as Comparative Example 5.

（充電試験３）
化成及び初期充電を終えた後、落下試験に供してない蓄電池および落下試験５回行った蓄電池をそれぞれ２０ケづつ用意し、周囲温度２５℃において０．１ＩｔＡの電流で４８時間充電し、キャップの排気孔からの漏液発生の有無を調べた。
また、化成及び初期充電を終えた後、落下試験に供してない蓄電池および落下試験を５回行った蓄電池をそれぞれ２０ケづつ用意し、前記短絡試験と同様に短絡試験に供した。 (Charge test 3)
After completing the chemical conversion and initial charging, prepare 20 batteries each not subjected to drop test and 5 batteries subjected to drop test, charge for 48 hours at current of 0.1 ItA at ambient temperature 25 ° C, The presence or absence of leakage from the exhaust hole was examined.
In addition, after the chemical conversion and the initial charging were completed, 20 storage batteries that were not subjected to the drop test and 5 storage batteries that were subjected to the drop test were prepared, and were subjected to the short circuit test in the same manner as the short circuit test.

実施例２、実施例４、実施例５、比較例４、比較例５の短絡試験結果を表４に示す。

Figure 0004701636
表４に示したように、弁室内空き空間容積と弁室容積の比が０．２〜０．４の実施例４、２、５および弁室内空き空間容積と弁室容積の比が０．５の比較例５においては破壊が発生しなかったのに対して弁室内空き空間容積と弁室容積の比が０．１の比較例４においては破壊が発生した。実施例４、実施例５、実施例３および比較例５においては短絡試験において蓄電池の温度が上昇したときに弁体を構成するポリプロピレン樹脂成形体が塑性変形し、ゴム製弾性体のサイドに設けた空き空間内へ移動したためにゴム製弾性体の圧縮率が低下し、排気弁が動作したのに対して、比較例４においては弁室内の空き空間容積が小さいためにポリプロピレン成形体が軟化または溶融しても移動せずに元の位置に留まり、ゴム製弾性体の圧縮率が低下せず排気弁が動作しなかったために、シールが破壊されたものと考えられる。 Table 4 shows the short-circuit test results of Example 2, Example 4, Example 5, Comparative Example 4, and Comparative Example 5.
Figure 0004701636
 As shown in Table 4, Examples 4, 2, and 5 in which the ratio of the valve chamber free space volume to the valve chamber volume is 0.2 to 0.4, and the ratio of the valve chamber free space volume to the valve chamber volume is 0.00. In Comparative Example 5 of 5, no destruction occurred, whereas in Comparative Example 4 in which the ratio of the free space in the valve chamber to the volume of the valve chamber was 0.1, the destruction occurred. In Example 4, Example 5, Example 3 and Comparative Example 5, when the temperature of the storage battery rises in the short circuit test, the polypropylene resin molded body constituting the valve body is plastically deformed and provided on the side of the rubber elastic body. Since the compression rate of the rubber elastic body is reduced and the exhaust valve is operated due to the movement into the empty space, the polypropylene molded body is softened because the empty space volume in the valve chamber is small in Comparative Example 4. It is considered that the seal was broken because the rubber elastic body did not move and remained in the original position even when melted, and the compression rate of the rubber elastic body did not decrease and the exhaust valve did not operate.

実施例２、実施例４、実施例５、比較例４、比較例５の充電試験３の試験結果を表５に示す。

Figure 0004701636
表５に示したように、実施例４、実施例５、実施例３および比較例４においては充電試験中漏液した電池は発生しなかったが、比較例５においては排気弁を通って、漏液したものが認められた。比較例５の場合はゴム製弁体の直径が小さくなったために、実施例３〜５、比較例４とゴム製弾性体の圧縮率が同一にも拘わらず圧縮応力が過度に小さくなったために、ゴム製弁体の押圧力が不足し排気弁を通って漏液が発生したものと考えられる。また、落下試験を経たものは、ゴム製弾性体に変形が生じ、さらにゴム製弾性体の押圧力が低下したために排気弁を通って漏液したものがさらに多く発生したものと考えられる。なお、ゴム製弾性体の直径を小さくすることなく、熱可塑性樹脂成形体の直径を小さくすることによっても弁室内明き空間容積と弁室容積の比を大きくすることができるが、熱可塑性樹脂成形体の直径を小さくすると、後記の如く、キャップの変形を抑制する効果が得られなくなったり、熱可塑性樹脂のクリープ変形が大きくなったりする虞があるので好ましくない。
以上に記述した評価結果から、弁室内空き空間容積と弁室容積の比を０．２〜０．４にするのが良い。 Table 5 shows the test results of the charging test 3 of Example 2, Example 4, Example 5, Comparative Example 4, and Comparative Example 5.
Figure 0004701636
 As shown in Table 5, in Example 4, Example 5, Example 3 and Comparative Example 4, no battery leaked during the charging test occurred, but in Comparative Example 5, through the exhaust valve, Leakage was observed. In the case of Comparative Example 5, because the diameter of the rubber valve body was reduced, the compressive stress was excessively reduced in spite of the same compression rate as in Examples 3 to 5 and Comparative Example 4 and the rubber elastic body. It is considered that liquid rubber leaked through the exhaust valve due to insufficient pressure of the rubber valve. In addition, it is considered that in the case where the drop test was performed, the rubber elastic body was deformed, and more liquid leaked through the exhaust valve because the pressing force of the rubber elastic body was lowered. In addition, the ratio of the valve chamber clear space volume and the valve chamber volume can be increased by reducing the diameter of the thermoplastic resin molding without reducing the diameter of the rubber elastic body. If the diameter of the molded body is reduced, the effect of suppressing the deformation of the cap cannot be obtained as described later, and the creep deformation of the thermoplastic resin may be increased, which is not preferable.
From the evaluation results described above, the ratio of the free space in the valve chamber to the volume in the valve chamber is preferably 0.2 to 0.4.

（実施例６）
前記実施例２において、非圧縮状態におけるゴム製弾性体の厚さを１ｍｍ、ポリプロピレン樹脂成形体の厚さを０．６ｍｍ、弁室の高さ（内法）を１．２ｍｍとした。その他は、実施例２と同じとした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．３であった。該例を実施例６とする。
（実施例７）
前記実施例２において、非圧縮状態におけるゴム製弾性体の厚さを２．３ｍｍ、ポリプロピレン樹脂成形体の厚さを１．４ｍｍ、弁室の高さ（内法）を２．８ｍｍとした。その他は、実施例２と同じとした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．３であった。該例を実施例７とする。 (Example 6)
In Example 2, the thickness of the rubber elastic body in the uncompressed state was 1 mm, the thickness of the polypropylene resin molded body was 0.6 mm, and the height of the valve chamber (inner method) was 1.2 mm. Others were the same as in Example 2. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.3. This example is referred to as Example 6.
(Example 7)
In Example 2, the thickness of the rubber elastic body in the uncompressed state was 2.3 mm, the thickness of the polypropylene resin molded body was 1.4 mm, and the height of the valve chamber (inner method) was 2.8 mm. Others were the same as in Example 2. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.3. This example is referred to as Example 7.

（比較例６）
前記実施例２において、非圧縮状態におけるゴム製弾性体の厚さを０．７ｍｍ、ポリプロピレン樹脂成形体の厚さを０．４ｍｍ、弁室の高さ（内法）を０．８ｍｍとした。その他は、実施例２と同じとした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．３であった。該例を比較例６とする。
（比較例７）
前記実施例２において、非圧縮状態におけるゴム製弾性体の厚さを２．８ｍｍ、ポリプロピレン樹脂成形体の厚さを１．７ｍｍ、弁室の高さ（内法）を３．４ｍｍとした。その他は、実施例２と同じとした。該例のゴム製弾性体の圧縮率は４０％、弁室内の空き空間の弁室容積に対する比は０．３であった。該例を比較例７とする。 (Comparative Example 6)
In Example 2, the thickness of the rubber elastic body in the uncompressed state was 0.7 mm, the thickness of the polypropylene resin molded body was 0.4 mm, and the height of the valve chamber (inner method) was 0.8 mm. Others were the same as in Example 2. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.3. This example is referred to as Comparative Example 6.
(Comparative Example 7)
In Example 2, the thickness of the rubber elastic body in the uncompressed state was 2.8 mm, the thickness of the polypropylene resin molded body was 1.7 mm, and the height of the valve chamber (inner method) was 3.4 mm. Others were the same as in Example 2. The compression rate of the rubber elastic body in this example was 40%, and the ratio of the empty space in the valve chamber to the valve chamber volume was 0.3. This example is referred to as Comparative Example 7.

実施例６、実施例７および比較例６、７に係る蓄電池を前記実施例１〜４、比較例１〜３と同様に短絡試験、充電試験２に供した。   The storage batteries according to Example 6, Example 7, and Comparative Examples 6 and 7 were subjected to a short circuit test and a charge test 2 in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 3.

実施例２に併せて、実施例６、７および比較例６、７の短絡試験結果を表６に示す。

Figure 0004701636
表６に示したように、実施例６、実施例２、実施例７、比較例７において破裂の発生が認められなかったのに対して比較例６にシール破裂の発生が認められた。ポリプロピレン樹脂成形体は、常温においては剛直でありキャップを中から支える役目をしていると考えられる。該ポリプロピレン製成形体の厚さが小さい比較例６の場合、キャップを中から支える力が小さいために、落下試験を実施するとキャップが変形し、ガスケットの圧縮率が上昇し、排気弁の動作圧力が増大したために破裂に至ったものと考えられる。 In addition to Example 2, Table 6 shows the short-circuit test results of Examples 6 and 7 and Comparative Examples 6 and 7.
Figure 0004701636
 As shown in Table 6, in Example 6, Example 2, Example 7, and Comparative Example 7, the occurrence of rupture was not observed, whereas in Comparative Example 6, the occurrence of seal rupture was observed. The polypropylene resin molding is considered to be rigid at room temperature and to play a role of supporting the cap from the inside. In the case of Comparative Example 6 in which the thickness of the polypropylene molded body is small, since the force for supporting the cap from the inside is small, when the drop test is performed, the cap is deformed, the compression rate of the gasket is increased, and the operating pressure of the exhaust valve is increased. It is thought that the rupture was caused because of the increase of.

実施例２に併せて、実施例６、７および比較例６、７の充電試験２の試験結果を表７に示す。

Figure 0004701636
表７に示したように、実施例２、６、７及び比較例６においては漏液の発生が認められなかったのに対して、比較例７においては３ヶ月放置後において漏液の発生が認められた。比較例７においてはクリープ変形によってポリプロピレン樹脂成形体の厚さの現象が大きく、ゴム製弾性体の圧縮率が低下して排気弁の動作圧力が低下したために、充電中に封口板に設けた透孔を通って漏液が発生してものと考えられる。これに対して実施例２、６、７および比較例６はポリプロピレン樹脂成形体のクリープ変形による厚さの減少が小さく、ゴム製弾性体の圧縮率が低下しないために排気弁の弁作動圧が維持され、漏液発生が防止されたものと考えられる。
以上に記述した評価結果から、熱可塑性樹脂成形体の厚さを０．６〜１．４ｍｍとすることが好ましく、また、弁室の厚さを低く抑えその占有体積を出来るだけ小さくするためには、熱可塑性樹脂成形体の厚さを０．６〜１．０ｍｍとすることがさらに好ましい。 In addition to Example 2, Table 7 shows the test results of Charging Test 2 of Examples 6 and 7 and Comparative Examples 6 and 7.
Figure 0004701636
 As shown in Table 7, in Examples 2, 6, 7 and Comparative Example 6, no leakage was observed, whereas in Comparative Example 7, the leakage occurred after being left for 3 months. Admitted. In Comparative Example 7, the phenomenon of the thickness of the polypropylene resin molded body was large due to creep deformation, the compression rate of the rubber elastic body was reduced, and the operating pressure of the exhaust valve was reduced. It is thought that leakage occurs through the hole. On the other hand, in Examples 2, 6, 7 and Comparative Example 6, the decrease in thickness due to creep deformation of the polypropylene resin molded body is small, and the compression rate of the rubber elastic body does not decrease. It is considered that the occurrence of leakage was prevented.
From the evaluation results described above, it is preferable to set the thickness of the thermoplastic resin molded body to 0.6 to 1.4 mm, and to keep the valve chamber thickness low and the occupied volume as small as possible. More preferably, the thickness of the thermoplastic resin molded body is 0.6 to 1.0 mm.

前記実施例１に記述したように、機器へ装着する際に蓄電池に方向性がなく、装着し易いところからキャップ状端子が円筒状であることが好ましく、該キャップで囲まれた弁室内に配置する弁体もキャップの形状に合わせて円筒状であることが好ましい。図１において弁体を構成する熱可塑性樹脂成形体８の直径は特に限定されるものではないが、熱可塑性樹脂成形体８の直径が弁室の直径（キャップ２の筒状部の内径）に比べて小さく、熱可塑性樹脂成形体８の側面とキャップ２の内壁の間に大きな隙間があると、電池を落下させた際にキャップの変形を抑制する効果が得られない虞があり、また、弁体を弁室の中央に位置させる位置決めに支障を来す虞がある。このような虞を無くすためには熱可塑性樹脂成形体８の直径を弁室の直径の８０％以上にすることが好ましく９０％以上にすることがさらに好ましい。また、熱可塑性樹脂成形体８の直径がゴム製弾性体４の直径に比べて小さいと、ゴム製弾性体の押圧力によって熱可塑性樹脂成形体８がクリープ変形する度合いが大きくなり、ゴム製弾性体の圧縮率が時間の経過と共に低下する虞があり、さらにゴム製弾性体を均一に圧縮出来ない虞があるので、熱可塑性樹脂成形体８の直径をゴム製弾性体の直径に比べて大きく設定することが好ましい。   As described in the first embodiment, the cap terminal is preferably cylindrical because the storage battery has no directionality and is easy to mount when mounted on the device, and is disposed in the valve chamber surrounded by the cap. It is preferable that the valve body to be formed is also cylindrical in accordance with the shape of the cap. In FIG. 1, the diameter of the thermoplastic resin molded body 8 constituting the valve body is not particularly limited, but the diameter of the thermoplastic resin molded body 8 is equal to the diameter of the valve chamber (the inner diameter of the cylindrical portion of the cap 2). If there is a large gap between the side surface of the thermoplastic resin molded body 8 and the inner wall of the cap 2, the effect of suppressing the deformation of the cap may not be obtained when the battery is dropped, There is a possibility that the positioning of the valve body in the center of the valve chamber may be hindered. In order to eliminate such a concern, the diameter of the thermoplastic resin molded body 8 is preferably 80% or more, more preferably 90% or more of the diameter of the valve chamber. If the diameter of the thermoplastic resin molded body 8 is smaller than the diameter of the rubber elastic body 4, the degree of creep deformation of the thermoplastic resin molded body 8 due to the pressing force of the rubber elastic body increases, and the rubber elasticity Since the compression ratio of the body may decrease with time and the rubber elastic body may not be compressed uniformly, the diameter of the thermoplastic resin molded body 8 is larger than the diameter of the rubber elastic body. It is preferable to set.

また、本発明においては蓄電池温度が高温になり、軟化した熱可塑性樹脂成形体８が弁室内に設けた空き空間９に向かって移動し易くするために、ゴム製弾性体の中央部分における圧縮率を周縁部分の圧縮率に比べて高くし、軟化もしくは融解した熱可塑性樹脂成形体がゴム製弾性体の圧縮応力によて弁室の周縁部分に追いやられるように設定することが好ましい。ゴム製弾性体の中央部分における圧縮率を周縁部分の圧縮率に比べて高くする方法はとくに限定されるものではないが、例えば、弁体の中央部分と周縁部分の厚さを同じくし、図５に示すように封口板１に傾斜を設けて、弁室の中央部分の高さを周縁部分の高さに比べて小さくする方法、弁室の中央部分と周縁部分の高さを同じくし、図６に示すように弁体を構成するゴム製弾性体の中央部分の厚さを周縁部分の厚さに比べて大きくする方法が適用出来る。弁室の中央部分の高さと周縁部分の高さの差、ゴム製弾性体の中央部分の厚さと周縁部分の厚さの差は特に限定されるものではないが、５〜２０％が好ましい。その差が５％未満では弁室の中央部分の高さを小さくしたり、ゴム製弾性体の中央部分の厚さを大きくして効果が得られ難い。また、その差が２０％を超えるとゴム製弾性体の周縁部分の圧縮率が低下して排気弁の弁作動圧が低くなる虞があるので好ましくない。   Further, in the present invention, in order to make the storage battery temperature high and the softened thermoplastic resin molded body 8 easily move toward the empty space 9 provided in the valve chamber, the compressibility in the central portion of the rubber elastic body Is set to be higher than the compressibility of the peripheral portion so that the softened or melted thermoplastic resin molded body is driven to the peripheral portion of the valve chamber by the compression stress of the rubber elastic body. The method for increasing the compression rate in the central portion of the rubber elastic body compared to the compression rate in the peripheral portion is not particularly limited. For example, the thickness of the central portion and the peripheral portion of the valve body are the same, 5, the sealing plate 1 is inclined, and the height of the central portion of the valve chamber is smaller than the height of the peripheral portion, the height of the central portion and the peripheral portion of the valve chamber is the same, As shown in FIG. 6, a method of increasing the thickness of the central portion of the rubber elastic body constituting the valve body as compared with the thickness of the peripheral portion can be applied. The difference between the height of the central portion of the valve chamber and the height of the peripheral portion, and the difference between the thickness of the central portion of the rubber elastic body and the thickness of the peripheral portion are not particularly limited, but 5 to 20% is preferable. If the difference is less than 5%, it is difficult to obtain an effect by reducing the height of the central portion of the valve chamber or increasing the thickness of the central portion of the rubber elastic body. On the other hand, if the difference exceeds 20%, the compression ratio of the peripheral portion of the rubber elastic body is lowered and the valve operating pressure of the exhaust valve may be lowered.

本発明は、密閉形蓄電池内部の圧力が異常に上昇したときに蓄電池内部に蓄積した気体を外部に放出するための排気弁を備える密閉形蓄電池において、蓄電池の温度が１００℃を超える温度に昇温したり、さらに蓄電池を落下させるなどしてキャップが変形した状況下においても排気弁を確実に動作させて、蓄電池内部の圧力が上昇することによって蓄電池が破裂するのを防止するものであって、特に高温において蓄電池内部の圧力が急激に上昇する密閉形ニッケル水素蓄電池の破裂防止に有効であって、産業上の利用可能性の高いものである。   The present invention relates to a sealed storage battery having an exhaust valve for releasing the gas accumulated in the storage battery to the outside when the pressure inside the sealed battery rises abnormally, and the temperature of the storage battery rises to a temperature exceeding 100 ° C. Even when the cap is deformed by warming or dropping the storage battery, the exhaust valve is reliably operated to prevent the storage battery from rupturing due to an increase in the pressure inside the storage battery. In particular, it is effective in preventing the bursting of a sealed nickel-metal hydride storage battery in which the pressure inside the storage battery rises rapidly at high temperatures, and has high industrial applicability.

本発明の密閉形蓄電池の要部断面図である。It is principal part sectional drawing of the sealed storage battery of this invention. 従来の密閉形蓄電池の要部断面図である。It is principal part sectional drawing of the conventional sealed storage battery. 本発明電池及び比較例電池の周囲温度と排気弁の弁作動圧の関係を示すグラフである。It is a graph which shows the relationship between the ambient temperature of this invention battery and a comparative example battery, and the valve operating pressure of an exhaust valve. 実施例電池と比較例電池を落下試験に供したときの排気弁の弁作動圧を示すグラフである。It is a graph which shows the valve | bulb operating pressure of an exhaust valve when an Example battery and a comparative example battery are used for the drop test. 本発明の別の実施形態に係る密閉形蓄電池の要部断面図である。It is principal part sectional drawing of the sealed storage battery which concerns on another embodiment of this invention. 本発明の別の実施形態に係るゴム製弾性体の非圧縮状態における断面形状を示す図である。It is a figure which shows the cross-sectional shape in the non-compression state of the rubber-made elastic body which concerns on another embodiment of this invention.

符号の説明Explanation of symbols

１ 封口板
２ キャップ
３ 排気孔
４ ゴム製弾性体
８ 熱可塑性樹脂成形体
９ 空き空間
１０ 透孔





DESCRIPTION OF SYMBOLS 1 Sealing plate 2 Cap 3 Exhaust hole 4 Rubber elastic body 8 Thermoplastic resin molded body 9 Empty space 10 Through-hole





Claims (1)

中央部分に透孔を設けた封口板と該封口板の外面に固着されたキャップとで囲まれた弁室内に、圧縮されたゴム製弾性体と融点が１００〜２００℃の熱可塑性樹脂成形体を積層させた弁体を配置し、前記ゴム製弾性体で前記透孔を気密に封止してなる密閉形蓄電池用排気弁を備えた密閉形蓄電池であって、前記排気弁の圧縮されたゴム製弾性体の弁体に対する厚さの比を０．３〜０．７とし、前記弁室内に空き空間を設け、該空き空間の弁室に対する容積の比を０．２〜０．４としたことを特徴とする密閉形蓄電池。 In a valve chamber surrounded by a sealing plate provided with a through hole in the central portion and a cap fixed to the outer surface of the sealing plate, a compressed rubber elastic body and a thermoplastic resin molded body having a melting point of 100 to 200 ° C. A sealed storage battery having an exhaust valve for a sealed storage battery , wherein the exhaust valve is hermetically sealed with the rubber elastic body, wherein the exhaust valve is compressed. The ratio of the thickness of the rubber elastic body to the valve body is 0.3 to 0.7, an empty space is provided in the valve chamber, and the volume ratio of the empty space to the valve chamber is 0.2 to 0.4. sealed electric storage batteries, characterized in that the.
JP2004166314A 2004-06-03 2004-06-03 Sealed storage battery exhaust valve, sealed storage battery using the same, sealed nickel metal hydride storage battery Expired - Fee Related JP4701636B2 (en)

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