JP3957965B2

JP3957965B2 - Sealed lead acid battery

Info

Publication number: JP3957965B2
Application number: JP2000329872A
Authority: JP
Inventors: 英俊阿部
Original assignee: Furukawa Battery Co Ltd
Current assignee: Furukawa Battery Co Ltd
Priority date: 2000-10-30
Filing date: 2000-10-30
Publication date: 2007-08-15
Anticipated expiration: 2020-10-30
Also published as: JP2002134159A

Description

【０００１】
【発明の属する技術分野】
本発明は、セパレータとしてガラス繊維等からなり保液性に優れるリテーナマットを用い、電解液量として極板群から遊離する液がないか或いはあっても少量しか備えない密閉形鉛蓄電池に関するものである。
【０００２】
【従来の技術】
従来の密閉形鉛蓄電池は、電槽内に正極板と負極板をリテーナマットを介して交互に積層した極板群を収納し、互いに同極性極板耳を互いに溶接してストラップを形成し、該ストラップに極柱を設け、これを電槽内に収納し、蓋を施し、極柱を蓋に設けた端子と溶接し、蓋の注液口から、極板群が吸収保持できる程度の電解液を注入して、密閉形鉛蓄電池を得ている。
【０００３】
【発明が解決しようとする課題】
この種鉛蓄電池は良く知られ広く実用に供されているが、課題もある。その一つは、負極ストラップが腐食することである。
【０００４】
この課題を解決する為に、幾つかの試みが知られている。その一つの例は、特開平２−４９３５２号公報や特開平４−２０４９号公報に見られる如く、ストラップの上面を硫酸吸収物質や電解液保持体と呼ばれる物で覆う方法である。又、他の方法は、特開平４−２４９０６４号公報に見られる如く耐酸性の合成樹脂で覆う方法である。
【０００５】
しかしながら、これら方法は、ある程度の効果は発揮するが、長期に渡る効果の持続性の低いものであり、更なる改良が望まれる。
【０００６】
【課題を解決するための手段】
本発明は、より効果の持続する鉛蓄電池を得るべくなされたものである。効果の持続性が低い原因を、電位差に求めようとした。即ち、この負極ストラップは極板群とのイオン移動が殆ど無いこと、鉛蓄電池のフロート充電中に正極から酸素ガスが発生していると、負極ストラップ上部は貴へ分極して還元電位を超えるため、カソーディックな保護がされず、鉛の酸化反応が進み、また腐食生成物が溶解するために、腐食が負極ストラップ内部まで進み、遂には全体を腐食させるために、電池内で断線し作動しなくなる。
【０００７】
この考えで行くと、上記特開平４−２４９０６４号公報に記載される如く、耐酸性の発泡合成樹脂で、極板群上部からストラップ上面まで覆った場合は腐食防止が持続する筈である。しかしながら実際極板反応部の格子とストラップ間の電位差を測定した所、比較的大きな電位差が見られた。これは合成樹脂では、硫酸量が足りないのではと考え、電解液にシリカを混合したゲル状体を負極ストラップ上面から極板群に差し渡って設けた所、電位差が小さくなったことを見出した。
【０００８】
更に発明者は、腐食している鉛蓄電池の負極ストラップにこのゲル状体を施した所、やがて負極ストラップは腐食生成物が減少し、腐食のないストラップに生き返ることをも見出した。この事は、使用中の鉛蓄電池にゲル状体を施すことで鉛蓄電池を補修することが出来る事である。
【０００９】
尚、電解液のゲル状体に代え、無水硫酸カルシウム、硫酸カルシウム0.5水塩を水又は希硫酸で混練したペーストを用いても同様の作用をする。
【００１０】
【発明の実施の形態】
本発明の実施の形態を説明すると、鉛蓄電池の極板群の負極ストラップにこれを覆い且つ極板群上面に差し渡って、ゲル状硫酸、不織布にゲル状硫酸含浸塗布したもの又は硫酸カルシウムを希硫酸で混練したペースト等、硫酸イオンをゲル状或いはペースト状に固着保持した物を配したものである。
【００１１】
【実施例】
本発明に係る実施例について説明する。
【００１２】
（実施例１）
図１に示す様に、正極板及び負極板をセパレータとしてのガラス繊維からなるリテーナマットを介して交互に積層した極板群１の、正極板の耳２同士及び負極板３の耳４同士をそれぞれ溶接して正極ストラップ５及び負極ストラップ６を形成し、これを電槽７に収納した。セパレータとして用いたリテーナマット８と同材質のマット体９を負極ストラップを覆い極板群上部に差し渡って配置し、これに、シリカ濃度が２質量％添加した希硫酸をよく攪拌しながらゆっくりとマット体に供給し、該希硫酸をマット体に含浸させ硫酸イオン固着保持部材を構成した。その後常法により電槽７に蓋１０を施し、電解液として２質量％のシリカを含む希硫酸を極板群内に含浸する程度注液し密閉形鉛蓄電池を作成した。この鉛蓄電池をＡとする。尚、図中、１１は安全弁装置、１２，１３はそれぞれ正負極端子である。
【００１３】
（実施例２）
実施例１において、マット体に２質量％のシリカを含む希硫酸に代えて、マット体を用いず、希硫酸に１０質量％のシリカ添加して混合し、静置後ゲル状体（寒天状）となった希硫酸１４をゆっくりヘラ等ですくい、図２に示す様にこれを負極ストラップ６上面を覆い極板群１上に差し渡るように配置した。この操作は数回繰り返し行い差し渡る様にした。その他の構成は実施例１と同様にし密閉形鉛蓄電池を作成した。この鉛蓄電池をＢとする。
【００１４】
（実施例３）
実施例２において、シリカに代え、硫酸カルシウム0.5水塩を希硫酸と混ぜ合わせてペーストとし、これを負極ストラップの上面を覆い極板群の上面に差し渡る様にした。該ペーストは約５分程度で硬化した。その他の構成は実施例１と同様にし、密閉形鉛蓄電池を作成した。この鉛蓄電池をＣとする。
【００１５】
（実施例４）
実施例１において、マット体を負極ストラップ上面から極板群上面に差し渡り更に正極ストラップ上面まで差し渡して配置しこれに２質量％のシリカを含む希硫酸を含浸させた。その他の構成は実施例１と同様にし密閉形鉛蓄電池を作成した。この鉛蓄電池をＤとする。
【００１６】
（従来例１）
実施例１において、マット体を用いず、負極ストラップには何もしないで、その他の構成は実施例１と同様にした密閉形鉛蓄電池を作成した。この鉛蓄電池をＥとする。
【００１７】
（従来例２）
実施例１において、マット体として、スルフォン化ポリオレフィン樹脂の不織布からなるマット体を用い、これにシリカ等が含まない希硫酸を含浸した以外は実施例１と同様にして密閉形鉛蓄電池を形成した。この鉛蓄電池をＦとする。
【００１８】
このように作成した各鉛蓄電池を電槽化成して、充分に極板に塗布充填された活物質を活性化した後、2.23Ｖで定電圧充電を連続して行った。そして、充電電流が一定になったところで、硫酸第１水銀参照電極を用いて負極板及び負極ストラップ上部の電位差を測定した。その結果は表１の通りである。
【００１９】
【表１】

【００２０】
以上のように、本発明品は従来品に比較して、負極板と負極ストラップ上部の電位差が小さく、合成樹脂繊維マット体に希硫酸を含浸させた従来品Ｆの半分以下の電位差であった。
【００２１】
次に、これら電池を５０℃で、２．３４Ｖのフロート充電を半年間実施後、解体して負極ストラップを観測した。従来品Ｅは表面に腐食生成物である白色綿状の硫酸鉛が観測された、又従来品Ｆは硫酸鉛の観測は無かったが、電位差が大きくなっていた。一方、本発明品はいずれも硫酸鉛は観測されず、電位差も殆ど変化がなかった。これは、本発明品は負極ストラップ上面と極板群上面に差し渡って配置された硫酸保持部材により長期に渡りイオン導通を良好にし、負極ストラップ上部の電位を卑側に保ち得ることによるものである。
【００２２】
（実施例５）
次に、水銀／硫酸第１水銀参照電極を用いて測定した結果負極板電位が−1020〜−1050ｍＶ、負極ストラップ上面の電位が−930〜−950ｍＶで電位差が約100ｍＶにも達し、既に負極ストラップ上面に硫酸鉛が生成している密閉形鉛蓄電池を用い、実施例２の様に希硫酸に１０質量％のシリカ添加して混合したものを、チューブ付きのシリンジに入れ、鉛蓄電池の負極ストラップ上面から極板群の上面に差し渡って施し、温度５０℃で2.23Ｖのフロート充電を３ケ月行って変化を観測した。
【００２３】
その結果は、当初負極ストラップ上面にあった硫酸鉛の白色綿状結晶は還元され、鉛色を呈していた。
【００２４】
尚、負極ストラップ上面を覆う硫酸イオン固着保持部材は、負極ストラップ上面の全面を覆う必要は必ずしもなく一部でも覆っていれば良い。又、図３に示す様に、負極ストラップ６近傍に衝立１５を立て、該衝立内にゲル状体の希硫酸１４等を施して負極ストラップ上面と極板群上面に差し渡しても良い。
【００２５】
【発明の効果】
以上の通り、本発明は、負極ストラップ上面と極板群上面に差し渡って硫酸を配置したので、負極ストラップの腐食を防止し得、密閉形鉛蓄電池の寿命を向上し得る等の効果を奏するものである。
【図面の簡単な説明】
【図１】本発明一実施例密閉形鉛蓄電池断面図。
【図２】他の実施例の要部部分図。
【図３】他の実施例の要部部分図。
【符号の説明】
１極板群
６負極ストラップ
９マット体
１４ゲル状体の希硫酸[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed lead-acid battery that uses a retainer mat that is made of glass fiber or the like as a separator and has excellent liquid retention properties, and that has no or only a small amount of liquid that is released from the electrode plate group as an electrolyte amount. is there.
[0002]
[Prior art]
A conventional sealed lead-acid battery stores a group of electrode plates in which a positive electrode plate and a negative electrode plate are alternately stacked via a retainer mat in a battery case, and welds the same polarity electrode plate ears to each other to form a strap. The strap is provided with a pole column, this is housed in a battery case, a lid is applied, the pole column is welded to a terminal provided on the lid, and electrolysis to such an extent that the electrode plate group can be absorbed and retained from the liquid injection port of the lid. The liquid is injected to obtain a sealed lead-acid battery.
[0003]
[Problems to be solved by the invention]
This type of lead acid battery is well known and widely used, but there are also problems. One of them is that the negative strap is corroded.
[0004]
In order to solve this problem, several attempts are known. One example is a method of covering the upper surface of the strap with a so-called sulfuric acid-absorbing substance or an electrolytic solution holding body as seen in Japanese Patent Application Laid-Open Nos. 2-49352 and 4-2049. Another method is a method of covering with an acid-resistant synthetic resin as seen in JP-A-4-24964.
[0005]
However, these methods exhibit a certain degree of effect, but have a low long-lasting effect, and further improvement is desired.
[0006]
[Means for Solving the Problems]
The present invention has been made in order to obtain a lead-acid battery that is more effective. The cause of the low persistence of the effect was sought from the potential difference. That is, this negative electrode strap has almost no ion movement with the electrode plate group, and if oxygen gas is generated from the positive electrode during the float charging of the lead storage battery, the upper part of the negative electrode strap is polarized preciously and exceeds the reduction potential. Since the cathodic protection is not provided, the lead oxidation reaction proceeds, and the corrosion products dissolve, the corrosion proceeds to the inside of the negative electrode strap, and finally the wire breaks and operates in order to corrode the whole. Disappear.
[0007]
From this point of view, as described in Japanese Patent Laid-Open No. 4-249064, the corrosion prevention should continue when covered with an acid-resistant foamed synthetic resin from the upper part of the electrode plate group to the upper surface of the strap. However, when the potential difference between the lattice and the strap of the electrode plate reaction part was actually measured, a relatively large potential difference was observed. This is thought to be due to the fact that the amount of sulfuric acid is insufficient in the synthetic resin, and when the gel-like body in which silica was mixed with the electrolyte solution was provided across the electrode plate group from the upper surface of the negative electrode strap, it was found that the potential difference was reduced. It was.
[0008]
Furthermore, the inventor has also found that the gel strap is applied to the corroded negative electrode strap of the lead-acid battery, and eventually the corrosive product is reduced and the negative strap recovers to the strap without corrosion. This means that the lead storage battery can be repaired by applying a gel-like body to the lead storage battery in use.
[0009]
It should be noted that the same effect can be obtained by using a paste obtained by kneading anhydrous calcium sulfate or calcium sulfate 0.5 hydrate with water or dilute sulfuric acid instead of the gel-like body of the electrolytic solution.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described. A negative electrode strap of an electrode plate group of a lead storage battery is covered with the electrode strap, and is placed on the upper surface of the electrode plate group. Gel sulfuric acid, a non-woven fabric impregnated with gel sulfuric acid, or calcium sulfate is used. A paste in which sulfate ions are fixed and held in a gel or paste form, such as a paste kneaded with dilute sulfuric acid, is arranged.
[0011]
【Example】
Embodiments according to the present invention will be described.
[0012]
Example 1
As shown in FIG. 1, the positive electrode plate ears 2 and the negative electrode plate 3 ears 4 of the electrode plate group 1 in which the positive electrode plates and the negative electrode plates are alternately laminated via the retainer mats made of glass fibers as separators. Each was welded to form a positive electrode strap 5 and a negative electrode strap 6, which were stored in a battery case 7. A mat body 9 made of the same material as the retainer mat 8 used as a separator is placed across the negative electrode strap and across the upper part of the electrode plate group, and slowly added while stirring dilute sulfuric acid with a silica concentration of 2% by mass. The mat body was supplied to the mat body, and the dilute sulfuric acid was impregnated into the mat body to form a sulfate ion fixing and holding member. Thereafter, a lid 10 was applied to the battery case 7 by a conventional method, and a sealed lead-acid battery was prepared by injecting the electrode plate group so as to impregnate dilute sulfuric acid containing 2% by mass of silica as an electrolytic solution. Let this lead acid battery be A. In the figure, 11 is a safety valve device, and 12 and 13 are positive and negative terminals, respectively.
[0013]
(Example 2)
In Example 1, instead of the dilute sulfuric acid containing 2% by mass of silica in the mat body, without using the mat body, 10% by mass of silica was added to dilute sulfuric acid and mixed. The dilute sulfuric acid 14 thus obtained was slowly scooped with a spatula or the like and disposed so as to cover the upper surface of the negative electrode strap 6 and to be placed on the electrode plate group 1 as shown in FIG. This operation was repeated several times and then passed. Other configurations were the same as in Example 1, and a sealed lead-acid battery was created. Let this lead acid battery be B.
[0014]
(Example 3)
In Example 2, instead of silica, calcium sulfate 0.5 hydrate was mixed with dilute sulfuric acid to obtain a paste, which covered the upper surface of the negative electrode strap and passed over the upper surface of the electrode plate group. The paste hardened in about 5 minutes. Other configurations were the same as in Example 1, and a sealed lead-acid battery was created. Let this lead acid battery be C.
[0015]
Example 4
In Example 1, the mat body was disposed from the upper surface of the negative electrode strap to the upper surface of the electrode plate group and further to the upper surface of the positive electrode strap, and impregnated with dilute sulfuric acid containing 2% by mass of silica. Other configurations were the same as in Example 1, and a sealed lead-acid battery was created. Let this lead acid battery be D.
[0016]
(Conventional example 1)
In Example 1, a sealed lead-acid battery was prepared in which the mat body was not used and nothing was applied to the negative strap, and other configurations were the same as in Example 1. Let this lead acid battery be E.
[0017]
(Conventional example 2)
In Example 1, a sealed lead-acid battery was formed in the same manner as in Example 1 except that a mat body made of a nonwoven fabric of sulfonated polyolefin resin was used as the mat body, and this was impregnated with dilute sulfuric acid not containing silica or the like. . Let this lead acid battery be F.
[0018]
Each lead storage battery prepared in this manner was formed into a battery case, and after fully activating the active material coated and filled on the electrode plate, constant voltage charging was continuously performed at 2.23V. Then, when the charging current became constant, the potential difference between the negative electrode plate and the upper part of the negative electrode strap was measured using a mercuric sulfate reference electrode. The results are shown in Table 1.
[0019]
[Table 1]

[0020]
As described above, the product of the present invention had a smaller potential difference between the negative electrode plate and the upper part of the negative electrode strap than the conventional product, and was less than half the potential difference of the conventional product F in which the synthetic resin fiber mat was impregnated with dilute sulfuric acid. .
[0021]
Next, these batteries were subjected to a float charge of 2.34 V at 50 ° C. for half a year, and then disassembled to observe a negative electrode strap. In the conventional product E, white cotton-like lead sulfate as a corrosion product was observed on the surface, and in the conventional product F, no lead sulfate was observed, but the potential difference was large. On the other hand, no lead sulfate was observed in any of the products of the present invention, and the potential difference hardly changed. This is because the product of the present invention improves ion conduction over a long period of time by the sulfuric acid holding member arranged across the upper surface of the negative electrode strap and the upper surface of the electrode plate group, and can maintain the potential of the upper portion of the negative electrode strap on the base side. is there.
[0022]
(Example 5)
Next, as a result of measurement using a mercury / sulfuric acid mercuric acid reference electrode, the potential of the negative electrode plate was −1020 to −1050 mV, the potential of the upper surface of the negative electrode strap was −930 to −950 mV, and the potential difference reached about 100 mV. Using a sealed lead-acid battery with lead sulfate formed on the top, 10% by mass silica added to dilute sulfuric acid and mixing as in Example 2 is put into a syringe with a tube, and the negative electrode strap of the lead-acid battery It was applied across the upper surface of the electrode plate group from the upper surface, and the change was observed after performing float charging at 2.23 V at a temperature of 50 ° C. for 3 months.
[0023]
As a result, the white flocculent crystals of lead sulfate that were originally on the upper surface of the negative electrode strap were reduced and exhibited a lead color.
[0024]
Note that the sulfate ion fixing and holding member that covers the upper surface of the negative electrode strap does not necessarily need to cover the entire upper surface of the negative electrode strap, and may cover a part of it. In addition, as shown in FIG. 3, a partition 15 may be set up in the vicinity of the negative strap 6 and gelled dilute sulfuric acid 14 or the like may be provided in the partition and passed between the upper surface of the negative strap and the upper surface of the electrode plate group.
[0025]
【The invention's effect】
As described above, according to the present invention, since sulfuric acid is disposed across the upper surface of the negative electrode strap and the upper surface of the electrode plate group, corrosion of the negative electrode strap can be prevented, and the life of the sealed lead-acid battery can be improved. Is.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a sealed lead-acid battery according to an embodiment of the present invention.
FIG. 2 is a fragmentary partial view of another embodiment.
FIG. 3 is a fragmentary partial view of another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electrode group 6 Negative electrode strap 9 Mat body 14 Dilute sulfuric acid of gel

Claims

An electrode plate group in which positive and negative electrode plates are alternately stacked via a separator, and a strap formed by welding the ears of the same polarity plate of the electrode plate group to each other, and the electrode layered on at least the upper surface of the strap A sealed lead-acid battery in which a sulfate ion fixing and holding member is disposed across the upper surface of the plate group.

The sealed lead-acid battery according to claim 1, wherein the sulfate ion fixing and holding member is dilute sulfuric acid containing silica.

2. The sealed lead-acid battery according to claim 1, wherein the sulfate ion fixing and holding member is made of calcium sulfate kneaded with dilute sulfuric acid and solidified.