JP2004134252A

JP2004134252A - Electrode for lead battery

Info

Publication number: JP2004134252A
Application number: JP2002297859A
Authority: JP
Inventors: Atsushi Furukawa; 古川　淳; Hikari Sakamoto; 坂本　光; Isao Amamiya; 雨宮　功
Original assignee: Furukawa Battery Co Ltd
Current assignee: Furukawa Battery Co Ltd
Priority date: 2002-10-10
Filing date: 2002-10-10
Publication date: 2004-04-30
Anticipated expiration: 2022-10-10
Also published as: JP3689812B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for a lead battery by preventing a short circuit between electrodes from occurring upon a chemical treatment in a battery jar, where the chemical treatment in the battery jar makes an untreated electrode into the electrode for lead battery, the lead battery meets requirements of a lead battery for automotive use and industrial use, and the requirements are effective discharge performance, miniaturization, weight reduction, sealed packaging, and prolongation of a service life. <P>SOLUTION: The untreated electrode is manufactured through a step for charging an active material into a substrate, a step for pre-drying the substrate charged of the active material, a step for ripening the substrate, and a step for drying the substrate, where the electrode for lead battery is manufactured by chemical-treating the untreated electrode charged of the active material with dilute sulfuric acid after the ripening step for manufacturing the untreated electrode. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、未化成電極を電槽化成によって化成処理を行う電池用電極において、電槽化成による化成処理時の電極間短絡事故を未然に防止した鉛蓄電池用電極に関するものである。
【０００２】
【従来の技術】
近年、自動車のエンジンルームは装備の増加や無駄な空間の排除を狙ったデザインの要求から搭載部品の小型化の要求が厳しくり、かつ、自動車の燃費向上と排ガス量の削減から搭載部品の軽量化が求められている。
【０００３】
そこで、上記要求を満足し、かつ、電池性能を落とすことなく対処するためにショートピッチと称する極板間の間隔を狭めた設計が多用されるようになってきている。
【０００４】
しかし、このような設計で電極を電槽化成すると、電解液の注入と同時に未化成極板中の酸化鉛が硫酸と反応して硫酸鉛を生成し、電解液中の硫酸イオンがなくなり単なる水となってしまい、その結果、硫酸鉛の溶解度が増して多量の鉛イオンが解離し、化成工程での通電開始と同時に負極板上に針状のデンドライトが成長してセパレータを貫通し、正極にまで到達して短絡事故が発生する恐れがあった。
【０００５】
一方、利便性の観点から自動車用鉛蓄電池もシール型化が強く求められ、電極間をセパレートするセパレータに微細ガラス繊維マットに電解液を染み込ませる構造が提案されてきているが、かかる構造では電解液の絶対量が少ないためにショートピッチ設計では液式電池よりも更に短絡の問題が深刻化している。
【０００６】
鉛蓄電池に課せられる更なる課題は長寿命化である。長寿命化の観点からは、活物質ペーストの調整時に硫酸の添加量を減少して高密度化する手法が取られているが、この手法では注液時における未化成極板の硫酸との反応性が高まり、電解液比重の低下を促進することから、長寿命化の要望とは裏腹となり、致命的な欠陥になりかねない。
【０００７】
近時、自動車用鉛蓄電池に要求される上記特性は産業用鉛蓄電池についても同様であり、電池の効率的な放電性能、小型化、軽量化、シール型化並びに長寿命化の要求が厳しくなってきている。
【０００８】
このような問題を解決する目的で幾つかの提案がなされている。例えば、シール型鉛蓄電池用セパレータのガラス繊維径を微細化し、更に無機質粉体を含有、分散させることで平均孔径を小さくし、デンドライトの貫通による短絡を防止する提案がなされている（例えば特許文献１参照）。
【０００９】
また、電解液に硫酸セシウム、硫酸ナトリウム或いは硫酸マグネシウム等の硫酸塩を添加し、硫酸イオン濃度を一定以上に保つことで鉛イオンの解離を抑制し、デンドライトの成長による短絡を防止する提案がなされている（例えば特許文献２参照）。
【００１０】
また、アルミニウム又はアルミニウム化合物を電解液に添加することによって、電解液の硫酸イオンと水素イオンが消費されて中性乃至はアルカリ性になった場合には、アルミニウム酸化物がゾル化して粘度が高くなり、溶解した鉛イオンの移動が阻止され、短絡の発生を防止する提案がなされている（例えば特許文献３参照）。
【００１１】
その他、電解液や注液前の電池を予め冷やしておく提案や減圧により電解液を速やかに注入する技術（例えば非特許文献１参照）、活物質ペーストを基板に充填した直後に希硫酸に浸漬し、表面に硫酸鉛の層を設ける等の提案もなされている。
【００１２】
【特許文献１】
特開２００１−１８５１１４号（第４頁）
【特許文献２】
特開平４−１７９０６３号（第３頁）
【特許文献３】
特開昭６２−１３１４８０号（第２頁）
【非特許文献１】
Ｄｉｇａｔｒｏｎ／Ｆｉｒｉｎｇ　Ｃｉｒｃｕｉｔｓ，　Ｉｎｃ．発行「Ａ　Ｇｕｉｄｅ　ｔｏ　ＶＲＬＡ　Ｂａｔｔｅｒｙ　Ｆｏｒｍａｔｉｏｎ　Ｔｅｃｈｎｉｑｕｅｓ」２００１年、ｐ１５−１６
【００１３】
【発明が解決しようとする課題】
上述した提案の内、セパレータの改良は電極間の短絡防止に有効であるが、この技術はデンドライトの進行を遅延させるという二次的な効果を期待するものであり、根本的な解決方法ではない。
【００１４】
電槽化成時における未化成極板に電解液を注入する条件では局部的に急激な硫酸イオンの消費に対応する必要があり、この急激な硫酸イオンの消費に対処するには溶解度を越える程多量の硫酸塩を添加する必要があり非現実的である。また、これらの添加剤は電解液の導電率を低下させるため、特に低温での高率放電性能を低下させる問題もある。
【００１５】
電解液や電池を冷却して鉛イオンの溶解を抑制する手法に効果は認められるが、この手法を工業的に採用するには効果の度合いが低く根本的な解決にはならない。
【００１６】
活物質ペーストを基板に充填した直後に希硫酸に浸漬し、表面に硫酸鉛層を設けることは有効であるが、短絡を抑制するほどに硫酸鉛層を設けるには高濃度の希硫酸（通常の希硫酸濃度より若干濃い濃度の硫酸溶液）での処理が必要となり、その結果ペーストとの反応による発熱で水分が減少し、その後の熟成工程で金属鉛の酸化や格子との密着性を充分に確保できず、更に、硫酸鉛層の密度が下がり表面が軟化しやすくなる問題が発生する。
このように従来の方法では実用上不充分であった。
【００１７】
以上のような状況に加え、特に最近は地球環境問題などから、燃費や省資源から電池の小型軽量化、長寿命化が強く求められ、極板とセパレータを薄くし、かつ、活物質を高密度化する要求に応えて耐短絡性をより高いレベルで達成することが更に求められている。また、地球環境問題から燃費改善を更に進めるために、自動車用電池は１２Ｖから３６Ｖへと昇圧化やＨＥＶ（ハイブリット式電気自動車）に適合できることが緊急の課題となってきている。
これらの新しい用途に対応するためには、従来の６セル電池からその３倍の１８セル電池とし、長寿命のシール型電池であることが必要要件となり、１８セルを同時に電槽化成するためには、耐短絡性の向上がより高度に必要とされる。
【００１８】
以上の要望は自動車業界のみならず、ＩＴなどで多用されるバックアップ電源やエネルギー所蔵用電池においても同様である。
本発明は以上の現状に鑑みなされたものであり、高信頼性の鉛蓄電池を省資源などの要求のもとで達成するものである。
【００１９】
【課題を解決するための手段】
本発明の鉛蓄電池用電極は、基板への活物質ペースト充填工程、活物質を充填した基板の予備乾燥工程、熟成工程、乾燥工程を経て作製される未化成電極を電槽化成してなる鉛蓄電池用電極において、前記未化成電極を作製する熟成工程の後に、活物質を充填した未化成電極を希硫酸で処理してなることを特徴とするものである。
なお、基板へ充填する活物質中の硫酸／酸化鉛比率を７％以下とすることが好ましい。
【００２０】
【発明の実施の形態】
次に本発明の実施形態を詳細に説明する。
鉛蓄電池に求められる効率的な放電性能、小型化、軽量化、シール型化並びに長寿命化の要求に対処するには、公知例にあるように、電槽化成における電解液の注入時に硫酸イオンの濃度を高く維持することが最も有効で、未化成極板中の酸化鉛と電解液の反応を抑制することにより達成される。
【００２１】
本発明は、熟成工程の後で未化成極板表面を希硫酸で処理することにより、未化成極板表面の硫酸鉛濃度を著しく高めることができ、しかも表面の気孔を一時的に閉塞するため、このように処理した電極を電槽内にセットし、電解液を注入した際に、電解液と未化成極板の表面との反応のみならず、電解液が内部に染み込んで酸化鉛と反応する時間も遅延でき、電解液との反応を最小限に抑えて電解液濃度の急激な低下を抑制し、その結果、鉛イオンの溶解度が下がり、短絡の発生を防止することができる。
【００２２】
即ち、従来の技術で、基板への活物質充填工程後直ちに極板表面を濃度の高い希硫酸で処理した未化成極板の表面は三塩基性硫酸鉛や四塩基性硫酸鉛となり、表面に硫酸と反応し得る酸化鉛が残ってしまう。
【００２３】
一方、本発明のように熟成後に表面を希硫酸で処理することにより、電槽化成時に電解液と反応し得る酸化鉛量を大幅に減らすことがでる。また、かかる工程後に処理することで、極く薄い表面部分のみが溶解して極板表面の気孔を閉塞し、電解液が極板の内部へ浸透する時間を遅らせる一方、電池性能への影響も回避することができる。
【００２４】
活物質充填工程と乾燥工程の間に希硫酸で処理した未化成極板を更に熟成工程後に希硫酸で処理することは、本発明の処理時間の短縮化や用いる希硫酸の比重を下げられる点で有効である。
【００２５】
また、本発明の効果は、極板の活物質中の硫酸／酸化鉛比率が７質量％以下であれば良好であり、特に５質量％以下で顕著である。硫酸／酸化鉛比率が７質量％以上では極板中の硫酸鉛の量が多く、密度が下がり短寿命であると共に、溶解し難くなっているために短絡が発生し難いため、本発明の希硫酸処理を行ってもその効果が顕著に現れない。
なお、ここで硫酸とは、硫酸鉛等の硫酸根を硫酸に換算した値である。
【００２６】
本発明で用いる希硫酸は比重が１．０５〜１．４０の範囲が適当で、ペースト調製時の硫酸／酸化鉛比率や、活物質充填工程と乾燥工程の間、熟成工程後に希硫酸で処理する場合などに応じて適宜選択すればよい。また、希硫酸処理後に乾燥を行なう場合は、１００℃以下で行なうことが望ましい。１００℃を越えると活物質や格子界面が変形し、性能を低下させる恐れがある。
以上のようにして、電槽化成時における短絡の発生を回避できる。
【００２７】
実施例１
公知のＰｂ−Ｃａ−Ｓｎ−Ａｌ合金で鋳造式基板を製造した。鋳造した基板は１００℃で１時間熱処理を施し時効硬化させた。
正極は硫酸／酸化鉛比率３．０質量％の活物質ペーストを充填し、予備乾燥後４０℃、湿度９５％の雰囲気で２４時間熟成し、その後乾燥して正極未化成板とした。
負極も硫酸／酸化鉛比率３．０質量％の活物質ペーストを充填し、予備乾燥後４０℃、湿度９５％の雰囲気で２４時間熟成し、その後乾燥して負極未化成板とした。
次ぎに、これらを比重１．２０の希硫酸に約５秒浸漬し、表面に付着した余剰の希硫酸をスポンジローラーで吸い取り、６０℃で２時間乾燥して本発明の未化成極板とした。
【００２８】
これら正極極板、負極極板を目付け重量が１８０ｇ／ｍ^２の微細ガラス繊維セパレータと積層し、正極６枚、負極７枚、セパレータ１２枚で構成されたＤ２６サイズ、１８Ａｈの３６Ｖシール型鉛蓄電池を製造した。この未化成の電池を２０℃の水槽に入れ、各セルの内部を減圧状態で１８セルに同時に比重１．１５の希硫酸２００ｃｃを約３０秒で減圧注液し、１０分後に化成を開始した。化成は１Ａで１時間通電した後、電流を４Ａに上げて３０時間通電することで行なった。化成終了後、電池を解体して２１６枚のセパレータについてデンドライトの析出と短絡の有無を確認した。結果を表１に示す。
【００２９】
実施例２
正極及び負極ペーストの硫酸／酸化鉛比率を５質量％とした以外は実施例１と同様に電池を製造し、デンドライトの析出の有無を確認した。結果を表１に示す。
【００３０】
実施例３
正極及び負極ペーストの硫酸／酸化鉛比率を７質量％とした以外は実施例１と同様に電池を製造し、デンドライトの析出の有無を確認した。結果を表１に示す。
【００３１】
実施例４
正極及び負極ペーストの硫酸／酸化鉛比率を７．５質量％とした以外は実施例１と同様に電池を製造し、デンドライトの析出の有無を確認した。結果を表１に示す。
【００３２】
比較例１
実施例１と同じ公知のＰｂ−Ｃａ−Ｓｎ−Ａｌ合金で鋳造した鋳造式基板を製造し、実施例１と同様、鋳造した基板は１００℃で１時間熱処理を施し、時効硬化させた。正極、負極ともに、硫酸／酸化鉛比率３．０質量％のペーストを充填しで作成し、本発明の処理を行なわない未化成の極板とし、実施例１と同様の電池を製造し、デンドライトの析出の有無を確認した。結果を表１に併記する。
【００３３】
比較例２
正極及び負極ペーストの硫酸／酸化鉛比率を５質量％とした以外は比較例１と同様に電池を製造し、デンドライトの析出の有無を確認した。結果を表１に併記する。
【００３４】
比較例３
正極及び負極ペーストの硫酸／酸化鉛比率を７質量％とした以外は比較例１と同様に電池を製造し、デンドライトの析出の有無を確認した。結果を表１に併記する。
【００３５】
比較例４
正極及び負極ペーストの硫酸／酸化鉛比率を７．５質量％とした以外は比較例１と同様に電池を製造し、デンドライトの析出の有無を確認した。結果を表１に併記する。
【００３６】
【表１】

【００３７】
以上は、鉛合金で鋳造した基板を時効硬化させ、該基板に硫酸と酸化鉛のペーストを充填、予備乾燥、熟成、乾燥し、次いで希硫酸に浸漬して未化成極板とした実施例について説明したが、予備乾燥工程は必ずしも必要ではなく、また、熟成した後に希硫酸に浸漬し、次いで乾燥工程を施して未化成極板としても、上記実施例と同様の結果が得られた。
【００３８】
【発明の効果】
以上説明したように、本発明は自動車用鉛蓄電池、産業用鉛蓄電池に要求される電池の効率的な放電性能、小型化、軽量化、シール型化並びに長寿命化の要求を満足する鉛蓄電池用電極を提供しうる優れた効果を有するものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrode for a lead-acid battery in which an unformed electrode is subjected to a chemical conversion treatment by a battery case, in which an electrode short-circuit accident during the chemical conversion treatment by the battery case formation is prevented.
[0002]
[Prior art]
In recent years, automobile engine compartments have become increasingly demanding in terms of design, with the aim of increasing equipment and eliminating wasteful space. Is required.
[0003]
Therefore, in order to satisfy the above requirements and to cope with the battery performance without deteriorating the battery performance, a design called a short pitch, in which the interval between the electrode plates is narrowed, has been frequently used.
[0004]
However, when the electrode is formed in a battery case with such a design, the lead oxide in the unformed electrode plate reacts with sulfuric acid to generate lead sulfate at the same time as the injection of the electrolyte, and the sulfate ions in the electrolyte disappear and the mere water As a result, the solubility of lead sulfate increases and a large amount of lead ions are dissociated, and at the same time as the start of energization in the chemical conversion process, needle-like dendrites grow on the negative electrode plate and penetrate the separator to form a positive electrode. And a short circuit accident could occur.
[0005]
On the other hand, from the viewpoint of convenience, lead-acid batteries for automobiles are also strongly required to be sealed, and a structure in which an electrolytic solution is impregnated into a fine glass fiber mat in a separator that separates between electrodes has been proposed. Since the absolute amount of the liquid is small, the short-circuit problem is more serious in the short pitch design than in the liquid type battery.
[0006]
A further challenge to lead-acid batteries is to extend their life. From the viewpoint of prolonging the service life, a method of increasing the density by reducing the amount of sulfuric acid added when preparing the active material paste has been adopted.However, this method involves the reaction of unformed electrode plates with sulfuric acid during injection. Since this property is enhanced and the specific gravity of the electrolytic solution is promoted, it is contrary to a demand for a longer life, which may be a fatal defect.
[0007]
In recent years, the above-mentioned characteristics required for automotive lead-acid batteries are the same for industrial lead-acid batteries, and the demands for efficient discharge performance, miniaturization, weight reduction, seal type, and long life of batteries have become severe. Is coming.
[0008]
Several proposals have been made for the purpose of solving such a problem. For example, a proposal has been made to reduce the glass fiber diameter of a separator for a sealed lead-acid battery, further reduce and average the average pore diameter by containing and dispersing an inorganic powder, and to prevent a short circuit due to penetration of dendrites (for example, Patent Documents). 1).
[0009]
It has also been proposed to add a sulfate salt such as cesium sulfate, sodium sulfate or magnesium sulfate to an electrolytic solution to suppress the dissociation of lead ions by maintaining the sulfate ion concentration at a certain level or more, and to prevent a short circuit due to dendrite growth. (For example, see Patent Document 2).
[0010]
Also, by adding aluminum or an aluminum compound to the electrolytic solution, when sulfate ions and hydrogen ions of the electrolytic solution are consumed and become neutral or alkaline, the aluminum oxide becomes a sol and the viscosity increases. Proposals have been made to prevent the movement of dissolved lead ions and prevent the occurrence of a short circuit (for example, see Patent Document 3).
[0011]
Other proposals include pre-cooling the electrolyte or the battery before the injection, a technique for quickly injecting the electrolyte by reducing the pressure (for example, see Non-Patent Document 1), and immersing the active material paste in dilute sulfuric acid immediately after filling the substrate. Proposals have also been made such as providing a layer of lead sulfate on the surface.
[0012]
[Patent Document 1]
JP-A-2001-185114 (page 4)
[Patent Document 2]
JP-A-4-17963 (page 3)
[Patent Document 3]
JP-A-62-131480 (page 2)
[Non-patent document 1]
Digitron / Firing Circuits, Inc. Published "A Guide to VRLA Battery Formation Technologies", 2001, pp. 15-16.
[0013]
[Problems to be solved by the invention]
Among the proposals described above, improvement of the separator is effective in preventing short circuit between electrodes, but this technology is expected to have a secondary effect of delaying the progress of dendrite, and is not a fundamental solution. .
[0014]
It is necessary to cope with the rapid consumption of sulfate ions locally under the condition of injecting the electrolyte into the unformed electrode plate during the formation of the battery case. The addition of sulfate is not practical. In addition, since these additives lower the conductivity of the electrolytic solution, there is a problem that the high-rate discharge performance particularly at low temperatures is lowered.
[0015]
Although an effect is recognized in a method of suppressing the dissolution of lead ions by cooling an electrolytic solution or a battery, the degree of effect is low for industrially adopting this method and cannot be a fundamental solution.
[0016]
Although it is effective to immerse the active material paste in the dilute sulfuric acid immediately after filling the substrate and provide a lead sulfate layer on the surface, a high concentration of dilute sulfuric acid (usually (Sulfuric acid solution with a concentration slightly higher than the dilute sulfuric acid concentration), and as a result, the heat generated by the reaction with the paste reduces the water content. In addition, there is a problem that the density of the lead sulfate layer decreases and the surface is easily softened.
Thus, the conventional method was not practically sufficient.
[0017]
In addition to the above circumstances, especially in recent years, due to global environmental issues, there is a strong demand for smaller and lighter batteries and longer life from fuel efficiency and resource savings. There is a further need to achieve higher levels of short circuit resistance in response to demands for densification. In addition, in order to further improve fuel efficiency due to global environmental problems, it has become an urgent issue that a vehicle battery can be boosted from 12V to 36V and can be adapted to HEV (hybrid electric vehicle).
In order to respond to these new applications, it is necessary to use 18-cell batteries, which is three times as large as the conventional 6-cell batteries, and to have a long-life sealed type battery. Is required to have a higher degree of short-circuit resistance.
[0018]
The above demands are not limited to the automotive industry, but also apply to backup power supplies and energy storage batteries that are frequently used in IT and the like.
The present invention has been made in view of the above situation, and aims to achieve a highly reliable lead-acid battery under demands such as resource saving.
[0019]
[Means for Solving the Problems]
The lead-acid battery electrode of the present invention is a lead obtained by forming an unformed electrode formed through an active material paste filling step on a substrate, a predrying step of a substrate filled with an active material, an aging step, and a drying step into a battery case. The storage battery electrode is characterized in that, after the aging step for producing the unformed electrode, the unformed electrode filled with the active material is treated with dilute sulfuric acid.
Note that the ratio of sulfuric acid / lead oxide in the active material to be filled into the substrate is preferably set to 7% or less.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail.
To cope with the demands for efficient discharge performance, miniaturization, weight reduction, seal type, and long life required for lead-acid batteries, as is known in the art, sulfate ion is injected during the electrolytic solution formation in a battery case. It is most effective to keep the concentration of Pb at a high level, and this is achieved by suppressing the reaction between the lead oxide in the unformed electrode plate and the electrolytic solution.
[0021]
According to the present invention, by treating the surface of an unformed electrode plate with dilute sulfuric acid after the aging step, the concentration of lead sulfate on the surface of the unformed electrode plate can be significantly increased, and the pores on the surface are temporarily closed. When the electrode thus treated is set in a battery case and the electrolyte is injected, not only the reaction between the electrolyte and the surface of the unformed electrode plate, but also the electrolyte soaks inside and reacts with lead oxide. The reaction time with the electrolytic solution can be minimized, and a sharp decrease in the electrolytic solution concentration can be suppressed. As a result, the solubility of lead ions decreases, and the occurrence of a short circuit can be prevented.
[0022]
In other words, in the conventional technique, immediately after the step of filling the active material into the substrate, the surface of the unformed electrode plate in which the surface of the electrode plate is treated with a high concentration of dilute sulfuric acid becomes tribasic lead sulfate or tetrabasic lead sulfate, Lead oxide that can react with sulfuric acid remains.
[0023]
On the other hand, by treating the surface with dilute sulfuric acid after aging as in the present invention, the amount of lead oxide that can react with the electrolytic solution during battery formation can be significantly reduced. In addition, by treating after such a step, only an extremely thin surface portion dissolves and closes pores on the electrode plate surface, delaying the time for the electrolyte to penetrate into the electrode plate, and also affecting battery performance. Can be avoided.
[0024]
Treating the unformed electrode plate treated with dilute sulfuric acid between the active material filling step and the drying step with dilute sulfuric acid after the aging step further reduces the processing time of the present invention and the specific gravity of the dilute sulfuric acid used. Is effective in
[0025]
The effect of the present invention is good when the sulfuric acid / lead oxide ratio in the active material of the electrode plate is 7% by mass or less, and particularly remarkable when it is 5% by mass or less. When the sulfuric acid / lead oxide ratio is 7% by mass or more, the amount of lead sulfate in the electrode plate is large, the density is low, the life is short, and it is difficult to dissolve. Even if sulfuric acid treatment is performed, the effect is not remarkably exhibited.
Here, the term “sulfuric acid” is a value obtained by converting a sulfate group such as lead sulfate into sulfuric acid.
[0026]
The diluted sulfuric acid used in the present invention preferably has a specific gravity in the range of 1.05 to 1.40, and is treated with diluted sulfuric acid after the aging step, between the sulfuric acid / lead oxide ratio at the time of preparing the paste, the active material filling step and the drying step. It may be appropriately selected depending on the case. When drying is performed after the dilute sulfuric acid treatment, the drying is preferably performed at 100 ° C. or lower. If the temperature exceeds 100 ° C., the active material and the lattice interface may be deformed, and the performance may be deteriorated.
As described above, it is possible to avoid the occurrence of a short circuit during the formation of the battery case.
[0027]
Example 1
A cast substrate was manufactured from a known Pb-Ca-Sn-Al alloy. The cast substrate was heat-treated at 100 ° C. for 1 hour to age harden.
The positive electrode was filled with an active material paste having a sulfuric acid / lead oxide ratio of 3.0% by mass, preliminarily dried, aged in an atmosphere of 40 ° C. and 95% humidity for 24 hours, and then dried to obtain a positive electrode unformed plate.
The negative electrode was also filled with an active material paste having a sulfuric acid / lead oxide ratio of 3.0% by mass, preliminarily dried, aged in an atmosphere of 40 ° C. and 95% humidity for 24 hours, and then dried to obtain a negative electrode non-formed plate.
Next, these were immersed in dilute sulfuric acid having a specific gravity of 1.20 for about 5 seconds, excess dilute sulfuric acid adhering to the surface was absorbed with a sponge roller, and dried at 60 ° C. for 2 hours to obtain an unformed electrode plate of the present invention. .
[0028]
These positive electrode plate and negative electrode plate are laminated with a fine glass fiber separator having a basis weight of 180 g / m ² , and a D26 size, 18 Ah, 36 V sealed lead-acid battery composed of 6 positive electrodes, 7 negative electrodes, and 12 separators. Was manufactured. This unformed battery was placed in a water bath at 20 ° C., and 200 cc of dilute sulfuric acid having a specific gravity of 1.15 was simultaneously injected into 18 cells under reduced pressure in about 30 seconds while the inside of each cell was reduced in pressure, and formation was started 10 minutes later. . The formation was performed by energizing at 1 A for 1 hour, increasing the current to 4 A, and energizing for 30 hours. After the formation, the battery was disassembled and the presence or absence of dendrite precipitation and short-circuiting was confirmed for 216 separators. Table 1 shows the results.
[0029]
Example 2
A battery was produced in the same manner as in Example 1 except that the sulfuric acid / lead oxide ratio of the positive electrode paste and the negative electrode paste was changed to 5% by mass, and the presence or absence of dendrite deposition was confirmed. Table 1 shows the results.
[0030]
Example 3
A battery was manufactured in the same manner as in Example 1 except that the sulfuric acid / lead oxide ratio of the positive and negative electrode pastes was changed to 7% by mass, and the presence or absence of dendrite deposition was confirmed. Table 1 shows the results.
[0031]
Example 4
A battery was manufactured in the same manner as in Example 1 except that the sulfuric acid / lead oxide ratio of the positive electrode paste and the negative electrode paste was 7.5% by mass, and the presence or absence of dendrite was confirmed. Table 1 shows the results.
[0032]
Comparative Example 1
A cast-type substrate cast with the same known Pb-Ca-Sn-Al alloy as in Example 1 was manufactured, and similarly to Example 1, the cast substrate was subjected to heat treatment at 100 ° C. for 1 hour and age hardened. Both the positive electrode and the negative electrode were prepared by filling a paste with a sulfuric acid / lead oxide ratio of 3.0% by mass, and used as an unformed electrode plate not subjected to the treatment of the present invention. The presence or absence of precipitation was confirmed. The results are also shown in Table 1.
[0033]
Comparative Example 2
A battery was manufactured in the same manner as in Comparative Example 1 except that the sulfuric acid / lead oxide ratio of the positive electrode and the negative electrode paste was changed to 5% by mass, and the presence or absence of dendrite deposition was confirmed. The results are also shown in Table 1.
[0034]
Comparative Example 3
A battery was manufactured in the same manner as in Comparative Example 1 except that the sulfuric acid / lead oxide ratio of the positive electrode paste and the negative electrode paste was changed to 7% by mass, and the presence or absence of dendrite deposition was confirmed. The results are also shown in Table 1.
[0035]
Comparative Example 4
A battery was manufactured in the same manner as in Comparative Example 1 except that the sulfuric acid / lead oxide ratio of the positive electrode and the negative electrode paste was 7.5% by mass, and the presence or absence of dendrite was confirmed. The results are also shown in Table 1.
[0036]
[Table 1]

[0037]
The above is an example of age hardening a substrate cast with a lead alloy, filling the substrate with a paste of sulfuric acid and lead oxide, preliminary drying, aging, drying, and then immersing in dilute sulfuric acid to form an unchemically formed electrode plate. As described above, the pre-drying step is not always necessary, and the same result as in the above-described example was obtained even when the electrode was immersed in dilute sulfuric acid after aging and then subjected to the drying step to obtain an unformed electrode plate.
[0038]
【The invention's effect】
INDUSTRIAL APPLICABILITY As described above, the present invention relates to a lead-acid battery for automobiles and a lead-acid battery that satisfies the demands for efficient discharge performance, miniaturization, weight reduction, seal type and long life required for industrial lead-acid batteries. It has an excellent effect of providing an electrode for use.

Claims

A step of filling an active material paste into a substrate, a preliminary drying step of a substrate filled with an active material, an aging step, and an unformed electrode produced through a drying step; An electrode for a lead storage battery, characterized in that an unformed electrode filled with an active material is treated with dilute sulfuric acid after an aging step of producing the above.

The lead-acid battery electrode according to claim 1, wherein the ratio of sulfuric acid / lead oxide in the active material is 7% by mass or less.