JP4538864B2

JP4538864B2 - Lead acid battery and manufacturing method thereof

Info

Publication number: JP4538864B2
Application number: JP15082999A
Authority: JP
Inventors: 謙一前田; 今吉平沢; 裕治石井; 哲郎大越
Original assignee: Shin Kobe Electric Machinery Co Ltd
Current assignee: Shin Kobe Electric Machinery Co Ltd
Priority date: 1999-05-31
Filing date: 1999-05-31
Publication date: 2010-09-08
Anticipated expiration: 2019-05-31
Also published as: JP2000340252A

Description

【０００１】
【発明の属する技術分野】
本発明は鉛蓄電池及び該鉛蓄電池の製造方法に係り、特に鉛を主成分とする正極格子体に二酸化鉛を主成分とする正極活物質が充填された正極板を備えた鉛蓄電池及び該鉛蓄電池の製造方法に関する。
【０００２】
【従来の技術】
鉛蓄電池では、鉛の一部が酸化された鉛粉と水と希硫酸とを主成分とし、これらに必要に応じて添加物を添加して、練合によって得られたペーストを鉛（Ｐｂ）を主成分とする鋳造格子や連続多孔体に塗着（充填）し、乾燥させたペースト式極板が広く用いられている。ペースト式極板に更にセパレータ（隔離板）を組み合わせて極板群を構成し、極板群を電槽に組み込んだ後、希硫酸を加えて化成充電するか、化成充電後、電槽内に組み込むことによって、鉛蓄電池は電池本来の機能が付与される。このとき、正極活物質の主成分は、二酸化鉛（ＰｂＯ_２）になっている。
【０００３】
このようなペースト式極板を用いた鉛蓄電池には、正極添加剤として硫酸ナトリウム（Ｎａ_２ＳＯ_４）が添加されている。Ｎａ_２ＳＯ_４は練合時に正極ペーストに添加するもので、過放電時のイオン伝導度保持、活物質の利用率向上を主たる目的としている。
【０００４】
【発明が解決しようとする課題】
しかしながら、Ｎａ_２ＳＯ_４がペースト式極板の正極格子体近傍に存在していると、酸化生成物である硫酸イオンＳＯ_４ ^２−が鉛を主成分とする正極格子体を腐食させるので、鉛蓄電池の寿命性能が低下する、という問題がある。
【０００５】
本発明は上記問題を解決するためになされたものであり、Ｎａ_２ＳＯ_４による過放電時のイオン伝導度保持、活物質の利用率向上を図りつつ、正極格子体の腐食を抑制し長寿命化を実現することができる鉛蓄電池及び該鉛蓄電池の製造方法を提供することを課題とする。
【０００６】
【課題を解決するための手段】
上記課題を解決するために本発明の第１の態様は、鉛（Ｐｂ）を主成分とする正極格子体に二酸化鉛（ＰｂＯ_２）を主成分とする正極活物質が充填された正極板を備えた鉛蓄電池において、前記正極板は、前記正極格子体近傍に配置され硫酸ナトリウム（Ｎａ _２ＳＯ _４）が無添加の第１の活物質層と、前記正極板の表面に配置され正極既化活物質の０．５重量％〜１０重量％の硫酸ナトリウムが添加された第２の活物質層とを有することを特徴とする。本発明では、正極格子体近傍に硫酸ナトリウムが無添加の第１の活物質層が配置されているので、硫酸イオンによる正極格子体の腐食が抑制され、鉛蓄電池の長寿命化を図ることができると共に、正極板の表面に正極既化活物質の０．５重量％〜１０重量％の硫酸ナトリウムが添加された第２の活物質層が配置されているので、過放電時の伝導度を保持し正極活物質の利用率を向上させたまま、鉛蓄電池の長寿命化を図ることができる。
【０００７】
また、本発明の第２の態様は、鉛を主成分とする正極格子体に二酸化鉛を主成分とする正極活物質が充填された正極板を備えた鉛蓄電池の製造方法であって、硫酸ナトリウムが無添加の正極活物質ペーストを前記正極格子体近傍に配置して第１の活物質層を形成し、正極既化活物質の０．５重量％〜１０重量％の硫酸ナトリウムが添加された正極活物質ペーストを前記正極板の表面に配置して第２の活物質層を形成するステップを含む。本発明では、硫酸ナトリウムが無添加の正極活物質ペーストを正極格子体近傍に配置して第１の活物質層を形成し、正極既化活物質の０．５重量％〜１０重量％の硫酸ナトリウムが添加された正極活物質ペーストを正極板の表面に配置して第２の活物質層を形成するので、過放電時の伝導度を保持し活物質の利用率向上を図ることができると共に、硫酸ナトリウムが無添加の正極活物質ペーストを正極格子体に配置するので、正極格子体は硫酸イオンによる腐食が抑制され、鉛蓄電池の長寿命化を図ることができる。
【０００８】
【発明の実施の形態】
以下、図面を参照して本発明を自動車等の車両に搭載される車載用鉛蓄電池に適用した実施の形態について説明する。
【０００９】
図１に示すように、本実施形態の鉛蓄電池１０は鉛蓄電池１０の容器となる角形の電槽１を備えている。電槽１は成形性、電気的絶縁性、耐腐食性及び耐久性等の点で優れる、例えば、アクリルブタジェンスチレン（ＡＢＳ）、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）等の高分子樹脂が材質とされている。
【００１０】
図２に示すように、電槽１は一体成形により形成されており、外周壁（図２の符号１の箇所）の内部を仕切る隔壁６によって合計１８個のセル室が１列に画定された、いわゆる１８セルモノブロック電槽である。電槽１の上部は、ＡＢＳ、ＰＰ、ＰＥ等の高分子樹脂を材質とした蓋２と溶着又は接着され封口されている。
【００１１】
蓋２には、鉛蓄電池１０の外部から電解液を各セル室に注入可能とするためにセル室相当個数（１８個）の注液口が形成されており、これらの注液口は液口栓５により封口されている。また、両端セル室の上部に対応する蓋２の液口栓５より長側面寄りの隅部には、ロッド状の正極外部出力端子３及び負極外部出力端子４を蓋２から突出させるために２個の外部端子穴が長側面と平行に形成されている。正極外部出力端子３及び負極外部出力端子４は、電槽１の内部側から立設され、蓋２を貫通して突出すると共に蓋２に固定されている。
【００１２】
電槽１内に画定された１８個の各セル室には、図示しない極板群がそれぞれ１組ずつ収納されており、電槽１には合計１８組の極板群が収納されている。各極板群は、未化成負極板６枚及び未化成正極板５枚がガラス繊維からなるセパレータを介して積層されており、化成（初充電）後の各極板群の群電圧は２Ｖとされる。
【００１３】
未化成負極板は、鉛粉と、鉛粉に対して１３重量％の希硫酸（比重１．２６：２０°Ｃ）と、鉛粉に対して１２重量％の水と、を混練して負極活物質ペーストを作り、ペースト４０．０ｇを格子体からなる集電体に充填してから、温度５０°Ｃ、湿度９５％の雰囲気中に１８時間放置して熟成させた後に、温度２５°Ｃ、湿度４０％の雰囲気中に２時間放置し、乾燥させて作製される。
【００１４】
一方、未化成正極板の活物質ペーストは、鉛粉に対して０．０１重量％のカットファイバーを添加し、鉛粉に対して１３重量％の希硫酸（比重：１．２６：２０°Ｃ）と、鉛粉に対して１２重量％の水と、を混練して作製される。この混練中、冷却可能な混練釜により温度は一定に保たれる。正極活物質ペースト４０．０ｇを格子体からなる集電体に充填してから、温度５０°Ｃ、湿度９５％の雰囲気中に１８時間放置して熟成させた後に、温度２５°Ｃ、湿度４０％の雰囲気中に２時間放置し、乾燥させて未化成正極板が作製される。
【００１５】
各極板群の未化成正極板５枚及び未化成負極板６枚は、それぞれ同一極性の極板同士を接続する正極ストラップ及び負極ストラップに各セル室内で固定されている。図２紙面左端に収容される極板群の正極ストラップ及び図２紙面右端に収容される極板群の負極ストラップを除く各ストラップは、導電性を有しセル室間のストラップを接続するセル間接続体により、隣接する極性の異なるストラップに、電槽１内の隔壁６と交差して（隔壁６を貫通して）それぞれ接続されており、１８組の極板群は直列に接続されている。図２紙面左端に収容される極板群の正極ストラップ及び図２紙面右端に収容される極板群の負極ストラップは、上述した正極外部出力端子３及び負極外部出力端子４にそれぞれ接続されている。
【００１６】
本実施形態の鉛蓄電池１０を作製するには、極板群１８組を電槽１内の各セル室に収容し、セル間接続体により直列に接続した後、電槽１上部に蓋２を溶着又は接着して取り付ける。続いて、電槽１に化成液としての電解液を各注液口から注液し、未化成電池を作製する。この未化成電池を５．０Ａで２３時間化成した後、各注液口を液口栓５で封口することにより、鉛蓄電池１０を得ることができる。
【００１７】
＜参考例＞
次に、表１を参照して、本実施形態に従って作製した鉛蓄電池１０の参考例の詳細について説明する。
【００１８】
【表１】

【００１９】
参考例１の電池では、比重１．２２５（２０°Ｃ）の希硫酸に正極既化活物質量の３．０重量％のＮａ_２ＳＯ_４を添加して電解液（化成液）とした。参考例２の電池では、比重１．２２５（２０°Ｃ）の希硫酸に正極既化活物質量の０．５重量％のＮａ_２ＳＯ_４を添加して電解液とした。参考例３の電池では、比重１．２２５（２０°Ｃ）の希硫酸に正極既化活物質量の１０．０重量％のＮａ_２ＳＯ_４を添加して電解液とした。
【００２０】
参考例４の電池では、上述した未化成正極板の活物質ペースト混練時に、正極既化活物質量の３．０重量％のＮａ_２ＳＯ_４を添加し、比重１．２２５（２０°Ｃ）の希硫酸を電解液とした。すなわち、参考例４では、上述した各実施例及び後述する比較例と異なり、電解液にＮａ_２ＳＯ_４は添加されていない。参考例５の電池では、比重１．２２５（２０°Ｃ）の希硫酸に正極既化活物質量の０．２重量％のＮａ_２ＳＯ_４を添加して電解液とした。参考例６の電池では、比重１．２２５（２０°Ｃ）の希硫酸に正極既化活物質量の１５．０重量％のＮａ_２ＳＯ_４を添加して電解液とした。
【００２１】
＜試験・評価＞
[試験] 次に、このようにして作成した参考例１〜６の各電池について、４０°Ｃと７５°Ｃでの軽負荷寿命試験及び過放電放置特性試験を行った。なお、過放電放置特性試験では、過放電状態の各電池を３０日間放置した後、１．５Ａで２０ｈ充電し、ＪＩＳに基づく低温ハイレート試験を行い、６Ｖまでの放電時間が放置前に対し何％であったかを算出した。
【００２２】
[試験結果] 軽負荷寿命試験の試験結果を表２に、過放電放置特性試験の試験結果を表３に示す。
【００２３】
【表２】

【００２４】
【表３】

【００２５】
[評価] 表２に示したように、４０°Ｃ軽負荷寿命試験の結果、参考例１〜３の電池はいずれも約６０００回程度の寿命を有するのに対し、参考例４及び参考例６の電池では３０００回乃至４０００回程度と、寿命性能が劣っている。また、７５°Ｃ軽負荷寿命試験の結果でも、参考例１〜３の電池は、２８００回以上の寿命を有するのに対し、参考例４及び参考例６の電池では２１００回程度と、寿命性能が劣っている。一方、表３に示したように、過放電放置特性試験の結果、各電池は６Ｖまでの放電時間が放置前に対し７０％以上の性能を示したのに対し、参考例５の電池は５０％未満で過放電放置特性に劣っている。従って、参考例１〜参考例３の電池は、高い過放電放置特性を維持したまま、寿命特性が向上していることが分かる。
【００２６】
本実施形態による参考例１〜３の各電池は、正極格子体の腐蝕が抑制されるので、振動や急加減速等の応力が正極格子体に直接加わる車載用鉛蓄電池に適合するばかりか、作製時においてもＮａ_２ＳＯ_４無添加の正極活物質を正極格子体に充填し、電解液中にＮａ_２ＳＯ_４を添加すればよいので、従来技術の正極既化活物質に対して微量のＮａ_２ＳＯ_４が均一均等に混練されるまでの混練時間が短縮され、生産性の向上を図ることができる。
【００２７】
上記参考例１〜３では、一形態として電解液中に正極既化活物質の０．５〜１０重量％のＮａ_２ＳＯ_４を添加した例について説明したが、次に示す方法によっても参考例１〜３の鉛蓄電池と同様の効果を得ることができる。
（１）正極活物質中に正極既化活物質の０．１〜０．５重量％、化成液中に正極既化活物質の０．５〜１０重量％のＮａ_２ＳＯ_４を添加する。
（２）正極活物質層が少なくとも２層の活物質層からなり、正極格子体近傍ではＮａ_２ＳＯ_４無添加の活物質層、正極板表面では正極既化活物質の０．５〜１０重量％のＮａ_２ＳＯ_４を添加した活物質層とする。
（３）正極活物質層が少なくても２層の活物質層からなり、正極格子体近傍ではＮａ_２ＳＯ_４が無添加の活物質層、正極板表面では正極既化活物質の０．１〜３重量％のＮａ_２ＳＯ_４を添加した活物質層とし、化成液中に正極既化活物質の０．５〜１０重量％のＮａ_２ＳＯ_４を添加する。
【００２８】
また、本実施形態では１８セルを１列とした１８セルモノブロック電槽１について例示したが、本発明は、例えば、６セルのモノブロック電槽や仕切り板等により電槽内のセル室を画定する他の構造の鉛蓄電池にも適用することができ、更に、本実施形態では開放型の車載用鉛蓄電池１０について例示したが、密閉型の鉛蓄電池や据置用鉛蓄電池にも適用することができることはいうまでもない。
【００２９】
【発明の効果】
以上説明したように、本発明の第１の態様によれば、正極格子体近傍に硫酸ナトリウムが無添加の第１の活物質層が配置されているので、硫酸イオンによる正極格子体の腐食が抑制され、鉛蓄電池の長寿命化を図ることができると共に、正極板の表面に正極既化活物質の０．５重量％〜１０重量％の硫酸ナトリウムが添加された第２の活物質層が配置されているので、過放電時の伝導度を保持し正極活物質の利用率を向上させたまま、鉛蓄電池の長寿命化を図ることができる、という効果を得ることができる。また、本発明の第２の態様によれば、硫酸ナトリウムが無添加の正極活物質ペーストを正極格子体近傍に配置して第１の活物質層を形成し、正極既化活物質の０．５重量％〜１０重量％の硫酸ナトリウムが添加された正極活物質ペーストを正極板の表面に配置して第２の活物質層を形成するので、過放電時の伝導度を保持し活物質の利用率向上を図ることができると共に、硫酸ナトリウムが無添加の正極活物質ペーストを正極格子体に配置するので、正極格子体は硫酸イオンによる腐食が抑制され、鉛蓄電池の長寿命化を図ることができる、という効果を得ることができる。
【図面の簡単な説明】
【図１】本発明が適用される実施形態の鉛蓄電池の外観斜視図である。
【図２】実施形態の鉛蓄電池の電槽の平面図である。
【符号の説明】
１電槽
２蓋
３正極外部出力端子
４負極外部出力端子
５液口栓
６隔壁
１０鉛蓄電池[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lead-acid battery and a method for producing the lead-acid battery, and in particular, a lead-acid battery comprising a positive electrode plate in which a positive electrode grid mainly composed of lead is filled with a positive electrode active material mainly composed of lead dioxide, and the lead. The present invention relates to a method for manufacturing a storage battery.
[0002]
[Prior art]
In a lead acid battery, lead powder obtained by oxidizing a part of lead, water, and dilute sulfuric acid are added as main components, and additives are added to these as necessary, and the paste obtained by kneading is lead (Pb) Paste electrode plates that are coated (filled) on a cast lattice or a continuous porous body mainly composed of and dried are widely used. Combine the paste plate with separators (separation plates) to form a plate group, and incorporate the plate group into the battery case, then add dilute sulfuric acid for chemical charging, or after chemical charging, By incorporating the lead-acid battery, the original function of the battery is given. At this time, the main component of the positive electrode active material is lead dioxide (PbO ₂ ).
[0003]
Sodium sulfate (Na ₂ SO ₄ ) is added as a positive electrode additive to a lead storage battery using such a paste-type electrode plate. Na ₂ SO ₄ is added to the positive electrode paste at the time of kneading, and its main purpose is to maintain ionic conductivity during overdischarge and to improve the utilization rate of the active material.
[0004]
[Problems to be solved by the invention]
However, when the Na ₂ SO ₄ is present in the positive electrode grid near the paste type electrode plate, since the sulfate ions SO ₄ the oxidation product ² corrodes the positive grid body mainly composed of lead, lead There exists a problem that the lifetime performance of a storage battery falls.
[0005]
The present invention has been made in order to solve the above-mentioned problems, and maintains the ionic conductivity at the time of overdischarge with Na ₂ SO _{4 and} improves the utilization rate of the active material, and suppresses corrosion of the positive electrode grid body to achieve a long life. It is an object of the present invention to provide a lead storage battery that can be realized and a method for manufacturing the lead storage battery.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first aspect of the present invention is a positive electrode plate in which a positive electrode lattice body containing lead (Pb) as a main component is filled with a positive electrode active material containing lead dioxide (PbO ₂ ) as a main component. In the lead-acid battery provided, the positive electrode plate is disposed in the vicinity of the positive electrode lattice body , the first active material layer to which no sodium sulfate (Na ₂ SO ₄ ) is added, and the positive electrode plate is disposed on the surface of the positive electrode plate. And a second active material layer to which sodium sulfate of 0.5 wt% to 10 wt% of the active material is added . In the present invention, since the sodium sulfate in the vicinity positive grid body is first active material layer of additive-free is arranged, is suppressed corrosion of the positive grid body with sulfuric acid ions, it is possible to extend the life of the lead-acid battery is possible, since the second active material layer of sodium sulfate 0.5 wt% to 10 wt% of Seikyokusunde Kakatsu material on the front surface of the positive electrode plate is added is arranged, the conductivity of the overdischarge Thus, the life of the lead-acid battery can be extended while maintaining the utilization ratio of the positive electrode active material .
[0007]
A second aspect of the present invention is a method for producing a lead-acid battery comprising a positive electrode plate in which a positive electrode grid mainly composed of lead is filled with a positive electrode active material mainly composed of lead dioxide, the sulfuric acid A positive electrode active material paste without addition of sodium is disposed in the vicinity of the positive electrode grid to form a first active material layer, and 0.5 wt% to 10 wt% of sodium sulfate is added to the positive electrode active material. Disposing the positive electrode active material paste on the surface of the positive electrode plate to form a second active material layer. In the present invention, a positive electrode active material paste to which no sodium sulfate is added is arranged in the vicinity of the positive electrode lattice to form a first active material layer, and 0.5 wt% to 10 wt% sulfuric acid of the positive electrode active material is formed. Since the positive electrode active material paste to which sodium is added is disposed on the surface of the positive electrode plate to form the second active material layer, the conductivity during overdischarge can be maintained and the active material utilization rate can be improved. Since the positive electrode active material paste to which sodium sulfate is not added is disposed on the positive electrode grid, the positive electrode grid is prevented from being corroded by sulfate ions, and the life of the lead storage battery can be extended .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a vehicle-mounted lead-acid battery mounted on a vehicle such as an automobile will be described with reference to the drawings.
[0009]
As shown in FIG. 1, the lead storage battery 10 of the present embodiment includes a rectangular battery case 1 serving as a container for the lead storage battery 10. The battery case 1 is excellent in terms of moldability, electrical insulation, corrosion resistance, durability, and the like. For example, a polymer resin such as acrylic butadiene styrene (ABS), polypropylene (PP), or polyethylene (PE) is used as the material. It is said that.
[0010]
As shown in FIG. 2, the battery case 1 is formed by integral molding, and a total of 18 cell chambers are defined in one row by the partition walls 6 that partition the inside of the outer peripheral wall (location 1 in FIG. 2). This is a so-called 18-cell monoblock battery case. The upper part of the battery case 1 is welded or bonded to a lid 2 made of a polymer resin such as ABS, PP, PE or the like and sealed.
[0011]
The lid 2 is formed with a number (18) of liquid inlets corresponding to the cell chambers so that an electrolyte can be injected into each cell chamber from the outside of the lead storage battery 10. Sealed by a stopper 5. Further, in order to project the rod-like positive external output terminal 3 and negative external output terminal 4 from the lid 2 at the corners of the lid 2 corresponding to the upper part of the cell chambers at both ends of the lid 2 closer to the longer side than the liquid stopper 5. The external terminal holes are formed in parallel with the long side surface. The positive external output terminal 3 and the negative external output terminal 4 are erected from the inside of the battery case 1, protrude through the lid 2, and are fixed to the lid 2.
[0012]
Each of the 18 cell chambers defined in the battery case 1 stores a set of electrode plates (not shown), and the battery case 1 stores a total of 18 electrode plate groups. In each electrode plate group, six unformed negative electrode plates and five unformed positive electrode plates are laminated via a separator made of glass fiber, and the group voltage of each electrode plate group after formation (initial charge) is 2V. Is done.
[0013]
The unformed negative electrode plate is a negative electrode obtained by kneading lead powder, 13% by weight diluted sulfuric acid (specific gravity 1.26: 20 ° C.) with respect to the lead powder, and 12% by weight water with respect to the lead powder. An active material paste was prepared, and 40.0 g of paste was filled in a current collector made of a grid, and then left to stand for 18 hours in an atmosphere having a temperature of 50 ° C. and a humidity of 95%, and then a temperature of 25 ° C. It is prepared by leaving it in an atmosphere of 40% humidity for 2 hours and drying it.
[0014]
On the other hand, the active material paste of the unformed positive electrode plate is obtained by adding 0.01% by weight of cut fiber to the lead powder and 13% by weight of diluted sulfuric acid (specific gravity: 1.26: 20 ° C.) with respect to the lead powder. ) And 12% by weight of water with respect to the lead powder. During this kneading, the temperature is kept constant by a coolable kneading pot. After 40.0 g of the positive electrode active material paste was filled in a current collector made of a lattice, the plate was left to age for 18 hours in an atmosphere having a temperature of 50 ° C. and a humidity of 95%, and then a temperature of 25 ° C. and a humidity of 40 % In an atmosphere of 2% and dried to produce an unformed positive electrode plate.
[0015]
The five unformed positive electrode plates and the six unformed negative electrode plates of each electrode plate group are fixed in each cell chamber to a positive electrode strap and a negative electrode strap that connect electrode plates of the same polarity. Each of the straps except for the positive electrode strap of the electrode plate group accommodated at the left end of FIG. 2 and the negative electrode strap of the electrode plate group accommodated at the right end of FIG. The connecting members are connected to adjacent straps of different polarities so as to cross the partition wall 6 in the battery case 1 (through the partition wall 6), and 18 sets of electrode plates are connected in series. . The positive electrode strap of the electrode group accommodated at the left end of FIG. 2 and the negative strap of the electrode group accommodated at the right end of FIG. 2 are respectively connected to the positive external output terminal 3 and the negative external output terminal 4 described above. .
[0016]
In order to produce the lead storage battery 10 of this embodiment, 18 sets of electrode plates are accommodated in each cell chamber in the battery case 1 and connected in series by inter-cell connectors, and then the lid 2 is placed on the upper part of the battery case 1. Install by welding or gluing. Subsequently, an electrolytic solution as a chemical conversion solution is injected into the battery case 1 from each injection port to produce an unchemical conversion battery. After this unformed battery is formed at 5.0 A for 23 hours, each liquid inlet is sealed with a liquid stopper 5, whereby the lead storage battery 10 can be obtained.
[0017]
< Reference example>
Next, with reference to Table 1 will be described in detail reference example of lead-acid battery 10 made in accordance with the present embodiment.
[0018]
[Table 1]

[0019]
In the battery of Reference Example 1, 3.0 wt% Na ₂ SO ₄ of the positive electrode active material amount was added to dilute sulfuric acid having a specific gravity of 1.225 (20 ° C.) to obtain an electrolytic solution (chemical conversion solution). In the battery of Reference Example 2, 0.5 wt% Na ₂ SO ₄ of the positive electrode active material amount was added to dilute sulfuric acid having a specific gravity of 1.225 (20 ° C.) to obtain an electrolytic solution. In the battery of Reference Example 3, 10.0 wt% Na ₂ SO ₄ of the positive electrode active material amount was added to dilute sulfuric acid having a specific gravity of 1.225 (20 ° C.) to obtain an electrolyte solution.
[0020]
In the battery of Reference Example 4 , at the time of kneading the active material paste of the unformed positive electrode plate described above, 3.0 wt% of Na ₂ SO ₄ of the positive electrode active material amount was added, and the specific gravity was 1.225 (20 ° C.). Was used as an electrolyte. That is, in Reference Example 4 , Na ₂ SO ₄ is not added to the electrolytic solution, unlike the above-described Examples and Comparative Examples described later. In the battery of Reference Example 5 , 0.2 wt% Na ₂ SO ₄ of the positive electrode active material amount was added to dilute sulfuric acid having a specific gravity of 1.225 (20 ° C.) to obtain an electrolytic solution. In the battery of Reference Example 6 , 15.0 wt% Na ₂ SO ₄ of the positive electrode active material amount was added to dilute sulfuric acid having a specific gravity of 1.225 (20 ° C.) to obtain an electrolyte solution.
[0021]
<Test and evaluation>
[Test] Next, each of the batteries of Reference Examples 1 to 6 prepared as described above was subjected to a light load life test and an overdischarge leaving characteristic test at 40 ° C. and 75 ° C. In the overdischarge leaving characteristics test, each battery in an overdischarged state is left for 30 days, then charged at 1.5 A for 20 hours, a low temperature high-rate test based on JIS is performed, and the discharge time up to 6 V is higher than before % Was calculated.
[0022]
[Test Results] Table 2 shows the test results of the light load life test, and Table 3 shows the test results of the overdischarge storage property test.
[0023]
[Table 2]

[0024]
[Table 3]

[0025]
[Evaluation] As shown in Table 2, as a result of the 40 ° C light load life test, the batteries of Reference Examples 1 to 3 all had a life of about 6000 times, whereas Reference Examples 4 and 6 In the case of the battery, the life performance is inferior, about 3000 to 4000 times. Further, even 75 ° C light load life test results, battery of Example 1-3, while having 2800 or more times the lifetime, and about 2100 times in the battery of Reference Example 4 and Reference Example 6, life performance Is inferior. On the other hand, as shown in Table 3, as a result of the overdischarge leaving characteristics test, each battery showed a performance of 70% or more of the discharge time up to 6 V compared to that before being left, whereas the battery of Reference Example 5 showed 50%. Less than%, it is inferior to the overdischarge standing characteristics. Thus, the battery of Reference Example 1 to Reference Example 3, while maintaining high overdischarge storage characteristics, it can be seen that the life characteristics are improved.
[0026]
Each battery of Reference Examples 1 to 3 according to the present embodiment is not only suitable for in-vehicle lead storage batteries in which stress such as vibration and rapid acceleration / deceleration is directly applied to the positive electrode grid body because corrosion of the positive electrode grid body is suppressed. At the time of production, the positive electrode active material without addition of Na ₂ SO ₄ is filled in the positive electrode grid, and Na ₂ SO ₄ may be added to the electrolytic solution. The kneading time until Na ₂ SO ₄ is uniformly and uniformly kneaded is shortened, and the productivity can be improved.
[0027]
In the above Reference Examples 1 to 3 have been described as being added _{over Na} 2 SO ₄ of from 0.5 to 10 wt% Seikyokusunde Kakatsu material electrolytic solution as Ichikatachi state, by the following method reference The effect similar to the lead acid battery of Examples 1-3 can be acquired.
(1) 0.1 to 0.5% by weight of the positive electrode active material is added to the positive electrode active material, and 0.5 to 10% by weight of Na ₂ SO ₄ of the positive electrode active material is added to the chemical conversion liquid.
(2) The positive electrode active material layer is composed of at least two active material layers, an active material layer not containing Na ₂ SO _{4 in the} vicinity of the positive electrode lattice, and 0.5 to 10 wt% of the positive electrode active material on the positive electrode plate surface. % of the _Na 2 SO ₄ active material layer was added.
(3) The positive electrode active material layer is composed of at least two active material layers, an active material layer to which Na ₂ SO ₄ is not added in the vicinity of the positive electrode lattice, and 0.1% of the positive electrode active material on the surface of the positive electrode plate. An active material layer to which ˜3% by weight of Na ₂ SO ₄ is added is added, and 0.5 to 10% by weight of Na ₂ SO ₄ of the positive electrode active material is added to the chemical conversion liquid.
[0028]
Further, in the present embodiment, the 18-cell monoblock battery case 1 having 18 cells in one row is illustrated, but the present invention defines a cell chamber in the battery case by, for example, a 6-cell monoblock battery case or a partition plate. In this embodiment, the open-type lead-acid battery 10 for in-vehicle use is exemplified, but it may be applied to a sealed lead-acid battery or a stationary lead-acid battery. Needless to say, it can be done.
[0029]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the sodium sulfate in the vicinity positive grid body is first active material layer of additive-free is disposed, the corrosion of the positive grid body according sulfate ions The second active material layer in which 0.5% by weight to 10% by weight sodium sulfate of the positive electrode active material is added to the surface of the positive electrode plate while being suppressed, can extend the life of the lead storage battery. Since it is disposed, it is possible to obtain an effect that it is possible to extend the life of the lead-acid battery while maintaining the conductivity during overdischarge and improving the utilization rate of the positive electrode active material . In addition, according to the second aspect of the present invention, the positive electrode active material paste to which no sodium sulfate is added is disposed in the vicinity of the positive electrode lattice body to form the first active material layer, and the positive electrode active material 0. Since the positive electrode active material paste to which 5 wt% to 10 wt% of sodium sulfate is added is disposed on the surface of the positive electrode plate to form the second active material layer, the conductivity of the active material is maintained while maintaining the conductivity during overdischarge. it is possible to use rate increase, since sodium sulfate to place a positive electrode active material paste not added to the positive electrode grid, the positive electrode grid is suppressed corrosion by sulfate ions, possible to extend the life of the lead-acid battery The effect of being able to be obtained can be obtained.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a lead storage battery according to an embodiment to which the present invention is applied.
FIG. 2 is a plan view of a battery case of the lead storage battery according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery case 2 Cover 3 Positive electrode external output terminal 4 Negative electrode external output terminal 5 Liquid stopper 6 Bulkhead 10 Lead acid battery

Claims

In a lead-acid battery comprising a positive electrode plate in which a positive electrode grid mainly composed of lead (Pb) is filled with a positive electrode active material mainly composed of lead dioxide (PbO ₂ ), the positive electrode plate is in the vicinity of the positive electrode grid. A first active material layer to which no sodium sulfate (Na ₂ SO ₄ ) is added, and 0.5 wt% to 10 wt% sodium sulfate of the positive electrode active material arranged on the surface of the positive electrode plate. A lead-acid battery comprising: an added second active material layer.

A method for producing a lead-acid battery comprising a positive electrode plate filled with a positive electrode active material mainly composed of lead dioxide in a positive electrode lattice body mainly composed of lead, wherein the positive electrode active material paste free of sodium sulfate is added to the positive electrode active material paste A positive electrode active material paste, which is disposed in the vicinity of the positive electrode grid body to form a first active material layer and to which 0.5 wt% to 10 wt% sodium sulfate of the positive electrode active material is added, is applied to the surface of the positive electrode plate. A method for producing a lead-acid battery comprising the step of forming a second active material layer by disposing the first active material layer.