JP4815665B2

JP4815665B2 - Lead acid battery

Info

Publication number: JP4815665B2
Application number: JP2000358979A
Authority: JP
Inventors: 浩一米村; 章二堀江; 善博村田
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-11-27
Filing date: 2000-11-27
Publication date: 2011-11-16
Anticipated expiration: 2020-11-27
Also published as: JP2002164080A

Description

【０００１】
【発明の属する技術分野】
本発明は鉛蓄電池の改良に関するものであり、製品のコスト低減，軽量化，生産性向上を図った鉛蓄電池を提供するものである。
【０００２】
【従来の技術】
Ｐｂ−Ｃａ−Ｓｎ合金を格子体に用いた鉛蓄電池は、それ以前に主体であったＰｂ−Ｓｂ−Ａｓ合金を用いた鉛蓄電池に比べ、電解液の減液や自己放電が少なく、保存特性に優れるなどの特徴があり、広く使用されている。さらに、過放電放置後の充電受入性や深い充放電を行うサイクル寿命特性を向上するために、格子体の表面にＳｎやＳｂを含む薄膜を形成させる技術が提案されている。一方、通常の鉛蓄電池の構成は、正極板の枚数に対して、負極板の枚数は正極板の枚数よりも１枚多いのが一般的である。これは、負極板の枚数を増やすことで、正極の活物質量に対して負極の活物質量に余裕を持たせて、充電時の負極でのガス発生（分極）を遅らせることで定電流領域を長くし、正極板の充電を十分に行うためである。しかし近年では、電池のエネルギー密度の向上や軽量化、製品のコスト低減や生産性の向上を図るために、負極の添加剤を増加するなどして少ない活物質量でも充電受入性を向上させ、正極板と負極板とを同枚数にする構成の技術が提案されている。
【０００３】
【発明が解決しようとする課題】
しかしながら、カルシウム系合金を用いた鉛蓄電池において正極板と負極板の枚数を同枚数にすれば、コスト低減や生産性では有利になるものの、ある条件下のサイクル寿命においては容量が低下してしまい、早期に寿命に至ってしまうことが明らかとなってきた。さらに、近年多く用いられている合成樹脂製セパレータは、活物質の脱落による内部短絡を防止するため袋状にして極板を包み込む形が一般的であるが、正極板と負極板の枚数が同枚数の鉛蓄電池において負極板を袋詰めにした場合には寿命低下がより顕著に現れてしまう。この原因として、負極板を袋詰めした構成の鉛蓄電池は、正極板を袋詰めした鉛蓄電池に比べて、充電末期の電流値が小さく、特に正極板の充電不足が起こりやすくなるからである。
【０００４】
本発明は上記課題を解決するものであり、極板枚数を減少した場合や負極板をセパレータで袋詰めした場合の問題を克服して、鉛蓄電池の寿命低下を抑制することを目的とするものである。
【０００５】
【課題を解決するための手段】
上述した課題を解決するための手段として、本発明の請求項１に記載の発明は、Ｐｂ−Ｃａ−Ｓｎ系合金の表面の両面にＳｂを含む合金の薄膜を形成させた鉛合金シートをエキスパンド加工した格子体を正極に用い、かつ正極板と負極板が同枚数で構成した鉛蓄電池としたものである。また、さらに正極格子の網目部を構成する１升当たりの開口面積を、負極格子１升当たりの開口面積よりも小さくするものである。
【０００６】
また、請求項２に記載の発明は、請求項１記載の発明において、Ｓｂを含む合金はＰｂ−Ｓｂ系合金またはＰｂ−Ｓｎ−Ｓｂ系合金とした。
【０００７】
また、請求項３に記載の発明は請求項１または２に記載の構成を有し、負極板を袋状のセパレータで包み込むこととした。
【０００９】
【発明の実施の形態】
本発明を用いた鉛蓄電池の正極板に用いる格子は、図１に示すようにＰｂ−Ｃａ−Ｓｎ合金の連続鋳造体の両面にＳｂを含有する合金の薄膜を重ね合わせ、冷間圧延して一体化した鉛合金シートをエキスパンド加工することによって図２に示すような網目状の格子体とする。この格子体の網目部に活物質ペーストを充填した後、熟成乾燥工程を経て正極板とする。セパレータは微孔性ポリエチレン製シートを用い、正極板、より好ましくは負極板を包み込む形で極板群を構成する。これらの正極板、もしくは、負極板を袋詰めしたセパレータから図３に示すような正極板と負極板が同枚数の極板群を構成する。この本発明の構成による電池は、上述した課題である寿命サイクル時の正極での充電不足による早期の容量低下やセパレータ破損による正極−負極間の短絡を解消し、優れた寿命性能に寄与するものである。さらに、本発明の充電不足改善効果を特に顕著に得るためには、正極格子表面に形成したＳｂ層内に含有するＳｂ量を２．０質量％〜１０．０質量％、層の厚みを０．０１ｍｍ〜０．０５ｍｍとすることが好ましい。
【００１０】
【実施例】
以下、本発明の実施例を図面を参照にしながら説明する。
【００１１】
本発明の鉛蓄電池の格子合金は、図１に示すようにＰｂ−０．０７重量％Ｃａ−１．３重量％Ｓｎの厚み約１５ｍｍの連続鋳造体のＰｂ−Ｃａ−Ｓｎ合金シート１の両表面に、厚さ約０．２ｍｍのＰｂ−７質量％ＳｂのＰｂ−Ｓｂ合金シート２を重ね合わせて、段階的に圧延ローラ３で圧延することで鉛圧延シート４を作製した。鉛圧延シート４にエキスパンド加工を行い、図２に示すように網目状とし、この網目によって構成される格子体の升目に活物質ペーストを充填した後、単一極板に切断加工して正極板を作製した。この際、格子体の網目部を構成する升目の開口面積が約２．５ｃｍ²の大きいものと開口面積が約１ｃｍ²の小さいものとを作製した。図２に格子体の網目部を構成する升目を示す。
【００１２】
一方、負極板はＰｂ−０．０７質量％Ｃａ−０．３質量％Ｓｎ合金である厚み約０．８ｍｍを正極と同様に圧延しエキスパンド加工して格子体を作製し、これに活物質ペーストを充填することで得た。セパレータには、厚さ約０．３ｍｍの微孔性ポリエチレン製シートを用いて、正極板あるいは負極板を包み込む形の２種類の袋状セパレータを作製した。
【００１３】
上記の２種類の正極板とセパレータで袋詰めする極板を各々組み合わせて、１セル当たり正極板５枚、負極板５枚の両極同枚数からなる極板群を用い、５５Ｄ２３形の自動車用鉛蓄電池（１２Ｖ４８Ａｈ）を作製した。図３において６は正極板、７は負極板、８は袋状セパレータを示す。正，負極板の格子網目の升目の開口面積およびセパレータによる袋詰めの条件などについては表１に示した。
【００１４】
また、本発明例の電池Ｃ２および電池Ｃ４を含むＣ群との比較のために従来の製造法によるＰｂ−Ｃａ−Ｓｎ合金シート１の片面のみにＰｂ−Ｓｂ合金シート２を重ね合わせて同様に圧延した鉛圧延シートを作製し、この鉛圧延シートをエキスパンド加工して網目状の格子体を形成した。この格子体を用いた鉛蓄電池は表１に示すように本発明と同様の条件で作製し、比較例の鉛蓄電池Ｂ群とした。さらに、表１に示すように負極板の枚数を１枚多くした鉛蓄電池を構成し、これを従来例の鉛蓄電池Ａ群とした。
【００１５】
【表１】

【００１６】
表１に示した各々異なる構成の鉛蓄電池について、次のようなパターンの寿命試験を実施して評価した。この寿命試験は深い放電が入る放電傾向の使われ方を想定した試験パターンであり、ＪＩＳＤ５３０１軽負荷寿命試験においてサイクル中の放電を８分間、充電を１６分間として行った。この試験結果を表１に示す。前記の寿命試験評価は、従来の構成からなる鉛蓄電池Ａ群の寿命特性を１００として各々の構成からなる鉛蓄電池を比較した。
【００１７】
従来の鉛蓄電池Ａ群の特徴である、負極板枚数が正極板枚数よりも１枚多い群構成からなる鉛蓄電池Ａ▲１▼と正極板と負極板とが同枚数の構成からなる比較例の鉛蓄電池Ｂ▲１▼を比較すると、Ｂ▲１▼はＡ▲１▼に比べ寿命特性がかなり低下している。
【００１８】
さらに、正極板と負極板とが同枚数の構成でセパレータが負極板のみを包み込む形の電池Ｂ▲２▼およびＢ▲４▼は、従来の構成であるＡ群と比較すると寿命低下が著しいことが分かる。これは、負極板の枚数が正極板の枚数より多くない場合では、定電圧充電時に正極より充電効率が高い負極活物質の充電反応が完了し、正極の充電が十分に行われないまま充電末期に達してしまい、この充電不足反応がサイクルを繰り返すことによって蓄積され、寿命低下に至ったと考えられる。
【００１９】
また、セパレータが負極板のみを袋詰めするものも重要な因子になっていると考えられる。通常、正極板の寿命サイクルによる体積膨張や格子の伸びがセパレータにストレスを与えてしまうことから、正極板をセパレータで袋詰めするのではなく負極板のみを袋詰めするのが理想的であるが、負極板をセパレータで袋詰めした場合における正極板と負極板とが同枚数の構成の電池Ｂ▲２▼の結果からも分かるように、正極の充電不足はより加速していることが分かる。これは、正極活物質中の硫酸鉛の顕著な蓄積が見られたことによって確認することができた。また、Ｂ▲３▼やＢ▲４▼のように格子網目部の１升当たりの開口面積において正極が負極より小さい格子体を用いて極板内部での導電性向上を図ることにより若干の寿命向上は見られたが、充電効率の改善には不完全なものであった。
【００２０】
本発明例の鉛蓄電池である電池Ｃ２および電池Ｃ４は、Ｂ群の鉛蓄電池と同様に正極板と負極板が同枚数の構成からなる鉛蓄電池であるが、Ｂ群が大きく寿命特性が悪化しているのに対してＣ群における寿命特性の低下はわずかであった。これは、正極格子の両面にＳｂ薄膜を形成させた効果が大きいことを示しており、Ｓｂ層を正極格子の両面に付与することで正極の充電受入性が向上して正極の充電が十分に行われ、寿命低下の原因であった正極の充電不足の蓄積が解消されていると推測できる。
【００２１】
この作用効果は、サイクルが進むにしたがって正極格子の表面のＳｂ層からＳｂが電解液中に溶出し、セパレータを通過して負極に析出することによって負極の水素過電圧（分極）を低下させることによるものである。この結果として正極の分極の増大を引き起こし、正極は十分な充電電気量を確保することができ、充電効率の向上につながったことが考えられる。Ｓｂ層を正極格子の両面に付与することで、Ｓｂ層が片面にしかない場合よりもＳｂ作用効果が早期に現われ、それと同時により多くのＳｂが有効に作用したといえる。
【００２２】
さらに正極の両面のＳｂ層の効果を追及するために、片面だけに両面と同じ量のＳｂ層を形成させた格子体を正極板に用いた鉛蓄電池で寿命試験を行ったところ、寿命特性は従来の片面にＳｂ層を有する鉛蓄電池Ｂ群とほとんど同じで、減液量が増加しただけであった。このことから、寿命特性の向上につながるＳｂ作用は単に正極格子の表面のＳｂ層におけるＳｂ含有量を増加させただけでは効果はなく、正極の両面にＳｂ層を設けた場合のようにＳｂと硫酸の界面を広範囲に渡って格子表面上に存在させることが重要であるといえる。また、セパレータが負極板のみを包み込む形の鉛蓄電池であるＣ▲３▼，Ｃ▲４▼においても、片面にＳｂ層を付与した鉛蓄電池の寿命低下が著しかったのに対して、両面にＳｂ層を有する鉛蓄電池では寿命低下はわずかで、正極の充電不足の問題はないといえる。
【００２３】
次に、前記した深い放電が入る寿命試験とは別に過充電傾向で鉛蓄電池が使用されることを想定した寿命試験を行った。この試験条件は７５℃雰囲気中において、１３．８Ｖで連続１２０ｈ充電することを１サイクルとした過充電寿命試験である。この試験結果を同様に表１に示す。表１に示す結果からセパレータが正極板のみを包み込む構成である鉛蓄電池は、従来例，本発明例の鉛蓄電池に関係なく特性が悪いことが分かる。これは、サイクルにより正極格子が伸びてセパレータの底部に穴があき、正極と負極が短絡して寿命に至ったためである。これに対して、負極板をセパレータで包み込んだ鉛蓄電池は、短絡することなく良好な寿命特性を示した。
【００２４】
以上のように、鉛合金シートの両面にＳｂ層を形成させた格子体で、格子網目部を構成する升目の開口面積が小さいものを正極に用いて、なおかつ負極をセパレータで袋詰めした正極板と負極板とが同一枚数からなる鉛蓄電池Ｃ▲４▼は、深い放電試験パターンと過充電試験パターンの両方において、各々の構成からなる鉛蓄電池の中でも特に優れた寿命特性を示すことが分かった。
【００２５】
【発明の効果】
以上、Ｐｂ−Ｃａ−Ｓｎ鉛合金の両面にＳｂ薄膜を形成させた鉛合金シートをエキスパンド加工した網目状の格子体を正極に用いた極板群において、セル当たりの正極板と負極板が同数の構成からなる本発明の鉛蓄電池では、深い放電サイクルでの正極の充電不足による早期の容量低下を防ぎつつ、優れた過充電寿命特性を持つことが可能である。本発明はコスト低減や生産性向上に結びつく大きな効果を持つものである。
【図面の簡単な説明】
【図１】正極の鉛合金シートの工程を示す説明図
【図２】極板の格子体を示す正面図
【図３】極板群の構成を示す一部の断面を示した斜視図
【符号の説明】
１Ｐｂ−Ｃａ−Ｓｎ合金シート
２Ｐｂ−Ｓｂ合金シート
３圧延ローラ
４鉛圧延シート
５升目
６正極板
７負極板
８袋状セパレータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a lead storage battery, and provides a lead storage battery in which the cost of the product is reduced, the weight is reduced, and the productivity is improved.
[0002]
[Prior art]
Lead storage battery using Pb-Ca-Sn alloy for the lattice body has less electrolyte reduction and self-discharge than the lead storage battery using Pb-Sb-As alloy, which was the main body before that, and its storage characteristics And is widely used. Furthermore, in order to improve the charge acceptability after being left over-discharged and the cycle life characteristics for performing deep charge / discharge, a technique for forming a thin film containing Sn or Sb on the surface of the lattice has been proposed. On the other hand, the configuration of a normal lead-acid battery is generally such that the number of negative plates is one more than the number of positive plates relative to the number of positive plates. This is because the number of negative electrode plates is increased so that the amount of active material of the negative electrode is more than the amount of active material of the positive electrode, and the gas generation (polarization) at the negative electrode during charging is delayed, thereby maintaining a constant current region. This is to lengthen the length and sufficiently charge the positive electrode plate. However, in recent years, in order to improve the energy density and weight of the battery, reduce the cost of the product and improve the productivity, the charge acceptability can be improved even with a small amount of active material by increasing the additive of the negative electrode. A technique has been proposed in which the number of positive and negative electrode plates is the same.
[0003]
[Problems to be solved by the invention]
However, in lead-acid batteries using calcium-based alloys, if the number of positive and negative electrode plates is the same, it is advantageous in terms of cost reduction and productivity, but the capacity is reduced in the cycle life under certain conditions. It has become clear that it will reach the end of its life early. Furthermore, synthetic resin separators that are widely used in recent years are generally in the form of a bag that wraps the electrode plate in order to prevent an internal short circuit due to falling off of the active material, but the number of positive and negative electrode plates is the same. When the negative electrode plate is packaged in the number of lead-acid batteries, the life reduction appears more remarkably. This is because a lead-acid battery with a negative electrode plate packed has a smaller current value at the end of charging than a lead-acid battery packed with a positive electrode plate, and in particular, the positive electrode plate is likely to be insufficiently charged.
[0004]
The present invention solves the above-mentioned problems, and aims to overcome the problems of reducing the number of electrode plates or packing the negative electrode plate with a separator to suppress a decrease in the life of the lead-acid battery. It is.
[0005]
[Means for Solving the Problems]
As means for solving the above-described problems, the invention according to claim 1 of the present invention is an expanded lead alloy sheet in which a thin film of an alloy containing Sb is formed on both surfaces of a Pb—Ca—Sn alloy surface. The processed lattice body is used as a positive electrode, and a lead storage battery in which the positive electrode plate and the negative electrode plate are configured in the same number is used. Further, the opening area per square constituting the mesh part of the positive electrode grid is made smaller than the opening area per square of the negative electrode grid.
[0006]
The invention according to claim 2 is the invention according to claim 1, wherein the alloy containing Sb is a Pb—Sb alloy or a Pb—Sn—Sb alloy.
[0007]
The invention described in claim 3 has the configuration described in

claim

1 or 2 and wraps the negative electrode plate with a bag-like separator.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the grid used for the positive electrode plate of the lead-acid battery using the present invention is formed by superposing a thin film of an alloy containing Sb on both sides of a continuous cast body of Pb—Ca—Sn alloy, and cold rolling. The integrated lead alloy sheet is expanded to obtain a mesh-like lattice body as shown in FIG. After the active material paste is filled in the mesh portion of the lattice body, a positive electrode plate is obtained through an aging drying step. As the separator, a microporous polyethylene sheet is used, and the electrode plate group is configured to wrap around the positive electrode plate , more preferably the negative electrode plate. A positive electrode plate and a negative electrode plate as shown in FIG. 3 form the same number of electrode plate groups from these positive electrode plates or separators packed with negative electrode plates . The battery according to the structure of the present invention contributes to excellent life performance by eliminating the early capacity reduction due to insufficient charging at the positive electrode during the life cycle and short circuit between the positive electrode and the negative electrode due to separator breakage, which are the above-mentioned problems. It is. Furthermore, in order to obtain the effect of improving charging shortage of the present invention particularly remarkably, the amount of Sb contained in the Sb layer formed on the surface of the positive electrode lattice is 2.0 mass% to 10.0 mass%, and the thickness of the layer is 0. It is preferable that the thickness is 0.01 mm to 0.05 mm.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
As shown in FIG. 1, the lead alloy of the lead storage battery according to the present invention has a Pb—0.07 wt% Ca—1.3 wt% Sn thickness of about 15 mm and a continuous cast Pb—Ca—Sn alloy sheet 1. A Pb-Sb alloy sheet 2 having a thickness of about 0.2 mm and a Pb-Sb alloy sheet 2 having a thickness of about 0.2 mm was superposed on the surface, and the lead-rolled sheet 4 was produced by rolling with a rolling roller 3 step by step. The lead rolled sheet 4 is expanded to form a mesh as shown in FIG. 2, and the active material paste is filled into the grid of the lattice constituted by the mesh, and then cut into a single electrode plate to produce a positive electrode plate Was made. At this time, larger ones and the opening area of the opening area of about 2.5 cm ² squares constituting the mesh portion of the grid was prepared as small about 1 cm ^2. FIG. 2 shows a mesh constituting the mesh part of the lattice.
[0012]
On the other hand, the negative electrode plate is a Pb-0.07 mass% Ca-0.3 mass% Sn alloy having a thickness of about 0.8 mm, rolled in the same manner as the positive electrode, and expanded to produce a grid, and the active material paste Obtained by filling. As the separator, two types of bag-shaped separators were formed using a microporous polyethylene sheet having a thickness of about 0.3 mm so as to enclose the positive electrode plate or the negative electrode plate.
[0013]
The above two types of positive electrode plates and electrode plates packed with a separator are combined, and an electrode plate group consisting of the same number of both five positive electrode plates and five negative electrode plates per cell is used. A storage battery (12V48Ah) was produced. In FIG. 3, 6 is a positive electrode plate, 7 is a negative electrode plate, and 8 is a bag-like separator. Table 1 shows the opening area of the grid mesh of the positive and negative electrode plates and the conditions for packing with a separator.
[0014]
Further, for comparison with the group C including the battery C2 and the battery C4 of the example of the present invention, the Pb—Sb alloy sheet 2 is overlapped only on one side of the Pb—Ca—Sn alloy sheet 1 by the conventional manufacturing method in the same manner. A rolled lead rolled sheet was prepared, and the lead rolled sheet was expanded to form a mesh-like lattice body. As shown in Table 1, a lead-acid battery using this lattice was produced under the same conditions as in the present invention, and a lead-acid battery group B of Comparative Example was used. Furthermore, as shown in Table 1, a lead storage battery in which the number of negative electrode plates was increased by one was configured, and this was used as a conventional lead storage battery A group.
[0015]
[Table 1]

[0016]
The lead storage batteries having different configurations shown in Table 1 were evaluated by conducting a life test with the following pattern. This life test is a test pattern that assumes the use of a tendency to discharge with deep discharge. In the JIS D5301 light load life test, the discharge during the cycle was performed for 8 minutes and the charge was performed for 16 minutes. The test results are shown in Table 1. In the above-mentioned life test evaluation, the lead storage batteries having the respective configurations were compared with the life characteristics of the lead storage batteries A group having the conventional configuration as 100.
[0017]
A characteristic of the conventional lead-acid battery group A is that of the comparative example in which the lead-acid battery A (1), which has a group configuration in which the number of negative-electrode plates is one more than the number of positive-electrode plates, and the same number of positive-electrode plates and negative-electrode plates. Comparing the lead storage battery B (1), the life characteristics of B (1) are considerably lower than that of A (1).
[0018]
In addition, the batteries B <2> and B <4> in which the positive electrode plate and the negative electrode plate are configured in the same number and the separator wraps only the negative electrode plate have a significant decrease in life as compared with the conventional group A. I understand. This is because, when the number of negative electrode plates is not larger than the number of positive electrode plates, the charging reaction of the negative electrode active material having a higher charging efficiency than the positive electrode is completed during constant voltage charging, and the positive electrode is not fully charged and the end of charging is completed. This charge shortage reaction is accumulated by repeating the cycle, and it is considered that the lifetime is shortened.
[0019]
Moreover, it is thought that the thing in which a separator packs only a negative electrode plate is also an important factor. Normally, it is ideal to pack only the negative electrode plate instead of packing the positive electrode plate with the separator, because the volume expansion and lattice elongation due to the life cycle of the positive electrode plate will stress the separator. As can be seen from the results of the battery B {circle around (2)} having the same number of positive electrode plates and negative electrode plates when the negative electrode plates are packed with a separator, it can be seen that the insufficient charge of the positive electrode is accelerated. This could be confirmed by the remarkable accumulation of lead sulfate in the positive electrode active material. Further, by using a grid body in which the positive electrode is smaller than the negative electrode in the opening area per grid of the lattice network, as in B (3) and B (4), the conductivity is improved within the electrode plate, so that the life is slightly increased. Although an improvement was seen, it was incomplete to improve the charging efficiency.
[0020]
The batteries C2 and C4 , which are the lead storage batteries of the present invention, are lead storage batteries having the same number of positive and negative electrode plates as in the group B lead storage batteries. However, the group B is large and the life characteristics are deteriorated. On the other hand, the degradation of the life characteristics in the group C was slight. This indicates that the effect of forming the Sb thin film on both surfaces of the positive electrode grid is great, and by applying the Sb layer to both surfaces of the positive electrode grid, the charge acceptability of the positive electrode is improved and the positive electrode is sufficiently charged. It can be presumed that the accumulation of insufficient charging of the positive electrode, which was performed and caused the decrease in the life, has been resolved.
[0021]
This effect is due to the fact that Sb elutes from the Sb layer on the surface of the positive electrode lattice into the electrolyte as the cycle progresses, passes through the separator, and precipitates on the negative electrode, thereby reducing the hydrogen overvoltage (polarization) of the negative electrode. Is. As a result, the polarization of the positive electrode is increased, and the positive electrode can secure a sufficient amount of charge electricity, leading to an improvement in charge efficiency. By applying the Sb layer to both sides of the positive electrode grid, it can be said that Sb action and effects appear earlier than when the Sb layer is only on one side, and at the same time, more Sb acts effectively.
[0022]
Furthermore, in order to pursue the effect of the Sb layer on both sides of the positive electrode, when a life test was conducted with a lead storage battery using a grid body in which the same amount of Sb layer as the both sides was formed on only one side as a positive electrode plate, the life characteristics were It was almost the same as the conventional lead storage battery group B having an Sb layer on one side, and the amount of liquid reduction was only increased. For this reason, the Sb action that leads to the improvement of the life characteristics is not effective simply by increasing the Sb content in the Sb layer on the surface of the positive electrode lattice, and Sb and the Sb layer as in the case where the Sb layers are provided on both surfaces of the positive electrode. It can be said that it is important that the sulfuric acid interface exists over a wide range on the lattice surface. Further, in C <3> and C <4>, which are lead storage batteries in which the separator encloses only the negative electrode plate, the life reduction of the lead storage battery with the Sb layer provided on one side was remarkable, whereas Sb on both sides In a lead-acid battery having a layer, the life reduction is slight, and it can be said that there is no problem of insufficient charging of the positive electrode.
[0023]
Next, in addition to the life test in which deep discharge described above enters, a life test was performed assuming that a lead storage battery is used with an overcharge tendency. This test condition is an overcharge life test in which charging is performed for 1 hour at 13.8 V in a 75 ° C. atmosphere for one cycle. The test results are also shown in Table 1. From the results shown in Table 1, it can be seen that the lead storage battery in which the separator wraps only the positive electrode plate has poor characteristics regardless of the lead storage battery of the conventional example and the present invention example. This is because the positive electrode lattice was extended by the cycle and a hole was formed in the bottom of the separator, and the positive electrode and the negative electrode were short-circuited to reach the lifetime. On the other hand, the lead storage battery in which the negative electrode plate is wrapped with the separator showed good life characteristics without short circuit.
[0024]
As described above, a positive electrode plate in which an Sb layer is formed on both surfaces of a lead alloy sheet, and the one having a small opening area of the mesh constituting the lattice network is used for the positive electrode, and the negative electrode is bagged with a separator It was found that the lead storage battery C4 having the same number of the negative electrode plates and the negative electrode plate exhibits particularly excellent life characteristics among the lead storage batteries having the respective configurations in both the deep discharge test pattern and the overcharge test pattern. .
[0025]
【The invention's effect】
As described above, in the electrode plate group using the mesh-like lattice body obtained by expanding the lead alloy sheet in which the Sb thin film is formed on both surfaces of the Pb—Ca—Sn lead alloy as the positive electrode, the same number of positive electrode plates and negative electrode plates per cell. The lead storage battery of the present invention having the above structure can have excellent overcharge life characteristics while preventing an early capacity decrease due to insufficient charging of the positive electrode in a deep discharge cycle. The present invention has a great effect that leads to cost reduction and productivity improvement.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a process of a lead alloy sheet of a positive electrode. FIG. 2 is a front view showing a grid of electrode plates. FIG. 3 is a perspective view showing a partial cross section showing a configuration of a plate group. Explanation of]
DESCRIPTION OF SYMBOLS 1 Pb-Ca-Sn alloy sheet 2 Pb-Sb alloy sheet 3 Rolling roller 4 Lead rolled sheet 5 Grid 6 Positive electrode 7 Negative electrode 8 Bag-shaped separator

Claims

A Pb-Ca-Sn-based alloy cast body is formed by superimposing and rolling a thin film of an alloy containing Sb on both sides, and using an expanded lattice body as a positive electrode, and a positive electrode plate per cell And an electrode plate group having the same number of negative electrode plates, and the opening area per square constituting the mesh portion of the positive electrode grid is smaller than the opening area per square of the negative electrode grid. Lead acid battery.

The lead-acid battery according to claim 1, wherein the alloy containing Sb is a Pb-Sb alloy or a Pb-Sn-Sb alloy.

The lead-acid battery according to claim 1 or 2, wherein a negative electrode plate is wrapped in a microporous bag-shaped separator mainly composed of a synthetic resin.