JP3567969B2

JP3567969B2 - Sealed lead-acid battery

Info

Publication number: JP3567969B2
Application number: JP24477698A
Authority: JP
Inventors: 信治山田; 圭一長谷川; 能弘江口; 正明細川
Original assignee: Yuasa Corp
Current assignee: Yuasa Corp
Priority date: 1998-08-31
Filing date: 1998-08-31
Publication date: 2004-09-22
Anticipated expiration: 2018-08-31
Also published as: JP2000077092A

Description

【０００１】
【発明の属する技術分野】
本発明は、密閉形鉛蓄電池に関し、詳しくは電解液が主にガラスマットもしくは有機物多孔体もしくはガラス繊維と有機繊維の混紡多孔体よりなるセパレータに保持されてなるリテーナ式密閉形鉛蓄電池に関するものである。
【０００２】
【従来の技術とその課題】
近年、電気自動車用、ハイブリッド車用、ソーラーシステム用、ロードレベリング用等とサイクル用途の利用分野が広がりつつある密閉形鉛蓄電池のエネルギー密度を高くすることとサイクル寿命性能を向上させることが緊急の課題となっている。
【０００３】
ところで、電池の充電中に発生する酸素ガスを負極で吸収する、いわゆる酸素サイクルを利用した密閉形鉛蓄電池では、現在リテーナ式と呼ばれる方式が主流になっている。このリテーナ式とは、正極板と負極板との間に挿入した微細なガラス繊維もしくは有機繊維もしくはこれらを混紡したマット状セパレータで電池の充放電に必要な硫酸電解液の保持と両極の隔離を行う方式である。
【０００４】
このタイプの電池は通常、対向する面、すなわち作用面の面積が等しい正・負極板と、これらを隔離するための極板面積より大きいリテーナーが積層されてなる。従って、リテーナーには極板に直接面接する部分と、これら極板からはみ出た側縁とからなる。
【０００５】
このようなリテーナ式密閉形鉛蓄電池を放電した場合、電流分布の高い極板上部と電流分布の低い極板下部で電解液の濃度差が発生する。また、セパレータからはみ出た周縁に保持された電解液は、極板に面接する部分に保持された電解液より利用率が低くなり、両者間で電解液の濃度に差が発生する。
【０００６】
このような濃度差が発生すると、極板の周縁を境として外側と内側とで濃淡電池が形成され、同一極板内で充放電反応が行われる。放電反応の起こる電解液濃度の高い側、すなわち極板下部と極板側縁面では硫酸鉛の結晶が生成粗大化するとともに導電パスが減少し、すなわちサルフェーションが発生し、充電効率が低下する。
【０００７】
また、実際の使用条件に近い放電放置時間が長く、充電不足気味の充放電試験サイクルを続けると硫酸根が電解液でなく極板側に取り込まれたままの状態で回復しなくなり、電池容量がすぐに低下するという問題点を有していた。
【０００８】
また、この現象は活物質抵抗の低い負極板で顕著に現れ、活物質抵抗の高い正極板では比較的影響が小いため、正極に比べて、負極の蓄積硫酸鉛の割合が増大する傾向となる。この状態から充電しても負極が完全に充電される前に、正極が満充電され酸素を発生し始める。そして、負極では酸素ガス吸収反応が優勢となり、この反応のためにさらに負極の充電受け入れが悪くなるという悪循環を繰り返すことになった。
【０００９】
【発明が解決しようとする課題】
本発明は、上記問題点を鑑みてなされたものであって、その目的とするところは、主に負極板の周縁部で発生する濃淡電池放電による、硫酸鉛の生成粗大化と固定化、これらに伴う導電パスの減少すなわちサルフェーションを低減し、寿命性能の優れた密閉形鉛蓄電池を提供しようとすることにある。
【００１０】
【課題を解決するための手段】
本発明は、上記課題を解決するために、平板状のセパレータを介して正極板と負極板とを積層してなる極群に電解液を保持させ、流動する電解液を有しない密閉形鉛蓄電池であって、前記負極板の作用面が前記正極板の作用面より小さく、かつ前記負極板の作用面の側縁または／および下縁が前記正極板の作用面の側縁または／および下縁より内側（極板の中心に向かう側）に配置されていることを特徴とするものである。
【００１１】
【作用】
正極板より負極板の作用面を小さくして負極板の作用面の側縁と下縁が正極板の作用面の中に含まれるように配置すると、負極板の高さが正極板の高さより低くなるので、負極板が正極板の高さと同じ場合に比べ、負極板の上下間に発生する電解液濃度差が小さくなる。この結果、極板下部の濃淡電池放電による硫酸鉛の生成粗大化と導電パスの減少、すなわちサルフェーションを低減できる。
【００１２】
また、極板周縁部の電解液濃度差は本構造でも発生するが、従来品に比べて負極より正極の方が濃淡電池の影響を受け易いため、負極と正極の蓄積硫酸鉛の割合は等しくなるか、もしくは正極の方が増大する傾向となる。このため、従来品で見られた、負極が完全に充電される前に酸素ガス吸収反応が優勢となり、負極が充電できないというような現象が発生しなくなる。
【００１３】
以上の結果、実際の使用条件に近い放電放置時間が長く、充電不足気味の充放電試験サイクルを続けても電池容量が低下しにくくなる。
【００１４】
【発明の実施形態】
本発明の実施形態を図面に基づいて説明する。
【００１５】
（実施形態）
図１は、本発明の一実施形態を示す断面図、図２は図１の極群を示す側断面図であり、１は正極板、２は負極板、３はセパレータ、４は電槽、５は正極ストラップ、６は負極ストラップ、７は正極端子、８は負極端子、９は安全弁である。正極板１は、平板状のペースト式極板であり、作用面１ａが長方形で、その横幅Ｗｐが６５ｍｍ、高さＨｐが１２０ｍｍである。負極板２は、正極板１と同じ形状のペースト式極板であり、作用面２ａの面積が正極板１のそれより小さく横幅Ｗｎが５５ｍｍ、高さＨｎが１１０ｍｍである。セパレータ３は、平板状の微細ガラスマットからなり、長方形であって、正極板１と負極板２より大きく、横幅Ｗｓが７１ｍｍ，高さＨｓが１２６ｍｍである。このセパレータ３を正極板１と負極板２との間に挟んで極群が構成されている。
【００１６】
セパレータ３は、極板１と２に挟まれた部分、すなわち正負両極板に面接する部分３ａと、正極板１にだけ面接する部分３ｂと、正極板１と負極板２のどちらにも面接していない部分、すなわち極板に面接しない部分３ｃとからなっている。
【００１７】
また、負極板２は、上縁２ｂがセパレータ３を介して正極板１の上縁１ｂと同じ水平線上にあり、側縁２ｃがセパレータ３を介して正極板１の側縁１ｃより内側に位置し、下縁２ｄがセパレータ３を介して正極板１の下縁１ｄより上側に位置している。
【００１８】
上記構成の極群は、電槽４内に収納され、正極板１同士および、負極板２同士がストラップ５，６により連結され、このストラップ５，６からそれぞれ正極端子７と負極端子８が立設している。
【００１９】
前記極群に比重１．３２ｄの希硫酸電解液を含ませた。この時の電解液量は電槽４内に流動する電解液が出ないぎりぎりの値としている。
【００２０】
このような公称容量１６Ａｈ／３ＨＲの密閉形鉛蓄電池Ａを作製した。
【００２１】
（比較形態）
実施形態において、正負極板の上下寸法を共通とし負極の横幅寸法だけを小さくした電池Ｂと、正負極板の横幅寸法を共通とし負極板の上下寸法だけを小さくした電池Ｃと、従来通りの正負両極板の大きさを同等とした電池Ｄと、正負両極板の大きさを同等とし電池Ｄより極板とセパレータを小さくした電池Ｅを作製した。各電池の極板寸法を表１に示す。
【００２２】
【表１】

【００２３】
なお、電池Ｅ以外はセパレ−タ寸法が共通であり、電池Ｅのセパレータの上下寸法は１１６ｍｍ、横幅寸法は６１ｍｍである。
なお、各電池の初期容量は、Ａが１５．３Ａｈ、Ｂが１５．５Ａｈ、Ｃが１５．７Ａｈ、Ｄが１６．０Ａｈ、Ｅが１２．４Ａｈであった。
【００２４】
次に、上記電池Ａ〜Ｅをサイクル試験に供した。本試験で採用したサイクル試験は２５℃室温中で以下に示す（１）〜（４）を繰り返すものである。
【００２５】
（１）１Ｃ（Ｃは公称容量の値）の電流で８Ａｈ放電（従来品Ｄの３ＨＲ容量に対しＤＯＤ５０％放電に相当）を行う。
【００２６】
（２）６時間放置する。
【００２７】
（３）０．１０Ｃの電流で２．４Ｖ／セルになるまでの打ち切り充電を行う。
【００２８】
（４）６時間放置する。
【００２９】
また、上記サイクル試験１０サイクル毎に、３ＨＲ容量試験を行いその後０．１Ｃの電流で定格容量の１１５％まで充電を行った。
【００３０】
３ＨＲ容量試験とは、電池温度２５℃で１／３Ｃの電流で終止電圧１．６５Ｖ／セルまで放電することを示す。
【００３１】
サイクル試験中１０サイクルごとの容量試験結果を図３に、また、各電池の１００サイクル容量試験終了後充電末の正負両極板の極板両サイド１ｃｍ幅部分と極板下部１ｃｍ幅部分の硫酸鉛量を表２に示す。
【００３２】
これらより、本発明の電池Ａ，Ｂ，Ｃは従来の電池Ｄ，Ｅに比べてサイクルに伴う容量劣化が小さく、また、負極板に蓄積した硫酸鉛量も少ないことが分かった。
【００３３】
【表２】

【００３４】
なお、本実施形態中のセパレ−タ３が正極板１にだけ面する部分３ｂではセパレ−タに対する加圧力が減る。このために、部分３ｂが多いものほど電池Ｄより電解液量が多くなるが、この部分に負極板２と同等厚みのリテ−ナ−、もしくは耐酸性樹脂製のスペ−サ−を入れても良い。
【００３５】
適用する耐酸性樹脂例としては、熱可塑性樹脂（ポリエチレン、ポリスチレン、ポリプロピレン、ポリエステル等）熱硬化性樹脂（フェノール、フォルムアルデヒド等）がある。
【００３６】
また、本実施形態では既化成極板に電解液を注液するタイプの電池を示したが、電槽化成で作製する電池でも同様のことがいえる。
【００３７】
【発明の効果】
以上詳述したように、本発明による密閉形鉛蓄電池は正極板の作用面より負極板の作用面を小さくして正極板の作用面に負極板の作用面が全て含まれるように配置したので、負極に対する濃淡電池の悪影響を軽減出来、優れた寿命性能を実現することができる。
【図面の簡単な説明】
【図１】本発明品の一実施形態を示す断面図である。
【図２】図１の極群を示す側断面図である。
【図３】本実施形態と比較形態の容量特性を示すグラフである。
【符号の説明】
１正極板
１ａ正極板の作用面
１ｃ側縁
１ｄ下縁
２負極板
２ａ負極板の作用面
２ｃ側縁
２ｄ下縁
３セパレータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sealed lead-acid battery, and more particularly to a retainer-type sealed lead-acid battery in which an electrolyte is mainly held by a glass mat or a separator made of a porous organic material or a mixed fiber of glass fibers and organic fibers. is there.
[0002]
[Prior art and its problems]
In recent years, it has become urgent to increase the energy density and improve the cycle life performance of sealed lead-acid batteries, which are expanding their application fields for cycle applications such as electric vehicles, hybrid vehicles, solar systems, and load leveling. It has become a challenge.
[0003]
Meanwhile, in a sealed lead-acid battery using a so-called oxygen cycle in which oxygen gas generated during charging of a battery is absorbed by a negative electrode, a method called a retainer type is currently mainstream. The retainer type uses a fine glass fiber or organic fiber inserted between the positive electrode plate and the negative electrode plate, or a mat-shaped separator made of a mixture of these, to hold the sulfuric acid electrolyte required for charging and discharging the battery and to separate the two electrodes. It is a method to perform.
[0004]
This type of battery usually comprises a stack of positive and negative plates having opposing surfaces, i.e., active surfaces of equal area, and a retainer having a larger electrode plate area for separating them. Therefore, the retainer has a portion directly in contact with the electrode plates and side edges protruding from these electrode plates.
[0005]
When such a closed lead-acid storage battery is discharged, a difference in electrolyte concentration occurs between the upper part of the electrode plate having a high current distribution and the lower part of the electrode plate having a low current distribution. Further, the utilization rate of the electrolyte held on the periphery protruding from the separator becomes lower than that of the electrolyte held in a portion in contact with the electrode plate, and a difference occurs in the concentration of the electrolyte between the two.
[0006]
When such a concentration difference occurs, a concentration cell is formed on the outside and inside with the border of the electrode plate as a boundary, and a charge / discharge reaction is performed in the same electrode plate. On the side where the concentration of the electrolytic solution in which the discharge reaction occurs is high, that is, on the lower part of the electrode plate and on the side surface of the electrode plate, crystals of lead sulfate are generated and coarsened, and the number of conductive paths is reduced, that is, sulfation occurs, and the charging efficiency is reduced.
[0007]
In addition, the discharge leaving time close to the actual use conditions is long, and if the charge / discharge test cycle is continued with a feeling of insufficient charge, the sulfate is not recovered in the state of being taken in the electrode plate instead of the electrolytic solution, and the battery capacity is reduced. There was a problem that the temperature immediately decreased.
[0008]
In addition, this phenomenon appears remarkably in a negative electrode plate having a low active material resistance, and has a relatively small effect on a positive electrode plate having a high active material resistance. Therefore, the ratio of the accumulated lead sulfate in the negative electrode tends to increase as compared with the positive electrode. . Even after charging from this state, before the negative electrode is fully charged, the positive electrode is fully charged and starts generating oxygen. In the negative electrode, the oxygen gas absorption reaction became dominant, and this reaction repeated a vicious cycle in which the negative electrode received charge was further deteriorated.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems, and has as its object to mainly generate and fix lead sulfate by coarsening and discharging of a concentration cell generated at the periphery of a negative electrode plate. Accordingly, it is an object of the present invention to provide a sealed lead-acid battery which has a reduced life-span and a reduction in the number of conductive paths, that is, sulfation.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a sealed lead-acid battery having no electrolyte flowing by holding an electrolyte in a pole group formed by laminating a positive electrode plate and a negative electrode plate via a flat separator. Wherein the working surface of the negative electrode plate is smaller than the working surface of the positive electrode plate, and the side edge or / and lower edge of the working surface of the negative electrode plate is a side edge or / and / or a lower edge of the working surface of the positive electrode plate. It is characterized by being arranged more inside (on the side toward the center of the electrode plate).
[0011]
[Action]
When the working surface of the negative electrode plate is made smaller than that of the positive electrode plate and the side and lower edges of the working surface of the negative electrode plate are arranged so as to be included in the working surface of the positive electrode plate, the height of the negative electrode plate is higher than the height of the positive electrode plate. Since the height is lower, the difference in electrolyte concentration between the upper and lower sides of the negative electrode plate is smaller than when the height of the negative electrode plate is the same as the height of the positive electrode plate. As a result, coarsening of the production of lead sulfate due to the discharge of the concentration cell at the lower part of the electrode plate and a decrease in the number of conductive paths, that is, sulfation can be reduced.
[0012]
In addition, although the difference in electrolyte concentration at the periphery of the electrode plate also occurs in this structure, the ratio of the accumulated lead sulfate between the negative electrode and the positive electrode is equal because the positive electrode is more susceptible to the concentration cell than the negative electrode compared to the conventional product. Or the positive electrode tends to increase. For this reason, the oxygen gas absorption reaction becomes dominant before the negative electrode is completely charged, and the phenomenon that the negative electrode cannot be charged does not occur.
[0013]
As a result of the above, the discharge leaving time close to the actual use condition is long, and the battery capacity is unlikely to be reduced even if the charge / discharge test cycle in which the charge tends to be insufficient is continued.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0015]
(Embodiment)
1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a side cross-sectional view showing the electrode group of FIG. 1, 1 is a positive electrode plate, 2 is a negative electrode plate, 3 is a separator, 4 is a battery case, Reference numeral 5 denotes a positive electrode strap, 6 denotes a negative electrode strap, 7 denotes a positive electrode terminal, 8 denotes a negative electrode terminal, and 9 denotes a safety valve. The positive electrode plate 1 is a flat paste-type electrode plate, and has a rectangular working surface 1a, a width Wp of 65 mm, and a height Hp of 120 mm. The negative electrode plate 2 is a paste-type electrode plate having the same shape as the positive electrode plate 1, and has an area of the working surface 2 a smaller than that of the positive electrode plate 1, a width Wn of 55 mm, and a height Hn of 110 mm. The separator 3 is made of a flat plate-shaped fine glass mat, has a rectangular shape, is larger than the positive electrode plate 1 and the negative electrode plate 2, and has a width Ws of 71 mm and a height Hs of 126 mm. A pole group is formed by sandwiching the separator 3 between the positive electrode plate 1 and the negative electrode plate 2.
[0016]
The separator 3 has a portion sandwiched between the

electrode plates

1 and 2, that is, a portion 3 a in contact with the positive and negative bipolar plates, a portion 3 b in contact with only the positive electrode plate 1, and a portion in contact with both the positive electrode plate 1 and the negative electrode plate 2. And a portion 3c not in contact with the electrode plate.
[0017]
In the negative electrode plate 2, the upper edge 2 b is located on the same horizontal line as the upper edge 1 b of the positive electrode plate 1 via the separator 3, and the side edge 2 c is located inside the side edge 1 c of the positive electrode plate 1 via the separator 3. The lower edge 2 d is located above the lower edge 1 d of the positive electrode plate 1 via the separator 3.
[0018]
The electrode group having the above configuration is housed in a battery case 4, and the positive electrode plates 1 and the negative electrode plates 2 are connected by

straps

5 and 6, from which the positive terminal 7 and the negative terminal 8 stand. Has been established.
[0019]
The electrode group contained a dilute sulfuric acid electrolyte having a specific gravity of 1.32 d. The amount of the electrolyte at this time is a value just before the electrolyte flowing in the battery case 4 comes out.
[0020]
A sealed lead-acid battery A having such a nominal capacity of 16 Ah / 3HR was manufactured.
[0021]
(Comparative form)
In the embodiment, a battery B in which only the horizontal dimension of the negative electrode is reduced by making the vertical dimension of the positive and negative electrode plates common and a battery C in which only the vertical dimension of the negative electrode plate is reduced by sharing the horizontal dimension of the positive and negative electrode plates, A battery D having the same size of the positive and negative bipolar plates and a battery E having the same size of the positive and negative bipolar plates and a smaller electrode plate and separator than the battery D were produced. Table 1 shows the electrode plate dimensions of each battery.
[0022]
[Table 1]

[0023]
Note that the separator dimensions are common except for the battery E, and the vertical dimension of the separator of the battery E is 116 mm and the horizontal dimension is 61 mm.
The initial capacity of each battery was 15.3 Ah for A, 15.5 Ah for B, 15.7 Ah for C, 16.0 Ah for D, and 12.4 Ah for E.
[0024]
Next, the batteries A to E were subjected to a cycle test. The cycle test adopted in this test is a test in which the following (1) to (4) are repeated at a room temperature of 25 ° C.
[0025]
(1) An 8 Ah discharge (corresponding to a DOD 50% discharge with respect to the 3 HR capacity of the conventional product D) is performed at a current of 1 C (C is a value of a nominal capacity).
[0026]
(2) Leave for 6 hours.
[0027]
(3) Discontinuous charging is performed at a current of 0.10 C until the voltage reaches 2.4 V / cell.
[0028]
(4) Leave for 6 hours.
[0029]
In addition, a 3HR capacity test was performed every 10 cycles of the cycle test, and then the battery was charged with a current of 0.1 C to 115% of the rated capacity.
[0030]
The 3HR capacity test indicates that the battery is discharged to a final voltage of 1.65 V / cell at a battery temperature of 25 ° C. and a current of 1 / 3C.
[0031]
Figure 3 shows the results of the capacity test for every 10 cycles during the cycle test, and the lead sulfate of 1cm wide on both sides of the positive and negative bipolar plates and 1cm wide at the bottom of the positive and negative bipolar plates at the end of charging after completion of the 100 cycle capacity test of each battery. The amounts are shown in Table 2.
[0032]
From these results, it was found that the batteries A, B, and C of the present invention had less capacity deterioration due to the cycle and had a smaller amount of lead sulfate accumulated on the negative electrode plate than the conventional batteries D and E.
[0033]
[Table 2]

[0034]
In this embodiment, the pressure applied to the separator is reduced in the portion 3b where the separator 3 faces only the positive electrode plate 1. For this reason, the larger the portion 3b, the larger the amount of the electrolytic solution than the battery D. However, even if a retainer having the same thickness as the negative electrode plate 2 or a spacer made of an acid-resistant resin is put in this portion. good.
[0035]
Examples of applicable acid-resistant resins include thermoplastic resins (polyethylene, polystyrene, polypropylene, polyester, etc.) and thermosetting resins (phenol, formaldehyde, etc.).
[0036]
In the present embodiment, a battery of a type in which an electrolytic solution is injected into an already-formed electrode plate is described, but the same can be said for a battery manufactured by battery case formation.
[0037]
【The invention's effect】
As described in detail above, the sealed lead-acid battery according to the present invention is arranged such that the working surface of the negative electrode plate is smaller than the working surface of the positive electrode plate and the working surface of the positive electrode plate includes all the working surfaces of the negative electrode plate. In addition, the adverse effect of the concentration cell on the negative electrode can be reduced, and excellent life performance can be realized.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of the product of the present invention.
FIG. 2 is a side sectional view showing the pole group of FIG. 1;
FIG. 3 is a graph showing capacitance characteristics of the present embodiment and a comparative embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Positive electrode plate 1a Positive electrode working surface

1c Side edge

1d Lower edge 2 Negative electrode plate 2a Negative electrode working surface

2c Side edge

2d Lower edge 3 Separator

Claims

In a sealed lead-acid battery having no electrolyte flowing, an electrode group formed by laminating a positive electrode plate and a negative electrode plate with a flat separator interposed therebetween has a functioning surface of the negative electrode plate. of less than the working surface, and the side edges and / or lower edge of the working surface of the negative electrode plate is disposed inside the side edges and / or lower edge of the working surface of the positive electrode plate Rutotomoni, the upper edge of the negative electrode plate A sealed lead-acid battery, which is located on the same horizontal line as the upper edge of the positive electrode plate .