JP4221822B2

JP4221822B2 - Sealed lead acid battery

Info

Publication number: JP4221822B2
Application number: JP15906899A
Authority: JP
Inventors: 喜一小池; 雅之井出; 晴美室地
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1999-06-07
Filing date: 1999-06-07
Publication date: 2009-02-12
Anticipated expiration: 2019-06-07
Also published as: JP2000348758A

Description

【０００１】
【発明の属する技術分野】
本発明は、主に通信機器や無停電電源装置等の非常用バックアップ電源に用いられる密閉形鉛蓄電池に関するものである。
【０００２】
【従来の技術】
バックアップ用の密閉形鉛蓄電池は、放電容量が所定の値まで低下し寿命に達した後も交換されずに連続使用される場合がある。このとき、バックアップ電源に用いられる密閉形鉛蓄電池は常時トリクル充電により充電され、過充電状態となり、正極格子体が酸化腐食を受けて体積膨張してしまう。このような正極格子体の膨張によって正極板が上下及び左右に伸び、電槽を圧迫することによって電槽が変形したり亀裂が発生するものである。また、特に正極板の上方向の伸びは負極棚部と正極板との短絡を引き起こす。この短絡により電池電圧は低下するが、一般にトリクル充電においては定電圧充電が行われているために電池電圧の低下は充電電流の増加を招いて、さらに過充電を進行させることがある。
【０００３】
【発明が解決しようとする課題】
このような場合には、正極板が膨張し電槽を圧迫することにより電槽が変形したり、微少な亀裂が生じて漏液を引き起こすことがある。また、膨張した正極板が負極棚部等の負極部材と短絡する場合もある。
【０００４】
このような正極板の膨張による電槽変形・亀裂や、正極板と負極棚部との短絡を抑制するには正極板寸法を小さくして正極板と電槽内壁、あるいは正極板と負極板棚部との間隔を大きくすることが行われるが、このような方法によれば正極板の寸法を小さくするため電池容量の低下が避けられないものであった。
【０００５】
本発明は、上記のような課題を解決するもので、従来の密閉形鉛蓄電池と比較して電池容量を低下させることなく、正極板の膨張に起因する電槽の変形や亀裂また、正極板と負極棚部との短絡を抑制することにより信頼性を高めた密閉形鉛蓄電池を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
前記した目的を達成するために、本発明の請求項１に記載の発明は正極板と負極板とをセパレータを介して積層した極板群と、極板群を収納する電槽と、電槽の開口部を覆う蓋とを備え、前記極板群は蓄電池外部端子に接続される鉛合金の極柱もしくは隣接する極板群と接続する鉛合金の接続体を備え、前記極柱もしくは前記接続体は鉛合金の棚部を介して正極板の耳部もしくは負極板の耳部に接合された密閉形鉛蓄電池の、正極側の前記棚部において少なくとも棚部と前記接続体もしくは前記極柱との接合部の鉛合金結晶は正極板の耳部の長手方向に沿って形成したことを特徴とするものである。
【０００７】
請求項２に記載の発明は正極板の耳部はその長手方向が垂直方向となるよう正極板の上辺から突出して設けたことを特徴とするものであり、接合部の鉛合金結晶は垂直方向とするものである。
【０００８】
請求項３に記載の発明は請求項１もしくは請求項２の構成による密閉形鉛蓄電池において正極側の棚部と接続体もしくは極柱との接合部は１．０ｗｔ％以上の錫を含有する鉛合金を用いたことを特徴とするものである。
【０００９】
請求項４に記載の発明は前記正極板に用いる正極格子体として錫を１．０ｗｔ％以上含有する鉛−錫−カルシウム合金を用いたことを特徴とするものである。
【００１０】
請求項５に記載の発明は請求項４に記載の構成による密閉形鉛蓄電池において正極板に用いる正極格子体として複数のスリットを形成した鉛合金圧延シートを展開伸張して形成し、実質的に耳部長手方向の枠骨のないエキスパンド格子体を用いたことを特徴とするものである。
【００１１】
【発明の実施の形態】
本発明の一実施形態による密閉形鉛蓄電池を図面を用いて説明する。図１は本発明による密閉形鉛蓄電池の極板群を示す図である。正極板１はセパレータ３を介して負極板２と積層される。正極板１および負極板２はそれぞれ鉛合金からなる正極格子体（図示せず）と負極格子体（図示せず）に鉛粉（鉛及び鉛酸化物の混合粉体）にリグニン、硫酸バリウム、合成樹脂繊維等の所定の添加物を添加し、水および希硫酸で練合した活物質ペーストを充填して熟成乾燥したものである。
【００１２】
正極格子体および負極格子体にはそれぞれ正極耳部４、負極耳部５が設けられている。正極耳部４および負極耳部５は同極性の耳部同士が集合溶接されて正極棚部６、負極棚部７が形成されている。これらの棚部には極板群から蓄電池外部へ端子を取り出す正極柱８、負極柱９が接続されるか、隣接する極板群と接続する接続体（図示せず）がそれぞれの極性の棚部に接続されている。
【００１３】
本実施の形態においては、正極棚部６において正極棚部６と正極柱８もしくは接続体（図示せず）との接合部６ａの鉛合金結晶が、図２に示すように正極耳部４の長手方向に沿って配向した構成とするものである。このような構成によれば正極板が膨張して耳部がその長手方向への応力により正極棚部を圧迫することにより、接合部６ａには応力方向（耳部の長手方向）に沿った結晶粒界９が形成されているので、この結晶粒界９で滑りが発生し、接合部６ａが破断されて極板群の接続が遮断される。またこのような結晶粒界９を耳部の長手方向とするには結晶１０を耳部の長手方向に配向することが必要である。
【００１４】
このように、本実施の形態によれば極板群の接続を遮断することにより充電電流が遮断されるので正極板１が負極棚部７と短絡する以前に正極板１の膨張を停止することができる。また同様に正極板１による電槽内壁（図示せず）の圧迫を防止して電槽の変形や亀裂の発生を抑制することができる。
【００１５】
ここで接合部６ａの結晶の方向を耳部の長手方向（図１の構成においては垂直方向）に沿って形成させるためには接合部６ａを溶接により形成する際の冷却方向と冷却速度をコントロールすることが必要であり、例えば接合部６ａの垂直方向に結晶成長させるために接合部の上面もしくは下面のいずれかもしくは両方を側面より冷却する必要がある。例えば接合部を形成する際に用いる鋳型の冷却水用の配管を接合部の上面もしくは下面に隣接した位置に配置する、もしくは接合部の側面に対応する鋳型面を粗面処理等により熱伝導性を低下させて、相対的に上下方向での冷却がより速い速度で進行させることも可能である。
【００１６】
また、接合部６ａの結晶をある方向に優先的に配向させるためには接合部の鉛合金中に錫を１．０ｗｔ％以上添加することが好ましい。また正極格子体に用いる鉛合金としては錫を少なくとも１．０ｗｔ％以上含有する鉛−錫−カルシウム合金が好ましい。このような鉛合金は強度も大きく膨張速度も低い。よって、接合部６ａが破断する程度に応力が発生した場合における正極の膨張量をより小さくできるので、正極板寸法をより大きくしても必要な正極板−電槽内壁間距離あるいは正極板−負極棚部間距離を確保することができ、電池設計上、有利である。
【００１７】
また正極格子体としては耳部の長手方向への枠骨がないエキスパンド格子体を用いることが有効である。このようなエキスパンド格子体は耳部長手方向に優先的に膨張するからである。よって、正極板−電槽内壁間距離をより小さくとることが可能となる。
【００１８】
【実施例】
以下、本発明の実施例を図面を参照しながら説明する。図１は本実施例による密閉形鉛蓄電池の極板群を示す図であり、０．０８ｗｔ％カルシウムと種々の含有量の錫を含む鉛−錫−カルシウム合金を用いて幅４０ｍｍ×高さ７０ｍｍ×厚み３．５ｍｍの正極格子体を鋳造法とエキスパンド法によって作成しいずれも実施の形態で記載した活物質ペーストを充填し、熟成乾燥して正極板とした。負極板２については幅４０ｍｍ×高さ７０ｍｍ×厚み２．６ｍｍのエキスパンド格子に活物質ペーストを充填し、熟成乾燥したものを用いた。エキスパンド格子体は耳部の長手方向、本実施例においては正極板の左右両側部に縦枠骨のない形状のものである。
【００１９】
これらの正極板１の３枚と負極板２の４枚とをガラスマットからなるセパレータ３を重ね合せた後、正極板１の正極耳部４を櫛状の鋳型に挿入し、この耳部の上に足し鉛を配置するとともに耳部に隣接して正極柱部品を配置した後、この足し鉛を用いて酸素−水素ガスバーナーで溶接し正極棚部６とした。この正極棚部６には外部端子と接続される正極柱８もしくは隣接する極板群との接続端子となる接続体（図示せず）が一体に設けられている。負極棚部７も同様にして作製し、極板群を作製した。この極板群を６個電槽に入れ、電解液である希硫酸を注入後充電して１２Ｖ６．５Ａｈの密閉形鉛蓄電池を作製した。なお、正極板１の幅と伝送内壁との空間は、一般的に用いられている正極板幅の６％とし、また正極板１の上辺と負極棚部までの寸法も正極板高さの６％に設定した。
【００２０】
この１２Ｖ６．５Ａｈの密閉形鉛蓄電池を表１に示す構成で作製した。正極格子合金中の錫濃度を従来の０．６ｗｔ％から１．０、および１．６ｗｔ％に変化させた。また正極格子体としては前記した鋳造法による正極格子もしくはエキスパンド法による正極格子を用いた。正極棚部６の溶接に用いる足し鉛としては錫濃度を０．５、０．８、１．０および２．５ｗｔ％を含む鉛−錫合金を用いた。
【００２１】
【表１】

【００２２】
なお、正極棚部６における正極柱８との接合部６ａの鉛合金結晶が正極耳部の長手方向、すなわち垂直方向に成長するよう、棚部を作製する時の鋳型の冷却部、すなわち冷却水配管を棚部の下面に配置し、冷却水を流しながら棚部を溶接した。このようにして作製した正極棚部の特に極柱との接合部についてその結晶状態を観察した。
【００２３】
密閉形鉛蓄電池のトリクル充電寿命の評価としては６０℃の雰囲気中で１３．８Ｖ定電圧でトリクル充電を行い、２週間毎に０．２５ＣＡ放電で容量を確認して初期の１／２に低下した時点で寿命としたが、試験自体は電槽変形や正極板と負極棚との短絡が発生するまで継続した。なお、電槽の変形等の以上は目視で観察し、充電電流を記録計で監視することにより、急激に充電電流が増加した場合は電池内部短絡、充電電流が０となった場合には断線と判断し、試験終了して電池分解評価を行った。電池分解評価では電池の内部短絡や正極棚部と正極柱との断線状態や正極板と電槽内壁との余裕率を測定した。余裕率は電槽内壁−正極板間の寸法の試験前の正極板幅である４０ｍｍに対する百分率とした。これらの結晶状態の観察結果とトリクル充電寿命評価結果と電池分解結果を表２に示す。
【００２４】
【表２】

【００２５】
表１及び表２に示した結果から、正極棚部の極柱との接合部での結晶状態を耳部の長手方向とすることにより、電槽の変形・亀裂や正極と負極との短絡をする以前に正極棚部６における正極柱との接合部で結晶の方向に沿った結晶粒界でのすべりが発生して、正極棚部と正極柱との接続が遮断されて正極板の膨張が停止することがわかった。
【００２６】
また、正極棚部の合金組成としては１．０ｗｔ％以上の錫を含有する鉛−錫合金であることが好ましい。この組成によれば耳部の長手方向、すなわち、本実施例では垂直方向に結晶を容易に成長させることができ、より電槽の変形・亀裂や短絡の発生する以前に確実に正極棚部と正極柱部との接続を遮断することができる。
【００２７】
正極の格子合金組成としては１．０ｗｔ％以上の錫を含有する鉛−カルシウム−錫合金が好ましい。１．０ｗｔ％未満の錫含有量の場合、正極格子の伸びが発生しても正極格子自体の強度が弱い。このような場合、格子の伸びにより発生する応力は格子自体の変形により緩和され、応力が正極棚部に有効に伝達されず、正極棚部と正極柱との接続が遮断されない。１．０ｗｔ％以上の錫を含有する鉛−カルシウム−錫合金を正極格子体に用いた場合には格子の強度が十分に確保されているため、格子の膨張による応力が格子自体の変形によって緩和されることなく、正極棚部と正極柱に垂直方向の応力が伝達され、この部分での遮断が行われ、充電を停止してこれ以上の蓄電池の過充電を防止することができる。よって、１．０ｗｔ％以上の錫を含有する鉛−カルシウム−錫合金を正極格子体として用いた場合により確実に正極棚部と正極柱部との接続を遮断できる。
【００２８】
また、このことにより、正極板と電槽内壁間の寸法や正極板と負極棚部との寸法をより小さく、すなわち正極板の寸法をより大きくできることから電池容量を確保する上で有利である。正極格子体の製法としては鋳造格子体よりもエキスパンド格子体の方が正極板の膨張方向を耳部の長手方向に優先することができるために、より好ましい。
【００２９】
エキスパンド格子体は側部に格子枠骨が存在しないために格子の伸びは耳部の長手方向にほぼ限定されることから、正極棚部と正極柱との間の接続が遮断された時点では電槽内壁と正極板の寸法が依然として広く確保されていることから電槽変形・亀裂に対してより安全な構成を得ることができる。またこのことは前記したように電槽内壁と正極板との間の寸法を小さくすることができ、蓄電池の高容量化や小型化に結び付けることが可能である。
【００３０】
【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寿命を過ぎて使用されることにより過充電となっても正極棚部と正極柱部での接続を遮断してさらに過充電された場合に発生する正極板の膨張とこれにより電槽内壁の変形・亀裂あるいは正極板と負極板との短絡を防止することができるものである。
【図面の簡単な説明】
【図１】本発明の一実施形態による密閉形鉛蓄電池の極板群を示す図
【図２】本発明の一実施形態による密閉形鉛蓄電池の正極棚部での正極柱との接合部の鉛合金結晶状態を示す図
【符号の説明】
１正極板
２負極板
３セパレータ
４正極耳部
５負極耳部
６正極棚部
６ａ接続部
７負極棚部
８正極柱
９負極柱
１０結晶粒界
１１結晶[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed lead-acid battery used mainly for an emergency backup power source such as a communication device or an uninterruptible power supply.
[0002]
[Prior art]
The sealed lead-acid battery for backup may be used continuously without being replaced even after the discharge capacity is reduced to a predetermined value and the life is reached. At this time, the sealed lead-acid battery used for the backup power source is always charged by trickle charge and is overcharged, and the positive electrode lattice body undergoes oxidative corrosion and expands in volume. Due to such expansion of the positive electrode lattice body, the positive electrode plate extends vertically and horizontally, and the battery case is deformed or cracked by pressing the battery case. In particular, the upward elongation of the positive electrode plate causes a short circuit between the negative electrode shelf and the positive electrode plate. Although the battery voltage decreases due to this short circuit, since the constant voltage charging is generally performed in trickle charging, the decrease in the battery voltage causes an increase in the charging current and may further cause the overcharging to proceed.
[0003]
[Problems to be solved by the invention]
In such a case, the positive electrode plate expands and presses the battery case, so that the battery case may be deformed or a minute crack may be generated to cause liquid leakage. Further, the expanded positive electrode plate may be short-circuited with a negative electrode member such as a negative electrode shelf.
[0004]
In order to suppress battery cell deformation / cracking due to expansion of the positive electrode plate and short circuit between the positive electrode plate and the negative electrode shelf, the positive electrode plate is made smaller in size and the positive electrode plate and the inner wall of the battery case, or the positive electrode plate and the negative electrode plate shelf. However, according to such a method, since the size of the positive electrode plate is reduced, a reduction in battery capacity is inevitable.
[0005]
The present invention solves the above-described problems, and does not reduce the battery capacity as compared with a conventional sealed lead-acid battery. It is an object of the present invention to provide a sealed lead-acid battery with improved reliability by suppressing a short circuit between the battery and the negative electrode shelf.
[0006]
[Means for Solving the Problems]
In order to achieve the above-described object, the invention according to claim 1 of the present invention includes a group of electrode plates in which a positive electrode plate and a negative electrode plate are stacked via a separator, a battery case for housing the electrode plate group, and a battery case. And the electrode plate group includes a lead alloy pole column connected to a storage battery external terminal or a lead alloy connection body connected to an adjacent electrode plate group, and the pole column or the connection The body of the sealed lead-acid battery joined to the ear of the positive electrode plate or the ear of the negative electrode plate via a lead alloy shelf, at least the shelf and the connection body or the pole column in the shelf on the positive electrode side The lead alloy crystal of the joint portion is formed along the longitudinal direction of the ear portion of the positive electrode plate.
[0007]
The invention according to claim 2 is characterized in that the ear portion of the positive electrode plate is provided so as to protrude from the upper side of the positive electrode plate so that the longitudinal direction thereof is vertical, and the lead alloy crystal of the joint portion is in the vertical direction. It is what.
[0008]
According to a third aspect of the present invention, in the sealed lead-acid battery according to the first or second aspect of the present invention, the joint between the positive electrode side shelf and the connecting body or the pole column contains 1.0 wt% or more of lead. It is characterized by using an alloy.
[0009]
The invention described in claim 4 is characterized in that a lead-tin-calcium alloy containing 1.0 wt% or more of tin is used as a positive electrode lattice used for the positive electrode plate.
[0010]
The invention according to claim 5 is formed by unfolding and extending a lead alloy rolled sheet formed with a plurality of slits as a positive electrode grid used in the positive electrode plate in the sealed lead-acid battery having the configuration according to claim 4, The present invention is characterized in that an expanded lattice body having no frame bone in the longitudinal direction of the ear portion is used.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A sealed lead-acid battery according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing an electrode plate group of a sealed lead-acid battery according to the present invention. The positive electrode plate 1 is laminated with the negative electrode plate 2 via the separator 3. The positive electrode plate 1 and the negative electrode plate 2 are each composed of a positive electrode grid (not shown) and a negative electrode grid (not shown) made of a lead alloy, lead powder (a mixed powder of lead and lead oxide), lignin, barium sulfate, A predetermined additive such as a synthetic resin fiber is added, and an active material paste kneaded with water and dilute sulfuric acid is filled and aged and dried.
[0012]
The positive electrode lattice body and the negative electrode lattice body are provided with a positive electrode ear portion 4 and a negative electrode ear portion 5, respectively. The positive electrode ear 4 and the negative electrode ear 5 are collectively welded to each other with the same polarity ears to form a positive electrode shelf 6 and a negative electrode shelf 7. These shelves are connected to positive poles 8 and negative poles 9 for taking out the terminals from the electrode plate group to the outside of the storage battery, or connected bodies (not shown) connected to the adjacent electrode plate groups have respective polar shelves. Connected to the department.
[0013]
In the present embodiment, in the positive electrode shelf 6, the lead alloy crystal of the joint 6a between the positive electrode shelf 6 and the positive electrode column 8 or the connection body (not shown) is formed in the positive electrode ear 4 as shown in FIG. The configuration is oriented along the longitudinal direction. According to such a configuration, the positive electrode plate expands and the ear portion presses the positive electrode shelf portion with the stress in the longitudinal direction, so that the crystal along the stress direction (longitudinal direction of the ear portion) is applied to the joint portion 6a. Since the grain boundary 9 is formed, slip occurs at the crystal grain boundary 9, the joint 6a is broken, and the electrode plate group is disconnected. In order to make such a crystal grain boundary 9 in the longitudinal direction of the ear portion, it is necessary to orient the crystal 10 in the longitudinal direction of the ear portion.
[0014]
As described above, according to the present embodiment, since the charging current is cut off by cutting off the connection of the electrode plate group, the expansion of the positive electrode plate 1 is stopped before the positive electrode plate 1 is short-circuited with the negative electrode shelf 7. Can do. Similarly, the positive electrode plate 1 can be prevented from pressing the inner wall (not shown) of the battery case, and the deformation and cracking of the battery case can be suppressed.
[0015]
Here, in order to form the crystal direction of the joint portion 6a along the longitudinal direction of the ear portion (vertical direction in the configuration of FIG. 1), the cooling direction and the cooling speed when the joint portion 6a is formed by welding are controlled. For example, in order to grow a crystal in the vertical direction of the joint portion 6a, it is necessary to cool either or both of the upper surface and the lower surface of the joint portion from the side surface. For example, the mold cooling water pipe used to form the joint is placed at a position adjacent to the upper or lower surface of the joint, or the mold surface corresponding to the side of the joint is thermally conductive by roughening or the like. The cooling in the vertical direction can be made to proceed at a higher speed.
[0016]
In order to preferentially orient the crystals of the joint 6a in a certain direction, it is preferable to add 1.0 wt% or more of tin into the lead alloy of the joint. The lead alloy used for the positive electrode grid is preferably a lead-tin-calcium alloy containing at least 1.0 wt% of tin. Such a lead alloy has high strength and low expansion rate. Therefore, since the amount of expansion of the positive electrode when stress is generated to such an extent that the joint 6a breaks can be reduced, the required distance between the positive electrode plate-battery inner wall or the positive electrode plate-negative electrode even if the positive electrode plate size is increased. The distance between shelves can be secured, which is advantageous in terms of battery design.
[0017]
In addition, it is effective to use an expanded lattice having no frame bone in the longitudinal direction of the ear as the positive electrode lattice. This is because such an expanded lattice body preferentially expands in the longitudinal direction of the ear. Therefore, the distance between the positive electrode plate and the inner wall of the battery case can be made smaller.
[0018]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a group of electrode plates of a sealed lead-acid battery according to the present embodiment, using a lead-tin-calcium alloy containing 0.08 wt% calcium and various contents of tin, 40 mm wide × 70 mm high. X A positive electrode grid having a thickness of 3.5 mm was prepared by a casting method and an expanding method, both of which were filled with the active material paste described in the embodiment, and aged and dried to obtain a positive electrode plate. For the negative electrode plate 2, an expanded lattice having a width of 40 mm, a height of 70 mm, and a thickness of 2.6 mm was filled with an active material paste and aged and dried. The expanded lattice body has a shape without a vertical frame on the longitudinal direction of the ear portion, in this embodiment, on the left and right sides of the positive electrode plate.
[0019]
After these three positive electrode plates 1 and four negative electrode plates 2 are laminated with a separator 3 made of glass mat, the positive electrode ears 4 of the positive electrode plate 1 are inserted into a comb-shaped mold, The lead was placed on top and the positive pole part was placed adjacent to the ear, and then welded with an oxygen-hydrogen gas burner using this lead to form the positive shelf 6. The positive electrode shelf 6 is integrally provided with a connection body (not shown) that serves as a connection terminal to the positive pole 8 connected to an external terminal or an adjacent electrode plate group. The negative electrode shelf 7 was produced in the same manner to produce an electrode plate group. Six electrode plates were put in a battery case, charged with dilute sulfuric acid as an electrolytic solution, and charged to prepare a sealed lead-acid battery of 12 V 6.5 Ah. Note that the space between the width of the positive electrode plate 1 and the transmission inner wall is 6% of the commonly used positive electrode plate width, and the dimension between the upper side of the positive electrode plate 1 and the negative electrode shelf is 6% of the positive electrode plate height. %.
[0020]
This 12V6.5Ah sealed lead-acid battery was fabricated with the configuration shown in Table 1. The tin concentration in the positive electrode lattice alloy was changed from the conventional 0.6 wt% to 1.0 and 1.6 wt%. Further, as the positive electrode lattice body, the positive electrode lattice by the casting method or the positive electrode lattice by the expanding method was used. As the additional lead used for welding the positive electrode shelf 6, a lead-tin alloy containing tin concentrations of 0.5, 0.8, 1.0, and 2.5 wt% was used.
[0021]
[Table 1]

[0022]
In addition, the cooling part of the mold when producing the shelf part, that is, the cooling water so that the lead alloy crystal of the joint part 6a with the positive electrode column 8 in the positive electrode shelf part 6 grows in the longitudinal direction of the positive electrode ear part, that is, the vertical direction. Piping was arrange | positioned on the lower surface of the shelf part, and the shelf part was welded, flowing cooling water. The crystal state of the positive electrode shelf thus produced, particularly the junction with the pole column, was observed.
[0023]
For the evaluation of trickle charge life of sealed lead-acid batteries, trickle charge is performed at a constant voltage of 13.8V in an atmosphere of 60 ° C, and the capacity is confirmed by 0.25 CA discharge every two weeks. However, the test itself continued until the battery case was deformed or a short circuit between the positive electrode plate and the negative electrode shelf occurred. In addition, the deformation of the battery case etc. is observed visually, and the charging current is monitored with a recorder. If the charging current suddenly increases, the battery is short-circuited. If the charging current becomes 0, the battery is disconnected. The test was terminated and battery disassembly evaluation was performed. In the battery disassembly evaluation, the internal short circuit of the battery, the disconnection state between the positive electrode shelf and the positive electrode column, and the margin ratio between the positive electrode plate and the inner wall of the battery case were measured. The margin was taken as a percentage of 40 mm, which is the width of the positive electrode plate before the test, between the inner wall of the battery case and the positive electrode plate. Table 2 shows observation results of these crystal states, trickle charge life evaluation results, and battery decomposition results.
[0024]
[Table 2]

[0025]
From the results shown in Tables 1 and 2, by making the crystal state at the junction with the pole column of the positive electrode shelf the longitudinal direction of the ear part, deformation / cracking of the battery case and short circuit between the positive electrode and the negative electrode are prevented. Before the positive electrode shelf 6 slips at the grain boundary along the crystal direction at the junction with the positive electrode column in the positive electrode shelf 6, the connection between the positive electrode shelf and the positive electrode column is cut off, and the positive electrode plate expands. I found it to stop.
[0026]
The alloy composition of the positive electrode shelf is preferably a lead-tin alloy containing 1.0 wt% or more of tin. According to this composition, the crystal can be easily grown in the longitudinal direction of the ear portion, that is, in the vertical direction in the present embodiment, and the positive electrode shelf portion is surely secured before the battery case is deformed / cracked or short-circuited. The connection with the positive column can be cut off.
[0027]
As the lattice alloy composition of the positive electrode, a lead-calcium-tin alloy containing 1.0 wt% or more of tin is preferable. When the tin content is less than 1.0 wt%, the strength of the positive electrode lattice itself is weak even if the positive electrode lattice is elongated. In such a case, the stress generated by the elongation of the lattice is relieved by deformation of the lattice itself, the stress is not effectively transmitted to the positive electrode shelf, and the connection between the positive electrode shelf and the positive electrode column is not interrupted. When a lead-calcium-tin alloy containing 1.0 wt% or more of tin is used for the positive electrode lattice, the strength of the lattice is sufficiently secured, so the stress due to expansion of the lattice is relieved by deformation of the lattice itself Without being done, the stress in the vertical direction is transmitted to the positive electrode shelf and the positive electrode column, and this portion is cut off, and charging can be stopped to prevent further overcharge of the storage battery. Therefore, when the lead-calcium-tin alloy containing 1.0 wt% or more of tin is used as the positive electrode lattice body, the connection between the positive electrode shelf and the positive electrode column can be more reliably cut off.
[0028]
In addition, this is advantageous in securing battery capacity because the size between the positive electrode plate and the inner wall of the battery case and the size between the positive electrode plate and the negative electrode shelf can be made smaller, that is, the size of the positive electrode plate can be made larger. As a manufacturing method of the positive electrode lattice body, the expanded lattice body is more preferable than the cast lattice body because the expansion direction of the positive electrode plate can be given priority over the longitudinal direction of the ear portion.
[0029]
In the expanded grid, there is no grid frame bone on the side, so the extension of the grid is almost limited in the longitudinal direction of the ear, so when the connection between the positive pole shelf and the positive pole is cut off, Since the dimensions of the inner wall of the tank and the positive electrode plate are still widely secured, it is possible to obtain a safer configuration against battery cell deformation and cracking. In addition, as described above, the size between the inner wall of the battery case and the positive electrode plate can be reduced, which can lead to an increase in capacity and size of the storage battery.
[0030]
【The invention's effect】
As described above in detail, the sealed lead-acid battery according to the present invention is overcharged by disconnecting the connection between the positive electrode shelf and the positive electrode column even if it is overcharged by being used beyond its lifetime. This can prevent the expansion of the positive electrode plate and the deformation / cracking of the inner wall of the battery case or the short circuit between the positive electrode plate and the negative electrode plate.
[Brief description of the drawings]
FIG. 1 is a diagram showing a group of electrode plates of a sealed lead-acid battery according to an embodiment of the present invention. FIG. 2 is a diagram of a joint with a positive pole in a positive electrode shelf of the sealed lead-acid battery according to an embodiment of the present invention. Diagram showing lead alloy crystal state 【Explanation of symbols】
DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Negative electrode plate 3 Separator 4 Positive electrode ear | edge part 5 Negative electrode ear | edge part 6 Positive electrode shelf part 6a Connection part 7 Negative electrode shelf part 8 Positive electrode pillar 9 Negative electrode pillar 10 Grain boundary 11 Crystal

Claims

An electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator, a battery case that houses the electrode plate group, and a lid that covers the opening of the battery case, and the electrode plate group is connected to a battery external terminal A lead alloy pole column or a lead alloy connection body connected to an adjacent electrode plate group, and the pole column or the connection body is a lead alloy ear or a negative electrode ear via a lead alloy shelf. In the sealed lead-acid battery joined to the part, the lead alloy crystal at least in the joined part with the pole column or the connecting body in the shelf part on the positive electrode side is formed along the longitudinal direction of the ear part of the positive electrode plate, Sealed lead-acid battery.

The sealed lead-acid battery according to claim 1, wherein the ear portion of the positive electrode plate is provided so as to protrude from the upper side of the positive electrode plate so that the longitudinal direction thereof is a vertical direction.

3. The lead alloy containing 1.0 wt% or more of tin is used for a joint between the shelf on the positive electrode side and the connection body or the pole column, according to claim 1. Sealed lead acid battery.

The sealed lead-acid battery according to claim 3, wherein a lead-tin-calcium alloy containing 1.0 wt% or more of tin is used as a positive electrode grid used for the positive electrode plate.

5. A lead alloy rolled sheet having a plurality of slits formed as the positive electrode grid is developed and expanded to use an expanded grid substantially free of a frame in the longitudinal direction of the ear portion. The sealed lead-acid battery described in 1.