JP2004311051A

JP2004311051A - Control valve type lead acid storage battery

Info

Publication number: JP2004311051A
Application number: JP2003099095A
Authority: JP
Inventors: Takehiro Sasaki; 健浩佐々木; Tomoki Fujimori; 智貴藤森; Toshibumi Yoshimine; 俊文吉嶺
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-04-02
Filing date: 2003-04-02
Publication date: 2004-11-04
Anticipated expiration: 2023-04-02
Also published as: JP4265260B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve type lead acid storage battery excellent in reliability by preventing cracks and deformations at a positive electrode shelf in the battery in which a Pb-Ca-Sn alloy excellent in a corrosion resistance is used as a positive electrode grid and a Pb-Sn alloy excellent in weldability with a current collecting lug is used as the shelf. <P>SOLUTION: A positive electrode plate 1 has a cast grid made of Pb-Ca-Sn alloy containing Sn of ≥1.6 mass%, and when the summation of cross-sectional areas of longitudinal ribs 5a, 5b arranged in a longitudinal direction of the grid is set to S1 and the summation of cross-sectional areas of transverse ribs 6a, 6b arranged in a transverse direction of the grid is set to S2, the ratio (S1/(S1+S2)) is set to ≥0.45, the ratio (S3/S4) between the cross-sectional area (S3) of the positive electrode shelf to collectively weld a positive current collecting lug portion 3 and the summation (S4) of the cross-sectional area of the lug portion 3 is set to ≥0.60, and the positive electrode shelf is composed of the Pb-Sn alloy containing Sn of ≥2.2 mass%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明はバックアップ電源等に利用される制御弁式鉛蓄電池に関するものである。
【０００２】
【従来の技術】
制御弁式鉛蓄電池は数Ａｈ〜数千Ａｈの広い容量範囲に適用できる。また、比較的安価であることから、コンピュータ用の無停電電源からビル用非常用電源といったバックアップ用電源に広く用いられている。
【０００３】
このようなバックアップ用電源において、制御弁式鉛蓄電池はバックアップ放電に備えて、商用電源が正常に供給される間は常時充電される。このような充電はトリクル充電と呼ばれ、蓄電池の自己放電分を補うためになされる。トリクル充電として過充電による蓄電池の性能低下を抑制するために、蓄電池の充電電圧が所定値を超えない制御する定電圧充電が一般に行われている。
【０００４】
一方、このようなバックアップ用に用いる制御弁式鉛蓄電池は数年から十数年といった寿命が要求され、このような長期にわたる使用期間中での安全性が要求される。特に長期にわたってトリクル充電が行われることによって、正極格子や正極棚といった正極部材は腐食を受ける。
【０００５】
これらの正極部材の耐食性を改善するためにこれらの部材に用いる鉛合金中にＳｎを添加することが行われている。例えば正極格子体に適切な耐食性に優れた合金として特許文献１には０．０３質量％〜０．０９質量％のＣａと１．０５質量％〜１．５０質量％のＳｎを含むＰｂ−Ｃａ−Ｓｎ合金が示されている。
【０００６】
このような組成の鉛合金を正極格子に用いた場合、腐食とこれによる正極格子の変形を抑制できる。しかしながら、このような組成の鉛合金であっても腐食量を皆無とすることはできず、若干変形することは避けることはできない。一方このような組成のＰｂ−Ｃａ−Ｓｎ合金はＣａとＳｎの添加によってその強度は純Ｐｂに比較して極めて高くなる傾向にある。そして、正極格子自体の変形量は抑制できるものの、正極格子の変形によって発生する応力が正極格子耳部から正極棚部に集中する傾向にあった。このような応力は正極格子耳部の長さ方向に正極棚部を突き上げるようにかかるため、正極棚が破断することがあった。
【０００７】
また、正極棚に用いる合金として２．２質量％〜３．０質量％のものを用いた場合、この正極棚にクラックが発生する頻度が高くなることがわかってきた。正極棚合金中のＳｎ量を２．２質量％未満とした場合にクラック発生は抑制できるものの、正極棚は正極集電耳に押されて上方に塑性変形する。また、このような合金では正極集電耳部との溶接性が悪化し、棚と集電耳との間に隙間やクラックを発生させることがあった。
【０００８】
一方、２．２質量％〜３．０質量％のＳｎを含むＰｂ−Ｓｎ合金では正極集電耳部との溶接性は良好であるが、前記したような正極棚自体にクラックが発生といった問題があった。
【０００９】
【特許文献１】
特開平８−１２４５６３号公報
【００１０】
【発明が解決しようとする課題】
本発明は前記したような耐食性に優れたＰｂ−Ｃａ−Ｓｎ合金を正極格子体に、また集電耳との溶接性に優れたＰｂ−Ｓｎ合金を正極棚に用いた制御弁式鉛蓄電池において正極棚におけるクラックや変形を抑制し、信頼性に優れた制御弁式鉛蓄電池を提供することを目的とする。
【００１１】
【課題を解決するための手段】
前記した課題を解決するために、本発明の請求項１に係る発明は、正極板と負極板とをリテーナを介して配置してなる極板群に電解液を含浸保持した制御弁式鉛蓄電池であって、正極板は１．６質量％以上のＳｎを含むＰｂ−Ｃａ−Ｓｎ合金からなる鋳造格子体を備え、鋳造格子体の縦方向に配置された縦骨の断面積の総和をＳ１とし、鋳造格子体の横方向に配置された横骨の断面積の総和をＳ２としたとき、比率（Ｓ１／（Ｓ１＋Ｓ２））を０．４５以上とし、正極板の集電耳部を集合溶接する正極棚の断面積（Ｓ３）と正極の集電耳部の断面積の総和（Ｓ４）との比率（Ｓ３／Ｓ４）を０．６０以上とし、かつ正極棚をＳｎを２．２質量％以上含むＰｂ−Ｓｎ合金で構成したことを特徴とする制御弁式鉛蓄電池を示すものである。
【００１２】
【発明の実施の形態】
本発明の実施の形態による制御弁式鉛蓄電池（以下、電池）を図面を参照して説明する。図１に示したように、本発明の電池に用いる正極板１は集電耳部３を一体に設けた正極格子２と活物質４とからなる。ここで活物質４としては従来からのものを用いることができる。本発明では正極格子２としてＳｎを１．６質量％以上含むＰｂ−Ｃａ−Ｓｎ合金を鋳造して得たものを用いる。本発明ではＣａ量を限定するものではないが、ペースト充填時等に格子の変形が生じない程度、すなわち０．０３質量％〜０．１０質量％の範囲内のものを用いることができる。
【００１３】
そして、正極格子２はその上下に渡って連続した縦枠骨５ａとその左右に渡って連続した横枠骨６ａおよびこれら枠骨の内部に形成され、格子の上下に渡って連続した縦中骨５ｂと格子の左右に渡って連続した横中骨６ｂを備えている。
【００１４】
本発明においては、正極格子２を構成する縦枠骨５ａと縦中骨５ｂの断面積の総和、すなわち、正極格子２をＡ−Ａ´で切断した場合に現れる縦枠骨５ａ断面と縦中骨５ｂ断面の総和をＳ１、正極格子２を構成する横枠骨６ａと横中骨６ｂの断面積の総和、すなわち、正極格子２をＢ−Ｂ´で切断した場合に現れる横枠骨６ａ断面と横中骨６ｂ断面の総和をＳ１としたとき、比率（Ｓ１／（Ｓ１＋Ｓ２））を０．４５以上とする。
【００１５】
このような正極格子２から得た正極板１と負極板１２とがリテーナ１１を介して配置し、同極性極板の集電耳部を集合溶接して棚部を形成し、極板群１５とする。リテーナ１１としては従来と同様、ガラス繊維マット等の耐酸性を有した繊維の不織布を用いることができる。また、正極棚１３には接続体１４といった、他のセルと接続したり、電池端子と接続するための極柱等の接続部材が設けられている。
【００１６】
本発明の電池において、正極棚断面１３ａの断面積をＳ３、正極板１における集電耳部３の断面３ａの断面積の総和をＳ４としたときに、比率（Ｓ３／Ｓ４）を０．６０以上とする。また、正極棚と２．２質量％以上のＳｎを含むＰｂ−Ｓｎ合金で構成する。そしてこの極板群１５を電槽に収納し、以降は常法に従って電池を組み立てることにより、本発明の制御弁式鉛蓄電池を得ることができる。
【００１７】
本発明では正極格子における縦骨の断面積の総和Ｓ１と横骨断面積に総和Ｓ２との関係を規定することによって正極格子が腐食した場合の縦方向の伸びに対して横方向の伸びを優先させることができる。これにより、集電耳部３が正極棚１３に与える応力を低減することが可能となる。しかしながら、正極格子体として耐食性に優れた１．６質量以上のＳｎを含むＰｂ−Ｃａ−Ｓｎ合金を用いた場合には腐食による変形量は少なくなるものの、格子強度自体は増かしているので集電耳部３が正極棚１３に与える応力は大きい。また、正極棚１３は２．２質量％以上のＳｎの添加により、棚の上下方向に結晶粒界が成長しやすくなる。そして集電耳部３の応力によって正極棚１３に微小なクラックを発生させ、棚腐食の要因となる。
【００１８】
このような正極格子合金と正極棚合金の組み合わせによって生じる正極棚１３での微小なクラックの発生を抑制するため、本発明では正極の集電耳部３の断面３ａの断面積総和Ｓ３と正極棚断面１３ａの断面積Ｓ４の比率（Ｓ３／Ｓ４）を０．６０以上とするものである。
【００１９】
【実施例】
▲１▼実施例１
１２Ｖ１５Ａｈの制御弁式鉛蓄電池（以下、電池）について、本発明例による電池と比較例による電池を作成し、正極棚部の耐久性を評価した。これらの各電池ではＰｂ−０．０８質量％Ｃａ−２．２質量％Ｓｎ合金を鋳造して得た格子体を正極に、Ｐｂ−０．０８質量％Ｃａ−０．４質量％Ｓｎ合金を鋳造した得た格子体を負極に用いた。これらの格子体にそれぞれボールミル法による鉛粉を水と希硫酸で練合したペーストを充填し、それぞれ熟成乾燥することによって未化成の正極板と負極板を得た。これらの極板の寸法は正極、負極とも高さが１１５ｍｍ，幅が５８．５、厚みはそれぞれ３．５ｍｍ、２．０ｍｍである。
【００２０】
これらの正極板３枚と負極板枚とを最大直径２μｍのガラス繊維マットであるリテーナとを積層した。そして同極性極板の集電耳部をそれぞれ櫛歯状の鋳型に配置し、鋳型に溶融した足し鉛を流し込み、この足し鉛を凝固させて正極棚と負極棚を形成することによって極板群を作成した。ここで足し鉛としてＰｂ−２．５質量％Ｓｎ合金を用いた。
【００２１】
これらの極板群を電槽内に収納し、以降は常法に従って制御弁式鉛蓄電池を作成した。正極格子体については発明の実施の形態で説明した縦枠骨と縦中骨の断面積の総和をＳ１、横枠骨と横中骨の断面積の総和をＳ２としたときの比率（Ｓ１／（Ｓ１＋Ｓ２））と、正極棚の断面積をＳ３、正極板の集電耳部の断面積の総和をＳ４としたときの比率（Ｓ３／Ｓ４）を表１に示した組み合わせとすることにより本発明例および比較例の電池を作成とした。なお、正極の集電耳部の幅は８．０ｍｍとし、厚みを変化させることにより、集電耳部の断面積の総和Ｓ４を変化させた。
【００２２】
【表１】

【００２３】
表１に示した各電池について正極棚部の耐久試験を行った。耐久試験として、充電電圧１３．６５Ｖで２ヶ月間連続充電し、その後０．２５ＣＡ放電にて容量確認を行うサイクルを繰返して行った。充電時の雰囲気温度は６０℃とした。そしてこの容量が初期の５０％以下になった時点で耐久試験終了とし、このときの電池容量と前回の電池容量とを直線で結び、この直線と容量５０％のラインとが交わる充電期間を耐久寿命とした。また、各試験終了電池は分解し、正極棚の状態を観察した。これらの耐久寿命試験の結果を前記した表１に示した。
【００２４】
表１に示した結果より比率（Ｓ１／（Ｓ１＋Ｓ２））が０．４５以上、かつ比率（Ｓ３／Ｓ４）を０．６０以上とすることにより、正極棚でのクラックやこれによる破断の発生を抑制し、かつ良好な耐久寿命期間を得ることができる。本発明では比率（Ｓ１／（Ｓ１＋Ｓ２））を０．４５以上とすることにより、格子体の伸びを横方向に優先させて発生させる。また、棚断面積（Ｓ３）の正極集電耳部の総断面積（Ｓ４）に対する比率（Ｓ３／Ｓ４）を０．６０以上とすることにより、正極棚のクラックやこれによる破断の発生を抑制することができる。
【００２５】
本発明において、比率（Ｓ１／（Ｓ１＋Ｓ２））を０．４５以上とすることにより、格子縦方向への変形を抑制できるが、この比率を０．８とした場合には集電効率の低下により放電電圧が低下し、寿命期間が若干低下することから、この比率は０．７０以下とすることが好ましい。
【００２６】
また比率（Ｓ３／Ｓ４）に関しては０．６０以上とすることにより、正極棚のクラックの発生を抑制できる。なお、本発明はこの比率の上限を限定するものではない。しかしながら、この比率を大きくするにしたがい棚体積と重量が増大する。したがって、この比率は許容できる電池体積と重量に応じてその上限値を定めればよい。
【００２７】
▲２▼実施例２
つぎに実施例１において本発明例の電池Ｃ２について表２に示したように、正極格子合金と正極棚合金中に含まれるＳｎ量を変化させて電池を作成し、これら各電池について実施例１で行った耐久寿命試験と同じ条件で耐久寿命試験を行った。これらの結果を表２に示す。
【００２８】
【表２】

【００２９】
表２に示した結果から、正極格子合金中のＳｎ濃度が１．４０質量％の場合には耐久寿命期間が極端に短くなる傾向がある。この電池を分解したところ、正極格子体が腐食により断線していた。一方、正極棚にはクラックの発生はなく、正常であった。そして正極格子合金中のＳｎ濃度を１．６０質量％以上とした場合には、耐久寿命期間は長くなる。しかしながら、正極棚合金中のＳｎ濃度が２．００質量％のものでは正極棚の端部が上方へ反り、正極の集電耳部と正極棚との間にクラックが発生していた。これはＳｎ濃度を２．００質量％まで低下させた場合、正極の集電耳部と正極棚との溶接性が低下し、これらの間に隙間が発生するとともに、正極棚自体の強度も低下したことによると推測できる。
【００３０】
したがって、本発明の正極棚におけるクラック発生を抑制効果と耐久寿命の伸長効果を得るためには正極棚中のＳｎ濃度を２．２質量％以上、正極格子合金中のＳｎ濃度を１．６質量％以上とすることが好ましい。なお、本発明の効果を得る上でこれらＳｎ濃度の上限値を設定するものではないが、正極格子合金中のＳｎ濃度については２．４質量％、正極棚中のＳｎ濃度については３．０質量％を超えた量を添加しても耐久寿命の伸長が見られない他、Ｐｂに比較して高価なＳｎの使用量が増加するため、上限値をそれぞれ２．４質量％、３．０質量％とすることが好ましい。
【００３１】
【発明の効果】
以上、説明してきたように、本発明は前記したような耐食性に優れたＰｂ−Ｃａ−Ｓｎ合金を正極格子体に、また集電耳との溶接性に優れたＰｂ−Ｓｎ合金を正極棚に用いた制御弁式鉛蓄電池において正極棚におけるクラックや変形を抑制し、信頼性に優れた制御弁式鉛蓄電池を提供できることから、工業上、極めて有用である。
【図面の簡単な説明】
【図１】本発明の電池の正極板を示す図
【図２】本発明の電池の極板群を示す図
【符号の説明】
１正極板
２正極格子
３集電耳部
３ａ（集電耳部の）断面
４活物質
５ａ縦枠骨
５ｂ縦中骨
６ａ横枠骨
６ｂ横中骨
１１リテーナ
１２負極板
１３正極棚
１３ａ正極棚断面
１４接続体
１５極板群[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control valve type lead storage battery used for a backup power source or the like.
[0002]
[Prior art]
The control valve type lead acid battery can be applied to a wide capacity range of several Ah to several thousand Ah. Further, since it is relatively inexpensive, it is widely used for backup power sources such as uninterruptible power sources for computers to emergency power sources for buildings.
[0003]
In such a backup power source, the control valve type lead storage battery is always charged while the commercial power source is normally supplied in preparation for backup discharge. Such charging is called trickle charging and is performed to compensate for the self-discharge of the storage battery. In order to suppress performance degradation of the storage battery due to overcharge as trickle charge, constant voltage charging is generally performed in which the charge voltage of the storage battery does not exceed a predetermined value.
[0004]
On the other hand, such a valve-regulated lead-acid battery used for backup is required to have a life of several years to several tens of years, and safety during such a long period of use is required. In particular, when trickle charging is performed over a long period of time, the positive electrode members such as the positive electrode grid and the positive electrode shelf are corroded.
[0005]
In order to improve the corrosion resistance of these positive electrode members, Sn is added to the lead alloy used for these members. For example, Pb-Ca containing 0.03% by mass to 0.09% by mass of Ca and 1.05% by mass to 1.50% by mass of Sn is disclosed in Patent Document 1 as an alloy having excellent corrosion resistance suitable for a positive electrode grid. A -Sn alloy is shown.
[0006]
When a lead alloy having such a composition is used for the positive electrode grid, corrosion and deformation of the positive electrode grid due to this can be suppressed. However, even a lead alloy having such a composition cannot eliminate the amount of corrosion, and some deformation cannot be avoided. On the other hand, the strength of the Pb—Ca—Sn alloy having such a composition tends to be extremely higher than that of pure Pb by the addition of Ca and Sn. Although the amount of deformation of the positive electrode lattice itself can be suppressed, the stress generated by the deformation of the positive electrode lattice tends to concentrate from the positive electrode lattice ear to the positive electrode shelf. Since such stress is applied so as to push up the positive electrode shelf in the length direction of the positive electrode lattice lug, the positive electrode shelf may break.
[0007]
Further, it has been found that when an alloy used for the positive electrode shelf is 2.2% by mass to 3.0% by mass, the frequency of occurrence of cracks in the positive electrode shelf is increased. Although cracking can be suppressed when the Sn content in the positive electrode shelf alloy is less than 2.2% by mass, the positive electrode shelf is pushed by the positive electrode current collector ear and plastically deforms upward. Moreover, in such an alloy, the weldability with the positive electrode current collection ear | edge part deteriorated, and the gap | interval and the crack might be generated between a shelf and the current collection ear | edge.
[0008]
On the other hand, the Pb—Sn alloy containing Sn of 2.2% by mass to 3.0% by mass has good weldability with the positive electrode current collector ear part, but the problem that the positive electrode shelf itself is cracked as described above. was there.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-124563
[Problems to be solved by the invention]
The present invention relates to a control valve type lead-acid battery using a Pb—Ca—Sn alloy excellent in corrosion resistance as described above as a positive electrode grid body and a Pb—Sn alloy excellent in weldability with a current collecting ear as a positive electrode shelf. It aims at providing the control valve type lead acid battery which suppressed the crack and deformation | transformation in a positive electrode shelf, and was excellent in reliability.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, the invention according to claim 1 of the present invention is a control valve type lead-acid battery in which an electrode plate group in which a positive electrode plate and a negative electrode plate are arranged via a retainer is impregnated and held with an electrolyte. The positive electrode plate includes a cast lattice body made of a Pb—Ca—Sn alloy containing 1.6 mass% or more of Sn, and the sum of the cross-sectional areas of the longitudinal bones arranged in the longitudinal direction of the cast lattice body is S1. When the sum of the cross-sectional areas of the lateral bones arranged in the lateral direction of the cast lattice is S2, the ratio (S1 / (S1 + S2)) is 0.45 or more, and the current collecting ears of the positive electrode plate are welded together. The ratio (S3 / S4) of the cross-sectional area (S3) of the positive electrode shelf to the sum of the cross-sectional areas (S4) of the current collecting ears of the positive electrode is 0.60 or more, and the positive electrode shelf has 2.2% by mass of Sn. The control valve type lead acid battery characterized by having comprised with the Pb-Sn alloy containing the above is shown.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A control valve type lead storage battery (hereinafter referred to as a battery) according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the positive electrode plate 1 used in the battery of the present invention is composed of a positive electrode grid 2 and an active material 4 provided with current collecting ears 3 integrally. Here, a conventional material can be used as the active material 4. In the present invention, the positive electrode lattice 2 is obtained by casting a Pb—Ca—Sn alloy containing 1.6 mass% or more of Sn. In the present invention, the amount of Ca is not limited, but it is possible to use a material that does not cause deformation of the lattice at the time of paste filling or the like, that is, within a range of 0.03% by mass to 0.10% by mass.
[0013]
The positive grid 2 is formed in the vertical frame bone 5a continuous over the upper and lower sides thereof, the horizontal frame bone 6a continuous over the left and right sides thereof, and the longitudinal middle bones formed in the frame bones and continuous over the upper and lower sides of the grid. 5b and a transverse middle bone 6b continuous across the left and right sides of the lattice.
[0014]
In the present invention, the sum of the cross-sectional areas of the vertical frame bones 5a and the vertical central bones 5b constituting the positive grid 2, that is, the vertical frame bone 5a cross section and the vertical central that appear when the positive grid 2 is cut along AA ′. The sum of the cross-sections of the bones 5b is S1, and the cross-sectional area of the lateral frame bones 6a and 6b constituting the positive grid 2 is summed, that is, the cross-section of the lateral frame bones 6a that appears when the positive grid 2 is cut along BB '. When the sum of the cross sections of the transverse medial bone 6b is S1, the ratio (S1 / (S1 + S2)) is 0.45 or more.
[0015]
A positive electrode plate 1 and a negative electrode plate 12 obtained from such a positive electrode grid 2 are arranged via a retainer 11, and a current collecting ear portion of the same polarity electrode plate is collectively welded to form a shelf portion. And As the retainer 11, a non-woven fabric of fibers having acid resistance such as a glass fiber mat can be used as in the conventional case. Further, the positive electrode shelf 13 is provided with a connecting member such as a pole column for connecting to another cell or connecting to a battery terminal, such as the connection body 14.
[0016]
In the battery of the present invention, the ratio (S3 / S4) is 0.60, where S3 is the cross-sectional area of the positive-electrode shelf cross-section 13a and S4 is the total cross-sectional area of the cross-section 3a of the current collecting ear portion 3 in the positive electrode plate 1. That's it. Moreover, it comprises a Pb-Sn alloy containing a positive electrode shelf and 2.2 mass% or more of Sn. And this electrode plate group 15 is accommodated in a battery case, and the control valve type lead acid battery of this invention can be obtained by assembling a battery according to a conventional method after that.
[0017]
In the present invention, by prescribing the relationship between the sum S1 of the cross-sectional areas of the vertical bones in the positive grid and the sum S2 of the cross-sectional areas of the horizontal bones, priority is given to the lateral stretch over the vertical stretch when the positive grid is corroded. Can be made. As a result, the stress applied to the positive electrode shelf 13 by the current collecting ear portion 3 can be reduced. However, when a Pb—Ca—Sn alloy containing 1.6 mass or more of Sn, which has excellent corrosion resistance, is used as the positive electrode lattice, the amount of deformation due to corrosion is reduced, but the lattice strength itself is increased. The stress which the current collection ear | edge part 3 gives to the positive electrode shelf 13 is large. Further, the addition of 2.2 mass% or more of Sn in the positive electrode shelf 13 facilitates the growth of crystal grain boundaries in the vertical direction of the shelf. And the micro crack is generated in the positive electrode shelf 13 by the stress of the current collection ear | edge part 3, and it becomes a factor of shelf corrosion.
[0018]
In order to suppress the occurrence of minute cracks in the positive electrode shelf 13 caused by such a combination of the positive electrode lattice alloy and the positive electrode shelf alloy, in the present invention, the total cross-sectional area S3 of the cross section 3a of the current collecting ear portion 3 of the positive electrode and the positive electrode shelf The ratio (S3 / S4) of the cross-sectional area S4 of the cross-section 13a is 0.60 or more.
[0019]
【Example】
(1) Example 1
Regarding a 12V15Ah control valve type lead storage battery (hereinafter referred to as a battery), a battery according to an example of the present invention and a battery according to a comparative example were prepared, and the durability of the positive electrode shelf was evaluated. In each of these batteries, a grid obtained by casting a Pb-0.08 mass% Ca-2.2 mass% Sn alloy is used as a positive electrode, and a Pb-0.08 mass% Ca-0.4 mass% Sn alloy is used. The lattice body obtained by casting was used for the negative electrode. These grids were each filled with a paste obtained by kneading lead powder by water and dilute sulfuric acid by a ball mill method, and aged and dried, respectively, to obtain an unformed positive electrode plate and negative electrode plate. The dimensions of these plates are 115 mm in height and 58.5 in width for both the positive electrode and the negative electrode, and the thickness is 3.5 mm and 2.0 mm, respectively.
[0020]
The three positive electrode plates and the negative electrode plate were laminated with a retainer which is a glass fiber mat having a maximum diameter of 2 μm. Then, the current collecting ears of the same polarity electrode plate are arranged in comb-shaped molds, the molten lead is poured into the mold, and the lead is solidified to form a positive electrode shelf and a negative electrode shelf. It was created. Here, a Pb-2.5 mass% Sn alloy was used as additional lead.
[0021]
These electrode plate groups were housed in a battery case, and thereafter, a control valve type lead storage battery was prepared according to a conventional method. For the positive grid, the ratio (S1 / S1) is defined as S1 in which the sum of the cross-sectional areas of the vertical frame bone and the longitudinal middle bone described in the embodiment of the invention is S1, and the sum of the cross-sectional areas of the horizontal frame bone and the horizontal middle bone is S2. (S1 + S2)), and the ratio (S3 / S4) when the cross-sectional area of the positive electrode shelf is S3 and the sum of the cross-sectional areas of the current collecting ears of the positive electrode plate is S4 is the combination shown in Table 1. Inventive and comparative batteries were prepared. The width of the current collecting ear portion of the positive electrode was 8.0 mm, and the total S4 of the cross-sectional area of the current collecting ear portion was changed by changing the thickness.
[0022]
[Table 1]

[0023]
Each battery shown in Table 1 was subjected to a durability test of the positive electrode shelf. As an endurance test, a cycle in which the battery was continuously charged at a charging voltage of 13.65 V for 2 months and then the capacity was confirmed by 0.25 CA discharge was repeated. The ambient temperature during charging was 60 ° C. The durability test ends when the capacity falls below 50% of the initial value. The battery capacity at this time and the previous battery capacity are connected with a straight line, and the charging period in which the straight line intersects the line with the capacity of 50% is durable. The life is assumed. Moreover, each test completion | finish battery was decomposed | disassembled and the state of the positive electrode shelf was observed. The results of these durability life tests are shown in Table 1 above.
[0024]
From the results shown in Table 1, when the ratio (S1 / (S1 + S2)) is 0.45 or more and the ratio (S3 / S4) is 0.60 or more, cracks in the positive electrode shelf and the occurrence of breakage due thereto are caused. It is possible to suppress and obtain a good durability life period. In the present invention, by setting the ratio (S1 / (S1 + S2)) to 0.45 or more, the elongation of the lattice body is generated with priority in the lateral direction. Further, by setting the ratio (S3 / S4) of the shelf cross-sectional area (S3) to the total cross-sectional area (S4) of the positive electrode current collecting ear portion to be 0.60 or more, the occurrence of cracks in the positive electrode shelf and breakage due thereto are suppressed. can do.
[0025]
In the present invention, by setting the ratio (S1 / (S1 + S2)) to 0.45 or more, deformation in the vertical direction of the lattice can be suppressed. However, when this ratio is set to 0.8, the current collection efficiency decreases. This ratio is preferably 0.70 or less because the discharge voltage is lowered and the lifetime is slightly reduced.
[0026]
Moreover, regarding the ratio (S3 / S4), the occurrence of cracks in the positive electrode shelf can be suppressed by setting the ratio to 0.60 or more. Note that the present invention does not limit the upper limit of this ratio. However, as this ratio is increased, shelf volume and weight increase. Therefore, the upper limit of the ratio may be determined according to the allowable battery volume and weight.
[0027]
(2) Example 2
Next, as shown in Table 2 for the battery C2 of the present invention in Example 1, batteries were prepared by changing the amount of Sn contained in the positive electrode lattice alloy and the positive electrode shelf alloy. The endurance life test was performed under the same conditions as the endurance life test performed in the above. These results are shown in Table 2.
[0028]
[Table 2]

[0029]
From the results shown in Table 2, when the Sn concentration in the positive electrode lattice alloy is 1.40% by mass, the durable life period tends to be extremely short. When this battery was disassembled, the positive electrode grid was disconnected due to corrosion. On the other hand, the positive electrode shelf was normal with no cracks. When the Sn concentration in the positive electrode lattice alloy is 1.60% by mass or more, the durable life period becomes long. However, when the Sn concentration in the positive electrode shelf alloy is 2.00% by mass, the end of the positive electrode shelf warps upward, and a crack is generated between the current collecting ear portion of the positive electrode and the positive electrode shelf. This is because when the Sn concentration is reduced to 2.00% by mass, the weldability between the current collecting ear portion of the positive electrode and the positive electrode shelf decreases, a gap is generated between them, and the strength of the positive electrode shelf itself also decreases. It can be guessed that it was.
[0030]
Therefore, in order to obtain the effect of suppressing the occurrence of cracks in the positive electrode shelf of the present invention and the effect of extending the durable life, the Sn concentration in the positive electrode shelf is 2.2% by mass or more and the Sn concentration in the positive electrode lattice alloy is 1.6% by mass. % Or more is preferable. In order to obtain the effects of the present invention, the upper limit of these Sn concentrations is not set. However, the Sn concentration in the positive electrode lattice alloy is 2.4% by mass, and the Sn concentration in the positive electrode shelf is 3.0%. Even if an amount exceeding mass% is added, the endurance life is not increased, and the amount of expensive Sn used is increased compared to Pb, so the upper limit values are 2.4 mass% and 3.0 mass respectively. It is preferable to set it as the mass%.
[0031]
【The invention's effect】
As described above, in the present invention, the Pb—Ca—Sn alloy having excellent corrosion resistance as described above is used as the positive electrode lattice body, and the Pb—Sn alloy having excellent weldability with the current collecting ear is used as the positive electrode shelf. Since the control valve type lead storage battery used can suppress cracks and deformation in the positive electrode shelf and can provide a control valve type lead storage battery excellent in reliability, it is extremely useful industrially.
[Brief description of the drawings]
FIG. 1 is a diagram showing a positive electrode plate of a battery of the present invention. FIG. 2 is a diagram showing a group of electrode plates of the battery of the present invention.
DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Positive electrode grating | lattice 3 Current collection ear | edge part 3a (current collection ear | edge part) Section 4 Active material 5a Vertical frame bone 5b Vertical frame bone 6a Horizontal frame bone 6b Horizontal frame 11 Retainer 12 Negative electrode plate 13 Positive electrode shelf 13a Positive electrode shelf Section 14 Connector 15 Electrode group

Claims

正極板と負極板とをリテーナを介して配置してなる極板群に電解液を含浸保持した制御弁式鉛蓄電池であって、
前記正極板は１．６質量％以上Ｓｎを含むＰｂ−Ｃａ−Ｓｎ合金からなる鋳造格子体を備え、前記鋳造格子体の縦方向に配置された縦骨の断面積の総和をＳ１とし、前記鋳造格子体の横方向に配置された横骨の断面積の総和をＳ２としたとき、比率（Ｓ１／（Ｓ１＋Ｓ２））を０．４５以上とし、前記正極板の集電耳部を集合溶接する正極棚の断面積（Ｓ３）と正極の前記集電耳部の断面積の総和（Ｓ４）との比率（Ｓ３／Ｓ４）を０．６０以上とし、かつ前記正極棚をＳｎを２．２質量％以上含むＰｂ−Ｓｎ合金で構成することを特徴とする制御弁式鉛蓄電池。A control valve type lead-acid battery in which a positive electrode plate and a negative electrode plate are placed through a retainer and impregnated and held with an electrolyte solution,
The positive electrode plate includes a cast lattice body made of a Pb—Ca—Sn alloy containing Sn of 1.6 mass% or more, and the sum of the cross-sectional areas of longitudinal bones arranged in the longitudinal direction of the cast lattice body is S1, When the sum of the cross-sectional areas of the transverse bones arranged in the lateral direction of the cast grid is S2, the ratio (S1 / (S1 + S2)) is 0.45 or more, and the current collecting ears of the positive electrode plate are collectively welded The ratio (S3 / S4) between the cross-sectional area of the positive electrode shelf (S3) and the sum of the cross-sectional areas of the current collecting ears of the positive electrode (S4) is 0.60 or more, and the positive electrode shelf has 2.2 mass of Sn. A valve-regulated lead-acid battery comprising a Pb—Sn alloy containing at least%.