JP4374867B2

JP4374867B2 - Lead-acid battery positive grid and lead-acid battery using the same

Info

Publication number: JP4374867B2
Application number: JP2003044553A
Authority: JP
Inventors: 道男榑松
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2003-02-21
Filing date: 2003-02-21
Publication date: 2009-12-02
Anticipated expiration: 2023-02-21
Also published as: JP2004253324A

Description

【０００１】
【発明の属する技術分野】
本発明は、鉛蓄電池の極板格子の形状に関するものである。
【０００２】
【従来の技術】
鉛蓄電池の極板は鉛もしくは鉛合金の格子体に活物質を充填した構成を有している。この格子体としては溶融鉛を鋳型中で凝固させた鋳造格子体や圧延鉛合金シートにスリットを千鳥状に形成し、このスリットを展開したエキスパンド格子体が用いられている。エキスパンド格子体は格子体を薄型化でき、生産性に優れることから、広く用いられている。
【０００３】
このエキスパンド格子体６０１は図６に示したようにエキスパンド網目６０２と一体に下枠骨６０３と上枠骨６０４が形成されており、この上枠骨６０４に集電耳部６０５を備えている。このようなエキスパンド格子体６０１は鋳造格子とは異なり、左右両側部に枠骨を有しておらず、さらには格子中骨形状の自由度が低いことから、集電効率の面で鋳造格子体と比較して不利であり、格子体による電圧降下もより大きく、電池の放電電圧を低下させる一因となっていた。
【０００４】
さらにエキスパンド格子体６０１を正極に用いた場合、エキスパンド格子体６０１は酸化腐食を受け、枠骨を有していない２辺の延長方向、すなわち、図６の矢印Ａ方向へ伸びる。そして伸びたエキスパンド格子体６０１は負極と短絡し、急激に電池の容量が低下するという問題があった。
【０００５】
これらの格子体による電圧低下を抑制し、かつ腐食による伸びを抑制するため、従来から上枠骨、特に上枠骨の集電部分を太くあるいは大きくすることが有効であることが知られている（例えば、特許文献１参照）。
【０００６】
また、集電耳に補強部を設けるとともに、格子体が伸びた状態で発生する上枠骨の屈曲点位置を規定しているものもある（例えば、特許文献２参照）。この特許文献２では格子体が伸びた場合に上枠骨の変形を屈曲点で優先的に発生させ、この屈曲点の位置を負極棚下に設けることによって、上枠骨が変形しても、負極端と接触短絡しない構造とするものである。
【０００７】
ところが、このような屈曲点を設定した場合、格子体を構成する鉛合金組成によっては、この屈曲点での応力集中が急激に進行することがわかってきた。特に、Ｓｎ濃度を１．２質量％以上添加したＰｂ−Ｓｎ−Ｃａ合金は、合金自体の耐食性と強度が向上するために、正極に用いることによって電池の寿命性能を改善することができる。ところが、このような高耐食性・高強度の合金を用いると屈曲点に集中する応力の絶対値も大きくなり、ある時点で急激に上枠骨の変形が進行し、これに対応して電池の容量も急激に低下するという課題があった。このような急激な容量低下は変形した上枠骨の下部に存在する活物質が格子の変形に追随できずに脱落することによって発生していた。
【０００８】
正極から脱落した活物質に関して、正極板を袋状セパレータに包皮した場合、脱落活物質は袋状セパレータ内に留まるため、電池容量が低下する他は特性上、大きな影響を及ぼさない。ところが、正極を袋状セパレータに収納しない、特に負極板を袋状セパレータに収納した電池ではこれらの脱落活物質は電槽下部に蓄積する。特に自動車用電池のような、振動が避けられない用途で用いられる電池では、振動によって脱落活物質が電解液中を浮遊し、負極に付着することによって還元し、負極上に析出する。このような析出物が次第に成長し、正極と短絡するといった問題があった。
【０００９】
【特許文献１】
特開昭６０−３００５７号公報（第２８８頁、第４図）
【特許文献２】
特開平８−２０３５３３号公報（第５頁、第３図）
【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鉛蓄電池において、正極の腐食時に発生する格子変形と活物質脱落による電池の寿命低下という課題を解決し、耐食性に優れた極板格子と優れた寿命特性を有した鉛蓄電池を提供するものである。
【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、Ｓｎを１．２質量％以上、２．０質量％以下含む鉛合金シートを網状に展開して成るエキスパンド網目を備え、このエキスパンド網目に接して設けた上枠骨に集電部を備えるとともに、前記集電部を前記エキスパンド網目の中心線から偏芯して設けた鉛蓄電池の正極格子体であって、前記上枠骨の前記集電耳から前記中心線方向に前記エキスパンド網目端部に対応した部分は前記集電部から前記エキスパンド網目端部に近接するにしたがい高さ寸法（ｈ）を減少させた傾斜部と、前記エキスパンド網目端部に対応して設けた高さ寸法（ｈ）を一定とした平行部を備え、前記傾斜部と前記平行部の間を曲線で連結する円弧形状の連結部を設ける。
【００１３】
さらに、前記した傾斜部の上端の延長線と平行部の上端の延長線とがなす角をθ（°）、前記円弧形状の半径をＲ（ｍｍ）としたときに、前記θを１０〜４０°とし、かつ前記θと前記Ｒとの関係をＲ≧１０^(2-θ^/45)とするものである。
【００１５】
また、本発明の請求項２に係る発明は、請求項１の正極格子体に活物質を充填した正極板を用いたことを特徴とする鉛蓄電池を示すものである。
【００１６】
そして、本発明の請求項３に係る発明は請求項２の鉛蓄電池において、負極板を収納した袋状セパレータと正極板とを用いた極板群を備えたことを特徴とする鉛蓄電池を示すものである。
【００１７】
【発明の実施の形態】
本発明の実施の形態による鉛蓄電池の正極格子を図面を用いて説明する。
【００１８】
本発明による鉛蓄電池の正極格子１００は図１に示したように、集電耳部１０２を一体に設けた上枠骨１０１を有している。そして上枠骨１０１には活物質（図示せず）を充填するためのエキスパンド網目１０３を一体に設け、さらにこのエキスパンド網目１０３には極板底部に対応する下枠骨１０４を有している。
【００１９】
エキスパンド網目１０３はＰｂ−Ｃａ−Ｓｎ合金といった、Ｓｎを１．２質量％以上、２．０質量％含む鉛合金シートに千鳥状のスリットを形成し、このスリットを展開することにより形成される。集電耳部１０２はエキスパンド網目１０３の中心線（図１における線Ｌ）から偏芯して設けられている。なお、本発明ではＣａの濃度を規定するものではないが、エキスパンド加工時の加工性を考慮してＣａ濃度を０．０４質量％〜０．１０質量％の範囲とする。また、Ｓｎ濃度の増加によって、エキスパンド網目に亀裂や切断が生じるため、Ｓｎ濃度の上限を２．０質量％以下とする。
【００２０】
上枠骨１０１の集電耳部１０２から中心線Ｌ方向にエキスパンド網目１０３の端部までの部分１０４）は、集電耳部１０２からエキスパンド網目１０３の端部に近接するに従い高さ寸法（ｈ）を減少させていく傾斜部１０５と、エキスパンド網目１０３の端部から設けた高さ寸法（ｈ´）を一定とした平行部１０６を有している。
【００２１】
本発明では傾斜部１０５と平行部１０６との間に連結部１０７が設けられている。連結部１０７は円弧形状とする。さらに、傾斜部１０５の延長線１０８と平行部の延長線１０９とのなす角度をθ（°）とし、連結部１０７の円弧形状の半径をＲ（ｍｍ）とした時に、Ｒとθとの関係を式（１）の関係を満たすよう構成する。また、前記θを１０〜４０°とする。
【００２２】
Ｒ≧10^(2-θ^/45) …式（１）
その後、正極格子１００に活物質（図示せず）を充填し、熟成乾燥して正極板とし、この正極板を用いることによって本発明の鉛蓄電池を得ることができる。
【００２３】
上記の本発明の構成を用いることによって正極格子１００が腐食しても上枠骨の変形を抑制する。この変形抑制によって変形した上枠骨による正極−負極間の短絡と正極活物質の脱落による容量低下を抑制することができる。
【００２４】
また、正極活物質の脱落を抑制できるため、従来、脱落活物質を保持するために正極を袋状セパレータに収納していた構成に代えて、負極板を袋状セパレータに収納した構成を採用することができる。負極板を袋状セパレータに収納する構成では腐食によって変形する正極格子が袋状セパレータ底部を破損するといった正極板を袋状セパレータに収納することによって発生する問題がない。
【００２５】
したがって、本発明では負極板を袋状セパレータに収納した構成をとれば、正極活物質の脱落抑制と、袋状セパレータの底部破損抑制を両立して達成することができる。
【００２８】
正極格子１００に用いるＰｂ−Ｃａ−Ｓｎ合金中のＳｎ濃度を１．２０質量％以上とすることにより、Ｐｂ−Ｃａ−Ｓｎ合金の耐食性は向上し、正極格子の腐食進行を抑制でき、その分、鉛蓄電池を長寿命化できる点で有利である。ところがＰｂ−Ｃａ−Ｓｎ合金の引張り強度も向上するので、正極格子が腐食を受けた場合には正極格子への応力は増加する。前記した特許文献２のように、変形の屈曲点をある点に設定した場合、この屈曲点に応力が集中する。Ｓｎ濃度が１．２０質量％以上のＰｂ−Ｃａ−Ｓｎ合金ではＳｎ濃度が１．２質量％未満のものに比較して、この集中した応力値が急激に増大する。これにより、正極格子体の変形は急激に進行し、突然容量が低下して、電池が使用不能となる。
【００２９】
本発明の構成では上記のようなＳｎ濃度のＰｂ−Ｃａ−Ｓｎ合金を使用した場合でも上枠骨に加わる応力を分散させることにより、上枠骨の急激な変形を抑制することができる。
【００３０】
【実施例】
次に、本発明の実施例を説明する。
【００３１】
▲１▼実施例１
Ｐｂ−０．０５質量％Ｃａ−１．８質量％Ｓｎ合金の圧延シートを用いてロータリーエキスパンド法により図２に示すようなエキスパンド網目２０１を作成した。次にエキスパンド網目２０１に活物質を充填し、図２の破線で示した切断線２０２で打抜き、単一の極板とした後、熟成乾燥をおこなって、未化成の正極板とした。
【００３２】
本実施例においては、前記した本発明の実施の形態の正極格子のθおよびＲの値を種々の組み合わせで変化させることにより、本発明例の正極格子体と比較例の正極格子体を作成した。そしてこれらの正極板を用いて表１に示す８０Ｄ２６型（ＪＩＳＤ５３０１）の始動用鉛蓄電池を作成した。なお、本実施例では負極板を微孔性ポリエチレンシートで作成された袋状セパレータに収納し、正極板と組み合わせて極板群を作成した。
【００３３】
【表１】

【００３４】
これらの電池を４０℃雰囲気中で１４．８Ｖの定電圧で４週間連続充電し、充電終了後に電池を分解して、図３に示したように、正極格子３００の上枠骨３０１の上方向への変形量（ｄ）を測定した。そしてそれぞれの電池の変形量（ｄ）について電池４の変形量に対する比率を求め、その結果を変形量比ｄ´として表１に示した。
【００３５】
次に図４に縦軸にＲとθとの関係と変形量比（ｄ´）を示した。図４に示した結果から、θが１０〜４０°の範囲内であり、かつ下式（１）の範囲内での領域内で変形量比を極めて低く抑制できることがわかる。
【００３６】
Ｒ≧10^(2-θ^/45) … 式（１）
（但し、Ｒの単位はｍｍであり、かつ１０°≦θ≦４０°）
▲２▼実施例２
次に実施例１の表１に示した電池９および電池２２に関して鉛合金シート中のＳｎ濃度と、袋状セパレータに収納する極板の極性を変化させた電池を作成した。これらの電池を表２に示す。
【００３７】
【表２】

【００３８】
これら表２に示した電池について充電と放電とを繰返して行う寿命サイクル試験を行った。試験条件は充電を４０℃雰囲気中で１４．８Ｖの定電圧充電を１週間、放電を２５℃雰囲気中で３００Ａで５秒間の定電流放電とした。これらの充電と放電を繰返して行い、放電５秒目の電圧が７．２Ｖまで低下した時点を寿命サイクル数とした。これらの寿命試験の結果を図５に示す。
【００３９】
図５に示した結果から、正極格子に用いたＰｂ−Ｃａ−Ｓｎ合金中のＳｎ濃度が１．２０質量％以上の領域では比較例の電池は急激に寿命低下している。一方、本発明例の電池ではＳｎが１．２０質量％以上であっても良好な寿命特性を示す。
【００４０】
中でも負極板を袋状セパレータに収納した本発明例の電池では極めて優れた寿命特性を示した。
【００４１】
比較例の電池でＳｎ濃度を１．２０質量％以上としたものは正極格子の上枠骨の変形が一箇所に集中し、その点で上枠骨が折り曲がった状態となっていた。一方、本発明例ではこのようなＳｎ濃度であっても上枠骨の変形は一箇所に集中せず、変形が分散していた。また、Ｓｎ濃度を１．２０質量％未満に低下させていくにしたがい、上枠骨が一箇所で集中的に折れ曲がる変形から上枠骨全体が変形する状態に変化した。また、Ｓｎ濃度低下にしたがい、寿命サイクル数自体も低下した。したがって、本発明のよればＳｎ濃度が１．２０質量％以上の領域においても極めて良好な寿命特性を得ることができる。
【００４２】
また、特に本発明では正極格子の変形抑制により、脱落活物質量も抑制できるので、従来のような正極板を袋状セパレータに収納する必要がない。したがって、正極板を袋状セパレータに収納した時の問題点、すなわち、袋状セパレータの底部の破損による正極−負極間の短絡という問題を回避できる。
【００４３】
【発明の効果】
以上、説明してきたように本発明の構成によれば、腐食時に発生する格子変形と活物質脱落による電池寿命の低下という課題を解決し、長寿命な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】本発明による正極格子を示す図
【図２】エキスパンド網目を示す図
【図３】上枠骨の変形量測定位置を示す図
【図４】Ｒ、θ別の変形量比ｄ´を示す図
【図５】寿命試験結果を示す図
【図６】従来のエキスパンド格子体を示す図
【符号の説明】
１００正極格子
１０１上枠骨
１０２集電耳部
１０３エキスパンド網目
１０４（上枠骨の）部分
１０５傾斜部
１０６平行部
１０７連結部
１０８延長線
１０９延長線
２０１エキスパンド網目
２０２切断線
３００正極格子
３０１上枠骨
６０１エキスパンド格子体
６０２エキスパンド網目
６０３下枠骨
６０４上枠骨
６０５集電耳部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the shape of an electrode plate grid of a lead storage battery.
[0002]
[Prior art]
The electrode plate of the lead storage battery has a structure in which an active material is filled in a lead or lead alloy lattice. As this lattice body, there are used an expanded lattice body in which slits are formed in a staggered pattern in a cast lattice body obtained by solidifying molten lead in a mold or a rolled lead alloy sheet, and the slits are developed. Expanded lattice bodies are widely used because they can be made thinner and have excellent productivity.
[0003]
As shown in FIG. 6, the expanded lattice body 601 is formed with a lower frame bone 603 and an upper frame bone 604 integrally with the expanded mesh 602, and the upper frame bone 604 includes a current collecting ear portion 605. Unlike the cast grid, such an expanded grid body 601 does not have frame bones on both the left and right sides, and further, since the degree of freedom in the shape of the center of the grid is low, the cast grid body in terms of current collection efficiency. The voltage drop due to the grid body is larger, which is a cause of lowering the discharge voltage of the battery.
[0004]
Further, when the expanded lattice body 601 is used for the positive electrode, the expanded lattice body 601 is subjected to oxidative corrosion and extends in the extending direction of two sides having no frame bone, that is, in the direction of arrow A in FIG. The expanded expanded lattice 601 is short-circuited with the negative electrode, causing a problem that the capacity of the battery is rapidly reduced.
[0005]
Conventionally, it has been known that it is effective to thicken or enlarge the current collecting portion of the upper frame bone, particularly the upper frame bone, in order to suppress voltage drop due to these grid bodies and to suppress elongation due to corrosion. (For example, refer to Patent Document 1).
[0006]
In addition, there is a case in which a reinforcing portion is provided on the current collecting ear and a position of a bending point of the upper frame bone generated in a state where the lattice body is extended (see, for example, Patent Document 2). In Patent Document 2, when the lattice body is extended, deformation of the upper frame bone is preferentially generated at the bending point, and even if the upper frame bone is deformed by providing the position of the bending point under the negative electrode shelf, it is negative. It is designed to prevent contact short circuit with extremes.
[0007]
However, it has been found that when such a bending point is set, the stress concentration at the bending point proceeds rapidly depending on the lead alloy composition constituting the lattice body. In particular, a Pb—Sn—Ca alloy having a Sn concentration of 1.2% by mass or more improves the corrosion resistance and strength of the alloy itself. Therefore, the life performance of the battery can be improved by using it for the positive electrode. However, when such a high corrosion resistance and high strength alloy is used, the absolute value of the stress concentrated at the bending point also increases, and at some point the deformation of the upper frame suddenly progresses. However, there was a problem that it decreased rapidly. Such a rapid capacity drop has occurred when the active material present in the lower part of the deformed upper frame bone falls off without following the deformation of the lattice.
[0008]
When the positive electrode plate is encased in a bag-like separator with respect to the active material that has fallen off from the positive electrode, the drop-off active material stays in the bag-like separator, so that there is no significant effect on characteristics other than the reduction in battery capacity. However, in a battery in which the positive electrode is not housed in the bag-shaped separator, and particularly in the battery in which the negative electrode plate is housed in the bag-shaped separator, these falling active materials accumulate in the lower part of the battery case. In particular, in a battery used in an application where vibration is unavoidable, such as a battery for automobiles, the falling active material floats in the electrolyte due to vibration and is reduced by adhering to the negative electrode, and is deposited on the negative electrode. There was a problem that such precipitates gradually grew and short-circuited with the positive electrode.
[0009]
[Patent Document 1]
JP 60-30057 (page 288, Fig. 4)
[Patent Document 2]
JP-A-8-203533 (page 5, FIG. 3)
[0010]
[Problems to be solved by the invention]
In the lead storage battery as described above, the present invention solves the problem of lattice deformation that occurs during corrosion of the positive electrode and the decrease in battery life due to loss of the active material, and has an electrode plate lattice excellent in corrosion resistance and lead having excellent life characteristics. A storage battery is provided.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention includes an expanded mesh formed by developing a lead alloy sheet containing Sn in an amount of 1.2% by mass or more and 2.0% by mass or less in a net shape. A positive grid of a lead-acid battery, wherein the upper frame bone provided in contact with the expanded mesh is provided with a current collector, and the current collector is eccentric from a center line of the expanded mesh, A portion of the frame bone corresponding to the end of the expanded mesh in the center line direction from the current collecting ear is an inclined portion in which the height dimension (h) is decreased from the current collecting portion to the end of the expanded mesh. When the includes a parallel portion which is a constant expanded mesh edge height provided corresponding to (h), Ru provided connecting portions of arc shape connecting between the parallel portion and the inclined portion in the curve .
[0013]
Furthermore, when the angle formed by the extension line at the upper end of the inclined portion and the extension line at the upper end of the parallel portion is θ (°) and the radius of the arc shape is R (mm), the θ is 10 to 40. And the relation between θ and R is R ≧ 10 ^(2- θ ^{/ 45)} .
[0015]
Further, the invention according to claim 2 of the present invention shows a lead storage battery characterized by using a positive electrode plate in which the positive electrode grid body of claim 1 is filled with an active material .
[0016]
The invention according to claim 3 of the present invention in lead acid battery according to claim 2, shows a lead-acid battery, characterized in that it includes a electrode plate group and using a bag-shaped separator and the positive electrode plate housing the negative electrode plate Is.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The positive grid of lead 蓄 battery according to an embodiment of the present invention will be described with reference to the drawings.
[0018]
As shown in FIG. 1, the positive electrode grid 100 of the lead storage battery according to the present invention has an upper frame bone 101 provided with a current collecting ear portion 102 integrally. The upper frame bone 101 is integrally provided with an expanded mesh 103 for filling an active material (not shown), and the expanded mesh 103 further has a lower frame bone 104 corresponding to the bottom of the electrode plate.
[0019]
The expanded mesh 103 is formed by forming a staggered slit in a lead alloy sheet containing 1.2 mass% or more and 2.0 mass% of Sn, such as a Pb-Ca-Sn alloy , and developing the slit. The current collecting ear portion 102 is provided eccentric from the center line of the expanded mesh 103 (line L in FIG. 1). In addition, although the density | concentration of Ca is not prescribed | regulated in this invention, Ca density | concentration shall be 0.04 mass%-0.10 mass% in consideration of the workability at the time of an expand process. Moreover, since an increase in Sn concentration causes cracks and breaks in the expanded mesh, the upper limit of Sn concentration is set to 2.0% by mass or less .
[0020]
A portion 104) of the upper frame bone 101 from the current collecting ear 102 to the end of the expanded mesh 103 in the center line L direction increases in height as it approaches the end of the expanded mesh 103 from the current collecting ear 102. ) And a parallel portion 106 having a constant height (h ′) provided from the end of the expanded mesh 103.
[0021]
In the present invention, a connecting portion 107 is provided between the inclined portion 105 and the parallel portion 106. The connecting portion 107 has an arc shape. Further, when the angle formed between the extension line 108 of the inclined portion 105 and the extension line 109 of the parallel portion is θ (°) and the radius of the arc shape of the connecting portion 107 is R (mm), the relationship between R and θ. Is configured to satisfy the relationship of the expression (1). Further, the θ is set to 10 to 40 °.
[0022]
R ≧ 10 ^(2- θ ^{/ 45)} (1)
Thereafter, the positive electrode grid 100 is filled with an active material (not shown), aged and dried to obtain a positive electrode plate, and the lead storage battery of the present invention can be obtained by using this positive electrode plate.
[0023]
By using the above-described configuration of the present invention, deformation of the upper frame bone is suppressed even if the positive grid 100 is corroded. Capacitance reduction due to the short-circuit between the positive electrode and the negative electrode due to the upper frame bone deformed by the deformation suppression and the loss of the positive electrode active material can be suppressed.
[0024]
In addition, since the positive electrode active material can be prevented from falling off, a configuration in which the negative electrode plate is housed in the bag-shaped separator is used instead of the conventional structure in which the positive electrode is housed in the bag-shaped separator in order to hold the falling active material. be able to. In the configuration in which the negative electrode plate is accommodated in the bag-like separator, there is no problem that occurs when the positive electrode plate that is deformed by corrosion breaks the bottom of the bag-like separator and the positive electrode plate is accommodated in the bag-like separator.
[0025]
Therefore, in the present invention, if the negative electrode plate is housed in the bag-shaped separator, it is possible to achieve both the suppression of the positive electrode active material falling and the bottom damage suppression of the bag-shaped separator.
[0028]
By setting the Sn concentration in the Pb—Ca—Sn alloy used for the positive electrode lattice 100 to be 1.20% by mass or more, the corrosion resistance of the Pb—Ca—Sn alloy is improved, and the corrosion progression of the positive electrode lattice can be suppressed. This is advantageous in that the life of the lead-acid battery can be extended. However, since the tensile strength of the Pb—Ca—Sn alloy is also improved, the stress on the positive grid increases when the positive grid is corroded. When the bending point of deformation is set to a certain point as in Patent Document 2 described above, stress concentrates on this bending point. In a Pb—Ca—Sn alloy having a Sn concentration of 1.20% by mass or more, this concentrated stress value increases abruptly as compared with a Sn concentration of less than 1.2% by mass. As a result, the deformation of the positive electrode lattice progresses rapidly, the capacity is suddenly reduced, and the battery becomes unusable.
[0029]
In the configuration of the present invention, even when the Pb—Ca—Sn alloy having the Sn concentration as described above is used, rapid deformation of the upper frame bone can be suppressed by dispersing the stress applied to the upper frame bone.
[0030]
【Example】
Next, examples of the present invention will be described.
[0031]
(1) Example 1
An expanded network 201 as shown in FIG. 2 was prepared by a rotary expanding method using a rolled sheet of Pb-0.05 mass% Ca-1.8 mass% Sn alloy. Next, the expanded mesh 201 was filled with an active material, punched with a cutting line 202 shown by a broken line in FIG. 2 to form a single electrode plate, and then aged and dried to obtain an unformed positive electrode plate.
[0032]
In this example, the positive electrode lattice of the example of the present invention and the positive electrode lattice of the comparative example were prepared by changing the values of θ and R of the positive electrode lattice of the embodiment of the present invention described above in various combinations. . Then, using these positive electrode plates, 80D26 type (JIS D5301) lead acid batteries for starting shown in Table 1 were prepared. In this example, the negative electrode plate was housed in a bag-like separator made of a microporous polyethylene sheet, and an electrode plate group was prepared in combination with the positive electrode plate.
[0033]
[Table 1]

[0034]
These batteries were continuously charged at a constant voltage of 14.8 V in an atmosphere of 40 ° C. for 4 weeks, and after the completion of charging, the batteries were disassembled, and as shown in FIG. The amount of deformation (d) was measured. The ratio of the deformation amount (d) of each battery to the deformation amount of the battery 4 was determined, and the result is shown in Table 1 as the deformation amount ratio d ′.
[0035]
Next, FIG. 4 shows the relationship between R and θ and the deformation ratio (d ′) on the vertical axis. From the results shown in FIG. 4, it can be seen that θ is within a range of 10 to 40 °, and the deformation amount ratio can be suppressed to be extremely low in a region within the range of the following expression (1).
[0036]
R ≧ 10 ^(2- θ ^{/ 45)} Equation (1)
(However, the unit of R is mm and 10 ° ≦ θ ≦ 40 °)
(2) Example 2
Next, a battery in which the Sn concentration in the lead alloy sheet and the polarity of the electrode plate accommodated in the bag-like separator were changed with respect to the battery 9 and the battery 22 shown in Table 1 of Example 1 was prepared. These batteries are shown in Table 2.
[0037]
[Table 2]

[0038]
The batteries shown in Table 2 were subjected to a life cycle test in which charging and discharging were repeated. The test conditions were a constant voltage discharge of 14.8 V for 1 week in a 40 ° C. atmosphere and a constant current discharge for 5 seconds at 300 A in a 25 ° C. atmosphere. These charging and discharging were repeated, and the time when the voltage at the 5th discharge was reduced to 7.2 V was defined as the life cycle number. The results of these life tests are shown in FIG.
[0039]
From the results shown in FIG. 5, in the region where the Sn concentration in the Pb—Ca—Sn alloy used for the positive electrode lattice is 1.20% by mass or more, the battery of the comparative example has a sudden decrease in life. On the other hand, the batteries of the present invention show good life characteristics even if Sn is 1.20% by mass or more.
[0040]
Among them, the battery of the present invention example in which the negative electrode plate was housed in a bag-like separator showed extremely excellent life characteristics.
[0041]
In the battery of the comparative example in which the Sn concentration was 1.20% by mass or more, the deformation of the upper frame bone of the positive electrode lattice was concentrated in one place, and the upper frame bone was bent at that point. On the other hand, in the example of the present invention, even at such an Sn concentration, the deformation of the upper frame bone was not concentrated in one place, and the deformation was dispersed. Further, as the Sn concentration was decreased to less than 1.20% by mass, the entire upper frame bone was deformed from the deformation in which the upper frame bone was bent at a single location. Further, the life cycle number itself decreased as the Sn concentration decreased. Therefore, according to the present invention, extremely good life characteristics can be obtained even in a region where the Sn concentration is 1.20% by mass or more.
[0042]
In particular, in the present invention, since the amount of the falling active material can be suppressed by suppressing the deformation of the positive electrode grid, it is not necessary to store a conventional positive electrode plate in the bag-shaped separator. Therefore, the problem when the positive electrode plate is accommodated in the bag-shaped separator, that is, the short-circuit between the positive electrode and the negative electrode due to the breakage of the bottom of the bag-shaped separator can be avoided.
[0043]
【The invention's effect】
As described above, according to the configuration of the present invention, since it is possible to solve the problem of battery life reduction due to lattice deformation and active material loss caused by corrosion, and to provide a long-life lead storage battery, industrially, Useful.
[Brief description of the drawings]
FIG. 1 is a diagram showing a positive electrode lattice according to the present invention. FIG. 2 is a diagram showing an expanded mesh. FIG. 3 is a diagram showing a deformation amount measurement position of an upper frame bone. FIG. 5 is a diagram showing the life test results. FIG. 6 is a diagram showing a conventional expanded lattice.
DESCRIPTION OF SYMBOLS 100 Positive electrode grid 101 Upper frame bone 102 Current collecting ear part 103 Expanded mesh 104 (Upper frame bone) part 105 Inclined part 106 Parallel part 107 Connection part 108 Extension line 109 Extension line 201 Expanding mesh 202 Cutting line 300 Positive electrode grid 301 Upper frame Bone 601 Expanded lattice 602 Expanded mesh 603 Lower frame bone 604 Upper frame bone 605 Current collecting ear

Claims

With an expanded mesh formed by developing a lead alloy sheet containing Sn in an amount of 1.2% by mass or more and 2.0% by mass or less in a net shape, and having a current collector on an upper frame bone provided in contact with the expand mesh, A positive electrode grid of a lead storage battery in which the current collector is eccentrically provided from a center line of the expanded mesh, corresponding to the end of the expanded mesh in the center line direction from the current collecting ear of the upper frame bone The portion having the sloped portion having the height dimension (h) decreased as it approaches the end portion of the expanded mesh from the current collecting portion, and the height dimension (h) provided corresponding to the end portion of the expanded mesh. An arc-shaped connecting portion that includes a constant parallel portion and connects the inclined portion and the parallel portion with a curved line is formed, and an extension line at the upper end of the inclined portion and an extension line at the upper end of the parallel portion are formed. The angle is θ (°), and the radius of the arc shape is A positive electrode lattice body for a lead-acid battery, characterized in that, when R (mm), the θ is 10 to 40 °, and the relationship between the θ and the R is represented by the following formula (1) .
R ≧ 10 ^(2- θ ^{/ 45)} (1)

A lead-acid battery comprising a positive electrode plate filled with an active material in the positive electrode grid body according to claim 1 .

The lead acid battery according to claim 2 , further comprising an electrode plate group using a bag-shaped separator containing a negative electrode plate and the positive electrode plate.