JP3584076B2

JP3584076B2 - Electrode composition

Info

Publication number: JP3584076B2
Application number: JP03508195A
Authority: JP
Inventors: 正樹池松
Original assignee: Nippon Oil Corp
Current assignee: Eneos Corp
Priority date: 1995-02-23
Filing date: 1995-02-23
Publication date: 2004-11-04
Anticipated expiration: 2019-11-04
Also published as: JPH08236140A

Description

【０００１】
【産業上の利用分野】
この発明は、自動車用電池の電極組成物に関する。さらに詳しくは、始動特性および高温における耐久性にすぐれた電極組成物に関する。
【０００２】
【従来の技術】
ガソリンエンジン、デイーゼルエンジン等のエンジンを搭載する自動車の自動車用電池はエンジン始動時の電力供給、点灯負荷に対する電力供給等に不可欠のものである。このような役割を有する電池は、電極材料と電解液の選定によってその基本特性が定められる。
【０００３】
種々の金属の組み合わせによる代表的な電池の例を表１に示す。鉛電池は正極に鉛、負極に鉛酸化物を電極材料として用い、また電解液に硫酸水溶液を利用するもので１９世紀末には基本技術が提案されたが、その後、現在に至るまで実用電池の主流である。その理由は鉛電池のバランスの良さと信頼性の高さおよび鉛材料の安価と資源量の豊富さに支えられた費用対効果の良さなどにある。表１のように種々の新型電池が開発中であり理論特性からは鉛電池を上回る高性能が期待されるが、自動車用等の大型実用電池分野では、少なくとも今世紀内は鉛電池が主力と判断される。
【０００４】
【表１】

【０００５】
【発明が解決しようとする課題】
近年自動車側の環境の変化すなわち電気負荷の増加、コンピューター制御、エンジンルーム内の高温化等に伴い、自動車用電池の大容量、高始動性、高温耐久性が要求されている。この発明はこのような要求に応えるためになされたもので、その目的は鉛電池の改良された電極組成物を提供することにある。
【０００６】
【課題を解決するための手段】
この発明は、正極、負極および電解液からなる電極組成物において、
１．（１）鉛を合金の主成分とし、アンチモンを合金中１〜３重量％、銀、すず、ビスマス、テルル、ヒ素、セレン、イオウおよび銅からなる群より選ばれた少なくとも３種の物質を合金中１〜６重量％含有する格子合金、および
（２）二酸化鉛を活物質の主成分とし、活物質中０．７〜１．３重量％のグラファイトおよび０．３〜０．７重量％のゼオライトを混合してなる活物質
よりなる正極Ｘ重量部；
２．（３）鉛を合金の主成分とし、合金中０．０７〜０．１２重量％のカルシウムおよび０．０１５〜０．０３重量％のアルミニウムを含有する格子合金、および
（４）海綿状鉛を活物質の主成分とし、ピロカテキン、フミン酸、硫酸バリウムおよび炭素からなる群より選ばれた少なくとも２種の物質を活物質中０．５〜５重量％含有する活物質よりなる負極Ｙ重量部；ならびに
３．温度２０℃において１．２６〜１．２８の比重を有する稀硫酸である電解液Ｄ重量部よりなり、
上記Ｘ，ＹおよびＤが下記式
Ｄ＝ｑ×（Ｘ＋Ｙ），Ｙ＝（１．０〜１．２）×Ｘ
（但し、１．５≧ｑ≧１．３である）
で表わされる電極組成物である。
【０００７】
正極は上述のように（１）鉛を主成分とする鉛合金と、（２）二酸化鉛を主成分とする活物質とより成る。（１）鉛合金は活物質を保持し、かつ電流の導体であり、格子合金とも称される。正極の格子合金としては、従来機械的強度に劣る純鉛にかえて、より機械的強度のすぐれた鉛アンチモン合金、鉛カルシウム合金が提案されていた。鉛アンチモン合金は、深い放電を繰り返す重負荷に耐久性があるが、水素の過電圧を低下させるので、自己放電や水の電気分解をひきおこす等の欠点があった。鉛カルシウム合金は、鋳造性が劣り、深い放電、高温での急激な容量低下などの欠点があった。本発明者は種々検討の結果、アンチモンは前述のように水素過電圧を低下させるため、できるだけ少量におさえる必要があるが、少なすぎると合金の結晶粒が粗くなり鋳造性が悪化するが鉛を主成分とし、少量のアンチモンを加え、さらに、銀、すず、グラファイト、ビスマス、テルル、ゼオライト、ヒ素、セレン、イオウ、銅から選ばれた少なくとも３物質を加えることにより合金の結晶が微細化し、鋳造性が良好になることを見出した。
【０００８】
ここで鉛以外の成分の合金中の含有量はアンチモンが１〜３重量％、その他の成分が１〜６重量％の範囲で、好ましくは上記１０種の成分すべてが合金中に含まれるものである。
【０００９】
正極の上記格子合金に保持される活物質は、二酸化鉛を主成分とし、全活物質中０．７〜１．３重量％のグラファイトおよび０．３〜０．７重量％のゼオライトを混和してなるものである。
グラファイトおよびゼオライトは放電容量の向上効果を有し、上記含有量の範囲外のものはこれらの作用の発現が充分に行われない。
【００１０】
負極は、上述のように（３）鉛を主成分とする鉛合金と（４）海綿状鉛を主成分とする活物質とよりなる。（３）鉛合金は、活物質を保持し、かつ電流の導体であり、格子合金とも称される。負極の格子合金としては、自己放電の大きい鉛アンチモン合金に代えてカルシウムおよびアルミニウムをそれぞれ０．０７〜０．１２重量％および０．０１５〜０．０３重量％を含む鉛合金が好ましいことがわかった。カルシウムは自己放電の抑制作用を、アルミニウムは酸化防止作用を有し、上記含有量の範囲外のものは、これらの作用の発現は不充分である。
【００１１】
負極の上記格子合金に保持される活物質は海綿状鉛に、ピロカテキン（カテコール）、フミン酸、硫酸バリウム、および炭素からなる群から選ばれた少なくとも２種の物質を、活物質中０．５〜５重量％含むものである。
ピロカテキン、フミン酸、および硫酸バリウムは防縮および放電容量向上の作用を、炭素は放電容量の向上、耐久性の向上の作用を有し、含有量の合計が５重量％を超えると活物質としての性能の発現を阻害し、０．５％未満では上記作用の発現が不充分となる。
【００１２】
電解液は２０℃で比重が１．２６〜１．２８である稀硫酸が好ましい。比重が１．２６より小さいと電池の容量が低下する。濃度が高くなるにしたがって電池の容量は増加するが、高濃度では電気抵抗が大になり、また粘度も高くなってかえって容量の減少を招く。また活物質の劣化や格子金属の腐食を促進する。したがって比重の上限は１．２８が適当である。
【００１３】
上記正極、負極、および電解液とからなる鉛電池において、さらにこれらの重量的な関係が、正極重量Ｘ、負極重量Ｙおよび電解液重量Ｄとの間に
Ｄ＝ｑ×（Ｘ＋Ｙ），Ｙ＝（１．０〜１．２）×Ｘ
（但し、１．５≧ｑ≧１．３）
であることが好ましいことがわかった。ｑが１．５をこえると始動性が劣り、１．３未満であると寿命が短くなる。
【００１４】
なお本願発明の正極の格子金属は片面に活物質を保持しつつ電槽内に垂直に配置されるが、その格子金属の下端に水平に側板をとりつけ断面がＬ字型になるようにし、この際側板がＳｉおよびＳｉＯ_２よりなり、活物質の脱落を防ぐのが好ましい。但し、この側板の重量は、前記重量Ｘには含まれないものである。
【００１５】
【実施例】
以下、本発明を参考例により説明する。
参考例１．
正極格子金属として
鉛９６．８重量％
アンチモン１．５重量％
銀０．２重量％
すず０．５重量％
グラファイト０．２重量％
ビスマス０．２重量％
テルル０．２重量％
ゼオライト０．２重量％
ヒ素０．１５重量％
セレン０．０３重量％
イオウ０．０１重量％
銅０．０１重量％
からなる鉛合金を用い、活物質として
二酸化鉛９８．５重量％
グラファイト１．０重量％
ゼオライト０．５重量％
の混合物を保持させ正極とした。
【００１６】
負極格子金属として
鉛９９．８８重量％
カルシウム０．１０重量％
アルミニウム０．０２重量％
からなる鉛合金を用い、活物質として
海綿状鉛９９．２５重量％
ピロカテキン０．５０重量％
フミン酸０．１０重量％
硫酸バリウム０．１０重量％
炭素０．０５重量％
の混合物を保持させ負極とした。
【００１７】
電解液は２０℃において１．２６０の比重を有する硫酸水溶液を用いた。
正極＋負極の重量の１．４倍の電解液を用いたＤ−２６型電池を組立て、コールドクラッキング電流（ＣＣＡ）の測定および、エンジンルーム内の高温化に対応して７５℃における寿命試験を同型の市販品と比較して行った。
ＣＣＡの測定は、低温下で完全充電した電池を用い、−１８℃の条件下で端子電圧が３０秒目に７．２Ｖとなる際の放電電流を測定した。高い電流値ほど低温始動性が良いことを示す。
測定の結果、市販標準品６７０Ａ、市販最高級品７３５Ａに対し、実施例１の電池においては７７５Ａを示し、本願発明のすぐれていることが明らかになった。高温での寿命試験は７５℃の状態下で２５Ａで４分間の放電と１４．８Ｖで１０分間の充電を１回として充放電回数（サイクル）を繰り返し、Ｄ−２６型電池に定められた判定電流５８２Ａを流した際の３０秒目電圧が７．２Ｖ以下になる回数を寿命回数として測定した。
測定結果を図１に示す。この図により従来の市販最高級品と比較して本発明品の高温下での長寿命化および長期にわたる高性能の持続が証明された。
【００１８】
【発明の効果】
以上説明したように、本発明の電極組成物は、これを組み込んだ鉛電池は、低温始動性および高温耐久性にすぐれ、高性能の自動車用電池を提供することができる。
【図面の簡単な説明】
【図１】本発明の電極組成物を組み込んだ鉛電池の高温における寿命を従来品と比較した図である。[0001]
[Industrial applications]
The present invention relates to an electrode composition for an automotive battery. More specifically, the present invention relates to an electrode composition having excellent starting characteristics and durability at high temperatures.
[0002]
[Prior art]
2. Description of the Related Art An automobile battery for an automobile equipped with an engine such as a gasoline engine or a diesel engine is indispensable for supplying electric power when starting the engine, supplying electric power to a lighting load, and the like. The basic characteristics of a battery having such a role are determined by selecting an electrode material and an electrolytic solution.
[0003]
Table 1 shows examples of typical batteries using various combinations of metals. Lead batteries use lead for the positive electrode, lead oxide for the negative electrode, and an aqueous solution of sulfuric acid for the electrolyte. Basic technologies were proposed at the end of the 19th century. Mainstream. The reasons are the good balance and high reliability of lead batteries and the cost-effectiveness supported by the low cost and abundant resources of lead materials. As shown in Table 1, various new batteries are under development, and theoretical characteristics are expected to outperform lead batteries. However, in the field of large practical batteries such as automobiles, lead batteries are considered to be the mainstay for at least this century. Is done.
[0004]
[Table 1]

[0005]
[Problems to be solved by the invention]
2. Description of the Related Art In recent years, with a change in the environment on the vehicle side, that is, an increase in electric load, computer control, a high temperature in an engine room, and the like, a large capacity, high startability, and high-temperature durability of a vehicle battery have been required. The present invention has been made to meet such a demand, and an object of the present invention is to provide an improved electrode composition for a lead battery.
[0006]
[Means for Solving the Problems]
The present invention provides a positive electrode, a negative electrode and an electrode composition comprising an electrolytic solution ,
1. (1) lead as the main component of the alloy, antimony 1-3 wt% in the alloy, silver, tin, bismuth, tellurium, arsenic, selenium, at least three materials selected from the group consisting of sulfur and copper the grid alloy containing 1-6 wt% in the alloy, and (2) lead dioxide as a main component of the active material, 0.7 to 1.3 wt% of graphite and 0.3 to 0.7 wt active material % Of a positive electrode composed of an active material obtained by mixing a zeolite in an amount of 10% by weight ;
2. (3) a lattice alloy containing lead as a main component of the alloy and containing 0.07 to 0.12% by weight of calcium and 0.015 to 0.03% by weight of aluminum in the alloy; and (4) spongy lead. As a main component of the active material, a negative electrode Y part by weight of an active material containing 0.5 to 5% by weight in the active material of at least two kinds of substances selected from the group consisting of pyrocatechin, humic acid, barium sulfate and carbon And 3. An electrolyte D which is a diluted sulfuric acid having a specific gravity of 1.26 to 1.28 at a temperature of 20 ° C.,
The above X, Y and D are represented by the following formula: D = q × (X + Y), Y = (1.0 to 1.2) × X
(However, 1.5 ≧ q ≧ 1.3)
An electrode composition represented by
[0007]
As described above, the positive electrode is composed of (1) a lead alloy mainly containing lead, and (2) an active material mainly containing lead dioxide. (1) A lead alloy holds an active material and is a current conductor, and is also called a lattice alloy. As a positive electrode lattice alloy, a lead-antimony alloy and a lead-calcium alloy having better mechanical strength have been proposed instead of pure lead having poor mechanical strength. Lead-antimony alloys are durable to heavy loads that repeat deep discharges, but have the drawback of causing self-discharge and electrolysis of water because they reduce the overvoltage of hydrogen. Lead-calcium alloys have drawbacks such as poor castability, deep discharge, and a sharp drop in capacity at high temperatures. As a result of various studies, the inventor of the present invention has to reduce the amount of antimony as described above in order to reduce the hydrogen overvoltage, but if it is too small, the crystal grains of the alloy become coarse and castability deteriorates, but lead is mainly used. As a component, a small amount of antimony is added, and further, at least three substances selected from silver, tin, graphite, bismuth, tellurium, zeolite, arsenic, selenium, sulfur, and copper are added to refine the crystal of the alloy, thereby improving castability. Was found to be good.
[0008]
Here, the content of the components other than lead in the alloy is in the range of 1 to 3% by weight of antimony and 1 to 6% by weight of the other components, and preferably all of the above 10 components are contained in the alloy. is there.
[0009]
The active material held by the lattice alloy of the positive electrode contains lead dioxide as a main component, and is mixed with 0.7 to 1.3% by weight of graphite and 0.3 to 0.7% by weight of zeolite in the total active material. It is.
Graphite and zeolite have the effect of improving the discharge capacity, and those having a content outside the above range do not exhibit these effects sufficiently.
[0010]
As described above, the negative electrode is composed of (3) a lead alloy mainly containing lead and (4) an active material mainly containing spongy lead. (3) A lead alloy holds an active material and is a conductor of electric current, and is also called a lattice alloy. As the lattice alloy of the negative electrode, a lead alloy containing 0.07 to 0.12% by weight and 0.015 to 0.03% by weight of calcium and aluminum, respectively, is preferable in place of the lead-antimony alloy having a large self-discharge. Was. Calcium has an effect of suppressing self-discharge, and aluminum has an antioxidant effect. If the content is outside the above range, these effects are insufficiently exhibited.
[0011]
The active material held in the lattice alloy of the negative electrode is spongy lead, and at least two kinds of substances selected from the group consisting of pyrocatechin (catechol), humic acid, barium sulfate, and carbon are added to the active material. It contains 5 to 5% by weight.
Pyrocatechin, humic acid, and barium sulfate act to prevent shrinkage and improve discharge capacity, and carbon has actions to improve discharge capacity and durability. When the total content exceeds 5% by weight, it becomes an active material. If the content is less than 0.5%, the expression of the above effect will be insufficient.
[0012]
The electrolytic solution is preferably dilute sulfuric acid having a specific gravity of 1.26 to 1.28 at 20 ° C. If the specific gravity is smaller than 1.26, the capacity of the battery decreases. As the concentration increases, the capacity of the battery increases. However, at a high concentration, the electric resistance increases and the viscosity also increases, resulting in a decrease in the capacity. In addition, it promotes deterioration of the active material and corrosion of the lattice metal. Therefore, the upper limit of the specific gravity is appropriately 1.28.
[0013]
In the above lead battery including the positive electrode, the negative electrode, and the electrolyte, the weight relationship between the positive electrode weight X, the negative electrode weight Y, and the electrolyte weight D is D = q × (X + Y), Y = (1.0-1.2) × X
(However, 1.5 ≧ q ≧ 1.3)
Was found to be preferable. If q exceeds 1.5, startability is poor, and if it is less than 1.3, the life is shortened.
[0014]
The grid metal of the positive electrode of the present invention is vertically arranged in the battery case while holding the active material on one side, and a horizontal side plate is attached to the lower end of the grid metal so that the cross section becomes L-shaped. Preferably, the side plate is made of Si and SiO ₂ to prevent the active material from falling off. However, the weight of the side plate is not included in the weight X.
[0015]
【Example】
Hereinafter, the present invention will be described by reference examples.
Reference Example 1.
96.8% by weight of lead as positive grid metal
Antimony 1.5% by weight
Silver 0.2% by weight
Tin 0.5% by weight
Graphite 0.2% by weight
Bismuth 0.2% by weight
Tellurium 0.2% by weight
0.2% by weight of zeolite
Arsenic 0.15% by weight
Selenium 0.03% by weight
Sulfur 0.01% by weight
Copper 0.01% by weight
98.5% by weight of lead dioxide as active material
Graphite 1.0% by weight
Zeolite 0.5% by weight
The mixture was retained to obtain a positive electrode.
[0016]
99.88% by weight lead as negative electrode grid metal
0.10% by weight of calcium
0.02% by weight of aluminum
99.25% by weight spongy lead as active material
Pyrocatechin 0.50% by weight
Humic acid 0.10% by weight
Barium sulfate 0.10% by weight
0.05% by weight of carbon
The mixture was kept as a negative electrode.
[0017]
As the electrolyte, an aqueous solution of sulfuric acid having a specific gravity of 1.260 at 20 ° C. was used.
Assembling a D-26 type battery using 1.4 times the weight of the positive electrode + the negative electrode, measuring the cold cracking current (CCA), and conducting a life test at 75 ° C in response to the high temperature in the engine room The comparison was made with a commercial product of the same type.
The CCA was measured using a battery that was fully charged at a low temperature, and the discharge current when the terminal voltage reached 7.2 V at 30 seconds under a condition of −18 ° C. A higher current value indicates better cold startability.
As a result of the measurement, the battery of Example 1 showed 775 A in comparison with the commercially available standard product 670 A and the commercially available high-grade product 735 A, indicating that the present invention is superior. The life test at a high temperature is repeated at a temperature of 75 ° C. with a discharge at 25 A for 4 minutes and a charge at 14.8 V for 10 minutes as one cycle, and the number of cycles (cycles) is repeated. The number of times that the voltage at the 30th second when the current 582A was supplied became 7.2 V or less was measured as the number of lifetimes.
FIG. 1 shows the measurement results. From this figure, it was proved that the product of the present invention has a longer life at a high temperature and a long-lasting high performance as compared with the conventional high-end product on the market.
[0018]
【The invention's effect】
As described above, a lead battery incorporating the electrode composition of the present invention is excellent in low-temperature startability and high-temperature durability, and can provide a high-performance automotive battery.
[Brief description of the drawings]
FIG. 1 is a diagram comparing the life at high temperature of a lead battery incorporating an electrode composition of the present invention with a conventional battery.

Claims

In an electrode composition comprising a positive electrode, a negative electrode and an electrolytic solution ,
Lead as a main component of the alloy, antimony 1-3 wt% in the alloy, silver, tin, bismuth, tellurium, arsenic, selenium, at least three substances in the alloy selected from the group consisting of sulfur and copper A lattice alloy containing 1 to 6% by weight, and
Two lead oxide as the main component of the active material, the positive electrode X parts by weight consisting of the active material obtained by mixing an active material in 0.7 to 1.3 wt% of graphite and 0.3 to 0.7 wt% zeolite ;
Lead as a main component of the alloy, the lattice alloy containing 0.07 to 0.12 wt% of calcium and 0.015 to 0.03 weight percent aluminum in the alloy, and the sea flocculent lead active material composed mainly And a Y part by weight of an active material containing 0.5 to 5% by weight of at least two materials selected from the group consisting of pyrocatechin, humic acid, barium sulfate and carbon in the active material ;
In temperature 20 ° C. consists electrolyte D parts by weight of dilute sulfuric acid having a specific gravity of 1.26 to 1.28,
The above X, Y and D are represented by the following formula: D = q × (X + Y), Y = (1.0 to 1.2) × X
(However, 1.5 ≧ q ≧ 1.3)
An electrode composition represented by the formula:

The electrode composition according to claim 1, wherein a cross section of the positive electrode has an L shape, and a horizontal portion is made of silicon and silicon oxide.