JPH0430145B2 - - Google Patents
Info
- Publication number
- JPH0430145B2 JPH0430145B2 JP57222313A JP22231382A JPH0430145B2 JP H0430145 B2 JPH0430145 B2 JP H0430145B2 JP 57222313 A JP57222313 A JP 57222313A JP 22231382 A JP22231382 A JP 22231382A JP H0430145 B2 JPH0430145 B2 JP H0430145B2
- Authority
- JP
- Japan
- Prior art keywords
- hydroxide
- zinc
- nickel
- cadmium
- positive electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
Description
産業上の利用分野
本発明は、密閉形ニツケル−カドミウム蓄電池
の改良に関するものである。
従来例の構成とその問題点
密閉形ニツケル−カドミウム蓄電池は、水酸化
ニツケルを主体とする正極と、水酸化カドミウム
を主体とする負極と、正、負両極を隔離するセパ
レータと、電解液としての水酸化カリウム、水酸
化ナトリウム、水酸化リチウム等のアルカリ水溶
液とから構成されている。
負極としては、一般に焼結式、ペースト式等の
カドミウム極が用いられ、正極としては、多孔性
ニツケル焼結基板に、電解法、化学含浸法等の手
段によつて、正極活物質となる水酸化ニツケル、
水酸化コバルト等を充填したものが用いられてい
る。また最近ではスポンジ状の金属ニツケル基板
に、水酸化ニツケルを主体とした活物質ペースト
を充填した、高容量を有するニツケル正極も提案
されている。
従来の焼結式ニツケル正極の活物質充填工程
は、例えば化学含浸法のように含浸工程、アルカ
リ処理工程、水洗工程、乾燥工程等、数多くの工
程が必要であり、高容量の正極を得るためには、
これら工程の数回に及ぶ繰り返しが必要となり、
非常に煩雑となつている。
一方、スポンジ状の金属ニツケル基板（90〜95
％の多孔度）を用いる方法は、孔径の大きいもの
が選択できることにより、基板中にペースト状の
活物質を直接充填でき、しかも充填後、加圧加工
を行うだけの簡単な工程で、高容量を有するニツ
ケル正極の製造が可能である。また正極板の特性
としては、容量面では、従来の焼結式の正極板の
単位体積当りの容量密度が350〜450ｍAh／cm6程
度であるのに対し、470〜520ｍAh／cm6程度の高
容量が得られ、大電流での放電特性も、焼結式の
ものと同等の性能が得られる。
しかし、従来のスポンジ状の金属ニツケル基板
を用いる正極（以下スポンジメタル正極という）
は、焼結式ニツケル正極に比べ、その基板の物理
強度が弱く、充電、放電の繰り返しによつて、極
板のふくれを生じ、正負極間に設置されたセパレ
ータを圧縮し、充放電特性に大きく寄与するセパ
レータ中の電解液を押し出して、放電特性を劣化
させる傾向が焼結式正極に比べて大きかつた。す
なわち、充電用サイクル寿命は、焼結式に比べ若
干劣つているという欠点があつた。
また、充放電サイクルによる放電々圧の低下度
合いも、従来の焼結式正極に比べ若干大きくなつ
ている。
発明の目的
本発明は、以上のようなスポンジメタル正極の
サイクル寿命特性を改善するもので、正極活物質
組成を改良することにより、充電用サイクル、と
くに低温での充放電サイクルによる容量低下と、
放電々圧低下を抑制することを目的とする。
発明の構成
本発明は、正極活物質としての水酸化ニツケル
を主体とし、これに導電材としての金属ニツケル
粉末、活物質の利用率を高めるための金属コバル
ト粉末、さらに充放電サイクルによる容量低下を
防止するための水酸化カドミウム及び容量低下を
防止し、かつ放電々圧を高める作用を有する水酸
化亜鉛、亜鉛、亜鉛酸化物のいずれかまたは混合
物を添加した構成の活物質混合物をスポンジ状ニ
ツケル基板に充填した正極を用いることを特徴と
する密閉形ニツケル−カドミウム蓄電池である。
以下に本発明の原理を説明する。
密閉形ニツケル−カドミウム蓄電池において、
充電、放電特性を維持させるためには、正極、負
極及びその間に設置されたセパレータ内に、充放
電反応に寄与するアルカリ電解液が適度に分布し
ていなければならない。
充放電の繰り返しによる充放電特性の劣化、す
なわち充放電サイクル寿命劣化の大きな原因とし
ては、充放電の繰り返しによる電解液分布の不均
一化がある。
正極、負極の両活物質は、それぞれ充電時、放
電時において異なつた体積を有するため、両極、
特に正極は充電放の繰り返しによつて膨張、収縮
を繰り返し、次第に電極全体が膨張する傾向があ
る。
このようにして膨張した正極板は、セパレータ
を圧縮し、セパレータ中に分布していた電解液を
押し出して電解液の分布は不均一となり、電池の
充電、放電特性が劣化する。
このような傾向は、スポンジ状金属ニツケル基
板などのようにその基板強度の弱いもの、あるい
は活物質密度、容量密度の高い極板ほど大きい。
つまり、単位体積当たりの放電容量が大きいほど
この膨張傾向が大きくなる。
また、充放電の繰り返しを行う雰囲気温度を見
ると、正極活物質が深い充電を受けやすい（充電
容量も大きくなる）低温側で、その傾向が特に大
きくなる。これは、正極活物質の水酸化ニツケル
の充電受け入れ性の温度差によるもので、常温で
は水酸化ニツケル活物質の理論容量に対し、90〜
95％の活物質が充放電反応に寄与するが、低温で
は水酸化ニツケルが、さらに深い充電を受け通常
の理論容量以上の値を示すことがある。
このように低温で深い充電、放電を受けた水酸
化ニツケルの膨張、収縮は大きく、充電放電サイ
クル時の正極の膨張を促進する。
スポンジメタル正極の充放電サイクル寿命特性
は、常温あるいは高温側では、従来の焼結式正極
と同等の長寿命を有するが、低温においては焼結
式に比べ若干劣つていた。
従来のスポンジメタル正極の活物質組成は、水
酸化ニツケル、金属コバルト、金属ニツケルより
成つていたが、本発明者らは低温側でのサイクル
寿命特性の劣化が上記のような理由によるもので
あることに鑑み、従来の活物質組成を変更するこ
とによつて、低温でのサイクル寿命特性を向上す
ることを試みた。その結果、正極活物質としての
水酸化ニツケル、金属コバルト、金属ニツケルの
混合物に、水酸化カドミウムあるいは亜鉛もしく
は水酸化亜鉛、酸化亜鉛等の亜鉛化合物を付加す
ることにより、低温側での充電の受け入れ性が抑
制されることにより、充放電サイクル時の正極板
のふくれも低減され、充放電サイクルによる容量
劣化が大幅に改善されることを見い出した。
また、このようなサイクルによる容量劣化抑制
の効果は、亜鉛または亜鉛化合物よりも、水酸化
カドミウムの方が優れている。しかし、亜鉛また
は亜鉛化合物を添加したものは、放電時の電圧が
高くなる。この理由は明らかでないが、亜鉛また
は亜鉛化合物の添加により、充電時に水酸化ニツ
ケルが放電々圧の高い高次の酸化物になることに
よるものと思われる。
以上のようにサイクル寿命特性の容量維持特
性、放電々圧の低下防止の両面を同時に改良する
ためには、水酸化カドミウムと、亜鉛または水酸
化亜鉛、酸化亜鉛等の亜鉛化合物を適当な割合、
すなわち重量比で８：２〜２：８の範囲で水酸化
ニツケルに対しその20重量％以下ですればよいも
のと思われる。
実施例の説明
以下、実施例によつて、本発明を詳細に説明す
る。
正極基板としては、多孔度95％を有するスポン
ジ状の金属ニツケルを用いた。また、正極活物質
混合物としては、水酸化ニツケル、金属コバルト
粉末、金属ニツケル粉末、水酸化カドミウム及び
水酸化亜鉛の混合物を用い、これに水と少量の結
着剤、例えばカルボキシメチルセルロースを加え
てペースト状にした。
次表は、実施例において検討した活物質混合物
組成の重量比率を示したものである。
INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to improvements in sealed nickel-cadmium storage batteries. Conventional structure and its problems A sealed nickel-cadmium storage battery consists of a positive electrode mainly composed of nickel hydroxide, a negative electrode mainly composed of cadmium hydroxide, a separator that isolates the positive and negative electrodes, and an electrolytic solution. It is composed of aqueous alkaline solutions such as potassium hydroxide, sodium hydroxide, and lithium hydroxide. As the negative electrode, a sintered or paste type cadmium electrode is generally used, and as the positive electrode, water, which becomes the positive electrode active material, is added to a porous sintered nickel substrate by means such as electrolysis or chemical impregnation. nickel oxide,
Those filled with cobalt hydroxide or the like are used. Recently, a high-capacity nickel positive electrode has also been proposed, in which a sponge-like metallic nickel substrate is filled with an active material paste mainly composed of nickel hydroxide. The conventional active material filling process for sintered nickel positive electrodes requires many steps, such as chemical impregnation, an alkali treatment process, a water washing process, and a drying process, to obtain a high-capacity positive electrode. for,
These steps need to be repeated several times,
It has become very complicated. On the other hand, a sponge-like metal nickel substrate (90~95
% porosity), it is possible to directly fill the paste-like active material into the substrate by selecting a material with a large pore diameter, and it is also a simple process of pressurizing the substrate after filling, resulting in high capacity. It is possible to manufacture a nickel positive electrode having the following properties. In terms of capacity, the positive electrode plate has a high capacity density of about 470 to 520 mAh/cm 6 , whereas the capacity density per unit volume of conventional sintered positive electrode plates is about 350 to 450 mAh/cm 6 . Capacity is obtained, and discharge characteristics at large currents are equivalent to those of the sintered type. However, the conventional positive electrode using a sponge-like metal nickel substrate (hereinafter referred to as a sponge metal positive electrode)
The physical strength of the substrate is weaker than that of sintered nickel positive electrodes, and repeated charging and discharging causes the electrode plates to bulge, compressing the separator installed between the positive and negative electrodes, and affecting the charge-discharge characteristics. Compared to sintered positive electrodes, there was a greater tendency for the electrolytic solution in the separator, which contributes greatly, to be pushed out, thereby degrading the discharge characteristics. That is, the charging cycle life was slightly inferior to that of the sintered type. Furthermore, the degree of decrease in discharge pressure due to charge/discharge cycles is also slightly greater than that of conventional sintered positive electrodes. Purpose of the Invention The present invention improves the cycle life characteristics of the sponge metal positive electrode as described above, and by improving the composition of the positive electrode active material, the capacity decrease due to charging cycles, especially low-temperature charging/discharging cycles, is reduced.
The purpose is to suppress the drop in discharge pressure. Structure of the Invention The present invention mainly consists of nickel hydroxide as a positive electrode active material, metal nickel powder as a conductive material, metal cobalt powder to increase the utilization rate of the active material, and furthermore, to reduce capacity loss due to charge/discharge cycles. A sponge-like nickel substrate is coated with an active material mixture containing cadmium hydroxide to prevent capacity reduction, and zinc hydroxide, zinc, and zinc oxide, which have the effect of preventing capacity reduction and increasing discharge pressure, or a mixture thereof. This is a sealed nickel-cadmium storage battery characterized by using a positive electrode filled with nickel-cadmium. The principle of the present invention will be explained below. In sealed nickel-cadmium storage batteries,
In order to maintain charging and discharging characteristics, an alkaline electrolyte that contributes to the charging and discharging reactions must be appropriately distributed within the positive electrode, the negative electrode, and the separator installed between them. A major cause of deterioration of charge-discharge characteristics due to repeated charging and discharging, that is, deterioration of charge-discharge cycle life, is uneven distribution of electrolyte solution due to repeated charging and discharging. The active materials of the positive and negative electrodes have different volumes during charging and discharging, respectively.
In particular, the positive electrode tends to expand and contract repeatedly due to repeated charging and discharging, and the entire electrode tends to gradually expand. The positive electrode plate expanded in this way compresses the separator and pushes out the electrolyte distributed in the separator, resulting in uneven distribution of the electrolyte and deteriorating the charging and discharging characteristics of the battery. This tendency is greater for substrates with weaker strength, such as sponge-like metal nickel substrates, or electrode plates with higher active material density and higher capacity density.
In other words, the greater the discharge capacity per unit volume, the greater this expansion tendency becomes. Furthermore, when looking at the ambient temperature at which charging and discharging are repeated, the tendency is particularly strong at low temperatures where the positive electrode active material is more likely to undergo deep charging (the charging capacity is also increased). This is due to the temperature difference in charge acceptance of nickel hydroxide, which is the positive electrode active material.At room temperature, the theoretical capacity of nickel hydroxide active material is 90~
Although 95% of the active material contributes to charge/discharge reactions, at low temperatures the nickel hydroxide can undergo a deeper charge and exhibit a value higher than the normal theoretical capacity. As described above, nickel hydroxide undergoes deep charging and discharging at low temperatures and undergoes significant expansion and contraction, promoting expansion of the positive electrode during charging and discharging cycles. The charge/discharge cycle life characteristics of the sponge metal positive electrode were as long as those of conventional sintered positive electrodes at room temperature or high temperatures, but were slightly inferior to those of the sintered type at low temperatures. The active material composition of conventional sponge metal positive electrodes consisted of nickel hydroxide, metallic cobalt, and metallic nickel, but the present inventors found that the deterioration of cycle life characteristics at low temperatures was due to the above reasons. In view of this, an attempt was made to improve the cycle life characteristics at low temperatures by changing the composition of conventional active materials. As a result, by adding cadmium hydroxide or zinc or a zinc compound such as zinc hydroxide or zinc oxide to a mixture of nickel hydroxide, cobalt metal, and nickel metal as the positive electrode active material, it is possible to accept charging at low temperatures. It has been found that by suppressing this property, blistering of the positive electrode plate during charge/discharge cycles is also reduced, and capacity deterioration due to charge/discharge cycles is significantly improved. Furthermore, cadmium hydroxide is more effective in suppressing capacity deterioration due to such cycles than zinc or zinc compounds. However, when zinc or a zinc compound is added, the voltage during discharge becomes higher. Although the reason for this is not clear, it is thought that the addition of zinc or a zinc compound causes nickel hydroxide to become a higher-order oxide with a high discharge pressure during charging. As mentioned above, in order to simultaneously improve both the capacity maintenance characteristics of cycle life characteristics and prevention of decrease in discharge pressure, it is necessary to add cadmium hydroxide and zinc or zinc compounds such as zinc hydroxide or zinc oxide in appropriate proportions.
In other words, it is considered that the weight ratio should be in the range of 8:2 to 2:8 and the amount should be 20% by weight or less based on nickel hydroxide. DESCRIPTION OF EMBODIMENTS The present invention will now be described in detail with reference to Examples. As the positive electrode substrate, a sponge-like metal nickel having a porosity of 95% was used. In addition, as the positive electrode active material mixture, a mixture of nickel hydroxide, metal cobalt powder, metal nickel powder, cadmium hydroxide, and zinc hydroxide is used, and water and a small amount of a binder such as carboxymethyl cellulose are added to this to make a paste. It was made into a shape. The following table shows the weight ratios of the active material mixture compositions studied in the examples.
【表】
なお、負極には、通常のペースト式カドミウム
極を、また電解液には一般に使用されている水酸
化カリウムと水酸化リチウムとの混合水溶液を使
用した。
上記正極、負極を用い、1500ｍAh相当の密閉
形ニツケル−カドミウム蓄電池を試作し、電池容
量試験、及び充放電サイクル試験をした。
電池容量試験は、通常の方法で、20℃におい
て、150ｍＡの電流で16時間充電し、300ｍＡで放
電したときの電池容量を求めた。この電池容量と
正極板体積から求めた正極板単位体積当たりの容
量密度と、正極活物質混合物中の水酸化ニツケル
に対する水酸化カドミウム、水酸化亜鉛混合物の
重量比率との関係を第１図に示す。
サイクル寿命特性向上の目的で添加する水酸化
カドミウム、水酸化亜鉛は、電池容量には寄与し
ない。従つて第１図に示すように、正極板中の水
酸化カドミウム、水酸化亜鉛比率が増加するに従
つて正極の容量密度は低下し、その比率が20％以
上になると、正極の容量密度が従来の焼結式正極
のレベルに近づき、高容量を指向したスポンジメ
タル正極の特長が減少するとともに、水酸化カド
ミウムが凝集するため、スポンジ状ニツケル基板
への活物質の充填が困難となる問題も生じた。
第２図、第３図、第４図は、低温（０℃）での
充放電サイクル寿命特性を示す。充放電サイクル
の条件は、０℃において、500ｍＡの電流で４時
間30分充電し、1500ｍＡ相当の定抵抗で75分放電
する条件とした。
なお、図中の放電時間は、電池電圧が1.0Vと
なるまでの時間であり、放電平均電圧は、放電時
間の中点の電池電圧である。
第２図は、水酸化カドミウムの添加効果を示す
ものであり、図中のａ，ｂ，ｃは水酸化カドミウ
ムの添加比率が水酸化亜鉛に対して０、１、２％
のときの放電時間を表し、ｄは２％のときの放電
平均電圧を示している。
水酸化カドミウムを全く添加しない場合ａは、
放電時間が充放電回数とともに徐々に増大し、そ
の後急速に劣化することがわかる。これは先に述
べたように、充放電回数の進行とともに、充電の
受け入れ性が向上し、従つて放電時間も増大して
極板のふくれを生じ、その後電池特性が急速に劣
化したものと思われる。
水酸化カドミウムの添加比率が、水酸化ニツケ
ルに対して１％の場合ｂでは、まだ上記のような
傾向が認められる。水酸化ニツケルに対する添加
比率が２％の場合ｃでは、容量の劣化はほとんど
認められなくなる。第２図には、水酸化カドミウ
ム添加比率として２％までのみ表示しているが、
２％以上の添加でも、その特性は２％添加のもの
と同様であつた。
第３図は、同様な実験を水酸化亜鉛について行
つたものである。図中のｅ，ｆ，ｇは、それぞれ
水酸化亜鉛の添加比率が０、２、15％の場合の放
電時間を示すものであり、ｈは添加比率が15％の
ものの放電平均電圧を示すものである。図から明
らかなように、水酸化亜鉛を添加した場合は放電
時間の劣化抑制の効果は、水酸化カドミウムの場
合よりも小さいが、放電々圧が高いという特徴が
ある。
第４図は水酸化カドミウムと水酸化亜鉛の両者
をそれぞれ水酸化亜鉛に対する比率で５％添加し
たときの結果である。図から明らかなように両者
を同時に添加すると、放電時間の維持性、放電々
圧の特性の両面がともに改善されることがわか
る。
このように、サイクル寿命における放電時間の
特性、放電々圧の特性を同時に改善するために
は、水酸化カドミウムと水酸化亜鉛の相剰効果が
必要となる。この両者を添加する場合、添加の絶
対量も重要であるが、両者の比率も同時に重要と
なる。水酸化カドミウムに対する水酸化亜鉛の比
率が小さい場合は、放電容量特性のみが改善さ
れ、その逆の場合は、放電々圧面のみが改善され
る。種々検討した結果、水酸化カドミウムと水酸
化亜鉛との適正比率は重量比で２：８から８：２
程度であるという結果を得た。
また、実施例では亜鉛化合物として水酸化亜鉛
のみを示したが、亜鉛、あるいは酸化亜鉛を用い
ても、水酸化亜鉛と同様な効果が得られる。
このように、従来のスポンジメタル正極の活物
質混合物に、水酸化カドミウムと亜鉛もしくは水
酸化亜鉛等の亜鉛化合物を適正な割合で添加する
と、サイクル寿命特性が大幅に改善される。添加
量としては、両者の効果が発揮される最低量がそ
れぞれ水酸化ニツケルに対して２重量％であり、
また、容量密度の問題から両者の合計量は20重量
％以下である。両者の比率は２：８〜８：２の範
囲の間にあることが好ましい。
発明の効果
以上のように、本発明によれば、スポンジ状ニ
ツケル基板に水酸化ニツケルを主とする活物質混
合物を充填した正極を用いる密閉形ニツケル−カ
ドミウム蓄電池の充放電サイクル寿命特性を改善
することができる。[Table] A normal paste-type cadmium electrode was used as the negative electrode, and a commonly used mixed aqueous solution of potassium hydroxide and lithium hydroxide was used as the electrolyte. Using the above positive and negative electrodes, a sealed nickel-cadmium storage battery with a capacity of 1500 mAh was prototyped, and a battery capacity test and a charge/discharge cycle test were conducted. In the battery capacity test, the battery capacity was determined by charging at 20° C. for 16 hours at a current of 150 mA and discharging at 300 mA using the usual method. Figure 1 shows the relationship between the capacity density per unit volume of the positive electrode plate determined from the battery capacity and the positive electrode plate volume, and the weight ratio of the cadmium hydroxide and zinc hydroxide mixture to nickel hydroxide in the positive electrode active material mixture. . Cadmium hydroxide and zinc hydroxide, which are added for the purpose of improving cycle life characteristics, do not contribute to battery capacity. Therefore, as shown in Figure 1, as the ratio of cadmium hydroxide and zinc hydroxide in the positive electrode plate increases, the capacity density of the positive electrode decreases, and when the ratio exceeds 20%, the capacity density of the positive electrode decreases. The characteristics of the sponge metal cathode, which approaches the level of conventional sintered cathodes and aims for high capacity, are diminished, and cadmium hydroxide aggregates, making it difficult to fill the sponge-like nickel substrate with active material. occured. FIG. 2, FIG. 3, and FIG. 4 show charge/discharge cycle life characteristics at low temperature (0° C.). The charging/discharging cycle conditions were as follows: charging at 0° C. for 4 hours and 30 minutes at a current of 500 mA, and discharging for 75 minutes at a constant resistance equivalent to 1500 mA. Note that the discharge time in the figure is the time until the battery voltage reaches 1.0V, and the discharge average voltage is the battery voltage at the midpoint of the discharge time. Figure 2 shows the effect of adding cadmium hydroxide, and a, b, and c in the figure indicate the addition ratio of cadmium hydroxide to zinc hydroxide of 0, 1, and 2%.
represents the discharge time when d is 2%, and d represents the discharge average voltage when 2%. If no cadmium hydroxide is added, a:
It can be seen that the discharge time gradually increases with the number of charges and discharges, and then rapidly deteriorates. This is probably because, as mentioned earlier, as the number of charging and discharging cycles progresses, the receptivity to charging improves, and the discharging time also increases, causing the electrode plates to bulge, after which the battery characteristics rapidly deteriorate. It will be done. In case b, where the addition ratio of cadmium hydroxide is 1% to nickel hydroxide, the above-mentioned tendency is still observed. When the addition ratio to nickel hydroxide is 2% (c), almost no deterioration in capacity is observed. Although Figure 2 only shows the cadmium hydroxide addition ratio up to 2%,
Even when 2% or more was added, the properties were similar to those with 2% addition. FIG. 3 shows a similar experiment conducted with zinc hydroxide. In the figure, e, f, and g indicate the discharge time when the addition ratio of zinc hydroxide is 0, 2, and 15%, respectively, and h indicates the discharge average voltage when the addition ratio is 15%. It is. As is clear from the figure, when zinc hydroxide is added, the effect of suppressing discharge time deterioration is smaller than when cadmium hydroxide is added, but the discharge pressure is high. FIG. 4 shows the results when both cadmium hydroxide and zinc hydroxide were added at a ratio of 5% to zinc hydroxide. As is clear from the figure, when both are added at the same time, both the maintainability of the discharge time and the characteristics of the discharge pressure are improved. In this way, in order to simultaneously improve the discharge time characteristics and the discharge pressure characteristics during the cycle life, a mutual effect of cadmium hydroxide and zinc hydroxide is required. When adding both, the absolute amount added is important, but the ratio of both is also important. When the ratio of zinc hydroxide to cadmium hydroxide is small, only the discharge capacity characteristics are improved, and vice versa, only the discharge pressure surface is improved. As a result of various studies, the appropriate ratio of cadmium hydroxide and zinc hydroxide is 2:8 to 8:2 by weight.
The result was that it was about the same level. Further, although only zinc hydroxide is shown as the zinc compound in the examples, the same effect as zinc hydroxide can be obtained even if zinc or zinc oxide is used. Thus, when cadmium hydroxide and zinc or a zinc compound such as zinc hydroxide are added in appropriate proportions to the active material mixture of a conventional sponge metal positive electrode, the cycle life characteristics are significantly improved. As for the amount added, the minimum amount in which both effects are exhibited is 2% by weight relative to nickel hydroxide.
Further, due to capacity density issues, the total amount of both is 20% by weight or less. The ratio between the two is preferably between 2:8 and 8:2. Effects of the Invention As described above, according to the present invention, the charge/discharge cycle life characteristics of a sealed nickel-cadmium storage battery using a positive electrode in which a sponge-like nickel substrate is filled with an active material mixture mainly composed of nickel hydroxide can be improved. be able to.
第１図は水酸化カドミウム、水酸化亜鉛の添加
量と正極容量密度との関係を示す図、第２図は水
酸化カドミウム添加とサイクル寿命の関係を示す
図、第３図は水酸化亜鉛添加とサイクル寿命の関
係を示す図、第４図は水酸化カドミウムと水酸化
亜鉛とを添加した場合のサイクル寿命特性を示す
図である。
Figure 1 is a diagram showing the relationship between the amount of cadmium hydroxide and zinc hydroxide added and the positive electrode capacity density, Figure 2 is a diagram showing the relationship between the addition of cadmium hydroxide and cycle life, and Figure 3 is the relationship between the addition of cadmium hydroxide and zinc hydroxide. FIG. 4 is a diagram showing the cycle life characteristics when cadmium hydroxide and zinc hydroxide are added.
Claims (1)
した水酸化ニツケルを主体として金属ニツケル粉
末及び金属コバルト粉末を含む活物質混合物とか
らなる正極を備え、前記活物質混合物が、水酸化
亜鉛、亜鉛及び亜鉛酸化物よりなる群から選択し
た少なくとも１種を水酸化亜鉛換算値で水酸化ニ
ツケルに対して２重量％以上、水酸化カドミウム
を水酸化ニツケルに対して２重量％以上、かつ両
者の和が水酸化ニツケルに対して20重量％以下で
含み、前記水酸化亜鉛、亜鉛及び亜鉛酸化物より
なる群から選んだ少なくとも１種の水酸化亜鉛換
算値と水酸化カドミウムとの比が重量比で８：２
ないし２：８である密閉形ニツケル−カドミウム
蓄電池。1. A positive electrode consisting of a sponge-like nickel substrate and an active material mixture containing nickel hydroxide as a main ingredient, a metal nickel powder, and a metal cobalt powder, which is filled in the substrate, and the active material mixture contains zinc hydroxide, zinc, and zinc. At least one selected from the group consisting of oxides is contained in an amount of 2% by weight or more based on nickel hydroxide in terms of zinc hydroxide, and cadmium hydroxide is 2% by weight or more based on nickel hydroxide, and the sum of both is water. Contains 20% by weight or less based on nickel oxide, and has a weight ratio of at least one zinc hydroxide equivalent value selected from the group consisting of zinc hydroxide, zinc and zinc oxide and cadmium hydroxide of 8: 2
or 2:8 sealed nickel-cadmium storage battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57222313A JPS59112574A (en) | 1982-12-17 | 1982-12-17 | Enclosed type nickel-cadmium storage battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57222313A JPS59112574A (en) | 1982-12-17 | 1982-12-17 | Enclosed type nickel-cadmium storage battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59112574A JPS59112574A (en) | 1984-06-29 |
| JPH0430145B2 true JPH0430145B2 (en) | 1992-05-20 |
Family
ID=16780399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57222313A Granted JPS59112574A (en) | 1982-12-17 | 1982-12-17 | Enclosed type nickel-cadmium storage battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59112574A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5700596A (en) * | 1991-07-08 | 1997-12-23 | Matsushita Electric Industrial Co., Ltd. | Nickel hydroxide active material powder and nickel positive electrode and alkali storage battery using them |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6040667B2 (en) * | 1978-01-27 | 1985-09-12 | 松下電器産業株式会社 | Manufacturing method of nickel electrode |
-
1982
- 1982-12-17 JP JP57222313A patent/JPS59112574A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59112574A (en) | 1984-06-29 |
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