JPH10284078A - Hydride secondary battery and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydride secondary battery which enhance an utilization factor of a pasty nickel positive electrode, has excellent storage characteristics at a high temperature and has excellent cycle characteristics. SOLUTION: In a hydride secondary battery composed of a positive electrode with nickel hydroxide for active material, a negative electrode comprising hydrogen occluded alloy and electrolyte comprising alkali aqueous solution, the nickel hydroxide is powder a particle of which has a particle size of 2-40 μm and an average particle diameter of 8±2 μm, and in this powder, powder particles with not less than the average diameter are spherical and not less than 95% by weight of the particles with not more than the average diameter are also spherical, and furthermore, cobalt powder a particle of which has an average particle diameter of not more than 1 μm by the BET absorption method and a specific surface of 1-10 m<2> /g is contained in the positive electrode with the nickel hydroxide powder for the active material.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、正極の活物質とし
てペ─スト式水酸化ニツケルを用いた水素化物二次電池
とその製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydride secondary battery using a paste-type nickel hydroxide as an active material of a positive electrode and a method for producing the same.

【０００２】[0002]

【従来の技術】水素吸蔵合金を用いた水素化物二次電池
は、多量の水素を吸蔵、放出する能力を有し、アルカリ
水溶液中でも電気化学的に水素の吸蔵、放出を行うこと
が可能であり、ニツケル極を正極に用いた場合、次式の
ように電池反応が起こる。負極の反応式中、ＭはＬａＮ
ｉ₅ 系やＴｉ−Ｎｉ系などの水素吸蔵合金である。 2. Description of the Related Art A hydride secondary battery using a hydrogen storage alloy has the ability to store and release a large amount of hydrogen, and is capable of electrochemically storing and releasing hydrogen even in an alkaline aqueous solution. When the nickel electrode is used as the positive electrode, a battery reaction occurs as in the following equation. In the reaction formula of the negative electrode, M is LaN
i ₅ based or Ti-Ni-based hydrogen storage alloy and the like.

【０００３】正極および負極の反応式において、充電で
は、反応は右に進み、アルカリ水溶液中の水を電気分解
して、水素を吸蔵し、水酸基を生じ、この水酸基と正極
であるＮｉ（ＯＨ）₂ とが反応して、ＮｉＯＯＨとな
り、水を生じる。また、放電の場合は、反応は左に進
み、上記と逆の反応となる。つまり、負極では充電で水
素の吸蔵が起こり、放電で水素の放出となる。[0003] In the reaction formula of the positive electrode and the negative electrode, in charging, the reaction proceeds to the right, electrolyzes water in the alkaline aqueous solution, absorbs hydrogen, and generates a hydroxyl group. Reacts with ₂ to form NiOOH, producing water. In the case of discharge, the reaction proceeds to the left, and the reaction is the reverse of the above. That is, in the negative electrode, hydrogen is absorbed by charging, and hydrogen is released by discharging.

【０００４】ニツケル極としては、特開平１−２２７３
６３号公報などに開示のように、高容量化や低価格化の
ために、空孔率が９５％以上、孔径が数μｍ〜１００μ
ｍ程度の導電性多孔基材を用い、これに水酸化ニツケル
を主体とする活物質スラリ─を担持させる、いわゆるペ
─スト式が知られている。A nickel pole is disclosed in Japanese Patent Laid-Open No. 1-2273.
As disclosed in, for example, Japanese Patent Application Laid-Open No. 63-63, the porosity is 95% or more and the pore diameter is several μm to 100 μm for high capacity and low cost.
A so-called paste type in which a conductive porous base material of about m is supported and an active material slurry mainly composed of nickel hydroxide is supported thereon.

【０００５】[0005]

【発明が解決しようとする課題】しかし、ペ─スト式電
極は、焼結式電極に比べて孔径が大きいため、活物質の
集電体までの距離が長く、利用率や負荷特性に劣る。
「湯浅時報」Ｎｏ．６５，第２８頁（１９８８年）に
は、正極中にコバルト粉末やコバルト化合物粉末などの
導電助剤を加えて利用率を向上させることが提案されて
いるが、この種の電池のさらなる高容量化のためには、
活物質である水酸化ニツケル自体の利用率を向上させる
ことが必要であり、また導電助剤としてさらに適したも
のを用いて利用率のより一層の向上を図ることが望まれ
る。However, since the paste type electrode has a larger hole diameter than the sintered type electrode, the distance between the active material and the current collector is long, and the utilization factor and load characteristics are inferior.
"Yuasa Higashi" No. 65, p. 28 (1988), it is proposed to improve the utilization factor by adding a conductive aid such as cobalt powder or cobalt compound powder to the positive electrode. In order to
It is necessary to improve the utilization rate of nickel hydroxide itself, which is an active material, and it is desired to further improve the utilization rate by using a more suitable conductive assistant.

【０００６】本発明は、上記従来の事情にてらして、ペ
─スト式ニツケル正極の利用率を向上させ、また高温時
の貯蔵特性にすぐれ、サイクル特性にすぐれた水素化物
二次電池とその製造方法を提供することを目的としてい
る。In view of the above-mentioned conventional circumstances, the present invention improves the utilization rate of a paste-type nickel positive electrode, has excellent storage characteristics at high temperatures, and has excellent cycle characteristics, and its production. It is intended to provide a way.

【０００７】[0007]

【課題を解決するための手段】本発明者らは、上記の目
的に対して、鋭意検討したところ、ペ─スト式電極に用
いられる従来の水酸化ニツケル粉末は、一般に、硫酸ニ
ツケル水溶液に水酸化ナトリウムを加えて水酸化ニツケ
ルの沈殿物を得、これを水洗、乾燥してつくられている
が、このものは通常数μｍ〜数１０μｍ程度の粒子径を
有して、粒度分布の幅が広く、しかも、粒子径の大きな
ものは球状であるが、小さなものはダンゴ状のいびつな
形状を有しており、そのために、水酸化ニツケルの理想
的な利用率は１１０％程度であるにもかかわらず、実際
には９５〜１００％程度までの利用率しか得られていな
いことが判明した。Means for Solving the Problems The present inventors diligently studied the above object, and found that the conventional nickel hydroxide powder used for the paste type electrode is generally prepared by adding aqueous nickel sulfate solution to water. A precipitate of nickel hydroxide is obtained by adding sodium oxide, washed with water, and dried. This is usually made with a particle size of several μm to several tens μm, and the width of the particle size distribution is Large particles having a large particle diameter are spherical, while small particles have a distorted dango-like shape. Therefore, the ideal utilization rate of nickel hydroxide is about 110%. Regardless, it has been found that only a utilization rate of about 95 to 100% has actually been obtained.

【０００８】本発明者らは、この知見をもとにさらに検
討を加えた結果、水酸化ニツケル粉末の上記製造に際し
て反応、水洗、乾燥、粉砕などの諸条件を適宜選択する
と、粒度分布が狭くてかつ粒子径の小さいものまで球状
を呈するような特定の水酸化ニツケル粉末が得られ、こ
のものを正極の活物質として用いることにより、またこ
の活物質を用いた正極中に導電助剤として特定粒径およ
び特定比表面積のコバルト粉末を含ませたときに、正極
の利用率が飛躍的に向上し、しかも高温時の貯蔵特性に
すぐれ、サイクル特性にすぐれた高容量の水素化物二次
電池が得られることを見い出し、本発明を完成するに至
つた。The present inventors have further studied based on this finding, and as a result, when the conditions such as reaction, washing, drying and pulverization are appropriately selected in the above-mentioned production of the nickel hydroxide powder, the particle size distribution becomes narrow. A specific nickel hydroxide powder having a spherical shape up to a small particle diameter is obtained, and by using this powder as an active material of a positive electrode, and as a conductive auxiliary agent in a positive electrode using the active material. When a cobalt powder having a particle size and a specific specific surface area is included, the utilization rate of the positive electrode is dramatically improved, and a high-capacity hydride secondary battery having excellent storage characteristics at high temperatures and excellent cycle characteristics is provided. The inventors have found that the present invention has been completed, and have completed the present invention.

【０００９】すなわち、本発明は、水酸化ニツケルを活
物質とする正極と水素吸蔵合金よりなる負極とアルカリ
水溶液よりなる電解液とセパレ─タを有する水素化物二
次電池において、上記の水酸化ニツケルは粒度が２〜４
０μｍ、平均粒径が８±２μｍの粉末で、この粉末は平
均粒径以上の粒子が球状でかつ平均粒径以下の粒子の９
５重量％以上も球状であり、さらにこの水酸化ニツケル
粉末を活物質とする正極中に平均粒径１μｍ以下でＢＥ
Ｔ吸着法による比表面積が１〜１０m²／ｇのコバルト粉
末を含むことを特徴とする水素化物二次電池に係るもの
である。That is, the present invention relates to a hydride secondary battery comprising a positive electrode containing nickel hydroxide as an active material, a negative electrode comprising a hydrogen storage alloy, an electrolytic solution comprising an alkaline aqueous solution, and a separator. Has a particle size of 2 to 4
0 μm and a powder having an average particle size of 8 ± 2 μm.
5% by weight or more is spherical, and furthermore, BE having an average particle size of 1 μm or less in a positive electrode using this nickel hydroxide powder as an active material.
The present invention relates to a hydride secondary battery including a cobalt powder having a specific surface area of 1 to 10 m ² / g by a T adsorption method.

【００１０】また、本発明は、水酸化ニツケルを活物質
とする正極と水素吸蔵合金よりなる負極とアルカリ水溶
液よりなる電解液とセパレ─タを有する水素化物二次電
池の製造方法において、上記の水酸化ニツケルとして、
粒度が２〜４０μｍ、平均粒径が８±２μｍであつて、
平均粒径以上の粒子が球状でかつ平均粒径以下の粒子の
９５重量％以上も球状である粉末を使用し、この水酸化
ニツケル粉末とさらに平均粒径１μｍ以下でＢＥＴ吸着
法による比表面積が１〜１０m²／ｇのコバルト粉末を含
むペ─ストを導電性多孔基材に担持させ、これを乾燥
し、圧縮成形したのち、アルカリ水溶液中に浸漬処理す
ることにより、正極を作製することを特徴とする水素化
物二次電池の製造方法に係るものである。The present invention also relates to a method for producing a hydride secondary battery having a positive electrode using nickel hydroxide as an active material, a negative electrode made of a hydrogen storage alloy, an electrolytic solution made of an alkaline aqueous solution, and a separator. As nickel hydroxide,
The particle size is 2 to 40 μm, the average particle size is 8 ± 2 μm,
Use a powder in which particles having an average particle size of at least 95% by weight of particles having a spherical shape and having a mean particle size of at most 95% by weight are used. A paste containing ^{1 to} 10 m ² / g of cobalt powder is supported on a conductive porous substrate, dried, compression molded, and then immersed in an alkaline aqueous solution to produce a positive electrode. The present invention relates to a method for producing a hydride secondary battery.

【００１１】[0011]

【発明の実施の形態】本発明に用いられる水酸化ニツケ
ルは、マイクロトラツプ法により測定される粒度が２〜
４０μｍ、平均粒径が８±２μｍの粉末であつて、この
粉末はＳＥＭ（走査型電子顕微鏡）による観察で平均粒
径以上の粒子が球状でかつ平均粒径以下の粒子の９５重
量％以上も球状である、つまり、従来のものに比べて、
粒度分布の幅が狭くて均一な粒子からなり、かつ粒径の
大きいものだけでなく粒径の小さい粒子までもが球状で
あることを特徴とする。本発明では、このような水酸化
ニツケル粉末を正極の活物質として用いることにより、
水酸化ニツケル自体の利用率が飛躍的に向上して、これ
と特定のコバルト粉末からなる導電助剤との相互作用に
より、高容量でかつ高温貯蔵特性、サイクル特性にすぐ
れた水素化物二次電池が得られることを見い出したもの
である。DESCRIPTION OF THE PREFERRED EMBODIMENTS Nickel hydroxide used in the present invention has a particle size of 2 to 2 as measured by a microtrap method.
40 μm, powder having an average particle size of 8 ± 2 μm, and this powder was observed by SEM (scanning electron microscope), where particles having an average particle size of more than 95% by weight were spherical and particles having an average particle size of not more than 95% by weight. It is spherical, that is, compared to the conventional one,
It is characterized in that it is composed of uniform particles having a narrow particle size distribution, and that not only particles having a large particle size but also particles having a small particle size are spherical. In the present invention, by using such nickel hydroxide powder as an active material of the positive electrode,
A hydride secondary battery with high capacity, high-temperature storage characteristics, and excellent cycle characteristics due to the drastic improvement in the use rate of nickel hydroxide itself and the interaction of this with a conductive additive made of a specific cobalt powder. Is obtained.

【００１２】従来のように小さい粒子が均一な球状とな
らずダンゴ状となる水酸化ニツケル粉末では、結晶性が
低いため、電気化学的反応の効率が悪くなり、そのぶん
正極の利用率が低くなる。これに対して、本発明の上記
水酸化ニツケル粉末は結晶性が高く、電気化学的反応の
効率が良くなり、正極の利用率が向上するとともに、粒
度分布が狭いため、上記反応が各粒子で均一に起こりや
すく、これも利用率の向上や長寿命化に寄与しているも
のと考えられる。In the conventional nickel hydroxide powder in which small particles do not form a uniform spherical shape but become dango-like, the crystallinity is low, so that the efficiency of the electrochemical reaction is deteriorated, and the utilization rate of the positive electrode is reduced. Become. On the other hand, the nickel hydroxide powder of the present invention has high crystallinity, improves the efficiency of the electrochemical reaction, improves the utilization rate of the positive electrode, and has a narrow particle size distribution. It is likely to occur uniformly, which is also considered to have contributed to the improvement of the utilization rate and the extension of the service life.

【００１３】本発明の水酸化ニツケル粉末は、ニツケル
を含む水溶液に通常コバルトや亜鉛を溶解させた硫酸溶
液を混合した液とアルカリ水溶液とアンモニウムイオン
供給体を同時にかつ連続的に供給して反応液とし、この
液中のニツケルイオンの濃度を４０mg／リツトル以下と
し、これを５〜２０℃に保持し、水酸化ナトリウムを加
えてｐＨ９〜１２に調整し、熟成は反応浴を撹拌しなが
ら１２時間以上行い、その際のｐＨは９〜１２の範囲に
調整して、水酸化ニツケルの沈澱物を得、この沈澱物を
吸引ろ過し、水洗後８０〜１２０℃で乾燥することによ
り、調製することができる。この方法は、従来の調製方
法と比べると、大きくは低温（５〜２０℃）で水酸化ニ
ツケルを調製している点で異なつている。The nickel hydroxide powder according to the present invention is obtained by simultaneously and continuously supplying a solution obtained by mixing a sulfuric acid solution in which cobalt or zinc is dissolved in an aqueous solution containing nickel, an alkaline aqueous solution and an ammonium ion donor simultaneously and continuously. The concentration of nickel ions in this solution was adjusted to 40 mg / liter or less, and the solution was maintained at 5 to 20 ° C., adjusted to pH 9 to 12 by adding sodium hydroxide, and aged for 12 hours while stirring the reaction bath. The pH is adjusted in the range of 9 to 12 to obtain a precipitate of nickel hydroxide, and the precipitate is filtered by suction, washed with water, and dried at 80 to 120 ° C. Can be. This method differs from the conventional preparation method in that nickel hydroxide is prepared at a low temperature (5 to 20 ° C.).

【００１４】このように調製される水酸化ニツケル粉末
は、ＢＥＴ吸着法により測定される細孔半径が従来の水
酸化ニツケル粉末と同じ７〜８Åにピ─クを有するとと
もに、５〜６Åの範囲にもピ─クを有するという特異な
性状を示し、通常、７〜８Åのピ―クの強度（ｌａ）と
上記の５〜６Åのピ―クの強度（ｌｂ）との比（ｌａ：
ｌｂ）が１００：５０以上となるものである。また、こ
の水酸化ニツケル粉末は、上記小さな細孔のために、粒
子表面に凹凸がなく、水酸化ニツケル自体がいびつでな
く、球状に近い形態をとるものである。The nickel hydroxide powder thus prepared has a pore radius measured by the BET adsorption method of 7 to 8 ° which is the same as that of the conventional nickel hydroxide powder, and is in the range of 5 to 6 °. Also, it has a peculiar property that it has a peak, and usually, the ratio (la :) of the peak intensity (la) of 7 to 8 mm to the peak intensity (lb) of 5 to 6 mm described above.
lb) is 100: 50 or more. In addition, the nickel hydroxide powder has no irregularities on the particle surface due to the small pores, and the nickel hydroxide itself is not distorted but has a shape close to a sphere.

【００１５】また、通常は、ＢＥＴ吸着法により測定さ
れる比表面積が５〜２０m²／ｇ、ＢＥＴ吸着法により測
定される細孔容積が０．０１５〜０．０３０cc／ｇ、平
均細孔半径が２５〜５０Åの範囲に入つている。ＢＥＴ
吸着法により測定される比表面積とは、窒素吸着法（ユ
アサアイオニクス、オ─トソ─プ１）で１〜１００Å、
試料１ｇ、測定時間１２７分、吸着側での測定値であ
る。Usually, the specific surface area measured by the BET adsorption method is 5 to ²⁰ m ² / g, the pore volume measured by the BET adsorption method is 0.015 to 0.030 cc / g, and the average pore radius is Is in the range of 25 to 50 °. BET
The specific surface area measured by the adsorption method is 1 to 100Å in the nitrogen adsorption method (Yuasa Ionics, Othosop 1),
These are the values measured on the adsorption side for 1 g of the sample, for a measurement time of 127 minutes.

【００１６】本発明において導電助剤として用いられる
コバルト粉末は、平均粒径が１μｍ以下、好ましくは
０．５〜０．８μｍで、かつＢＥＴ吸着法による比表面
積が１〜１０m²／ｇ、好ましくは１〜５m²／ｇとなるも
のである。また、原子吸光分析により、コバルト含有量
が９０〜９９重量％の範囲にあるのが望ましい。なお、
ＢＥＴ吸着法の測定条件は、試料５ｇ、脱気温度１２０
℃、脱気時間３００分で、脱着側での測定値を示すもの
であり、原子吸光分析は、試料０．５ｇを塩酸に溶解さ
せて、波長２４０．７ｎｍで測定したものである。The cobalt powder used as a conductive additive in the present invention has an average particle size of 1 μm or less, preferably 0.5 to 0.8 μm, and a specific surface area by BET adsorption method of 1 to 10 m ² / g, preferably Is 1 to 5 m ² / g. According to atomic absorption analysis, the cobalt content is desirably in the range of 90 to 99% by weight. In addition,
The measurement conditions of the BET adsorption method were as follows: sample 5 g, degassing temperature 120
It shows a measured value on the desorption side at 300 ° C. and a deaeration time of 300 minutes. In the atomic absorption analysis, 0.5 g of a sample was dissolved in hydrochloric acid and measured at a wavelength of 240.7 nm.

【００１７】このようなコバルト粉末を導電助剤に用い
ると、その粒度が小さいため、正極中において均一なコ
バルトの導電ネツトワ―クを形成し、とくに活物質とし
て用いる前記特定の水酸化ニツケル粉末が前記球状であ
るため、上記ネツトワ―クが上記活物質を極めて均一に
被覆することになり、導電助剤としての役割が最大限に
発揮されて、活物質の利用率を高め、また高温貯蔵時に
上記ネツトワ―クが破壊されて容量の低下を招くという
心配が回避され、高温貯蔵特性、サイクル特性にすぐれ
た水素化物二次電池を得ることができる。また、上記す
ぐれた導電機能により、導電助剤の使用量を少なくでき
ため、材料コストの低減に寄与でき、さらに導電助剤を
少なくできるぶん、水酸化ニツケル粉末からなる活物質
の量を多くでき、この点からも高容量化に寄与させるこ
とができる。When such a cobalt powder is used as a conductive additive, the particle size is small, so that a uniform conductive network of cobalt is formed in the positive electrode. In particular, the specific nickel hydroxide powder used as an active material is Due to the spherical shape, the network coats the active material extremely uniformly, thereby maximizing its role as a conductive additive, increasing the utilization of the active material, and increasing the storage efficiency at high temperatures. The concern that the network is broken and the capacity is reduced is avoided, and a hydride secondary battery having excellent high-temperature storage characteristics and cycle characteristics can be obtained. In addition, due to the excellent conductive function, the amount of the conductive auxiliary agent can be reduced, which can contribute to a reduction in material cost. Further, the amount of the conductive auxiliary agent can be reduced, and the amount of the active material composed of nickel hydroxide powder can be increased. This also contributes to higher capacity.

【００１８】これに対し、従来のように、平均粒径が１
μｍを超えるような大きな粒径のコバルト粉末などを導
電助剤としたときには、水酸化ニツケル粉末からなる活
物質の表面に形成される導電ネツトワ―クが均一なもの
とならないため、活物質の利用率が低下し、また高温貯
蔵時に上記ネツトワ―クが破壊されやすいため、容量の
低下を招きやすい。また、そのために、導電助剤の量を
多くすると、そのぶん活物質の量が減少したり、生産性
やコスト面で不利となる。On the other hand, as in the prior art, the average particle size is 1
When cobalt powder with a large particle size exceeding μm is used as the conductive additive, the conductive network formed on the surface of the active material composed of nickel hydroxide powder is not uniform, so that the active material is used. The rate is lowered, and the network is easily broken during high-temperature storage, so that the capacity is apt to be reduced. In addition, when the amount of the conductive auxiliary agent is increased, the amount of the active material is reduced, and the productivity and cost are disadvantageous.

【００１９】本発明のコバルト粉末は、合成条件を選択
することにより容易に調製できる。代表的には、コバル
ト炭酸塩をアルゴン雰囲気中２５０〜３５０℃で焼成し
たのち、塩化水素ガスを含むアルゴン雰囲気中９００〜
１，１００℃で加熱し、さらに真空中６００〜８００℃
で加熱処理して、コバルト酸化物を生成し、その後、水
素ガス雰囲気中で還元することにより、調製することが
できる。この方法は、塩化コバルトと蓚酸から蓚酸コバ
ルトを合成しこれを熱分解してコバルト粉末を得るとい
う従来の方法とは、異なつている。The cobalt powder of the present invention can be easily prepared by selecting synthesis conditions. Typically, after sintering cobalt carbonate at 250 to 350 ° C. in an argon atmosphere, 900 to 350 ° C. in an argon atmosphere containing hydrogen chloride gas.
Heat at 1,100 ° C, then 600-800 ° C in vacuum
To produce a cobalt oxide, and then reducing it in a hydrogen gas atmosphere to prepare it. This method is different from the conventional method of synthesizing cobalt oxalate from cobalt chloride and oxalic acid and thermally decomposing it to obtain cobalt powder.

【００２０】本発明において、正極は、前記の水酸化ニ
ツケル粉末を活物質とし、導電助剤として上記のコバル
ト粉末と必要によりカルボニルニツケル粉末などを使用
し、これらの活物質および導電助剤とカルボキシメチル
セルロ―ス、ポリテトラフルオロエチレンなどのバイン
ダとを混練して、ペ―ストを調製し、このペ─ストをニ
ツケル発泡体などの導電性多孔基材に担持させ、これを
乾燥し、圧縮成形したのち、アルカリ水溶液中で浸漬処
理することにより、作製される。In the present invention, the positive electrode uses the above-mentioned nickel hydroxide powder as an active material, uses the above-mentioned cobalt powder and, if necessary, carbonyl nickel powder or the like as a conductive aid, and uses these active materials and the conductive aid as a carboxylate. A paste is prepared by kneading a binder such as methylcellulose and polytetrafluoroethylene, and the paste is supported on a conductive porous base material such as a nickel foam, and dried and compressed. After being molded, it is produced by immersion treatment in an alkaline aqueous solution.

【００２１】その際、導電助剤であるコバルト粉末は、
活物質である前記の水酸化ニツケル粉末に対して、２〜
１５重量％の範囲で使用すればよく、従来の導電助剤の
添加量（６〜２０重量％）に比べて相対的に少なくする
ことができる。これは、コバルト粉末の前記特性と活物
質である水酸化ニツケル粉末の前記特性に基づくもので
あり、このように少ない量に設定しても、正極中におい
て良好な導電ネツトワ―クを形成できる特徴を有してい
る。At this time, the cobalt powder as the conductive auxiliary is
With respect to the nickel hydroxide powder as the active material,
It may be used in the range of 15% by weight, which can be relatively reduced as compared with the conventional additive amount of the conductive additive (6 to 20% by weight). This is based on the above-mentioned properties of the cobalt powder and the above-mentioned properties of the nickel hydroxide powder as the active material. Even when such a small amount is set, a good conductive network can be formed in the positive electrode. have.

【００２２】このように作製される正極に対して、水素
吸蔵合金よりなる負極を使用し、この正負両極とさらに
これらを分離するナイロン不織布などのセパレ―タを電
池缶内に装填するとともに、電解液として水酸化ナトリ
ウムや水酸化カリウムなどの水溶液にＬｉＯＨなどの電
解質を溶解させたアルカリ水溶液を注入することによ
り、本発明の水素化物二次電池が得られる。A negative electrode made of a hydrogen-absorbing alloy is used for the positive electrode produced in this manner, and the positive and negative electrodes and a separator such as a nylon nonwoven fabric for separating the positive and negative electrodes are loaded into a battery can. By injecting an alkaline aqueous solution in which an electrolyte such as LiOH is dissolved in an aqueous solution such as sodium hydroxide or potassium hydroxide as a liquid, the hydride secondary battery of the present invention can be obtained.

【００２３】負極に用いる水素吸蔵合金としては、Ｍｍ
（Ｌａ，Ｃｅ，Ｎｄ，Ｐｒ）−Ｎｉ系、Ｔｉ−Ｎｉ系、
Ｔｉ−ＮｉＺｒ（Ｔｉ_2-x Ｚｒ_x Ｖ_4-y Ｎｉ_y ）_1-z Ｃ
ｒ_z系（ｘ＝０〜１．５、ｙ＝０．６〜３．５、ｚ＝
０．２以下）、Ｔｉ−Ｍｎ系、Ｚｒ−Ｍｎ系などの各種
合金が挙げられる。これらの水素吸蔵合金は、通常は、
カルボキシメチルロ─ス、ポリテトラフルオロエチレン
などのバインダと混練してペ─ストとされ、これをニツ
ケル発泡体基材などに担持させ、乾燥したのち、圧縮成
形することにより、シ―ト状に成形される。The hydrogen storage alloy used for the negative electrode is Mm
(La, Ce, Nd, Pr) -Ni-based, Ti-Ni-based,
_{Ti-NiZr (Ti 2-x} Zr x V 4-y Ni y) 1-z C
r _z system (x = 0 to 1.5, y = 0.6 to 3.5, z =
0.2 or less), various alloys such as Ti-Mn-based and Zr-Mn-based alloys. These hydrogen storage alloys are usually
The paste is kneaded with a binder such as carboxymethyl rose or polytetrafluoroethylene to form a paste. The paste is supported on a nickel foam base material, dried, and then compression-molded to form a sheet. Molded.

【００２４】[0024]

【実施例】つぎに、本発明の実施例を記載して、より具
体的に説明する。以下において、部とあるのは重量部を
意味する。また、実施例１，２で用いたタイプＡ，Ｂの
水酸化ニツケル粉末は、下記の合成例１，２により、タ
イプＣのコバルト粉末は、下記の合成例３により、それ
ぞれ得たものである。Next, an embodiment of the present invention will be described in more detail. In the following, “parts” means “parts by weight”. The nickel hydroxide powders of types A and B used in Examples 1 and 2 were obtained according to Synthesis Examples 1 and 2 below, and the cobalt powder of type C was obtained according to Synthesis Example 3 below. .

【００２５】＜合成例１＞硫酸ニツケル５０重量％の水
溶液１０Kgと、コバルト２ｇ、亜鉛４ｇをそれぞれ溶解
させた硫酸溶液５Kgと、２５重量％の水酸化ナトリウム
水溶液と、７重量％のアンモニア水溶液とを、同時にか
つ連続的に供給し、反応液内のニツケルイオンの濃度を
４０mg／リツトル以下に調整した。この混合溶液を１０
〜１５℃に保持し、ｐＨ９〜１２になるように調整し
た。得られた水酸化ニツケルの沈澱物を吸引ろ過し、水
洗後、９０〜９５℃で乾燥して、コバルトと亜鉛が水酸
化ニツケルの内部に均一に固溶した水酸化ニツケル粉末
（タイプＡ）を得た。<Synthesis Example 1> 10 kg of an aqueous solution containing 50% by weight of nickel sulfate, 5 kg of a sulfuric acid solution in which 2 g of cobalt and 4 g of zinc were respectively dissolved, an aqueous solution of 25% by weight of sodium hydroxide, and an aqueous solution of 7% by weight of ammonia Was supplied simultaneously and continuously, and the concentration of nickel ions in the reaction solution was adjusted to 40 mg / liter or less. This mixed solution is added to 10
It was kept at 〜15 ° C. and adjusted to pH 9-12. The obtained nickel hydroxide precipitate is filtered by suction, washed with water, and dried at 90 to 95 ° C. to obtain a nickel hydroxide powder (type A) in which cobalt and zinc are uniformly dissolved in the nickel hydroxide. Obtained.

【００２６】このタイプＡの水酸化ニツケル粉末は、Ｉ
ＣＰ法（発光分光分析法、日本ジヤ─レル・アツシユＩ
ＣＰ７２７、シングルモ─ド）による測定で、コバルト
含有量が１重量％、亜鉛含有量が２重量％であつた。こ
の水酸化ニツケル粉末について、ＳＥＭ（倍率１，００
０倍）により観察した結果は、図１に示されるとおりで
あり、平均粒径以上の粒子が球状でかつ平均粒径以下の
粒子の９５重量％以上も球状であつた。This type A nickel hydroxide powder is
CP method (emission spectroscopy, Nippon Jarrell Atsushi I
CP727, single mode), the cobalt content was 1% by weight and the zinc content was 2% by weight. This nickel hydroxide powder was subjected to SEM (magnification: 1,000
The result of observation by (0 ×) is as shown in FIG. 1, where particles having an average particle size or more were spherical and 95% by weight or more of the particles having an average particle size or less were spherical.

【００２７】また、マイクロトラツプ法により粒度分布
を調べた結果は、図４に示されるとおりであり、粒度が
２〜４０μｍ、平均粒径が９．２μｍであつた。さら
に、ＢＥＴ吸着法により細孔半径を測定した結果は、図
７の曲線−７ａに示されるとおりであり、７〜８Åのピ
─クのほかに、５〜６Åにもピ─クを有し、７〜８Åの
ピ─クの強度（ｌａ）と５〜６Åのピ─クの強度（ｌ
ｂ）の比（ｌａ：ｌｂ）は１００：８３であつた。ま
た、ＢＥＴ吸着法による比表面積は５m²／ｇ、細孔容積
は０．０１５cc／ｇ、平均細孔半径は２５Åであつた。FIG. 4 shows the result of examining the particle size distribution by the micro trap method. The particle size was 2 to 40 μm, and the average particle size was 9.2 μm. Further, the result of the measurement of the pore radius by the BET adsorption method is as shown by a curve -7a in FIG. 7, and in addition to the peak at 7 to 8 °, the peak also exists at 5 to 6 °. , 7-8 peak intensity (la) and 5-6 peak intensity (l)
The ratio (la: lb) of b) was 100: 83. The specific surface area by the BET adsorption method was 5 m ² / g, the pore volume was 0.015 cc / g, and the average pore radius was 25 °.

【００２８】＜合成例２＞コバルトを２ｇ、亜鉛を１０
ｇとした以外は、合成例１と同様にして、水酸化ニツケ
ル粉末（タイプＢ）を得た。ＩＣＰ法による測定で、コ
バルト含有量は１重量％、亜鉛含有量は５重量％であつ
た。このタイプＢの水酸化ニツケル粉末について、ＳＥ
Ｍ（倍率１，０００倍）により観察した結果は、図２に
示されるとおりであり、平均粒径以上の粒子が球状でか
つ平均粒径以下の粒子の９５重量％以上も球状であつ
た。<Synthesis Example 2> 2 g of cobalt and 10 g of zinc
A nickel hydroxide powder (type B) was obtained in the same manner as in Synthesis Example 1 except that g was used. The cobalt content was 1% by weight and the zinc content was 5% by weight as determined by ICP method. For this type B nickel hydroxide powder, SE
The result of observation by M (magnification: 1,000 times) is as shown in FIG. 2, where particles having an average particle size or more were spherical and 95% by weight or more of particles having an average particle size or less were spherical.

【００２９】また、マイクロトラツプ法により粒度分布
を調べた結果は、図５に示されるとおりであり、粒度が
２〜４０μｍ、平均粒径が７．２μｍであつた。さら
に、ＢＥＴ吸着法により細孔半径を測定した結果は、図
７の曲線−７ｂに示されるとおりであり、７〜８Åのピ
─クのほかに、５〜６Åにもピ─クを有し、７〜８Åの
ピ─クの強度（ｌａ）と５〜６Åのピ─クの強度（ｌ
ｂ）の比（ｌａ：ｌｂ）は１００：７０であつた。ま
た、ＢＥＴ吸着法による比表面積は２０m²／ｇ、細孔容
積は０．０３０cc／ｇ、平均細孔半径は５０Åであつ
た。The result of examining the particle size distribution by the micro trap method is shown in FIG. 5, where the particle size was 2 to 40 μm and the average particle size was 7.2 μm. Further, the result of measuring the pore radius by the BET adsorption method is as shown by a curve -7b in FIG. 7, and in addition to the peak at 7 to 8 °, the peak also exists at 5 to 6 °. , 7-8 peak intensity (la) and 5-6 peak intensity (l)
The ratio (la: lb) of b) was 100: 70. Further, the specific surface area by the BET adsorption method was 20 m ² / g, the pore volume was 0.030 cc / g, and the average pore radius was 50 °.

【００３０】＜合成例３＞コバルト炭酸塩（純度９０重
量％）を、アルゴン雰囲気中３００℃で２時間焼成した
のち、塩化水素ガスを含むアルゴン雰囲気中９５０℃で
１０時間加熱し、さらに真空中７００℃で２時間加熱処
理して、コバルト酸化物を生成した。その後、９００〜
１，２００℃の水素ガス雰囲気中でこのコバルト酸化物
を還元することにより、コバルト粉末（タイプＣ）を得
た。<Synthesis Example 3> Cobalt carbonate (purity: 90% by weight) was calcined at 300 ° C. for 2 hours in an argon atmosphere, then heated at 950 ° C. for 10 hours in an argon atmosphere containing hydrogen chloride gas, and further vacuum. Heat treatment was performed at 700 ° C. for 2 hours to produce cobalt oxide. After that, 900 ~
This cobalt oxide was reduced in a hydrogen gas atmosphere at 1,200 ° C. to obtain a cobalt powder (type C).

【００３１】このタイプＣのコバルト粉末について、Ｓ
ＥＭ観察（倍率５，０００倍）したところ、図８に示さ
れるように、非常に微粒子であることが確認され、平均
粒径は０．９μｍ、ＢＥＴ吸着法による比表面積は１．
４m²／ｇ、原子吸光分析によるコバルト含有量は９９重
量％であつた。For this type C cobalt powder, S
As a result of EM observation (magnification: 5,000), as shown in FIG. 8, it was confirmed that the particles were very fine, the average particle diameter was 0.9 μm, and the specific surface area by BET adsorption was 1.
The content of cobalt was 4 m ² / g and the content of cobalt by atomic absorption analysis was 99% by weight.

【００３２】実施例１ 市販のＭｍ（Ｌａ、Ｃｅ、Ｎｄ、Ｐｒ）、Ｎｉ、Ｃｏ、
Ｍｎ、ＡｌおよびＭｏ（いずれも純度９９．９重量％以
上）の各試料を、Ｍｍ（Ｌａ：０．３２原子％、Ｃｅ：
０．４８原子％、Ｎｄ：０．１５原子％、Ｐｒ：０．０
４原子％）、Ｎｉ：３．５５原子％、Ｃｏ：０．７５原
子％、Ｍｎ：０．４原子％、Ａｌ：０．３原子％、Ｍ
ｏ：０．０４原子％の組成になるように、高周波溶解炉
によつて加熱溶解し、水素吸蔵合金を得た。この合金を
耐圧容器中で１０^-4Ｔｏｒｒまで真空引きを行い、アル
ゴンガスで３回パ─ジを行つたのち、水素圧力１４Kg／
cm²で２４時間保持し、水素を排気し、さらに４００℃
で加熱し、水素を完全に放出することにより、２０〜１
００μｍの粉末を得た。Example 1 Commercially available Mm (La, Ce, Nd, Pr), Ni, Co,
Each sample of Mn, Al, and Mo (all with a purity of 99.9% by weight or more) was subjected to Mm (La: 0.32 atomic%, Ce:
0.48 atomic%, Nd: 0.15 atomic%, Pr: 0.0
4 atomic%), Ni: 3.55 atomic%, Co: 0.75 atomic%, Mn: 0.4 atomic%, Al: 0.3 atomic%, M
o: The composition was heated and melted in a high-frequency melting furnace so as to have a composition of 0.04 atomic% to obtain a hydrogen storage alloy. This alloy is evacuated to 10 ⁻⁴ Torr in a pressure vessel, purged with argon gas three times, and then subjected to a hydrogen pressure of 14 kg / g.
cm ² for 24 hours, evacuated hydrogen, and further heated to 400 ° C.
To release hydrogen completely, so that 20 to 1
A powder of 00 μm was obtained.

【００３３】この合金粉末１００部に、３重量％のカル
ボキシメチルセルロ─ス水溶液５０部、６０重量％のポ
リテトラフルオロエチレン（以下、ＰＴＦＥという）分
散剤溶液５部、カルボニルニツケル粉末１０部を混合
し、ペ─ストを調製した。このペ─ストをニツケル発泡
体基材に充填担持させ、乾燥後、圧縮成形した。その
後、所定サイズに裁断して、負極シ─トとした。To 100 parts of this alloy powder, 50 parts of a 3% by weight aqueous solution of carboxymethyl cellulose, 5 parts of a 60% by weight polytetrafluoroethylene (hereinafter referred to as PTFE) dispersant solution, and 10 parts of carbonyl nickel powder are mixed. Then, a paste was prepared. The paste was filled and supported on a nickel foam base material, dried, and compression molded. Thereafter, the sheet was cut into a predetermined size to obtain a negative electrode sheet.

【００３４】これとは別に、タイプＡの水酸化ニツケル
粉末１００部に、タイプＣのコバルト粉末６部、ニツケ
ル粉末１０部、２重量％のカルボキシメチルセルロ─ス
水溶液５０部、６０重量％のＰＴＦＥ分散剤溶液５部を
混合し、ペ─ストとした。このペ─ストをニツケル発泡
体基材に充填担持させ、８０℃で２時間乾燥後、１トン
／cm² で圧縮成形して、シ─ト状とした。これを８０℃
のアルカリ水溶液に２時間浸漬処理したのち、８０℃の
空気中で乾燥した。ついで、８０℃の温水で２時間水洗
し、さらに８０℃で１時間乾燥したのち、圧縮成形し、
所定サイズに裁断して、正極シ─トを作製した。Separately, 100 parts of nickel hydroxide powder of type A, 6 parts of cobalt powder of type C, 10 parts of nickel powder, 50 parts of a 2% by weight carboxymethyl cellulose aqueous solution, and 60 parts by weight of PTFE Five parts of the dispersant solution were mixed to give a paste. The paste was filled and supported on a nickel foam base material, dried at 80 ° C. for 2 hours, and compression-molded at 1 ton / cm ² to form a sheet. 80 ℃
Was immersed in an aqueous alkaline solution for 2 hours, and then dried in air at 80 ° C. Then, it was washed with warm water of 80 ° C. for 2 hours, further dried at 80 ° C. for 1 hour, and compression-molded.
The sheet was cut into a predetermined size to produce a positive electrode sheet.

【００３５】上記の負極シ―トと正極シ─トをナイロン
不織布製のセパレ─タを介して捲回し、単４サイズの電
極缶に入れ、これに電解液（３０重量％水酸化カリウム
水溶液１リツトルにＬｉＯＨを１７ｇ溶解させたアルカ
リ水溶液）を注入した。樹脂製封口体に正極タブをスポ
ツト溶接し、負極の最外周部分は缶の側面に接触させた
のち、密封した。これを７０℃で６時間保存し、０．１
Ｃ（１２０ｍＡ）で１５時間充電し、０．２Ｃ（２２０
ｍＡ）で１．０Ｖまで放電した。このサイクルを放電容
量が一定になるまで繰り返し、水素化物二次電池を作製
した。The above-mentioned negative electrode sheet and positive electrode sheet are wound through a separator made of a non-woven fabric of nylon, placed in a AAA-size electrode can, and an electrolytic solution (30% by weight aqueous solution of potassium hydroxide 1) is added thereto. An aqueous alkaline solution in which 17 g of LiOH was dissolved) was injected into the liter. The positive electrode tab was spot-welded to the resin sealing body, and the outermost peripheral portion of the negative electrode was brought into contact with the side surface of the can and then sealed. This was stored at 70 ° C. for 6 hours,
C (120 mA) for 15 hours, 0.2 C (220 mA
(mA) to 1.0 V. This cycle was repeated until the discharge capacity became constant, to produce a hydride secondary battery.

【００３６】実施例２ 正極の水酸化ニツケル粉末として、タイプＡの水酸化ニ
ツケル粉末１００部に代えて、タイプＢの水酸化ニツケ
ル粉末１００部を用いた以外は、実施例１と同様にし
て、水素化物二次電池を作製した。Example 2 The procedure of Example 1 was repeated, except that 100 parts of type A nickel hydroxide powder was used instead of 100 parts of type A nickel hydroxide powder as the positive electrode nickel hydroxide powder. A hydride secondary battery was manufactured.

【００３７】比較例１ 正極の水酸化ニツケル粉末として、タイプＡの水酸化ニ
ツケル粉末１００部に代えて、市販の水酸化ニツケル粉
末１００部を用い、かつ正極の導電助剤であるタイプＣ
のコバルト粉末６部に代えて、市販のコバルト粉末１０
部を用いた以外は、実施例１と同様にして、水素化物二
次電池を作製した。COMPARATIVE EXAMPLE 1 As the positive electrode nickel hydroxide powder, 100 parts of commercially available nickel hydroxide powder was used in place of 100 parts of type A nickel hydroxide powder, and type C, a positive electrode conductive additive, was used.
Commercial cobalt powder 10 instead of 6 parts of cobalt powder
A hydride secondary battery was produced in the same manner as in Example 1 except that the parts were used.

【００３８】比較例２ 正極の水酸化ニツケル粉末として、タイプＡの水酸化ニ
ツケル粉末１００部に代えて、市販の水酸化ニツケル粉
末１００部を用いた以外は、実施例１と同様にして、水
素化物二次電池を作製した。Comparative Example 2 The procedure of Example 1 was repeated except that 100 parts of commercially available nickel hydroxide powder was used instead of 100 parts of type A nickel hydroxide powder as the nickel hydroxide powder for the positive electrode. A nitride secondary battery was produced.

【００３９】なお、比較例１，２で用いた市販の水酸化
ニツケル粉末について、ＳＥＭ（倍率１，０００倍）に
より観察した結果は、図３に示されるとおりであり、平
均粒径以上の粒子は球状であつたが、平均粒径以下の粒
子はダンゴ状でいびつな形状であつた。また、マイクロ
トラツプ法により粒度分布を調べた結果は、図６に示さ
れるとおりであり、粒度が０．４〜９６μｍ、平均粒径
が１２μｍで、粒度分布幅の広いものであつた。さら
に、ＢＥＴ吸着法により細孔半径を測定した結果は、図
７の曲線−７ｃに示されるとおりであり、７〜８Åにピ
─クがみられたが、５〜６Åにピ─クはみられなかつ
た。また、ＢＥＴ吸着法による比表面積は２０m²／ｇ、
細孔容積は０．０３０cc／ｇ、平均細孔半径は３５Åで
あつた。The results obtained by observing the commercially available nickel hydroxide powder used in Comparative Examples 1 and 2 by SEM (1,000 times magnification) are as shown in FIG. Was spherical, but particles smaller than the average particle size were in a dango-like and irregular shape. The result of examining the particle size distribution by the microtrap method is as shown in FIG. 6. The particle size was 0.4 to 96 μm, the average particle size was 12 μm, and the particle size distribution was wide. Further, the result of measuring the pore radius by the BET adsorption method is as shown by a curve -7c in FIG. 7, where a peak was observed at 7 to 8 °, but a peak was observed at 5 to 6 °. It wasn't. The specific surface area by the BET adsorption method is 20 m ² / g,
The pore volume was 0.030 cc / g and the average pore radius was 35 °.

【００４０】なおまた、比較例１で導電助剤として用い
た市販のコバルト粉末につき、ＳＥＭ観察（倍率５，０
００倍）したところ、図９に示されるように、タイプＣ
のコバルト粉末に比べて大きな粒子径を有し、全体に不
均一であることが確認され、平均粒径は３μｍ、ＢＥＴ
吸着法による比表面積は８m²／ｇ、原子吸光分析による
コバルト含有量は９９重量％であつた。The commercially available cobalt powder used as a conductive additive in Comparative Example 1 was observed by SEM (at a magnification of 5.0 or less).
00), as shown in FIG.
Has a larger particle size than that of the cobalt powder, and is confirmed to be non-uniform as a whole.
The specific surface area by the adsorption method was 8 m ² / g, and the cobalt content by atomic absorption analysis was 99% by weight.

【００４１】上記の実施例１，２および比較例１，２の
各水素化物二次電池について、正極の利用率、充電容量
および電池容量を調べた。これらの結果は、下記の表１
に示されるとおりであつた。また、高温貯蔵（６０℃で
４０日間放置）後、サイクル特性（１Ｃ×１．２時間充
電−１Ｃ放電を繰り返し、電池電圧が１．０Ｖに低下す
るまでのサイクル数）を調べ、その結果を図１０に示し
た。なお、図１０中、曲線−１０ａは実施例１の水素化
物二次電池、曲線−１０ｂは実施例２の水素化物二次電
池、曲線−１０ｃは比較例１の水素化物二次電池、曲線
−１０ｄは比較例２の水素化物二次電池、である。With respect to each of the hydride secondary batteries of Examples 1 and 2 and Comparative Examples 1 and 2, the utilization factor, charge capacity and battery capacity of the positive electrode were examined. These results are shown in Table 1 below.
The results were as shown in FIG. After high-temperature storage (leaving at 60 ° C. for 40 days), the cycle characteristics (the number of cycles until the battery voltage is reduced to 1.0 V by repeating the charging / discharging of 1 C × 1.2 hours-1 C) were examined. As shown in FIG. In FIG. 10, curve -10a is the hydride secondary battery of Example 1, curve -10b is the hydride secondary battery of Example 2, curve -10c is the hydride secondary battery of Comparative Example 1, and curve- 10d is a hydride secondary battery of Comparative Example 2.

【００４２】 [0042]

【００４３】上記結果から明らかなように、本発明の実
施例１，２の水素化物二次電池は、表１に示されるよう
に、正極利用率が、活物質および導電助剤としてそれぞ
れ従来のものを用いた比較例１の水素化物二次電池なら
びに活物質だけを従来のものとした比較例２の水素化物
二次電池に比べて、１０％程度高く、電池容量が高くな
つており、しかも、図１０に示されるように、高温貯蔵
後においてもすぐれたサイクル特性が得られているもの
であることがわかる。As is clear from the above results, as shown in Table 1, the hydride secondary batteries of Examples 1 and 2 of the present invention have the positive electrode utilization ratios of the conventional materials as the active material and the conductive auxiliary, respectively. In comparison with the hydride secondary battery of Comparative Example 1 and the hydride secondary battery of Comparative Example 2 in which only the active material was used, the battery capacity was increased by about 10%, and the battery capacity was increased. 10, it can be seen that excellent cycle characteristics are obtained even after storage at high temperature.

【００４４】[0044]

【発明の効果】以上のように、本発明は、水酸化ニツケ
ル粉末として特定性状のものを用い、かつ導電助剤とし
て特定のコバルト粉末を用いたことにより、ニツケル正
極の利用率が向上し、材料コストの低減を図れるととも
に、高温貯蔵特性にすぐれて、サイクル特性の改善され
た高容量の水素化物二次電池を提供できる。As described above, according to the present invention, the nickel hydroxide powder has a specific property, and the specific cobalt powder is used as a conductive additive, so that the utilization rate of the nickel positive electrode is improved. It is possible to provide a high-capacity hydride secondary battery that can reduce material cost and has excellent high-temperature storage characteristics and improved cycle characteristics.

【図面の簡単な説明】[Brief description of the drawings]

【図１】実施例１で用いたタイプＡの水酸化ニツケル粉
末の粒子構造を示す走査型電子顕微鏡（倍率１，０００
倍）写真である。FIG. 1 is a scanning electron microscope (1,000 magnification) showing the particle structure of a nickel hydroxide powder of type A used in Example 1.
Photo).

【図２】実施例２で用いたタイプＢの水酸化ニツケル粉
末の粒子構造を示す走査型電子顕微鏡（倍率１，０００
倍）写真である。FIG. 2 is a scanning electron microscope (1,000 magnification) showing a particle structure of a nickel hydroxide powder of type B used in Example 2.
Photo).

【図３】比較例１，２で用いた市販の水酸化ニツケル粉
末の粒子構造を示す走査型電子顕微鏡（倍率１，０００
倍）写真である。FIG. 3 is a scanning electron microscope (1,000 magnification) showing the particle structure of the commercially available nickel hydroxide powder used in Comparative Examples 1 and 2.
Photo).

【図４】実施例１で用いたタイプＡの水酸化ニツケル粉
末の粒度分布図である。FIG. 4 is a particle size distribution diagram of a nickel hydroxide powder of type A used in Example 1.

【図５】実施例２で用いたタイプＢの水酸化ニツケル粉
末の粒度分布図である。FIG. 5 is a particle size distribution diagram of type B nickel hydroxide powder used in Example 2.

【図６】比較例１，２で用いた市販の水酸化ニツケル粉
末の粒度分布図である。FIG. 6 is a particle size distribution diagram of a commercially available nickel hydroxide powder used in Comparative Examples 1 and 2.

【図７】実施例１，２で使用したタイプＡ，Ｂの水酸化
ニツケル粉末と比較例１，２で使用した市販の水酸化ニ
ツケル粉末の細孔半径を示す特性図である。FIG. 7 is a characteristic diagram showing the pore radii of the nickel hydroxide powders of types A and B used in Examples 1 and 2 and the commercially available nickel hydroxide powder used in Comparative Examples 1 and 2.

【図８】実施例１，２で用いたタイプＣのコバルト粉末
の粒子構造を示す走査型電子顕微鏡（倍率５，０００
倍）写真である。FIG. 8 is a scanning electron microscope (5,000 magnification) showing the particle structure of type C cobalt powder used in Examples 1 and 2.
Photo).

【図９】比較例１で用いた市販のコバルト粉末の粒子構
造を示す走査型電子顕微鏡（倍率５，０００倍）写真で
ある。9 is a scanning electron microscope (5,000-fold magnification) photograph showing the particle structure of a commercially available cobalt powder used in Comparative Example 1. FIG.

【図１０】実施例１，２の水素化物二次電池と比較例
１，２の水素化物二次電池についての高温貯蔵後のサイ
クル特性を示す特性図である。FIG. 10 is a characteristic diagram showing cycle characteristics of the hydride secondary batteries of Examples 1 and 2 and the hydride secondary batteries of Comparative Examples 1 and 2, after storage at a high temperature.

【符号の説明】[Explanation of symbols]

７ａ 実施例１で用いたタイプＡの水酸化ニツケル粉末 ７ｂ 実施例２で用いたタイプＢの水酸化ニツケル粉末 ７ｃ 比較例１，２で用いた市販の水酸化ニツケル粉末 １０ａ 実施例１の水素化物二次電池 １０ｂ 実施例２の水素化物二次電池 １０ｃ 比較例１の水素化物二次電池 １０ｄ 比較例２の水素化物二次電池 7a Nickel hydroxide powder of type A used in Example 1 7b Nickel hydroxide powder of type B used in Example 2 7c Commercially available nickel hydroxide powder used in Comparative Examples 1 and 10 10a Hydride of Example 1 Secondary battery 10b Hydride secondary battery of Example 2 10c Hydride secondary battery of Comparative Example 1 10d Hydride secondary battery of Comparative Example 2

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 水酸化ニツケルを活物質とする正極と水
素吸蔵合金よりなる負極とアルカリ水溶液よりなる電解
液とセパレ─タを有する水素化物二次電池において、上
記の水酸化ニツケルは粒度が２〜４０μｍ、平均粒径が
８±２μｍの粉末で、この粉末は平均粒径以上の粒子が
球状でかつ平均粒径以下の粒子の９５重量％以上も球状
であり、さらにこの水酸化ニツケル粉末を活物質とする
正極中に平均粒径１μｍ以下でＢＥＴ吸着法による比表
面積が１〜１０m²／ｇのコバルト粉末を含むことを特徴
とする水素化物二次電池。1. A hydride secondary battery comprising a positive electrode containing nickel hydroxide as an active material, a negative electrode comprising a hydrogen storage alloy, an electrolytic solution comprising an alkaline aqueous solution and a separator, wherein said nickel hydroxide has a particle size of 2 μm. ４０40 μm, powder having an average particle diameter of 8 ± 2 μm. The powder is spherical in which particles having an average particle diameter of not less than 95% by weight of particles having a particle diameter of not more than the average particle diameter. A hydride secondary battery comprising, in a positive electrode serving as an active material, cobalt powder having an average particle size of 1 μm or less and a specific surface area of 1 to 10 m ² / g by a BET adsorption method. 【請求項２】 水酸化ニツケル粉末は、細孔半径が少な
くとも７〜８Åのピ―クと５〜６Åのピ─クを有すると
ともに、７〜８Åのピ―クの強度（ｌａ）と５〜６Åの
ピ―クの強度（ｌｂ）との比（ｌａ：ｌｂ）が１００：
５０以上である請求項１に記載の水素化物二次電池。2. The nickel hydroxide powder has a peak having a pore radius of at least 7 to 8 ° and a peak of 5 to 6 °, and has a peak intensity (la) of 7 to 8 ° and 5 to 5 °. The ratio (la: lb) to the peak intensity (lb) of 6 ° is 100:
The hydride secondary battery according to claim 1, which is 50 or more. 【請求項３】 水酸化ニツケルを活物質とする正極と水
素吸蔵合金よりなる負極とアルカリ水溶液よりなる電解
液とセパレ─タを有する水素化物二次電池の製造方法に
おいて、上記の水酸化ニツケルとして、粒度が２〜４０
μｍ、平均粒径が８±２μｍであつて、平均粒径以上の
粒子が球状でかつ平均粒径以下の粒子の９５重量％以上
も球状である粉末を使用し、この水酸化ニツケル粉末と
さらに平均粒径１μｍ以下でＢＥＴ吸着法による比表面
積が１〜１０m²／ｇのコバルト粉末を含むペ─ストを導
電性多孔基材に担持させ、これを乾燥し、圧縮成形した
のち、アルカリ水溶液中に浸漬処理することにより、正
極を作製することを特徴とする水素化物二次電池の製造
方法。3. A method for producing a hydride secondary battery having a positive electrode using nickel hydroxide as an active material, a negative electrode made of a hydrogen storage alloy, an electrolytic solution made of an alkaline aqueous solution, and a separator, wherein said nickel hydroxide is used as said nickel hydroxide. , Particle size 2-40
a powder having an average particle diameter of 8 ± 2 μm, wherein particles having a particle diameter equal to or larger than the average particle diameter are spherical and at least 95% by weight of particles having a particle diameter equal to or smaller than the average particle diameter are used. A paste containing cobalt powder having an average particle diameter of 1 μm or less and a specific surface area by a BET adsorption method of 1 to 10 m ² / g is supported on a conductive porous substrate, dried, compression-molded, and then dried in an alkaline aqueous solution. A method for producing a hydride secondary battery, characterized in that a positive electrode is produced by immersion treatment.