JPH09283130A - Manufacture of hydrogen storage alloy electrode - Google Patents
Manufacture of hydrogen storage alloy electrodeInfo
- Publication number
- JPH09283130A JPH09283130A JP8092365A JP9236596A JPH09283130A JP H09283130 A JPH09283130 A JP H09283130A JP 8092365 A JP8092365 A JP 8092365A JP 9236596 A JP9236596 A JP 9236596A JP H09283130 A JPH09283130 A JP H09283130A
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen storage
- electrode
- storage alloy
- alloy
- alkaline solution
- 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.)
- Pending
Links
Classifications
-
- 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
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、水素ガスの吸蔵・
放出を可逆的に行うことのできる水素吸蔵合金を用いた
水素吸蔵合金電極の製造方法に関する。TECHNICAL FIELD The present invention relates to storage of hydrogen gas.
The present invention relates to a method for producing a hydrogen storage alloy electrode using a hydrogen storage alloy capable of reversibly releasing hydrogen.
【０００２】[0002]
【従来の技術】近年、ニッケル−カドミウム蓄電池に代
わるアルカリ蓄電池として、負極に金属水素化物、つま
り水素吸蔵合金を使ったニッケル−水素蓄電池が開発さ
れ、その製法などに多くの提案がされている。水素を可
逆的に吸蔵・放出しうる水素吸蔵合金を使用する水素吸
蔵合金電極は、その理論容量密度がカドミウム電極より
も大きく、デンドライトの形成などもないことから、長
寿命・無公害であり、しかも高エネルギー密度を有する
アルカリ蓄電池用負極として期待されている。2. Description of the Related Art In recent years, as an alkaline storage battery replacing the nickel-cadmium storage battery, a nickel-hydrogen storage battery using a metal hydride, that is, a hydrogen storage alloy for the negative electrode has been developed, and many proposals have been made for its manufacturing method. A hydrogen storage alloy electrode using a hydrogen storage alloy capable of reversibly storing and releasing hydrogen has a theoretical capacity density larger than that of a cadmium electrode and has no dendrite formation. Moreover, it is expected as a negative electrode for alkaline storage batteries having a high energy density.
【０００３】このような水素吸蔵合金電極の製造法とし
ては、水素吸蔵合金粉末もしくは水素吸蔵合金電極を、
アルカリ溶液に浸漬処理することにより、合金表面のコ
バルト、マンガン、バナジウム等の易溶解性の金属元素
をアルカリ溶液中に溶出させ、合金表面の金属ニッケル
量を相対的に多くして合金粉末、もしくは合金電極の電
気化学的活性を向上させるとともに、アルカリ溶液に溶
出する合金成分元素を合金粒子の表面や電極表面から除
去することによって、電池寿命を向上させようとする方
法がある。また、電極の電気化学的な反応性を向上させ
る目的で金属コバルト等を添加する方法も提案されてい
る。As a method of manufacturing such a hydrogen storage alloy electrode, a hydrogen storage alloy powder or a hydrogen storage alloy electrode is prepared.
By immersing in an alkaline solution, cobalt, manganese, vanadium, and other easily soluble metal elements on the surface of the alloy are dissolved into the alkaline solution, and the amount of metallic nickel on the surface of the alloy is relatively increased to increase the alloy powder, or There is a method of improving the electrochemical activity of the alloy electrode and, at the same time, improving the battery life by removing the alloy component elements eluted in the alkaline solution from the surfaces of the alloy particles and the electrode surface. Also, a method of adding metallic cobalt or the like for the purpose of improving the electrochemical reactivity of the electrode has been proposed.
【０００４】[0004]
【発明が解決しようとする課題】前記の処理により、ニ
ッケル−水素蓄電池の特性面、特に常温での高率放電特
性や低温での充放電特性には向上が見られる。しかし、
このアルカリ処理後の水素吸蔵合金電極を用いた電池で
も、低温過充電後の高率放電特性は十分に満足できるも
のではなかった。By the above treatment, the nickel-hydrogen storage battery is improved in its characteristics, particularly in high rate discharge characteristics at room temperature and charge / discharge characteristics at low temperature. But,
Even the battery using the hydrogen storage alloy electrode after the alkali treatment was not sufficiently satisfactory in the high rate discharge characteristics after the low temperature overcharge.
【０００５】本発明は、水素吸蔵合金電極の低温での水
素−酸素反応性をより活性化させることにより、低温過
充電特性を向上した水素吸蔵合金電極を提供することを
目的とする。An object of the present invention is to provide a hydrogen storage alloy electrode having improved low temperature overcharge characteristics by further activating the hydrogen-oxygen reactivity of the hydrogen storage alloy electrode at low temperatures.
【０００６】[0006]
【課題を解決するための手段】前記の課題を解決するた
めに、本発明の水素吸蔵合金電極の製造方法は、水素吸
蔵合金粉末を８０℃以上のアルカリ溶液中に浸漬処理
し、次いで還元剤を添加した後、これを水洗する工程
と、前記の処理を施した水素吸蔵合金粉末を用いて電極
を形成する工程とからなる。In order to solve the above-mentioned problems, a method for producing a hydrogen-absorbing alloy electrode of the present invention comprises dipping hydrogen-absorbing alloy powder in an alkaline solution at 80 ° C. or higher, and then reducing agent. After the addition of hydrogen, the step of washing this with water and the step of forming an electrode using the hydrogen storage alloy powder that has been subjected to the above-mentioned treatment are included.
【０００７】また、本発明は、水素吸蔵合金粉末を主体
に構成した電極を、８０℃以上のアルカリ溶液中に浸漬
処理し、次いで還元剤を添加した後に水洗する方法でも
ある。The present invention is also a method of immersing an electrode mainly composed of a hydrogen storage alloy powder in an alkaline solution at 80 ° C. or higher, then adding a reducing agent and washing with water.
【０００８】ここでのアルカリ溶液は水酸化カリウム、
水酸化ナトリウム、水酸化リチウムのうちの少なくとも
１つをアルカリ成分として溶解したものである。また、
このアルカリ溶液には、水素吸蔵合金に対して１０重量
％以下の金属コバルトに相当する酸化コバルトまたは水
酸化コバルトか、もしくは１０重量％以下の金属銅に相
当する酸化銅または水酸化銅を添加することが好まし
い。The alkaline solution here is potassium hydroxide,
At least one of sodium hydroxide and lithium hydroxide is dissolved as an alkaline component. Also,
To this alkaline solution, cobalt oxide or cobalt hydroxide corresponding to 10 wt% or less of metallic cobalt or copper oxide or copper hydroxide corresponding to 10 wt% or less of metallic copper is added to the hydrogen storage alloy. It is preferable.
【０００９】さらにアルカリ溶液は、不活性ガス雰囲気
中や大気を遮断した状態などの液への酸素の溶解が抑制
された、実質的に酸素ガスとの接触を断たれた状態で、
合金粉末または電極の浸漬処理をするのが好ましい。Further, the alkaline solution is such that the dissolution of oxygen in the liquid is suppressed, such as in an inert gas atmosphere or in a state where the air is shut off, and the contact with the oxygen gas is substantially cut off,
Immersion treatment of the alloy powder or the electrode is preferable.
【００１０】[0010]
【発明の実施の形態】請求項１，２に記載の本発明は、
前記のように水素吸蔵合金を、電極形成前の粉末の段階
もしくは電極構成後に、高温のアルカリ溶液中に浸漬処
理し、次いで還元剤を添加し、その後水洗するものであ
る。BEST MODE FOR CARRYING OUT THE INVENTION
As described above, the hydrogen storage alloy is immersed in a high-temperature alkaline solution after the step of powdering before electrode formation or after the electrode is formed, and then the reducing agent is added, followed by washing with water.
【００１１】アルカリ浸漬処理後に還元剤を添加するこ
とで、アルカリ溶液中に溶解しているコバルトもしくは
酸化状態のコバルトを金属に還元させ、微細で非常に活
性な金属コバルトを合金表面に付着させるか、もしくは
合金粉末中に混合することができる。Whether the cobalt dissolved in the alkaline solution or the cobalt in the oxidized state is reduced to a metal by adding a reducing agent after the alkali immersion treatment and fine and very active metallic cobalt is adhered to the alloy surface. Alternatively, it can be mixed in the alloy powder.
【００１２】前記従来のアルカリ処理は、合金表面のア
ルカリに可溶な成分もしくはアルカリで酸化する成分を
溶解もしくは酸化し、合金に含まれるニッケル等の電気
化学的に活性な成分を粉末表面に露出させて活性点を多
くすると共に、溶解成分の除去等により高温のアルカリ
溶液中における耐久性を向上させるものであった。ま
た、単に金属コバルトを添加したものでは、金属コバル
トの粒子径が非常に細かくないと添加効果を示さず、材
料コスト面でも高価であり、好ましい使用例とは言えな
かった。The above-mentioned conventional alkali treatment dissolves or oxidizes an alkali-soluble component or an alkali-oxidizable component on the surface of the alloy, and exposes electrochemically active components such as nickel contained in the alloy to the powder surface. In addition to increasing the number of active sites, it was possible to improve the durability in a high temperature alkaline solution by removing dissolved components and the like. Further, when the metal cobalt is simply added, the effect of addition is not exhibited unless the particle size of the metal cobalt is very small, and the material cost is also high, and it cannot be said to be a preferable use example.
【００１３】また、さらにアルカリ溶液に、水酸化コバ
ルトもしくは酸化コバルトか、水酸化銅もしくは酸化銅
が添加されていると、このコバルトもしくは銅も還元さ
れ、金属として合金表面に析出し、粉末の電気化学的活
性を高めることができる。Further, when cobalt hydroxide or cobalt oxide or copper hydroxide or copper oxide is added to the alkaline solution, the cobalt or copper is also reduced and deposited as a metal on the surface of the alloy, resulting in electric powder. Chemical activity can be increased.
【００１４】本発明においては、合金表面に析出・付着
もしくは合金粉末中に混合する活性な金属コバルトが、
合金表面に露出するニッケル等の活性金属との相乗効果
により、合金電極の電気化学的活性や、電極表面の水素
−酸素反応性を大きく向上させることができる。このこ
とにより、過充電時に正極より発生する酸素ガスと合金
内の水素との水素−酸素反応がスムーズに行われる。こ
の合金電極での水素−酸素反応性が高いほど、電池内の
酸素濃度の上昇が抑制されて実酸素発生電位が低減し、
過充電による電位の上昇（過充電の進行）が抑制され、
正極の水酸化ニッケルの過充電が抑制される。また、銅
は、従来のアルカリ処理により合金表面に生成する酸化
物に代わって析出することから、合金粒子間の接触抵抗
を減少させる。これらによって、低温過充電後の高率放
電特性が向上する。In the present invention, the active metallic cobalt that precipitates or adheres to the alloy surface or mixes in the alloy powder is
Due to the synergistic effect with the active metal such as nickel exposed on the surface of the alloy, the electrochemical activity of the alloy electrode and the hydrogen-oxygen reactivity of the electrode surface can be greatly improved. As a result, the hydrogen-oxygen reaction between the oxygen gas generated from the positive electrode during overcharge and the hydrogen in the alloy is smoothly performed. The higher the hydrogen-oxygen reactivity at this alloy electrode, the higher the oxygen concentration in the battery is suppressed, and the actual oxygen generation potential is reduced,
The rise in potential (progress of overcharge) due to overcharge is suppressed,
Overcharge of nickel hydroxide of the positive electrode is suppressed. In addition, copper is deposited instead of the oxide formed on the alloy surface by the conventional alkali treatment, and thus the contact resistance between the alloy particles is reduced. These improve the high rate discharge characteristics after low temperature overcharge.
【００１５】また、このアルカリ処理を大気中の酸素が
アルカリ溶液中に多量に溶解するような雰囲気下で行う
と、溶解した酸素により水素吸蔵合金の表面が酸化さ
れ、所定量以上に酸化分解するとともに、析出したコバ
ルトが再度溶解してしまう。従って、アルカリ溶液が実
質的に酸素ガスとの接触を断たれた状態で合金粉末また
は電極の浸漬処理をすることにより、前記のような不都
合を避けることができる。When the alkali treatment is carried out in an atmosphere in which a large amount of oxygen in the atmosphere is dissolved in the alkaline solution, the surface of the hydrogen storage alloy is oxidized by the dissolved oxygen and is oxidatively decomposed to a predetermined amount or more. At the same time, the precipitated cobalt is dissolved again. Therefore, the inconvenience as described above can be avoided by immersing the alloy powder or the electrode in a state where the alkaline solution is substantially disconnected from the oxygen gas.
【００１６】また、浸漬処理に用いるアルカリ溶液に添
加するコバルトや銅の量が水素吸蔵合金に対し多くなり
過ぎると、その効果は平衡状態となるが、処理により生
成する金属ニッケルやコバルト等が多くなり過ぎ、電極
容量が低下するので避けるべきである。If the amount of cobalt or copper added to the alkaline solution used for the dipping treatment becomes too large relative to the hydrogen storage alloy, the effect will be in an equilibrium state, but there will be a large amount of metallic nickel or cobalt produced by the treatment. It should be avoided because it becomes too much and the electrode capacity decreases.
【００１７】[0017]
【実施例】以下、本発明の実施例について図面を用いて
説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１８】（実施例１）水素吸蔵合金試料は、粒径４
５μｍ以下のＺｒＭｎ0.55Ｖ0.15Ｃｒ0.2Ｃｏ0.1Ｎｉ
1.1の組成の合金粉末を用いた。この合金粉末を、４０
ｇ／ｌの水酸化リチウムを溶解した濃度３０重量％のＫ
ＯＨ水溶液に、合金粉末に対して５重量％の金属コバル
ト量に相当する水酸化コバルトを添加して１２０℃に加
温したアルカリ溶液を密閉容器に入れ、この中で大気と
遮断した状態で浸漬処理し、次いで還元剤として次亜り
ん酸ナトリウムを添加した後、水洗、乾燥した。この合
金粉末を、カルボキシメチルセルロースの希水溶液を加
えて混合撹拌しペースト状にして、発泡状ニッケル多孔
体に充填し、乾燥、加圧して、本発明の水素吸蔵合金電
極を得た。(Example 1) The hydrogen storage alloy sample had a particle size of 4
ZrMn 0.55 V 0.15 Cr 0.2 Co 0.1 Ni of 5 μm or less
An alloy powder having a composition of 1.1 was used. 40% of this alloy powder
K having a concentration of 30% by weight in which g / l of lithium hydroxide is dissolved
Cobalt hydroxide corresponding to the amount of metallic cobalt of 5% by weight with respect to the alloy powder was added to the OH aqueous solution, and the alkaline solution heated to 120 ° C. was placed in a closed container and immersed therein in a state of being shielded from the atmosphere. After treatment, sodium hypophosphite was added as a reducing agent, washed with water and dried. A dilute aqueous solution of carboxymethyl cellulose was added to this alloy powder, and the mixture was stirred to form a paste, which was filled in a foamed nickel porous body, dried, and pressed to obtain a hydrogen storage alloy electrode of the present invention.
【００１９】比較のために、同条件でのアルカリ処理後
還元剤を添加せずに、水洗、乾燥を施した水素吸蔵合金
粉末を用いて同様にして電極を作成した。For comparison, an electrode was prepared in the same manner using the hydrogen storage alloy powder which had been washed with water and dried without adding a reducing agent after the alkali treatment under the same conditions.
【００２０】これらの水素吸蔵合金電極を負極とし、正
極には公知の発泡式ニッケル電極（理論充填電気量１０
５０〜１１００ｍＡｈ）を用い、セパレータには親水性
を付与したポリプロピレン不織布を用いて、渦巻状に旋
回し電極群を作成した。この電極群を電池ケースに挿入
し、比重１．３０のＫＯＨ水溶液に水酸化リチウム４０
ｇ／ｌを溶解した電解液を注入した後封口し、公称容量
１０００ｍＡｈの密閉型ニッケル−水素蓄電池を作成し
た。These hydrogen storage alloy electrodes are used as the negative electrode, and the known foamed nickel electrode (theoretical charging electric quantity 10
50 to 1100 mAh), and a polypropylene non-woven fabric having hydrophilicity was used as a separator, and the electrode group was formed by spirally swirling. Insert this electrode group into the battery case and add 40% lithium hydroxide to a KOH aqueous solution with a specific gravity of 1.30.
An electrolytic solution in which g / l was dissolved was injected and then sealed to prepare a sealed nickel-hydrogen storage battery having a nominal capacity of 1000 mAh.
【００２１】これらの電池を、２０℃において、充電は
０．２ＣｍＡで１２０％まで行い、放電は０．２ＣｍＡ
で終止電圧１．０Ｖまで放電する充放電を２０サイクル
行った後、０℃雰囲気下で０．１ＣｍＡで１ヵ月間の連
続過充電を行い、その後２０℃において１／２ＣｍＡで
終止電圧１．０Ｖまで放電する試験を行った。At 20 ° C., these batteries were charged at 0.2 CmA up to 120% and discharged at 0.2 CmA.
After carrying out 20 cycles of charging and discharging to discharge to a final voltage of 1.0V at 0 ° C, carry out continuous overcharge at 0.1CmA for 1 month, and then at 20 ° C a final voltage of 1.0V at 1 / 2CmA. The test to discharge up to was conducted.
【００２２】その結果を図１に示す。図１は連続過充電
後の１／２ＣｍＡ放電の放電電圧と放電容量を示したも
のである。図１において、Ａは本発明の処理を行った合
金を用いた電池、Ｂはアルカリ処理のみを行った合金を
用いた電池である。図１の結果、アルカリ処理のみを行
った合金を用いた電池Ｂは１／２ＣｍＡでの放電が公称
容量の１０％程度しかできていないが、本発明の処理を
行った合金を用いた電池Ａは９０％以上放電できてお
り、低温過充電特性が向上していることがわかる。The results are shown in FIG. FIG. 1 shows the discharge voltage and the discharge capacity of 1/2 CmA discharge after continuous overcharge. In FIG. 1, A is a battery using the alloy treated according to the present invention, and B is a battery using the alloy treated only with alkali. As shown in FIG. 1, the battery B using the alloy subjected to only the alkali treatment can discharge only about 10% of the nominal capacity at 1/2 CmA, but the battery A using the alloy subjected to the treatment of the present invention. It can be seen that the battery was discharged by 90% or more, and the low temperature overcharge characteristics were improved.
【００２３】なお、本実施例ではアルカリ処理溶液とし
て４０ｇ／ｌの水酸化リチウムを添加したＫＯＨ水溶液
を用いたが、水酸化リチウムの添加量は５ｇ／ｌ〜飽和
溶液でほぼ同様の効果が得られた。なお、ＫＯＨのみ、
あるいはＫＯＨに水酸化ナトリウムを添加したもの、水
酸化リチウムと水酸化ナトリウムの両方を添加したもの
でも同様の効果が得られる。In this example, an aqueous KOH solution containing 40 g / l of lithium hydroxide was used as the alkaline treatment solution. However, when the amount of lithium hydroxide added was 5 g / l to a saturated solution, almost the same effect was obtained. Was given. Only KOH,
Alternatively, the same effect can be obtained by adding sodium hydroxide to KOH or adding both lithium hydroxide and sodium hydroxide.
【００２４】前記本実施例では前記アルカリ溶液に合金
粉末に対して５重量％の金属コバルト量に相当する水酸
化コバルトを添加した。しかし、その添加量は１０重量
％以下であれば電極容量の低下の問題はなかった。ま
た、水酸化コバルトではなく酸化コバルト、水酸化銅、
酸化銅を添加した場合もほぼ同様の効果が得られる。In the present embodiment, cobalt hydroxide corresponding to the amount of metallic cobalt of 5% by weight with respect to the alloy powder was added to the alkaline solution. However, if the added amount is 10% by weight or less, there is no problem of reduction in electrode capacity. Also, instead of cobalt hydroxide, cobalt oxide, copper hydroxide,
Almost the same effect can be obtained when copper oxide is added.
【００２５】なお、本実施例では還元剤として次亜りん
酸ナトリウムを用いたが、次亜りん酸カリウム、ヒドラ
ジン、水素化ホウ素ナトリウム等その他の還元剤を用い
ても同様の効果が得られる。Although sodium hypophosphite was used as the reducing agent in this example, the same effect can be obtained by using other reducing agents such as potassium hypophosphite, hydrazine and sodium borohydride.
【００２６】（実施例２）水素吸蔵合金試料は、粒径４
５μｍ以下のＭｍＮｉ3.7Ｃｏ0.6Ｍｎ0.4Ａｌ0.2 5Ｃｒ
0.05の組成の合金粉末を用いた。この合金粉末を、カル
ボキシメチルセルロースの希水溶液を加えて混合撹拌し
ペースト状にして、発泡状ニッケル多孔体に充填し、乾
燥、加圧して電極を形成した。この合金電極を、２０ｇ
／ｌの水酸化リチウムと１０ｇ／ｌの水酸化ナトリウム
を溶解した濃度３０重量％のＫＯＨ水溶液に合金粉末に
対して５重量％の金属銅量に相当する水酸化銅を添加し
て９０℃に加温したアルカリ溶液を、密閉容器内に入
れ、この中で大気と遮断した状態で浸漬処理し、次いで
還元剤として次亜りん酸ナトリウムを添加した後、水
洗、乾燥し、本発明の水素吸蔵合金電極を得た。 比較
のために、同条件でのアルカリ処理後還元剤を添加せ
ず、水洗、乾燥した水素吸蔵合金電極を作成した。(Example 2) The hydrogen storage alloy sample had a particle size of 4
5 μm or less of MmNi 3.7 Co 0.6 Mn 0.4 Al 0.2 5 Cr
An alloy powder having a composition of 0.05 was used. This alloy powder was added with a dilute aqueous solution of carboxymethyl cellulose, mixed and stirred to form a paste, which was filled in a foamed nickel porous body, dried and pressed to form an electrode. 20g of this alloy electrode
Copper hydroxide corresponding to the amount of metallic copper of 5% by weight with respect to the alloy powder was added to a KOH aqueous solution having a concentration of 30% by weight in which 1 / l of lithium hydroxide and 10 g / l of sodium hydroxide were dissolved, and the temperature was raised to 90 ° C. The warmed alkaline solution is placed in a closed container, and is subjected to an immersion treatment in a state in which it is shielded from the atmosphere, then sodium hypophosphite is added as a reducing agent, washed with water and dried to store hydrogen according to the present invention. An alloy electrode was obtained. For comparison, a hydrogen storage alloy electrode was prepared by washing with water and drying without adding a reducing agent after alkali treatment under the same conditions.
【００２７】これらの水素吸蔵合金電極を負極とし、正
極には公知の発泡式ニッケル電極（理論充填電気量１０
５０〜１１００ｍＡｈ）を用い、セパレータには親水性
を付与したポリプロピレン不織布を用いて、渦巻状に旋
回し電極群を作成した。この電極群を電池ケースに挿入
し、比重１．３０のＫＯＨ水溶液に水酸化リチウム４０
ｇ／ｌを溶解した電解液を注入した後封口し、公称容量
１０００ｍＡｈの密閉型ニッケル−水素蓄電池を作成し
た。These hydrogen storage alloy electrodes are used as the negative electrode, and the positive electrode is a known foam type nickel electrode (theoretical filling electric charge 10
50 to 1100 mAh), and a polypropylene non-woven fabric having hydrophilicity was used as a separator, and the electrode group was formed by spirally swirling. Insert this electrode group into the battery case and add 40% lithium hydroxide to a KOH aqueous solution with a specific gravity of 1.30.
An electrolytic solution in which g / l was dissolved was injected and then sealed to prepare a sealed nickel-hydrogen storage battery having a nominal capacity of 1000 mAh.
【００２８】これらの電池を、２０℃において、充電は
０．２ＣｍＡで１２０％まで行い、放電は０．２ＣｍＡ
で終止電圧１．０Ｖまで放電する充放電を２サイクル行
った後、０℃雰囲気下で０．１ＣｍＡで１ヵ月間の連続
過充電を行い、その後２０℃において１ＣｍＡで終止電
圧１．０Ｖまで放電する試験を行った。At 20 ° C., these batteries were charged at 0.2 CmA up to 120% and discharged at 0.2 CmA.
After carrying out 2 cycles of charge and discharge to discharge to a final voltage of 1.0V at 0 ° C, continuously overcharge for 1 month at 0.1CmA, then discharge to a final voltage of 1.0V at 20 ° C at 1CmA. The test was done.
【００２９】その結果を図２に示す。図２は連続過充電
後の１ＣｍＡ放電の放電電圧と放電容量を示したもので
ある。図２において、Ｃは本発明の処理を行った合金電
極を用いた電池、Ｄはアルカリ処理のみを行った合金電
極を用いた電池である。図２の結果、アルカリ処理のみ
を行った合金電極を用いた電池Ｄは先のＢ同様に１Ｃｍ
Ａでの放電が公称容量の１０％程度しかできていない
が、本発明の処理を行った合金電極を用いた電池Ｃは９
０％以上放電できており、低温過充電特性が向上してい
ることがわかる。The results are shown in FIG. FIG. 2 shows the discharge voltage and the discharge capacity of 1 CmA discharge after continuous overcharge. In FIG. 2, C is a battery using the alloy electrode subjected to the treatment of the present invention, and D is a battery using the alloy electrode subjected to only alkali treatment. As a result of FIG. 2, the battery D using the alloy electrode only subjected to the alkali treatment had the same 1 Cm as the above B.
Although the discharge at A was only about 10% of the nominal capacity, the battery C using the alloy electrode treated according to the present invention was 9%.
It can be seen that the discharge was 0% or more, and the low temperature overcharge characteristics were improved.
【００３０】なお、この実施例ではアルカリ処理溶液と
して２０ｇ／ｌの水酸化リチウムと１０ｇ／ｌの水酸化
ナトリウムを添加したＫＯＨ水溶液を用いたが、水酸化
リチウム、水酸化ナトリウムの添加量は５ｇ／ｌ〜飽和
溶液でほぼ同様の効果が得られた。また、ＫＯＨのみ、
あるいはＫＯＨに水酸化リチウムか水酸化ナトリウムの
どちらか１つを添加したものでもほぼ同様の効果が得ら
れる。In this embodiment, an aqueous KOH solution containing 20 g / l of lithium hydroxide and 10 g / l of sodium hydroxide was used as the alkaline treatment solution, but the addition amount of lithium hydroxide and sodium hydroxide was 5 g. Almost the same effect was obtained with the saturated solution. Also, only KOH,
Alternatively, almost the same effect can be obtained by adding either one of lithium hydroxide or sodium hydroxide to KOH.
【００３１】なお、アルカリ溶液には合金粉末に対して
５重量％の金属銅量に相当する水酸化銅を添加している
が、その添加量は１０重量％以下であれば電極容量の低
下の問題はない。また、水酸化銅ではなく酸化銅、水酸
化コバルト、酸化コバルトを添加した場合も同様の効果
が得られる。Although copper hydroxide corresponding to the amount of metallic copper of 5% by weight with respect to the alloy powder is added to the alkaline solution, if the amount of addition is 10% by weight or less, the electrode capacity decreases. No problem. The same effect can be obtained when copper oxide, cobalt hydroxide or cobalt oxide is added instead of copper hydroxide.
【００３２】さらに還元剤として次亜りん酸ナトリウム
を用いたが、次亜りん酸カリウム、ヒドラジン、水素化
ホウ素ナトリウム等その他の還元剤を用いても同様の効
果が得られる。Although sodium hypophosphite was used as the reducing agent, the same effect can be obtained by using other reducing agents such as potassium hypophosphite, hydrazine and sodium borohydride.
【００３３】[0033]
【発明の効果】以上のように本発明による水素吸蔵合金
電極を用いることにより、低温過充電後の高率放電特性
に優れたニッケル−水素蓄電池を得ることができる。As described above, by using the hydrogen storage alloy electrode according to the present invention, a nickel-hydrogen storage battery having excellent high rate discharge characteristics after low temperature overcharge can be obtained.
【図１】実施例１における低温連続過充電後の放電特性
を示す図FIG. 1 is a diagram showing discharge characteristics after low-temperature continuous overcharge in Example 1.
【図２】実施例２における低温連続過充電後の放電特性
を示す図FIG. 2 is a diagram showing discharge characteristics after low-temperature continuous overcharge in Example 2.
Claims (5)
溶液中に浸漬処理し、次いで還元剤を添加した後、水洗
する工程と、前記の処理を施した水素吸蔵合金粉末を用
いて電極に形成する工程を有することを特徴とする水素
吸蔵合金電極の製造方法。1. A step of immersing a hydrogen-absorbing alloy powder in an alkaline solution at 80 ° C. or higher, then adding a reducing agent, and then washing with water, and using the hydrogen-absorbing alloy powder subjected to the above treatment to an electrode. A method of manufacturing a hydrogen storage alloy electrode, comprising the step of forming.
８０℃以上のアルカリ溶液中に浸漬処理し、次いで還元
剤を添加した後、水洗する工程を有することを特徴とす
る水素吸蔵合金電極の製造方法。2. A hydrogen storage alloy electrode, which comprises a step of immersing an electrode mainly composed of hydrogen storage alloy powder in an alkaline solution at 80 ° C. or higher, then adding a reducing agent, and then washing with water. Manufacturing method.
化ナトリウム、水酸化リチウムのうち少なくとも１つを
水に溶解している請求項１または２記載の水素吸蔵合金
電極の製造方法。3. The method for producing a hydrogen storage alloy electrode according to claim 1, wherein the alkaline solution has at least one of potassium hydroxide, sodium hydroxide and lithium hydroxide dissolved in water.
て１０重量％以下の金属コバルトに相当する酸化コバル
トまたは水酸化コバルトか、もしくは１０重量％以下の
金属銅に相当する酸化銅または水酸化銅が添加されてい
る請求項３記載の水素吸蔵合金電極の製造方法。4. The alkali solution contains cobalt oxide or cobalt hydroxide corresponding to 10% by weight or less of metallic cobalt, or copper oxide or hydroxide corresponding to 10% by weight or less of metallic copper in the alkaline solution. The method for producing a hydrogen storage alloy electrode according to claim 3, wherein copper is added.
た状態で、前記水素吸蔵合金粉末または電極の浸漬処理
がなされる請求項１〜４のいずれかに記載の水素吸蔵合
金電極の製造方法。5. The production of a hydrogen storage alloy electrode according to claim 1, wherein the hydrogen storage alloy powder or the electrode is immersed in a state where the alkaline solution is cut off from contact with oxygen gas. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8092365A JPH09283130A (en) | 1996-04-15 | 1996-04-15 | Manufacture of hydrogen storage alloy electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8092365A JPH09283130A (en) | 1996-04-15 | 1996-04-15 | Manufacture of hydrogen storage alloy electrode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09283130A true JPH09283130A (en) | 1997-10-31 |
Family
ID=14052396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8092365A Pending JPH09283130A (en) | 1996-04-15 | 1996-04-15 | Manufacture of hydrogen storage alloy electrode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09283130A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6409849B1 (en) | 1999-08-31 | 2002-06-25 | Sanyo Electric Co., Ltd. | Method of producing hydrogen-absorbing alloy for nickel-hydrogen alkaline storage cell |
| CN114836620A (en) * | 2022-03-29 | 2022-08-02 | 上海电气集团股份有限公司 | Method for recycling lithium from waste battery |
-
1996
- 1996-04-15 JP JP8092365A patent/JPH09283130A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6409849B1 (en) | 1999-08-31 | 2002-06-25 | Sanyo Electric Co., Ltd. | Method of producing hydrogen-absorbing alloy for nickel-hydrogen alkaline storage cell |
| CN114836620A (en) * | 2022-03-29 | 2022-08-02 | 上海电气集团股份有限公司 | Method for recycling lithium from waste battery |
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