JP3433008B2 - Method for producing hydrogen storage alloy for alkaline storage battery - Google Patents
Method for producing hydrogen storage alloy for alkaline storage batteryInfo
- Publication number
- JP3433008B2 JP3433008B2 JP16575396A JP16575396A JP3433008B2 JP 3433008 B2 JP3433008 B2 JP 3433008B2 JP 16575396 A JP16575396 A JP 16575396A JP 16575396 A JP16575396 A JP 16575396A JP 3433008 B2 JP3433008 B2 JP 3433008B2
- Authority
- JP
- Japan
- Prior art keywords
- alloy
- hydrogen storage
- storage alloy
- ions
- metal
- 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.)
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Classifications
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- 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
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- Battery Electrode And Active Subsutance (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、アルカリ蓄電池用
水素吸蔵合金の製造方法に関し、詳しくは水素吸蔵合金
の酸処理方法の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hydrogen storage alloy for an alkaline storage battery, and more particularly to an improvement in an acid treatment method for a hydrogen storage alloy.
【０００２】[0002]
【従来の技術】水素吸蔵合金を負極活物質として使用す
るニッケル・水素蓄電池では、水素吸蔵合金の活性度の
優劣により電池性能が左右される。このため、この種の
蓄電池では、粉砕し微細化した水素吸蔵合金粉末が用い
られている。微細な水素吸蔵合金粉末であると、電気化
学反応に関与する反応面積が大きくなり、また電極基板
への充填密度が高まるので、高エネルギー密度化を図り
易いからである。2. Description of the Related Art In a nickel-hydrogen storage battery using a hydrogen storage alloy as a negative electrode active material, the battery performance depends on the superiority or inferiority of the activity of the hydrogen storage alloy. Therefore, in this type of storage battery, pulverized and finely divided hydrogen storage alloy powder is used. This is because if the fine hydrogen storage alloy powder is used, the reaction area involved in the electrochemical reaction is increased and the packing density in the electrode substrate is increased, so that high energy density can be easily achieved.
【０００３】しかし、水素吸蔵合金は極めて活性な物質
であり、粉砕時や貯蔵時に酸化され表面に酸化皮膜を形
成する。この酸化被膜は、合金の電気導電性を低下させ
るとともに、電気化学的反応性を劣化させる。そこで、
従来より合金の電気化学的活性を回復させるための方法
が種々提案されている。However, the hydrogen storage alloy is an extremely active substance and is oxidized during pulverization or storage to form an oxide film on the surface. This oxide film reduces the electrical conductivity of the alloy as well as the electrochemical reactivity. Therefore,
Conventionally, various methods have been proposed for recovering the electrochemical activity of alloys.
【０００４】その中の一つに水素吸蔵合金の表面を酸性
水溶液で表面処理する酸処理法（特開平４−１７９０５
５号公報、特開平７−７３８７８号公報、特開平７−１
５３４６０号公報等）がある。この酸処理法は、処理操
作が簡単でかつ酸化皮膜等の除去効果に優れるという特
徴を有し、この方法の適用により比較的簡便に水素吸蔵
合金の電気化学的活性を回復させることができる。しか
し、この方法によっても、高率放電特性やサイクル特性
を十分に高めることができない。よって、更なる改良が
期待されている。One of them is an acid treatment method in which the surface of the hydrogen storage alloy is surface-treated with an acidic aqueous solution (JP-A-4-17905).
5, JP-A-7-73878, and JP-A 7-1.
53460 gazette). This acid treatment method is characterized in that the treatment operation is simple and the effect of removing an oxide film and the like is excellent, and by applying this method, the electrochemical activity of the hydrogen storage alloy can be relatively easily restored. However, even with this method, high rate discharge characteristics and cycle characteristics cannot be sufficiently improved. Therefore, further improvement is expected.
【０００５】[0005]
【発明が解決しようとする課題】本発明は、水素吸蔵合
金を酸性溶液で表面処理する酸処理法において、水素吸
蔵合金電極の高率放電特性やサイクル特性を一層高める
ことのできる処理条件を確立することを目的とする。DISCLOSURE OF THE INVENTION The present invention establishes treatment conditions capable of further enhancing the high rate discharge characteristics and cycle characteristics of a hydrogen storage alloy electrode in an acid treatment method of surface treating a hydrogen storage alloy with an acidic solution. The purpose is to do.
【０００６】[0006]
【課題を解決するための手段】本発明者らは、水素吸蔵
合金に対する酸処理法を鋭意研究した結果、酸処理液に
金属イオンを含有させることにより、水素吸蔵合金の電
気化学的活性が顕著に高まることを見出し、以下の構成
の本発明を完成させた。Means for Solving the Problems As a result of intensive studies on the acid treatment method for hydrogen storage alloys, the present inventors have found that the electrochemical activity of the hydrogen storage alloy is remarkable by incorporating metal ions in the acid treatment liquid. The present invention having the following constitution was completed.
【０００７】本発明の第１の態様は、初期ｐＨ値が０．
５〜３．０である酸溶液に金属イオンまたはビスマスイ
オンを添加した酸処理液（以下金属イオン含有酸処理液
という）を用いて水素吸蔵合金を表面処理し、ｐＨ４〜
６の域において当該金属イオン又はビスマスイオンを当
該水素吸蔵合金表面に析出させるアルカリ蓄電池用水素
吸蔵合金の製造方法であることを特徴とする。 A first aspect of the present invention, the initial pH value 0.
5 to 3.0 in acid solution with metal ions or bismuth
Acid treatment solution containing ON (hereinafter referred to as metal ion-containing acid treatment solution)
Surface treatment of the hydrogen storage alloy with
In the region of 6, the metal ion or bismuth ion
A method for producing a hydrogen storage alloy for an alkaline storage battery, wherein the hydrogen storage alloy is deposited on the surface of the hydrogen storage alloy .
【０００８】本発明の第２の態様は、上記第１の態様の
アルカリ蓄電池用水素吸蔵合金の製造方法において、前
記金属イオンが、ニッケルイオン、コバルトイオンより
なる群から１種以上選択されたものであることを特徴と
する。A second aspect of the present invention is the method for producing a hydrogen storage alloy for alkaline storage batteries according to the first aspect , wherein the metal ion is at least one selected from the group consisting of nickel ion and cobalt ion. It is characterized by being selected.
【０００９】本発明の第３の態様は、上記第１または第
２の態様のアルカリ蓄電池用水素吸蔵合金の製造方法に
おいて、前記金属イオン含有酸処理液には、更にｐＨ４
〜６の範囲内においてｐＨ緩衝作用を発揮する物質が添
加されていることを特徴とする。A third aspect of the present invention is the above-mentioned first or first aspect .
In the method for producing a hydrogen storage alloy for alkaline storage batteries according to the second aspect, the metal ion-containing acid treatment liquid further has a pH of 4
Substances added to exert Oite pH buffering action in the range 6 of
It is characterized by being added .
【００１０】本発明の第４の態様は、上記第３の態様の
アルカリ蓄電池用水素吸蔵合金の製造方法において、前
記ｐＨ緩衝作用を発揮する物質が、アルミニウムイオン
であることを特徴とする。[0010] A fourth aspect of the present invention is the manufacturing method of the third aspect of the <br/> for alkaline storage battery hydrogen storage alloy, before
Aluminum ion is a substance that exerts a pH buffering effect.
And characterized in that.
【００１１】[0011]
【実施の形態】以下では、本発明方法を適用した水素吸
蔵合金と、従来方法を適用した水素吸蔵合金との電気化
学的特性を比較検討することを通して、本発明水素吸蔵
合金の製造方法の内容を明らかにする。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the contents of the method for producing a hydrogen storage alloy of the present invention will be described by comparing and examining the electrochemical characteristics of the hydrogen storage alloy to which the method of the present invention is applied and the hydrogen storage alloy to which the conventional method is applied. To clarify.
【００１２】（水素吸蔵合金粉末の作製）市販のミッシ
ュメタル（Ｍｍ；Ｌａ，Ｃｅ，Ｎｄ，Ｐｒ等の希土類元
素の混合物）、ニッケル（Ｎｉ）、コバルト（Ｃｏ）、
アルミニウム（Ａｌ）、マンガン（Ｍｎ）を原材料と
し、それぞれが元素比で１：3.4 ：0.8 ：0.2 ：0.6 の
割合となるように混合し、高周波溶解炉を用いて組成式
ＭｍＮｉ3.4 Ｃｏ0.8 Ａｌ0. 2 Ｍｎ0.6 の水素吸蔵合金
鋳塊を作製した。この合金鋳塊に対し、１０００℃・１
０時間のアニール処理を行った。(Preparation of Hydrogen Storage Alloy Powder) Commercially available misch metal (Mm; mixture of rare earth elements such as La, Ce, Nd, Pr), nickel (Ni), cobalt (Co),
Aluminum (Al), and manganese (Mn) and a raw material, 1 each elementary ratio: 3.4: 0.8: 0.2 were mixed so that 0.6 ratio of the composition formula using a high frequency melting furnace MmNi 3.4 Co 0.8 Al 0 . were prepared of 2 Mn 0.6 hydrogen storage alloy ingot. 1000 ℃ ・ 1 for this alloy ingot
Annealing treatment was performed for 0 hours.
【００１３】前記合金鋳塊１Ｋｇに対し水１リットルを
用いて、ボールミル粉砕し、前記合金鋳塊を平均粒径５
０μｍの水素吸蔵合金となした。この合金を合金Ａとす
る。Ball crushing was performed by using 1 liter of water for 1 kg of the alloy ingot and the alloy ingot had an average particle size of 5
The hydrogen storage alloy was 0 μm. This alloy is designated as alloy A.
【００１４】（酸処理）
初期ｐＨが０．５、１、２、３、４の５通りの塩酸液を
調整し、各々の塩酸液に水酸化ニッケルを１重量％溶解
して、ニッケルイオンを含む塩酸溶液（金属イオン含有
酸処理液）を調製した。他方、初期ｐＨ１の塩酸液を４
つ用意し、各々に水酸化コバルト、水酸化銅、水酸化ビ
スマスの何れか１つを、１重量％溶解し、溶存する金属
イオン等が異なる４通りの金属イオン含有酸処理液を調
製した。更に、初期ｐＨ１の塩酸液に水酸化ニッケルと
水酸化アルミニウムをそれぞれ１重量％溶解した金属イ
オン含有酸処理液を調製した。なお、以下で「金属イオ
ン」というときは、ビスマスイオンを含めた意味で使用
されている。 (Acid treatment) Five kinds of hydrochloric acid solutions having an initial pH of 0.5, 1, 2, 3, 4 were prepared, and 1% by weight of nickel hydroxide was dissolved in each hydrochloric acid solution to remove nickel ions. A hydrochloric acid solution containing the same (a metal ion-containing acid treatment solution) was prepared. On the other hand, add hydrochloric acid solution with an initial pH of 4
One of cobalt hydroxide, copper hydroxide, and bismuth hydroxide was dissolved in each of them by 1% by weight to prepare four kinds of metal ion-containing acid treatment solutions having different dissolved metal ions and the like . Furthermore, a metal ion-containing acid treatment liquid was prepared by dissolving 1% by weight of nickel hydroxide and 1% by weight of aluminum hydroxide in a hydrochloric acid solution having an initial pH of 1. Note that in the following,
"," Means bismuth ions
Has been done.
【００１５】表１に、上記で調製した各処理液を一覧表
示する。なお、初期ｐＨとは、水素吸蔵合金を処理する
前の処理液ｐＨをいう。Table 1 shows a list of the treatment solutions prepared above. The initial pH means the pH of the treatment liquid before treating the hydrogen storage alloy.
【００１６】次に、上記各処理液を用いて前記合金Ａに
対し表面処理を行った。表面処理は、合金Ａに対し等重
量の処理液を加え、攪拌混合機で処理液ｐＨが７になる
まで攪拌する方法により行った。酸処理後の合金は精製
水で洗い乾燥して以下の実験に用いた。表１に示すよう
に、本発明にかかる金属イオン含有酸処理液で表面処理
したものを、Ｎｏ．１〜９とする。Next, surface treatment was performed on the alloy A using each of the treatment solutions described above. The surface treatment was performed by adding an equal weight of the treatment liquid to Alloy A and stirring the mixture with a stirring mixer until the pH of the treatment liquid reached 7. The alloy after the acid treatment was washed with purified water and dried, and used in the following experiments. As shown in Table 1, No. 1 was surface-treated with the metal ion-containing acid treatment liquid according to the present invention. 1 to 9.
【００１７】他方、比較例として、金属イオンを含まな
い初期ｐＨ１の塩酸液で表面処理した合金（Ｎｏ．１
１）、酸処理を全く行わない合金（Ｎｏ．１２）、及び
合金Ａに電解メッキ法により３wt％のニッケルメッキを
施し、かつ酸処理液での表面処理を行わない合金（Ｎ
ｏ．１０）を別途に用意した。このニッケルメッキ合金
は、金属イオンの効果を検証するためのものである。On the other hand, as a comparative example, an alloy surface-treated with a hydrochloric acid solution containing no metal ions and having an initial pH of 1 (No. 1).
1), an alloy which is not subjected to any acid treatment (No. 12), and an alloy which is plated with 3 wt% of nickel on the alloy A by an electrolytic plating method and is not surface-treated with an acid treatment solution (N.
o. 10) was prepared separately. This nickel-plated alloy is for verifying the effect of metal ions.
【００１８】なお、便宜上、以後の説明では酸処理を全
く行わなかった合金Ｎｏ．１０、１２も「処理済合金」
に含める。For the sake of convenience, in the following description, alloy No. No. 10 and 12 are also "treated alloys"
Include in.
【００１９】（実験）上記各処理済合金を負極活物質と
し、以下の方法により試験セル及びニッケル・水素蓄電
池を作製し、各種処理済合金の電気化学的特性（高率放
電特性およびサイクル特性）を測定した。そして、測定
結果に基づいて、処理液の違いと電気化学的特性の関係
を明らかにした。(Experiment) Using each of the above treated alloys as a negative electrode active material, a test cell and a nickel-hydrogen storage battery were prepared by the following method, and the electrochemical characteristics (high rate discharge characteristics and cycle characteristics) of each treated alloy were prepared. Was measured. Then, based on the measurement results, the relationship between the difference in the treatment liquid and the electrochemical characteristics was clarified.
【００２０】〈高率放電特性の測定方法〉高率放電特性
を測定するための試験セルを、次のようにして作製し
た。各種合金粉末１ｇに、導電剤としてカルボニルニッ
ケル１．２ｇ、結着剤としてポリテトラフルオロエチレ
ン粉末０．２ｇとを加えて混練し合金ペーストを調製す
る。この合金ペーストをニッケルメッシュで包み、プレ
ス加工して水素吸蔵合金電極（負極）を作製した。この
水素吸蔵合金電極と、この電極より十分に容量の大きい
公知の焼結式ニッケル電極（正極）とを容器内に配置
し、電解液として水酸化カリウムを過剰量入れた後、容
器を密閉して試験セルとする。<Method for Measuring High Rate Discharge Characteristics> A test cell for measuring high rate discharge characteristics was prepared as follows. To 1 g of each alloy powder, 1.2 g of carbonyl nickel as a conductive agent and 0.2 g of polytetrafluoroethylene powder as a binder were added and kneaded to prepare an alloy paste. This alloy paste was wrapped in nickel mesh and pressed to produce a hydrogen storage alloy electrode (negative electrode). This hydrogen storage alloy electrode and a known sintered nickel electrode (positive electrode) having a sufficiently larger capacity than this electrode were placed in a container, and an excessive amount of potassium hydroxide was added as an electrolytic solution, and then the container was closed. To make a test cell.
【００２１】この試験セルを用い、水素吸蔵合金１ｇ当
たり５０ｍＡの電流値（５０ｍＡ／ｇ−合金）で８時間
充電し、１時間休止した後、２００ｍＡ／ｇ−合金の電
流値で放電終止電圧が１．０Ｖに達するまで放電し、こ
の時の放電容量（ＣＨ）を測定した。この後、放電を１
時間休止して試験セルの電圧を回復させたのち、更に５
０ｍＡ／ｇ−合金の電流値で放電終止電圧が１．０Ｖに
達するまで放電し、この時の放電容量（ＣＬ）を測定し
た。ＣＨ及びＣＬを用い、数１に従って各処理済合金の
電気化学的活性度（％）を算出し、この値を高率放電特
性値とした。Using this test cell, the battery was charged at a current value of 50 mA per gram of hydrogen storage alloy (50 mA / g-alloy) for 8 hours, and after resting for 1 hour, the discharge end voltage was at a current value of 200 mA / g-alloy. The battery was discharged until it reached 1.0 V, and the discharge capacity (CH) at this time was measured. After this, discharge 1
After resting for a while to recover the voltage of the test cell,
Discharge was performed at a current value of 0 mA / g-alloy until the discharge end voltage reached 1.0 V, and the discharge capacity (CL) at this time was measured. Using CH and CL, the electrochemical activity (%) of each treated alloy was calculated according to Equation 1, and this value was taken as the high rate discharge characteristic value.
【００２２】[0022]
【数１】 高率放電特性値（活性度％）＝ＣＨ／（ＣＨ＋ＣＬ） ×１００ … 数１[Equation 1] High rate discharge characteristic value (% activity) = CH / (CH + CL) × 100 ...
【００２３】〈サイクル特性の測定方法〉サイクル特性
は、ニッケル・水素蓄電池を用い測定した。ニッケル・
水素蓄電池の作製方法は次の通りである。合金粉末に、
結着剤としてポリテトラフルオロエチレン粉末を、合金
重量に対し５ｗｔ％加え混練し合金ペーストを調製す
る。このペーストをパンチングメタルからなる集電体の
両面に塗着した後、プレスして水素吸蔵合金電極を作製
する。次いで、この電極（負極）と、この電極より容量
の小さい公知の焼結式ニッケル電極（正極）とを、セパ
レータを介して巻回し、渦巻型電極体となし、外装缶に
挿入し、さらにこの外装缶に３０ｗｔ％水酸化カリウム
水溶液を注液し、外装缶を密閉する。このようにして、
理論容量１０００ｍＡｈの円筒形ニッケル・水素蓄電池
を作製した。<Measuring method of cycle characteristics> The cycle characteristics were measured using a nickel-hydrogen storage battery. nickel·
The method for manufacturing the hydrogen storage battery is as follows. Alloy powder,
Polytetrafluoroethylene powder is added as a binder in an amount of 5 wt% with respect to the weight of the alloy, and the mixture is kneaded to prepare an alloy paste. This paste is applied to both sides of a collector made of punching metal and then pressed to prepare a hydrogen storage alloy electrode. Next, this electrode (negative electrode) and a known sintered nickel electrode (positive electrode) having a smaller capacity than this electrode are wound via a separator to form a spirally wound electrode body, which is then inserted into an outer can. A 30 wt% potassium hydroxide aqueous solution is poured into the outer can to seal the outer can. In this way
A cylindrical nickel-hydrogen storage battery with a theoretical capacity of 1000 mAh was produced.
【００２４】上記ニッケル・水素蓄電池に対し、先ず、
１００ｍＡで１６時間充電し、１時間休止した後、２０
０ｍＡで放電終止電圧が１．０Ｖになるまで放電し、更
に１時間休止するというサイクルを室温で３サイクル繰
り返す方法により、活性化処理を行った。この活性化処
理後の蓄電池に対し、１５００ｍＡで４８分充電し、１
時間休止した後、１５００ｍＡで放電終止電圧が１．０
Ｖになるまで放電し、更に１時間休止するというサイク
ルを繰り返し、放電容量が５００ｍＡｈ以下に達するま
でのサイクル回数を測定した。このサイクル回数をサイ
クル特性値（電池寿命値）として、各合金のサイクル特
性を評価した。First, for the nickel-hydrogen storage battery,
After charging for 16 hours at 100mA and resting for 1 hour, 20
The activation treatment was performed by repeating a cycle of discharging at 0 mA until the discharge end voltage became 1.0 V and then resting for 1 hour at room temperature for 3 cycles. Charge the storage battery after this activation treatment at 1500 mA for 48 minutes, and
After resting for 1 hour, the discharge end voltage is 1.0 at 1500 mA.
The cycle of discharging until reaching V and further resting for 1 hour was repeated, and the number of cycles until the discharge capacity reached 500 mAh or less was measured. The cycle characteristics of each alloy were evaluated using the number of cycles as the cycle characteristic value (battery life value).
【００２５】各種合金における結果を、合金処理条件と
ともに表１に示す。また、図１に水素吸蔵合金を金属イ
オン含有酸処理液で処理した場合（Ｎｏ．９を例とす
る）における溶液ｐＨの変化を模式的に示す。The results for various alloys are shown in Table 1 together with alloy treatment conditions. Further, FIG. 1 schematically shows a change in solution pH when a hydrogen storage alloy is treated with a metal ion-containing acid treatment liquid (for example, No. 9).
【００２６】[0026]
【表１】 [Table 1]
【００２７】表１から次のことが明らかとなる。本発明
にかかる金属イオン含有酸処理液で表面処理したＮｏ．
１〜９は、何れも比較例である合金Ｎｏ．１０〜１１に
比べ、高率放電特性及びサイクル特性ともに優れてい
た。但し、Ｎｏ．１〜５の比較から明らかな如く、処理
液の初期ｐＨが４のＮｏ．５は、Ｎｏ．１〜４に比べて
電池特性が顕著に悪くなった。このことから、処理液の
初期ｐＨは３以下とする必要がある。また、初期ｐＨが
同じで、金属イオンの種類のみが異なるＮｏ．２、Ｎ
ｏ．６〜９の各々の結果の比較から、銅イオン又はビス
マスイオンを含有する処理液よりも、ニッケルイオン又
はコバルトイオンを含有する処理液の方が、良好な電池
特性が得られた。更に、ニッケルイオンとアルミニウム
イオンを含有するＮｏ．９において、一層良好な結果が
得られた。このことから、処理液に含ませる金属イオン
としては、好ましくはニッケルイオン及びコバルトイオ
ンを用いるのがよい。また、より好ましくはアルミニウ
ムイオンを他の金属イオンと併用して用いるのがよいこ
とが判る。The following is clear from Table 1. No. 1 surface-treated with the metal ion-containing acid treatment liquid according to the present invention.
Alloy Nos. 1 to 9 are comparative examples. Compared with Nos. 10 to 11, both high rate discharge characteristics and cycle characteristics were excellent. However, No. As is clear from the comparison of Nos. 1 to 5, No. No. 5 is No. The battery characteristics were remarkably deteriorated as compared with Nos. 1 to 4. From this, the initial pH of the treatment liquid needs to be 3 or less. Moreover, the initial pH was the same, and only the kinds of metal ions were different. 2, N
o. From the comparison of the results of 6 to 9, it was found that the treatment liquid containing nickel ions or cobalt ions had better battery characteristics than the treatment liquid containing copper ions or bismuth ions. Further, No. 1 containing nickel ion and aluminum ion. In 9, even better results were obtained. Therefore, nickel ions and cobalt ions are preferably used as the metal ions contained in the treatment liquid. Further, it is more preferable to use aluminum ions in combination with other metal ions.
【００２８】以上の結果を更に詳細に検討する。処理液
での表面処理を全く行わなかったＮｏ．１２と、金属イ
オンを含まない酸性処理液で表面処理したＮｏ．１１と
の比較、及びＮｏ．１１とこの酸性処理液に金属イオン
を含有させたＮｏ．２、Ｎｏ．６〜９との比較から、合
金を酸性処理液で表面処理すると電気化学的特性が向上
するが、この酸性処理液に金属を溶解させた場合、一層
顕著に電気化学的特性が向上することが判る。他方、Ｎ
ｏ．１２とニッケルメッキしたＮｏ．１０との比較か
ら、メッキ法により合金表面に金属層を形成しても、殆
ど電池特性が向上しないことが判る。The above results will be examined in more detail. No. No surface treatment with the treatment liquid was performed. 12 and No. 12 surface-treated with an acidic treatment liquid containing no metal ion. Comparison with No. 11, and No. 11 No. 11 in which this acidic treatment liquid contained metal ions. 2, No. From the comparison with Nos. 6 to 9, when the alloy is surface-treated with the acidic treatment liquid, the electrochemical characteristics are improved, but when the metal is dissolved in the acidic treatment liquid, the electrochemical characteristics are more remarkably improved. I understand. On the other hand, N
o. No. 12 and nickel plated No. From the comparison with No. 10, it is understood that even if the metal layer is formed on the alloy surface by the plating method, the battery characteristics are hardly improved.
【００２９】図１に示すごとく、水素吸蔵合金を強酸
（当初ｐＨ０．５）で洗浄した場合、表面処理の進行に
つれ処理液ｐＨが上昇する。このことを踏まえ、上記の
結果を考察する。As shown in FIG. 1, when the hydrogen storage alloy is washed with a strong acid (initially pH 0.5), the pH of the treatment liquid rises as the surface treatment progresses. With this in mind, consider the above results.
【００３０】合金を酸性処理液で表面処理した場合、処
理液ｐＨが０．５〜４域においては、合金成分（希土類
元素、ニッケル、コバルト等、またはこれらの酸化物、
水酸化物）が処理液の水素イオンと反応し処理液中に溶
出するが、合金の各成分の溶解度や溶出速度は一様でな
いので、この溶出によって合金表面に凹凸が形成され、
合金の比表面積が増加し、また、金属酸化物等の溶出に
より合金表面にニッケルやコバルトの単離層が出現す
る。When the alloy is surface-treated with an acidic treatment liquid, alloy components (rare earth elements, nickel, cobalt, etc., or their oxides) are treated in the treatment liquid pH range of 0.5 to 4.
(Hydroxide) reacts with hydrogen ions in the treatment solution and is eluted into the treatment solution, but the solubility and elution rate of each component of the alloy are not uniform, so this elution forms irregularities on the alloy surface,
The specific surface area of the alloy increases, and nickel or cobalt isolation layers appear on the surface of the alloy due to elution of metal oxides.
【００３１】一方、合金成分と水素イオンの反応が進行
し処理液ｐＨがｐＨ４〜６域に上昇すると、金属の溶解
度が減少する。よって、処理液中に溶解していたニッケ
ルイオンやコバルトイオン等が、主に合金の凸部（単離
層部分）に再析出し沈着する。この析出・沈着により、
合金表面の金属単離層の厚みが増加する。この結果、水
素吸蔵合金の高率放電特性やサイクル特性が向上するこ
とになる。なぜなら、凹凸が多いほど、合金の比表面積
が大きくなり電気化学的反応面積が増加するので酸素ガ
ス吸収性能（サイクル特性）及び高率放電特性が良くな
る。また、合金表面の金属単離層（ニッケル層、コバル
ト層）はガス吸収反応及び放電反応の触媒性に富むの
で、さらに電極特性が向上する。On the other hand, when the reaction between the alloy components and hydrogen ions proceeds and the pH of the treatment liquid rises to the pH range of 4 to 6, the solubility of the metal decreases. Therefore, nickel ions, cobalt ions, etc. dissolved in the treatment liquid are re-precipitated and deposited mainly on the convex portions (isolated layer portion) of the alloy. By this deposition / deposition,
The thickness of the metal isolation layer on the alloy surface increases. As a result, the high rate discharge characteristics and cycle characteristics of the hydrogen storage alloy are improved. This is because the more the irregularities are, the larger the specific surface area of the alloy is and the larger the electrochemical reaction area is, so that the oxygen gas absorption performance (cycle characteristics) and the high rate discharge characteristics are improved. In addition, the metal isolation layer (nickel layer, cobalt layer) on the surface of the alloy is rich in catalytic properties for gas absorption reaction and discharge reaction, so that electrode characteristics are further improved.
【００３２】ここにおいて、本発明にかかる金属イオン
含有酸処理液は、コバルトやニッケルなどの金属イオン
が添加されているので、金属イオンが添加されていない
酸性溶液で表面処理する場合に比べ、ｐＨ４〜６域にお
ける金属イオンの析出量が多くなる。したがって、合金
表面の凹凸が大きくなり、また金属単離層（触媒層）の
厚みが一層厚くなる。その結果、高率放電特性やサイク
ル特性を一層顕著に向上させることができる。Here, the metal ion-containing acid treatment solution according to the present invention is a metal ion such as cobalt or nickel.
Since There has been added, compared with the case of surface treatment with an acidic solution of metal ions is not added, the greater the amount of precipitation of the metal ions in pH4~6 zone. Therefore, the unevenness of the alloy surface becomes large, and the thickness of the metal isolation layer (catalyst layer) becomes even thicker. As a result, the high rate discharge characteristic and the cycle characteristic can be more remarkably improved.
【００３３】なお、上述のことは、合金表面に金属を直
接メッキする方法を用いたＮｏ．１０と、Ｎｏ．１２の
比較結果により裏付けられる。即ち、メッキ法を用いた
場合であっても合金表面に金属層を形成できるが、メッ
キ法では金属が合金表面に均一に付着するため、金属表
面の凹凸をむしろ縮小するように作用する。よって、高
率放電特性やサイクル特性の向上効果がないものと考え
られる。It should be noted that, in the above description, No. 1 using the method of directly plating the surface of the alloy with metal. 10 and No. This is supported by 12 comparison results. That is, even if the plating method is used, a metal layer can be formed on the alloy surface, but since the metal uniformly adheres to the alloy surface by the plating method, it acts rather to reduce the unevenness of the metal surface. Therefore, it is considered that there is no effect of improving the high rate discharge characteristics and the cycle characteristics.
【００３４】また、ニッケルイオンとアルミニウムイオ
ン含有の酸処理液を用いて表面処理した合金Ｎｏ．９で
最も良好な結果が得られたのは、次の理由によると考え
られる。即ち、アルミニウムイオンはｐＨ４〜６域にお
いて、ｐＨ緩衝能を有するため、酸処理液のｐＨを４〜
６の範囲に長く留めるよう作用する。よって、処理液中
の金属イオンがより多く析出し合金表面に付着する結
果、合金の電気化学的特性が向上する。Further, alloy No. No. 1 surface-treated with an acid treatment liquid containing nickel ions and aluminum ions was used. The reason why the best result was obtained in No. 9 is considered to be as follows. That is, since aluminum ions have a pH buffering ability in the pH range of 4 to 6, the pH of the acid treatment solution is set to 4 to 4.
It works to keep it in the range of 6 for a long time. Therefore, as a result of more metal ions in the treatment liquid being deposited and adhering to the surface of the alloy, the electrochemical characteristics of the alloy are improved.
【００３５】[0035]
【発明の効果】以上から明らかなように、金属イオンを
含有する酸処理液を用いて水素吸蔵合金を表面処理する
本発明方法によると、水素イオンと合金成分との反応に
伴う処理液ｐＨの上昇過程において、水素吸蔵合金の表
面が電気化学反応を好適に行える性状に改質される。よ
って、アルカリ蓄電池用水素吸蔵合金に本発明方法を適
用すれば、高率放電特性やサイクル特性を顕著に向上さ
せることができる。As is apparent from the above, according to the method of the present invention for surface-treating a hydrogen storage alloy using an acid treatment liquid containing metal ions, the pH of the treatment liquid due to the reaction between hydrogen ions and alloy components is During the ascending process, the surface of the hydrogen storage alloy is modified so that the electrochemical reaction can be suitably performed. Therefore, when the method of the present invention is applied to the hydrogen storage alloy for alkaline storage batteries, high rate discharge characteristics and cycle characteristics can be remarkably improved.
【図１】表面処理における酸処理液のｐＨ上昇曲線を示
すグラフである。FIG. 1 is a graph showing a pH rise curve of an acid treatment liquid in surface treatment.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平７−73878（ＪＰ，Ａ) 特開 平７−153460（ＪＰ，Ａ) 特開 平７−320731（ＪＰ，Ａ) 特開 平７−326353（ＪＰ，Ａ) 特開 平４−110403（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/38 H01M 4/24 - 4/26 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-7-73878 (JP, A) JP-A-7-153460 (JP, A) JP-A-7-320731 (JP, A) JP-A-7- 326353 (JP, A) JP-A-4-110403 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) H01M 4/38 H01M 4/24-4/26
Claims (4)
液に金属イオンまたはビスマスイオンを添加した酸処理
液を用いて水素吸蔵合金を表面処理し、ｐＨ４〜６の域
において当該金属イオン又はビスマスイオンを当該水素
吸蔵合金表面に析出させることを特徴とするアルカリ蓄
電池用水素吸蔵合金の製造方法。[Claim 1] initial pH value is 0.5 to 3.0 San溶
Acid treatment by adding metal ions or bismuth ions to the solution
Surface treatment of hydrogen storage alloy using liquid, pH range of 4-6
The metal ion or bismuth ion in the hydrogen
A method for producing a hydrogen storage alloy for an alkaline storage battery, which comprises depositing on a surface of the storage alloy .
バルトイオンよりなる群から１種以上選択されたもので
ある、請求項１記載のアルカリ蓄電池用水素吸蔵合金の
製造方法。2. The method for producing a hydrogen storage alloy for an alkaline storage battery according to claim 1, wherein the metal ions are selected from the group consisting of nickel ions and cobalt ions.
添加した酸処理液には、ｐＨ４〜６の範囲内においてｐ
Ｈ緩衝作用を発揮する物質が添加されている、請求項１
または２記載のアルカリ蓄電池用水素吸蔵合金の製造方
法。3. The metal ion or bismuth ion
The pH of the added acid treatment liquid is within the range of 4 to 6.
A substance which exerts an H-buffering action is added.
Alternatively, the method for producing a hydrogen storage alloy for alkaline storage batteries according to the item 2.
添加した酸処理液は、ｐＨ４〜６の範囲内において緩衝
作用を発揮する物質としてのアルミニウムイオンを含有
する、請求項３記載のアルカリ蓄電池用水素吸蔵合金の
製造方法。 4. The metal ion or bismuth ion
The method for producing a hydrogen storage alloy for alkaline storage batteries according to claim 3, wherein the added acid treatment liquid contains aluminum ions as a substance exhibiting a buffering action within a pH range of 4 to 6.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16575396A JP3433008B2 (en) | 1996-06-26 | 1996-06-26 | Method for producing hydrogen storage alloy for alkaline storage battery |
| EP06076209A EP1713139A1 (en) | 1996-06-26 | 1997-06-20 | Hydrogen-absorbing alloy electrode and process for making the same |
| PCT/JP1997/002146 WO1997050135A1 (en) | 1996-06-26 | 1997-06-20 | Hydrogen storing alloy electrode and process for producing hydrogen storage alloy electrode |
| CNB971972249A CN1179434C (en) | 1996-06-26 | 1997-06-20 | Hydrogen storing alloy electrode and process for producing hydrogen storage alloy electrode |
| EP97927419A EP0945907B1 (en) | 1996-06-26 | 1997-06-20 | Process for producing a hydrogen storing alloy electrode |
| DE69736393T DE69736393T2 (en) | 1996-06-26 | 1997-06-20 | Process for producing a hydrogen-absorbing alloy electrode |
| KR1019980710482A KR100305176B1 (en) | 1996-06-26 | 1997-06-20 | Method for manufacturing hydrogen storage alloy electrode and hydrogen storage alloy electrode |
| US09/214,111 US6255018B1 (en) | 1996-06-26 | 1997-06-20 | Hydrogen storing alloy electrode and process for producing hydrogen storage alloy electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16575396A JP3433008B2 (en) | 1996-06-26 | 1996-06-26 | Method for producing hydrogen storage alloy for alkaline storage battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1012233A JPH1012233A (en) | 1998-01-16 |
| JP3433008B2 true JP3433008B2 (en) | 2003-08-04 |
Family
ID=15818417
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16575396A Expired - Fee Related JP3433008B2 (en) | 1996-06-26 | 1996-06-26 | Method for producing hydrogen storage alloy for alkaline storage battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3433008B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0945907B1 (en) * | 1996-06-26 | 2006-07-26 | SANYO ELECTRIC Co., Ltd. | Process for producing a hydrogen storing alloy electrode |
| JPH10149824A (en) * | 1996-11-20 | 1998-06-02 | Matsushita Electric Ind Co Ltd | Manufacture of hydrogen storage alloy electrode |
| JP3553752B2 (en) * | 1997-01-30 | 2004-08-11 | 三洋電機株式会社 | Method for producing hydrogen storage alloy electrode |
| JP2001093522A (en) * | 1999-09-22 | 2001-04-06 | Sanyo Electric Co Ltd | Hydrogen storage alloy particles and preparation |
-
1996
- 1996-06-26 JP JP16575396A patent/JP3433008B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1012233A (en) | 1998-01-16 |
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