JP3326197B2 - Hydrogen storage alloy electrode and method for producing the same - Google Patents
Hydrogen storage alloy electrode and method for producing the sameInfo
- Publication number
- JP3326197B2 JP3326197B2 JP15088592A JP15088592A JP3326197B2 JP 3326197 B2 JP3326197 B2 JP 3326197B2 JP 15088592 A JP15088592 A JP 15088592A JP 15088592 A JP15088592 A JP 15088592A JP 3326197 B2 JP3326197 B2 JP 3326197B2
- Authority
- JP
- Japan
- Prior art keywords
- battery
- hydrogen storage
- storage alloy
- alkali
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/383—Hydrogen absorbing alloys
-
- 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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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、金属−水素アルカリ蓄
電池に用いられる水素吸蔵合金電極，及びその製造方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen storage alloy electrode used for a metal-hydrogen alkaline storage battery and a method for producing the same.
【０００２】[0002]
【従来の技術】従来からよく用いられている蓄電池とし
ては、ニッケル−カドミウム蓄電池のようなアルカリ蓄
電池や，鉛蓄電池等がある。しかし、近年、これらの蓄
電池よりも軽量で、且つ、高容量となる可能性があると
いうことで、特に常圧で負極活物質である水素を可逆的
に吸蔵，放出する水素吸蔵合金を備えた電極を負極に用
い、水酸化ニッケル等の金属酸化物を正極活物質とする
電極を正極に用いた金属−水素アルカリ蓄電池が注目さ
れている。この電池の水素吸蔵合金電極での充放電反応
は、化１のように表される。2. Description of the Related Art Conventionally used storage batteries include alkaline storage batteries such as nickel-cadmium storage batteries and lead storage batteries. However, in recent years, it is possible to provide a hydrogen storage alloy that reversibly absorbs and releases hydrogen, which is a negative electrode active material, at normal pressure because of its lighter weight and higher capacity than these storage batteries. Attention has been paid to a metal-hydrogen alkaline storage battery using an electrode as a negative electrode and an electrode using a metal oxide such as nickel hydroxide as a positive electrode active material as a positive electrode. The charge / discharge reaction at the hydrogen-absorbing alloy electrode of this battery is expressed as shown in Chemical Formula 1.
【０００３】[0003]
【化１】 Embedded image
【０００４】〔上記式中、Ｍは水素吸蔵合金を，ＭＨは
水素が吸蔵された状態の水素吸蔵合金を示す。〕即ち、
充電は電解液中の水分子が合金表面上で水素原子とな
り、合金中に吸蔵される吸蔵反応によって行われる。一
方、放電は水素吸蔵合金が電気化学的に水素を放出する
放出反応によって行われる。そして、この放出反応は、
電極内部に蓄えられた原子状の水素が水素吸蔵合金の周
囲に存在するＯＨ- と反応することで進行する。しかし
ながら、水素吸蔵合金は空気中の酸素と容易に反応する
ため、サイクルを重ねるにつれて合金表面に酸化膜が存
在することになる。その結果、合金表面での上記充放電
反応が阻害されるため、サイクル特性が低下するという
課題を有する。[In the above formula, M represents a hydrogen storage alloy, and MH represents a hydrogen storage alloy in a state where hydrogen is stored. ]
The charging is performed by an occlusion reaction in which water molecules in the electrolyte become hydrogen atoms on the surface of the alloy and are absorbed in the alloy. On the other hand, the discharge is performed by a release reaction in which the hydrogen storage alloy electrochemically releases hydrogen. And this release reaction,
Proceeds by reacting with - atomic hydrogen stored in the internal electrode is OH present around the hydrogen storage alloy. However, since the hydrogen storage alloy easily reacts with oxygen in the air, an oxide film is present on the alloy surface as the cycle is repeated. As a result, the above-described charge / discharge reaction on the alloy surface is inhibited, so that there is a problem that the cycle characteristics deteriorate.
【０００５】そこで、合金表面にニッケルメッキを施
し、合金表面をニッケルで被覆することによって合金表
面の酸化を防止してサイクル特性の向上を図る方法が提
案されている。Therefore, there has been proposed a method of improving the cycle characteristics by applying nickel plating to the alloy surface and coating the alloy surface with nickel to prevent oxidation of the alloy surface.
【０００６】[0006]
【発明が解決しようとする課題】ところが、上記方法に
よれば、合金表面が完全にニッケルメッキで被覆されて
しまうため、サイクル初期における合金表面での充放電
反応が阻害される。したがって、初期容量が小さく、満
足のいく初期特性を得ることができないという課題を有
していた。However, according to the above method, since the alloy surface is completely covered with nickel plating, the charge / discharge reaction on the alloy surface in the early cycle is inhibited. Therefore, there is a problem that the initial capacity is small and satisfactory initial characteristics cannot be obtained.
【０００７】本発明は上記課題に鑑みてなされたもので
あり、従来と同等のサイクル特性を維持しながら、初期
特性を向上させることができる水素吸蔵合金電極，及び
その製造方法を提供することを目的とする。The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a hydrogen storage alloy electrode capable of improving initial characteristics while maintaining the same cycle characteristics as conventional ones, and a method of manufacturing the same. Aim.
【０００８】[0008]
【課題を解決するための手段】本発明は上記課題を解決
するため、以下のことを特徴とする。 水素を可逆的
に吸蔵，放出する水素吸蔵合金を含む水素吸蔵合金電極
において、上記合金表面の一部にはアルカリに可溶な金
属又はその酸化物が被覆され、且つ、他の表面部にはア
ルカリに溶出しにくい金属が被覆されていると共に、前
記被覆された合金に対して、前記アルカリに溶出しにく
い金属を20wt％以下とすることを特徴とする。 水素
吸蔵合金の表面の一部に、アルカリに可溶な金属又はそ
の酸化物を被覆させる第１ステップと、その他の水素吸
蔵合金の露出部に、アルカリに溶出しにくい金属を被覆
させる第２ステップとを有する水素吸蔵合金電極の製造
方法であって、前記被覆された合金に対して、前記アル
カリに溶出しにくい金属を20wt％以下とすることを特徴
とする。 The present invention has the following features to solve the above-mentioned problems. In a hydrogen storage alloy electrode including a hydrogen storage alloy that reversibly stores and releases hydrogen, a part of the surface of the alloy is coated with an alkali-soluble metal or an oxide thereof, and the other surface is coated with a metal. together with the metal hardly eluted in an alkali is covered, prior to
The coated alloy is difficult to dissolve in the alkali.
It is characterized in that the amount of metal is 20 wt% or less . A first step of coating a part of the surface of the hydrogen storage alloy with an alkali-soluble metal or an oxide thereof, and a second step of coating the exposed part of the other hydrogen storage alloy with a metal that is hardly eluted by the alkali Of hydrogen storage alloy electrode having
The method, wherein the coated alloy is
It is characterized by less than 20wt% of metal which is hardly eluted in potash.
And
【０００９】[0009]
【作用】上記の如く、水素吸蔵合金の表面の一部には
アルカリ可溶金属（又は金属酸化物）が、他の合金表面
部にはアルカリに溶解しにくい金属が、それぞれ被覆さ
れた電極を用いて電池を作製した場合には、電池内のア
ルカリ電解液によっで前記アルカリ可溶金属（又は金属
酸化物）が溶解するので、合金表面の一部には露出面
（即ち、反応面）が存在することになる。一方、他の合
金表面部にはアルカリに溶解しにくい金属が溶解せずに
被覆されたまま存在している。したがって、従来のよう
に、合金表面がメッキで完全に被覆されることがない。
その結果、合金表面の一部に存在する反応面での充放電
反応がサイクル初期の段階から速やかに進行するので初
期容量が向上し、更に充放電サイクルを繰り返した場合
でもアルカリに溶解しにくい金属によって合金の酸化が
防止できるので、従来と同等のサイクル特性を維持する
こともできる。As described above, an electrode in which an alkali-soluble metal (or metal oxide) is coated on a part of the surface of the hydrogen storage alloy, and a metal which is hardly soluble in alkali is coated on the other alloy surface. When the battery is manufactured by using the above, the alkali-soluble metal (or metal oxide) is dissolved by the alkaline electrolyte in the battery, so that an exposed surface (that is, a reaction surface) is partially formed on the alloy surface. Will exist. On the other hand, a metal that is hardly soluble in alkali remains coated on the other alloy surface without being dissolved. Therefore, unlike the conventional case, the alloy surface is not completely covered with the plating.
As a result, the charge / discharge reaction on the reaction surface existing on a part of the alloy surface progresses promptly from the initial stage of the cycle, so that the initial capacity is improved, and even if the charge / discharge cycle is repeated, the metal is hardly dissolved in alkali. As a result, oxidation of the alloy can be prevented, so that the same cycle characteristics as those of the related art can be maintained.
【００１０】[0010]
〔実施例１〕図１は本発明の一実施例に係る水素吸蔵合
金電極を用いた円筒型ニッケル−水素アルカリ蓄電池の
断面図であり、焼結式ニッケルから成る正極１と，水素
吸蔵合金（ＭｍＮｉ3.1 Ｃｏ0.9 Ａｌ0.2 Ｍｎ0.5 ）を
含む負極２と、これら正負両極１・２間に介挿されたセ
パレータ３とから成る電極群４は渦巻状に巻回されてい
る。この電極群４は負極端子兼用の外装罐６内に配置さ
れており、この外装罐６の上部開口にはパッキング７を
介して封口体８が装着されており、この封口体８の内部
にはコイルスプリング９が設けられている。このコイル
スプリング９は電池内部の内圧が異常上昇したときに矢
印Ａ方向に押圧されて内部のガスが大気中に放出される
ように構成されている。また、上記封口体８と前記正極
１とは正極用導電タブ１０にて接続されている。Embodiment 1 FIG. 1 is a sectional view of a cylindrical nickel-hydrogen alkaline storage battery using a hydrogen storage alloy electrode according to one embodiment of the present invention, in which a positive electrode 1 made of sintered nickel and a hydrogen storage alloy ( An electrode group 4 including a negative electrode 2 containing MmNi 3.1 Co 0.9 Al 0.2 Mn 0.5 ) and a separator 3 interposed between the positive and negative electrodes 1 and 2 is spirally wound. The electrode group 4 is disposed in an outer can 6 also serving as a negative electrode terminal, and a sealing body 8 is attached to the upper opening of the outer can 6 via a packing 7. A coil spring 9 is provided. The coil spring 9 is configured such that when the internal pressure inside the battery rises abnormally, it is pressed in the direction of arrow A and the gas inside is released to the atmosphere. The sealing body 8 and the positive electrode 1 are connected by a positive electrode conductive tab 10.
【００１１】ここで、上記構造の円筒型ニッケル−水素
アルカリ蓄電池を、以下のようにして作製した。先ず、
市販のＭｍ（ミッシュメタルであって、希土類元素の混
合物），Ｎｉ，Ｃｏ，Ａｌ，及びＭｎを元素比で１：3.
１：0.９：0.２：0.５の割合となるようにそれぞれ秤量
した後、アルゴン不活性雰囲気のアーク炉内で溶解して
溶湯を作成した。次に、上記溶湯を冷却することによ
り、ＭｍＮｉ3.1 Ｃｏ0.9 Ａｌ0.2Ｍｎ0.5 で示される
水素吸蔵合金鋳塊を作成した。続いて、この水素吸蔵合
金鋳塊の粒径が１００μｍ以下となるように機械的に粗
粉砕して水素吸蔵合金粉末を作製した後、図２に示すよ
うに、メカニカルアロイング処理，無電解メッキ，
アルカリ処理の３つの処理を施した。 メカニカルアロイング処理 上記水素吸蔵合金粉末２１と１重量％の酸化アルミニウ
ム（Ａｌ2 Ｏ3 ）とをボールミル内に充填し、更にボー
ルミル内にアルゴンガスを封入し、室温下、回転数８０
ｒｐｍで２０時間攪拌した。この結果、図２に示すよう
に、水素吸蔵合金粉末２１の表面の一部に酸化アルミニ
ウム２２が被覆されることになる。 無電解メッキ 上記メカニカルアロイング処理を施した水素吸蔵合金粉
末２１に、更にＮｉ（５重量％）の無電解メッキを施し
た。この結果、図２に示すように、水素吸蔵合金粉末２
１の表面の一部に酸化アルミニウム２２が、水素吸蔵合
金粉末２１の露出部に酸化アルミニウム２２がそれぞれ
被覆されることになる。 アルカリ処理 上記無電解メッキ処理後の水素吸蔵合金粉末２１を３０
重量％のＫＯＨ溶液（６０℃）に１時間浸積した。この
結果、水素吸蔵合金粉末２１の一部に被覆していた酸化
アルミニウム２２がＫＯＨ溶液によって溶解し、水素吸
蔵合金粉末２１の表面の一部には、図２に示すように、
反応面２４が存在することになる。Here, the cylindrical nickel-hydrogen alkaline storage battery having the above structure was manufactured as follows. First,
Commercially available Mm (a misch metal, a mixture of rare earth elements), Ni, Co, Al, and Mn in an elemental ratio of 1: 3.
After weighing each in a ratio of 1: 0.9: 0.2: 0.5, they were melted in an arc furnace under an inert atmosphere of argon to prepare a molten metal. Next, the molten metal was cooled to prepare a hydrogen storage alloy ingot represented by MmNi 3.1 Co 0.9 Al 0.2 Mn 0.5 . Subsequently, the hydrogen storage alloy ingot was mechanically coarsely pulverized so that the particle diameter of the ingot was 100 μm or less to prepare a hydrogen storage alloy powder. Then, as shown in FIG. ,
Three treatments of alkali treatment were performed. Mechanical alloying treatment The above-mentioned hydrogen storage alloy powder 21 and 1% by weight of aluminum oxide (Al 2 O 3 ) were filled in a ball mill, and argon gas was further sealed in the ball mill.
The mixture was stirred at rpm for 20 hours. As a result, as shown in FIG. 2, a part of the surface of the hydrogen storage alloy powder 21 is coated with the aluminum oxide 22. Electroless Plating The hydrogen absorbing alloy powder 21 subjected to the mechanical alloying treatment was further subjected to Ni (5% by weight) electroless plating. As a result, as shown in FIG.
Aluminum oxide 22 is coated on a part of the surface of aluminum alloy 1, and aluminum oxide 22 is coated on the exposed portion of hydrogen storage alloy powder 21. Alkali treatment The hydrogen storage alloy powder 21 after the above electroless plating is treated with 30
It was immersed in a weight% KOH solution (60 ° C.) for 1 hour. As a result, the aluminum oxide 22 coated on a part of the hydrogen storage alloy powder 21 is dissolved by the KOH solution, and on a part of the surface of the hydrogen storage alloy powder 21, as shown in FIG.
Reaction surface 24 will be present.
【００１２】しかる後、上記３つの処理がなされた水素
吸蔵合金粉末２１に結着剤としてのポリエチレンオキサ
イドを１重量％添加し、これらを均一に混合することに
よりペーストを作成した。この後、このペーストを、ニ
ッケルメッキが施されたパンチングメタル芯体の両面に
塗着し、室温で乾燥させ、更に所定の寸法に切断するこ
とより負極２を作製した。Thereafter, 1% by weight of polyethylene oxide as a binder was added to the hydrogen storage alloy powder 21 which had been subjected to the above three treatments, and these were uniformly mixed to prepare a paste. Thereafter, this paste was applied on both surfaces of a nickel-plated punched metal core, dried at room temperature, and further cut into predetermined dimensions to produce a negative electrode 2.
【００１３】次に、耐アルカリ性を有する不織布から成
るセパレータ３を介して上記負極２と，公知の焼結式ニ
ッケル正極１とから成る電極群４を作成した後、この電
極群４を電池缶６内に挿入した。次いで、この電池缶６
内に３０重量％のＫＯＨ水溶液を注液した後、更に電池
缶６を封口して、公称容量１０００ｍＡｈの円筒型ニッ
ケル−水素アルカリ蓄電池を作製した。Next, an electrode group 4 comprising the negative electrode 2 and a known sintered nickel positive electrode 1 is formed via a separator 3 made of a nonwoven fabric having alkali resistance. Inserted in. Next, this battery can 6
After injecting a 30% by weight aqueous solution of KOH therein, the battery can 6 was further sealed to produce a cylindrical nickel-hydrogen alkaline storage battery having a nominal capacity of 1000 mAh.
【００１４】このようにして作製した電池を以下、（Ａ
1 ）電池と称する。 〔実施例２〜６〕Ａｌ2 Ｏ3 の代わりに、Ａｌ，ＺｒＯ
2 ，Ｚｒ，ＳｉＯ2 ，Ｓｉをそれぞれ用いてメカニカル
アロイング処理を行った負極を用いる他は、上記実施例
１と同様にして電池を作製した。The battery fabricated in this manner is hereinafter referred to as (A)
1 ) Called a battery. Instead of Example 2-6] Al 2 O 3, Al, ZrO
A battery was fabricated in the same manner as in Example 1 except that a negative electrode subjected to mechanical alloying treatment using 2 , 2 , Zr, SiO 2 , and Si was used.
【００１５】このように作製した電池を以下、それぞれ
（Ａ2 ）電池〜（Ａ6 ）電池と称する。 〔実施例７〜１１〕Ｎｉの代わりに、Ｃｕ，Ｐｔ，Ａ
ｕ，Ｐｄ，Ａｇをそれぞれ用いて無電解メッキを施した
負極を用いる他は、上記実施例１と同様にして電池を作
製した。The batteries thus fabricated are hereinafter referred to as (A 2 ) battery to (A 6 ) battery, respectively. [Examples 7 to 11] Instead of Ni, Cu, Pt, A
A battery was fabricated in the same manner as in Example 1 except that a negative electrode electrolessly plated with u, Pd, and Ag was used.
【００１６】このように作製した電池を以下、それぞれ
（Ａ7 ）電池〜（Ａ11）電池と称する。 〔実施例１２〜１５〕メカニカルアロイング処理におけ
るＡｌ2 Ｏ3 の添加量を、0.５wt％，２wt％，５wt％，
１０wt％とそれぞれ変化させた負極を用いる他は、上記
実施例１と同様にして電池を作製した。The batteries fabricated in this manner are hereinafter referred to as (A 7 ) battery to (A 11 ) battery, respectively. [Examples 12 to 15] The addition amount of Al 2 O 3 in the mechanical alloying treatment was 0.5 wt%, 2 wt%, 5 wt%,
A battery was fabricated in the same manner as in Example 1 except that the negative electrode was changed to 10 wt%.
【００１７】このように作製した電池を以下、それぞれ
（Ａ12）電池〜（Ａ15）電池と称する。 〔実施例１６〜１９〕無電解メッキにおけるＮｉの添加
量を、2.５wt％，１０wt％，１５wt％，２０wt％とそれ
ぞれ変化させた負極を用いる他は、上記実施例１と同様
にして電池を作製した。The batteries thus fabricated are hereinafter referred to as (A 12 ) battery to (A 15 ) battery, respectively. [Examples 16 to 19] A battery was manufactured in the same manner as in Example 1 except that a negative electrode in which the amount of Ni added in electroless plating was changed to 2.5 wt%, 10 wt%, 15 wt%, and 20 wt%, respectively. Was prepared.
【００１８】このように作製した電池を以下、それぞれ
（Ａ16）電池〜（Ａ19）電池と称する。 〔実施例２０〕アルカリ処理を行わない負極を用いる他
は、上記実施例１と同様にして電池を作製した。The batteries thus fabricated are hereinafter referred to as (A 16 ) batteries to (A 19 ) batteries, respectively. Example 20 A battery was manufactured in the same manner as in Example 1 except that a negative electrode not subjected to an alkali treatment was used.
【００１９】このように作製した電池を以下、（Ａ20）
電池と称する。 〔比較例１〕メカニカルアロイング処理，及びアルカリ
処理を行わない負極を用いる他は、上記実施例１と同様
にして電池を作製した。このように作製した電池を以
下、（Ｘ1 ）電池と称する。 〔比較例２〕無電解メッキを行わない負極を用いる他
は、上記実施例１と同様にして電池を作製した。The battery fabricated in this manner is hereinafter referred to as (A 20 )
It is called a battery. Comparative Example 1 A battery was manufactured in the same manner as in Example 1 except that a negative electrode which was not subjected to mechanical alloying treatment and alkali treatment was used. The battery fabricated in this manner is hereinafter referred to as (X 1 ) battery. Comparative Example 2 A battery was manufactured in the same manner as in Example 1 except that a negative electrode not subjected to electroless plating was used.
【００２０】このように作製した電池を以下、（Ｘ2 ）
電池と称する。 〔比較例３〕メカニカルアロイング処理，無電解メッ
キ，及びアルカリ処理のいずれの処理も行わない負極を
用いる他は、上記実施例１と同様にして電池を作製し
た。このように作製した電池を以下、（Ｘ3 ）電池と称
する。 〔実験１〕上記本発明の（Ａ1 ）電池〜（Ａ20）電池，
及び比較例の（Ｘ1 ）電池〜（Ｘ 3 ）電池を用いて初期
容量を調べたので、その結果を下記表１に示す。尚、実
験は電池を電流0.２Ｃで６時間充電した後、同じく電流
0.２Ｃで電池電圧が1.０Ｖに達するまで放電を行うとい
う条件である。 〔実験２〕上記本発明の（Ａ1 ）電池〜（Ａ20）電池，
及び比較例の（Ｘ1 ）電池〜（Ｘ 3 ）電池を用いてサイ
クル寿命（初期容量の５０％に減少する時期）を調べた
ので、その結果を上記初期容量と共に下記表１に示す。
尚、実験は電池を電流１Ｃで1.２時間充電した後、同じ
く電流１Ｃで電池電圧が1.０Ｖに達するまで放電を行う
という条件である。 〔実験１及び実験２のまとめ〕The battery fabricated in this manner is hereinafter referred to as (XTwo)
It is called a battery. [Comparative Example 3] Mechanical alloying treatment,
A negative electrode that does not perform any of the
A battery was fabricated in the same manner as in Example 1 except that the battery was used.
Was. The battery fabricated in this manner is hereinafter referred to as (XThree) Battery
I do. [Experiment 1] (A)1) Battery ~ (A20)battery,
And (X1) Battery ~ (X Three) Initial with battery
The capacity was examined, and the results are shown in Table 1 below. In addition,
The test was conducted after charging the battery at a current of 0.2 C for 6 hours.
Discharge at 0.2C until the battery voltage reaches 1.0V
Condition. [Experiment 2] (A)1) Battery ~ (A20)battery,
And (X1) Battery ~ (X Three) Using a battery
The life of the car (when it decreases to 50% of the initial capacity) was examined.
Therefore, the results are shown in Table 1 below together with the initial capacity.
The experiment was performed after charging the battery at a current of 1 C for 1.2 hours.
Discharge until battery voltage reaches 1.0V at current 1C
It is a condition. [Summary of Experiment 1 and Experiment 2]
【００２１】[0021]
【表１】 [Table 1]
【００２２】上記表１から明らかなように、比較例の
（Ｘ1 ）電池はサイクル寿命は向上するものの初期容量
が低下していることが認められる。これは、水素吸蔵合
金粉末の表面が完全にニッケルメッキで被覆されている
ため、サイクル初期の段階での充放電反応が阻害される
ためと思われる。また、比較例の（Ｘ2 ）電池は初期容
量は向上するもののサイクル寿命が低下していることが
認められる。これは、充放電サイクルを繰り返す過程
で、水素吸蔵合金粉末が酸化することによるためと思わ
れる。更に、比較例の（Ｘ3 ）電池は初期容量，及びサ
イクル寿命が低下していることが認められる。これは、
サイクル初期の段階での充放電反応が阻害されるため，
及び充放電サイクルを繰り返す過程で水素吸蔵合金粉末
が酸化することによるためと思われる。As is evident from Table 1, the (X 1 ) battery of the comparative example has an improved cycle life but a reduced initial capacity. This is presumably because the surface of the hydrogen-absorbing alloy powder was completely covered with nickel plating, which hindered the charge / discharge reaction at the early stage of the cycle. Also, it can be seen that the (X 2 ) battery of the comparative example has an improved initial capacity but a reduced cycle life. This is probably because the hydrogen storage alloy powder is oxidized in the process of repeating the charge / discharge cycle. Further, it is recognized that the (X 3 ) battery of the comparative example has a reduced initial capacity and cycle life. this is,
Since the charge / discharge reaction in the early stage of the cycle is hindered,
This is probably because the hydrogen storage alloy powder is oxidized in the process of repeating the charge / discharge cycle.
【００２３】これらに対して、本発明の（Ａ1 ）電池〜
（Ａ20）電池は、水素吸蔵合金粉末の表面の一部に存在
する反応面での充放電反応がサイクル初期の段階から速
やかに進行するので初期容量が向上する。また、充放電
サイクルを繰り返した場合でもアルカリに溶解しにくい
金属によって水素吸蔵合金粉末の酸化が防止されるた
め、比較例の（Ｘ1 ）電池と略同等のサイクル寿命を得
ることができる。 〔その他の事項〕 上記実施例においては、アルカリに溶出しにくい金
属としてＮｉ，Ｃｕ，Ｐｔ，Ａｕ，Ｐｄ，Ａｇ等を用い
たが、本発明はこれらに何ら限定されるものではない。 アルカリ可溶金属（又は金属酸化物）としてＡｌ
（Ａｌ2 Ｏ3 ），Ｚｒ（ＺｒＯ2 ），Ｓｉ（ＳｉＯ2 ）
等を用いたが、本発明はこれらに何ら限定されるもので
はない。 アルカリ可溶金属（又は金属酸化物）と，アルカリ
溶解しにくい金属とを別の工程で被覆したが、同一の工
程（例えば、メカニカルアロイング処理）によって被覆
させることも勿論可能である。 メカニカルアロイング処理，及び無電解メッキを行
った後、アルカリ処理を行ったが、アルカリ未処理の電
極を用いて電池を作製した場合でも、水素吸蔵合金粉末
の表面に被覆されたアルカリ可溶金属（又は金属酸化
物）が電池内のアルカリ電解液によって溶出することに
なる。したがって、アルカリ処理を行わなかった場合で
も、アルカリ処理を行った場合と同様に水素吸蔵合金粉
末の表面に反応面が露出し、初期容量が向上するので、
アルカリ処理は必ずしも行う必要はない。 希土類系の水素吸蔵合金としてＭｍＮｉ3.1 Ｃｏ
0.9 Ａｌ0.2 Ｍｎ0.5 を用いたが、本発明はこれに何ら
限定されるものではなく、例えば、Ｔｉ−Ｍｎ系，Ｔｉ
−Ｆｅ系，Ｔｉ−Ｚｒ系，Ｍｇ−Ｎｉ系，Ｚｒ−Ｍｎ系
等の水素吸蔵合金を用いても上記実施例と同様の効果を
奏する。On the other hand, the (A 1 ) battery of the present invention
(A 20 ) The battery has an improved initial capacity because the charge / discharge reaction on the reaction surface existing on a part of the surface of the hydrogen storage alloy powder proceeds promptly from the initial stage of the cycle. Further, even when the charge / discharge cycle is repeated, the metal that is hardly dissolved in alkali prevents oxidation of the hydrogen storage alloy powder, so that a cycle life substantially equal to that of the (X 1 ) battery of the comparative example can be obtained. [Other Matters] In the above embodiments, Ni, Cu, Pt, Au, Pd, Ag and the like are used as metals which are hardly eluted with alkali. However, the present invention is not limited to these. Al as alkali-soluble metal (or metal oxide)
(Al 2 O 3 ), Zr (ZrO 2 ), Si (SiO 2 )
However, the present invention is not limited to these. Alkali-soluble metal (or metal oxide) and alkali
Although the hardly-dissolvable metal was coated in a separate step, it is of course possible to cover the same in the same step (for example, mechanical alloying). Alkaline treatment was performed after mechanical alloying and electroless plating. However, even when a battery was manufactured using electrodes that had not been treated with alkali, the alkali-soluble metal coated on the surface of the hydrogen storage alloy powder was used. (Or metal oxide) is eluted by the alkaline electrolyte in the battery. Therefore, even when the alkali treatment is not performed, the reaction surface is exposed on the surface of the hydrogen storage alloy powder as in the case where the alkali treatment is performed, and the initial capacity is improved.
It is not always necessary to perform the alkali treatment. MmNi 3.1 Co as a rare earth hydrogen storage alloy
Although 0.9 Al 0.2 Mn 0.5 was used, the present invention is not limited to this.
The same effect as in the above embodiment can be obtained by using a hydrogen storage alloy such as -Fe, Ti-Zr, Mg-Ni, or Zr-Mn.
【００２４】[0024]
【発明の効果】以上の本発明によれば、合金表面の一部
にはアルカリに可溶な金属又はその酸化物が被覆され、
且つ、他の表面部にはアルカリに溶出しにくい金属が被
覆されていると共に、前記被覆された合金に対して、前
記アルカリに溶出しにくい金属を20wt％以下とすること
で、水素吸蔵合金表面の一部に存在する反応面での充放
電反応がサイクル初期の段階から速やかに進行するので
初期容量が向上し、更に充放電サイクルを繰り返した場
合でもアルカリに溶解しにくい金属によって合金の酸化
が防止できるので、サイクル特性も向上するといった優
れた効果を奏する。According to the present invention described above, a part of the alloy surface is
Is coated with an alkali-soluble metal or its oxide,
In addition, other surfaces are coated with metals that are difficult to elute
Covered and with respect to the coated alloy,
Metals that are difficult to dissolve in alkali should be 20 wt% or less.
In, the charge / discharge reaction on the reaction surface present on a part of the hydrogen storage alloy surface proceeds promptly from the initial stage of the cycle, so the initial capacity is improved, and even when the charge / discharge cycle is repeated, it is difficult to dissolve in alkali. Since the oxidation of the alloy can be prevented by the metal, there is an excellent effect that the cycle characteristics are also improved.
【図１】本発明の一実施例に係る水素吸蔵合金電極を用
いた円筒型ニッケル−水素アルカリ蓄電池の部分断面斜
視図である。FIG. 1 is a partial cross-sectional perspective view of a cylindrical nickel-hydrogen alkaline storage battery using a hydrogen storage alloy electrode according to one embodiment of the present invention.
【図２】本発明の一実施例に係る水素吸蔵合金電極の製
造工程を示す図である。FIG. 2 is a view showing a manufacturing process of a hydrogen storage alloy electrode according to one embodiment of the present invention.
２１ 水素吸蔵合金粉末 ２２ 酸化アルミニウム ２３ ニッケルメッキ 21 Hydrogen storage alloy powder 22 Aluminum oxide 23 Nickel plating
───────────────────────────────────────────────────── フロントページの続き (72)発明者 西尾 晃治 守口市京阪本通２丁目18番地 三洋電機 株式会社内 (72)発明者 古川 修弘 守口市京阪本通２丁目18番地 三洋電機 株式会社内 (56)参考文献 特開 平２−51860（ＪＰ，Ａ) 特開 平２−256161（ＪＰ，Ａ) 特開 平３−201364（ＪＰ，Ａ) 特開 昭62−20244（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/24 H01M 4/26 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koji Nishio 2-18-18 Keihanhondori, Moriguchi City Sanyo Electric Co., Ltd. (72) Inventor Furukawa 2-18-18 Keihanhondori Moriguchi City, Sanyo Electric Co. 56) References JP-A-2-51860 (JP, A) JP-A-2-256161 (JP, A) JP-A-3-201364 (JP, A) JP-A-62-20244 (JP, A) (58) ) Surveyed field (Int.Cl. 7 , DB name) H01M 4/24 H01M 4/26
Claims (2)
合金を含む水素吸蔵合金電極において、 上記合金表面の一部にはアルカリに可溶な金属又はその
酸化物が被覆され、且つ、他の表面部にはアルカリに溶
出しにくい金属が被覆されていると共に、前記被覆され
た合金に対して、前記アルカリに溶出しにくい金属を20
wt％以下とすることを特徴とする水素吸蔵合金電極。1. A hydrogen storage alloy electrode including a hydrogen storage alloy that reversibly stores and releases hydrogen, wherein a part of the surface of the alloy is coated with an alkali-soluble metal or an oxide thereof, and Is coated with a metal which is hardly eluted with alkali, and
Metal that is difficult to elute in the alkali
A hydrogen storage alloy electrode characterized by being at most wt% .
に可溶な金属又はその酸化物を被覆させる第１ステップ
と、 その他の水素吸蔵合金の露出部に、アルカリに溶出しに
くい金属を被覆させる第２ステップとを有し、 前記被覆された合金に対して、前記アルカリに溶出しに
くい金属を20wt％以下とすること を特徴とする水素吸蔵
合金電極の製造方法。2. A first step of coating a part of the surface of the hydrogen storage alloy with an alkali-soluble metal or an oxide thereof, and forming a metal which is hardly eluted in the alkali on an exposed part of the other hydrogen storage alloy. A second step of coating , wherein the coated alloy is eluted with the alkali.
A method for producing a hydrogen-absorbing alloy electrode, comprising reducing the amount of swarf metal to 20% by weight or less .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15088592A JP3326197B2 (en) | 1992-06-10 | 1992-06-10 | Hydrogen storage alloy electrode and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15088592A JP3326197B2 (en) | 1992-06-10 | 1992-06-10 | Hydrogen storage alloy electrode and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05343058A JPH05343058A (en) | 1993-12-24 |
| JP3326197B2 true JP3326197B2 (en) | 2002-09-17 |
Family
ID=15506514
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15088592A Expired - Fee Related JP3326197B2 (en) | 1992-06-10 | 1992-06-10 | Hydrogen storage alloy electrode and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3326197B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3318141B2 (en) * | 1994-04-04 | 2002-08-26 | 松下電器産業株式会社 | Method for producing hydrogen storage alloy electrode |
| JP3481095B2 (en) * | 1997-09-30 | 2003-12-22 | 三洋電機株式会社 | Hydrogen storage alloy electrode and method for producing the same |
| JP4010630B2 (en) | 1998-03-09 | 2007-11-21 | 松下電器産業株式会社 | Hydrogen storage alloy electrode |
| JP4494566B2 (en) * | 1999-12-14 | 2010-06-30 | 株式会社三徳 | Negative electrode active material for alkaline secondary battery and method for producing the same |
| JP5354970B2 (en) * | 2008-06-17 | 2013-11-27 | 三洋電機株式会社 | Hydrogen storage alloy and alkaline storage battery |
| EP2738841B1 (en) | 2011-07-28 | 2018-09-12 | GS Yuasa International Ltd. | Negative electrode for alkaline storage battery and alkaline storage battery |
-
1992
- 1992-06-10 JP JP15088592A patent/JP3326197B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05343058A (en) | 1993-12-24 |
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