JPH0992271A - Hydrogen storage alloy electrode - Google Patents
Hydrogen storage alloy electrodeInfo
- Publication number
- JPH0992271A JPH0992271A JP7274763A JP27476395A JPH0992271A JP H0992271 A JPH0992271 A JP H0992271A JP 7274763 A JP7274763 A JP 7274763A JP 27476395 A JP27476395 A JP 27476395A JP H0992271 A JPH0992271 A JP H0992271A
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen storage
- storage alloy
- electrode
- powder
- particles
- 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
Abstract
Description
【０００１】[0001]
【技術分野】本発明は，アルカリ二次電池の水素吸蔵合
金電極に用いられる電極に関する。TECHNICAL FIELD The present invention relates to an electrode used as a hydrogen storage alloy electrode of an alkaline secondary battery.
【０００２】[0002]
【従来技術】アルカリ二次電池の負極電極に用いる水素
吸蔵合金としては，ＬａＮｉ5 ，ＭｍＮｉ5 （Ｍｍはミ
ッシュメタルを表す）等のＡＢ5 系，ＺｒＭｎ2 等のＡ
Ｂ2系の合金が広く知られている。これらの水素吸蔵合
金を用いた電極の作製方法としては，ペースト法，粉末
法，または，水素吸蔵合金粉末の微粉化を防ぐためにそ
の表面を無電解メッキ法によりＣｕ被膜により被覆した
後成形する方法等がある。2. Description of the Related Art As a hydrogen storage alloy used for a negative electrode of an alkaline secondary battery, an AB 5 system such as LaNi 5 , MmNi 5 (Mm represents a misch metal), an A such as ZrMn 2 or the like is used.
B 2 type alloys are widely known. As a method for producing an electrode using these hydrogen storage alloys, a paste method, a powder method, or a method of coating the surface of the hydrogen storage alloy powder with a Cu film by electroless plating in order to prevent pulverization and then molding Etc.
【０００３】しかし，いずれの作製方法を用いて作製し
ても，上記ＡＢ5 系，ＡＢ2 系を用いた水素吸蔵合金電
極は，合金自体の水素吸蔵量が少ないため，電極として
用いた場合の電池容量が少ないという問題がある。However, whichever manufacturing method is used, the hydrogen-absorbing alloy electrode using the AB 5 type and AB 2 type has a small hydrogen storage capacity in the alloy itself, and therefore, when used as an electrode. There is a problem that the battery capacity is low.
【０００４】一方，Ｖ（バナジウム）固溶体系の水素吸
蔵合金は，高い水素吸蔵量を示すが，Ｖ元素がアルカリ
溶液に溶出しやすいという特性を有するため，二次電池
の電極として用いることは困難とされていた。On the other hand, the hydrogen storage alloy of V (vanadium) solid solution system shows a high hydrogen storage capacity, but it is difficult to use it as an electrode of a secondary battery because it has a characteristic that V element easily elutes in an alkaline solution. Was said.
【０００５】これに対し，特開平６−２２８６９９号，
特願平６−５７５１３号，特願平６−５７５１４号，特
願平６−３２３５２３号の各明細書に示されているごと
く，水素吸蔵機能を有するマトリックス中に，Ｔｉ及び
Ｎｉ，又はＮｉ，又はＮｉを含むラーベス相のいずれか
を主成分とする合金相が三次元網目構造を形成している
ＶＴｉＮｉ固溶体系合金を開発することにより，Ｖ元素
の溶出を抑えることが可能となった。これによりＶ固溶
体系合金をアルカリ二次電池用電極に応用できるように
なった。On the other hand, JP-A-6-228699,
As described in Japanese Patent Application No. 6-57513, Japanese Patent Application No. 6-57514 and Japanese Patent Application No. 6-323523, Ti and Ni, or Ni, in a matrix having a hydrogen storage function, Alternatively, by developing a VTiNi solid solution system alloy in which an alloy phase containing either a Laves phase containing Ni as a main component forms a three-dimensional network structure, it has become possible to suppress the elution of V element. As a result, the V solid solution alloy can be applied to electrodes for alkaline secondary batteries.
【０００６】[0006]
【解決しようとする課題】しかしながら，上記従来の水
素吸蔵合金電極においては，次のような問題がある。即
ち，上記高水素吸蔵量のＶＴｉＮｉ固溶体系合金を用い
た電極であっても，ペースト法等の従来の製造方法によ
り製造した場合には，十分な電極特性，耐久性等が得ら
れない。However, the above conventional hydrogen storage alloy electrode has the following problems. That is, even an electrode using the above-mentioned VTiNi solid solution alloy having a high hydrogen storage capacity cannot obtain sufficient electrode characteristics and durability when manufactured by a conventional manufacturing method such as a paste method.
【０００７】例えば，ペースト法の場合には，有機物か
らなる結着剤が合金表面を覆うため，合金相の導電性，
集電効果及び触媒効果を阻害してしまい，十分な電極特
性は得られない。また，粉末法により，水素吸蔵合金粉
末と，導電性を有するＣｕもしくはＮｉ粉末とを単に混
合し，成形した電極においては，電極内部の導電性を十
分確保することができず，十分な電極特性は得られな
い。For example, in the case of the paste method, since the binder made of an organic substance covers the alloy surface, the conductivity of the alloy phase,
Sufficient electrode characteristics cannot be obtained because the current collection effect and catalyst effect are impaired. Further, in the electrode formed by simply mixing the hydrogen storage alloy powder and the Cu or Ni powder having conductivity by the powder method, the conductivity inside the electrode cannot be sufficiently secured, and sufficient electrode characteristics are not obtained. Can't get
【０００８】また，水素吸蔵合金電極を実用化するため
には，優れたサイクル寿命特性を有することが必要とさ
れる。ここで，サイクル寿命特性とは，充放電サイクル
を繰り返した場合に，初期の放電容量を維持する特性を
いう。In order to put the hydrogen storage alloy electrode into practical use, it is necessary to have excellent cycle life characteristics. Here, the cycle life characteristic is a characteristic that maintains an initial discharge capacity when a charge / discharge cycle is repeated.
【０００９】本発明は，かかる従来の問題点に鑑みてな
されたもので，ＶＴｉＮｉ固溶体系合金の持つ高水素吸
蔵量の特性を十分生かした，高放電容量でサイクル寿命
に優れた水素吸蔵合金電極を提供しようとするものであ
る。The present invention has been made in view of the above conventional problems, and makes full use of the characteristics of the high hydrogen storage capacity of VTiNi solid solution alloys, and has a high discharge capacity and excellent cycle life. Is to provide.
【００１０】[0010]
【課題の解決手段】請求項１の発明は，水素吸蔵合金粒
子の表面を導電性の金属被膜により被覆した導電性粒子
と，Ｎｉ粉末とを所定量混合し圧縮成形してなると共
に，上記水素吸蔵合金粒子は，水素吸蔵機能を有するマ
トリックス中に，Ｔｉ及びＮｉ，又はＮｉ，又はＮｉを
含むラーベス相を主成分とする三次元網目構造の第２相
を析出してなることを特徴とする水素吸蔵合金電極にあ
る。According to a first aspect of the present invention, a predetermined amount of electrically conductive particles obtained by coating the surface of hydrogen storage alloy particles with an electrically conductive metal coating and Ni powder are mixed and compression molded. The storage alloy particles are characterized in that a second phase having a three-dimensional network structure containing Ti and Ni or Ni or a Laves phase containing Ni as a main component is deposited in a matrix having a hydrogen storage function. It is in a hydrogen storage alloy electrode.
【００１１】本発明において最も注目すべきことは，上
記水素吸蔵合金粒子の表面は上記導電性の金属被膜によ
り被覆してあること及び上記Ｎｉ粉末と混合して圧縮成
形してなることである。さらに，上記水素吸蔵合金粒子
は，上記特定成分の三次元網目構造の第２相を有する合
金であることである。What is most noticeable in the present invention is that the surface of the hydrogen storage alloy particles is coated with the conductive metal coating and is mixed with the Ni powder and compression molded. Further, the hydrogen storage alloy particles are alloys having the second phase of the three-dimensional network structure of the specific component.
【００１２】上記Ｎｉ粉末は，周知のごとく，導電性を
有すると共に，触媒活性な特性を有する。上記ラーベス
相とは，一般式ＡＢ2 により表される立方晶又は六方晶
の結晶構造を有する合金相であり，例えば（Ｔｉ，Ｈ
ｆ）（Ｎｉ，Ｖ）2 等がある。As is well known, the Ni powder has conductivity and catalytically active characteristics. The Laves phase is an alloy phase having a cubic or hexagonal crystal structure represented by the general formula AB 2 , and includes, for example, (Ti, H
f) (Ni, V) 2 etc.
【００１３】上記圧縮成形は，１〜１５ｔｏｎ／ｃｍ2
の加圧力により行うことが好ましい。加圧力が１ｔｏｎ
／ｃｍ2 未満の場合には，かさ密度が十分に得られず，
充放電サイクル中に上記金属被膜の剥がれが生じるおそ
れがある。一方，１５ｔｏｎ／ｃｍ2 を超える場合に
は，電極が緻密になりすぎ，十分な電極特性が得られな
いという問題がある。The above compression molding is performed at 1 to 15 ton / cm 2
It is preferable that the pressure is applied. Pressure is 1 ton
If it is less than / cm 2 , sufficient bulk density cannot be obtained,
The metal coating may be peeled off during the charge / discharge cycle. On the other hand, when it exceeds 15 ton / cm 2 , there is a problem that the electrode becomes too dense and sufficient electrode characteristics cannot be obtained.
【００１４】次に，本発明における作用につき説明す
る。本発明の水素吸蔵合金電極においては，上記水素吸
蔵合金粒子は，上記マトリックス中に析出している上記
特定成分の三次元網目構造の第２相を有する。そして，
この三次元網目構造の第２相は，優れた導電性，集電効
果および触媒作用を有する。Next, the operation of the present invention will be described. In the hydrogen storage alloy electrode of the present invention, the hydrogen storage alloy particles have the second phase of the three-dimensional network structure of the specific component precipitated in the matrix. And
The second phase of this three-dimensional network structure has excellent conductivity, current collecting effect and catalytic action.
【００１５】また，水素吸蔵合金粒子の表面は上記導電
性の金属被膜により被覆してある。そのため圧縮成形後
には，各粒子の上記金属被膜は違いに接触し，電極全体
にわたって３次元的な導電組織を形成する。そして，こ
の３次元的な導電組織は，上記水素吸蔵合金粒子の優れ
た特性を減退させることなく効率よく発揮させる。それ
故，高い電池容量の電極を得ることができる。The surface of the hydrogen storage alloy particles is covered with the above-mentioned conductive metal film. Therefore, after compression molding, the metal coatings of the particles are in contact with each other and form a three-dimensional conductive structure over the entire electrode. Then, this three-dimensional conductive structure efficiently exhibits the excellent characteristics of the hydrogen storage alloy particles without deteriorating. Therefore, an electrode having a high battery capacity can be obtained.
【００１６】また，本発明においては，上記Ｎｉ粉末を
添加して混合してある。また，Ｎｉ粉末は導電性粒子間
もしくは導電性粒子間のすき間に点在する。そして，Ｎ
ｉ粉末は，優れた導電性を有し，触媒活性である。その
ため，Ｎｉ粉末は，金属被膜の割れによる導電性の低下
を防ぎ，又，過電圧の上昇を抑えることができる。それ
故，放電容量の低下が抑制され，サイクル寿命特性の優
れた電極を得ることができる。Further, in the present invention, the above Ni powder is added and mixed. Further, the Ni powder is scattered between the conductive particles or in the gaps between the conductive particles. And N
The i powder has excellent conductivity and is catalytically active. Therefore, the Ni powder can prevent a decrease in conductivity due to cracking of the metal coating and can suppress an increase in overvoltage. Therefore, the decrease in discharge capacity is suppressed, and an electrode with excellent cycle life characteristics can be obtained.
【００１７】また，請求項２の発明のように，上記導電
性粒子とＮｉ粉末を直接圧縮成形せずに，これらを導電
性の多孔質の基材の空孔中に充填して上記と同様の圧縮
成形を行うことにより電極を構成することもできる。即
ち，請求項２の発明は，水素吸蔵合金粒子の表面を，導
電性を有する金属被膜で被覆した導電性粒子と，触媒活
性なＮｉ粉末とを混合して導電性の多孔質の基材の空孔
中に充填し，圧縮成形してなると共に，水素吸蔵合金粒
子は，水素吸蔵機能を有するマトリックス中に，Ｔｉ及
びＮｉ，又はＮｉ，又はＮｉを含むラーベス相を主成分
とする三次元網目構造の第２相を析出してなることを特
徴とする水素吸蔵合金電極にある。Further, as in the second aspect of the present invention, the conductive particles and the Ni powder are not directly compression-molded, but these are filled in the pores of the conductive porous base material and the same as above. The electrode can also be formed by performing compression molding of. That is, according to the invention of claim 2, the conductive particles in which the surface of the hydrogen-absorbing alloy particles is coated with a conductive metal film and the catalytically active Ni powder are mixed to form a conductive porous substrate. The hydrogen-absorbing alloy particles are formed by filling voids and compression-molding, and the hydrogen-absorbing alloy particles are a three-dimensional network containing Ti and Ni, or Ni or Ni or a Laves phase as a main component in a matrix having a hydrogen-absorbing function. The hydrogen storage alloy electrode is characterized in that the second phase of the structure is deposited.
【００１８】この場合には，上記導電性粒子等を多孔質
の基材の空孔中に充填した状態で，その基材全体を圧縮
成形する。そのため，上記導電性粒子等がバラバラにな
ることもなく，例えば大型の電極等，比較的自由な形状
をとることができるフレキシブルな電極とすることがで
きる。その他，請求項１の発明と同様の作用効果が得ら
れる。In this case, the entire base material is compression-molded with the conductive particles and the like filled in the pores of the porous base material. Therefore, the conductive particles and the like do not come apart, and a flexible electrode that can take a relatively free shape such as a large electrode can be obtained. In addition, the same effect as the invention of claim 1 can be obtained.
【００１９】また，請求項３の発明のように，上記多孔
質の基材としては，ニッケルメッシュ，パンチングメタ
ル，又は発泡ニッケル等を用いることができる。これに
より，上記フレキシブル性を実現することができる。Further, as in the third aspect of the invention, nickel mesh, punching metal, nickel foam, or the like can be used as the porous base material. As a result, the above flexibility can be realized.
【００２０】次に，請求項４の発明のように，上記マト
リックスは，（β−Ｔｉ，Ｖ）系の固溶体型の合金であ
ることが好ましい。これにより，さらに電極特性に優れ
た水素吸蔵合金電極を得ることができる。尚，（β−Ｔ
ｉ，Ｖ）系の固溶体合金とは，体心立方格子のＴｉとＶ
との固溶体をいう。Next, as in the invention of claim 4, the matrix is preferably a (β-Ti, V) type solid solution type alloy. This makes it possible to obtain a hydrogen storage alloy electrode having further excellent electrode characteristics. In addition, (β-T
i, V) solid solution alloys are Ti and V of the body-centered cubic lattice.
And solid solution.
【００２１】次に，請求項５の発明のように，上記水素
吸蔵合金粒子を被覆する導電性の金属被膜としては，例
えば，Ｃｕ，Ｎｉもしくはそれらの合金を用いることが
できる。これらの金属は，導電性，触媒作用に優れてお
り，優れた集電効果を発揮する。ただし，これらの金属
を水素吸蔵合金粒子に被覆させずに単に混合しただけで
は，サイクル寿命性には良いが，十分な放電容量を得る
ことができない。Next, as the fifth aspect of the present invention, Cu, Ni or their alloys can be used as the conductive metal coating for coating the hydrogen storage alloy particles. These metals have excellent conductivity and catalytic action, and exhibit an excellent current collecting effect. However, if these metals are simply mixed without being coated on the hydrogen storage alloy particles, the cycle life is good, but sufficient discharge capacity cannot be obtained.
【００２２】さらに請求項５の発明のように，上記金属
被膜は水素吸蔵合金粒子に対して１５〜４０重量％被覆
してあることが好ましい。被覆量が１５重量％未満の場
合には，サイクル寿命が極端に悪くなるという問題があ
る。一方，４０重量％を超える場合には，放電容量が低
下するという問題がある。Further, as in the invention of claim 5, it is preferable that the metal coating covers 15 to 40% by weight of the hydrogen storage alloy particles. If the coating amount is less than 15% by weight, there is a problem that the cycle life becomes extremely poor. On the other hand, when it exceeds 40% by weight, there is a problem that the discharge capacity is lowered.
【００２３】また，請求項６の発明のように，上記触媒
活性なＮｉ粉末は，その粒径が１〜１５０μｍであり，
上記導電性粒子に対して５〜３０重量％混合してなるこ
とが好ましい。粒径が１μｍ未満の場合には，Ｎｉ粉末
を導電性粒子に均一に混合できないという問題があり，
一方１５０μｍを超える場合には，十分なかさ密度が得
られないという問題がある。また，混合量が５重量％未
満の場合には，Ｎｉ粉末の混合の効果が現われないとい
う問題があり，一方３０重量％を超える場合には，活物
質の量が減少し電池の容量が低下するという問題があ
る。According to the invention of claim 6, the catalytically active Ni powder has a particle size of 1 to 150 μm,
It is preferable to mix the conductive particles in an amount of 5 to 30% by weight. When the particle size is less than 1 μm, there is a problem that the Ni powder cannot be mixed uniformly with the conductive particles.
On the other hand, when it exceeds 150 μm, there is a problem that a sufficient bulk density cannot be obtained. Further, when the amount of the mixture is less than 5% by weight, the effect of mixing the Ni powder does not appear, while when it exceeds 30% by weight, the amount of the active material decreases and the battery capacity decreases. There is a problem of doing.
【００２４】また，請求項７の発明のように，上記導電
性粒子及びＮｉ粉末に対して，結着剤としての有機系バ
インダを０〜１０重量％混合することができる。上記結
着剤は，電極の強度を向上させる働きをするが，水素吸
蔵合金の種類等によっては，結着剤を必ずしも混合しな
くても実用上十分な強度を有する場合がある（０％）。
しかし，１０重量％までの結着剤を加えることにより，
より強固な電極とすることができ，さらにサイクル寿命
の優れた電極を得ることができる。一方，１０重量％を
超えると，上記導電性粒子及びＮｉ粉末における導電
性，触媒活性を有する部分が結着剤により覆われ，電極
特性が悪化するという問題がある。Further, as in the invention of claim 7, an organic binder as a binder can be mixed in an amount of 0 to 10% by weight with respect to the conductive particles and the Ni powder. The above-mentioned binder functions to improve the strength of the electrode, but depending on the type of the hydrogen storage alloy, it may have practically sufficient strength without necessarily mixing the binder (0%). .
However, by adding up to 10% by weight of binder,
A stronger electrode can be obtained, and an electrode having an excellent cycle life can be obtained. On the other hand, if it exceeds 10% by weight, there is a problem that the conductive particles and the Ni powder having conductive and catalytic activity are covered with the binder, and the electrode characteristics are deteriorated.
【００２５】また，請求項８の発明のように，上記圧縮
成形後，非酸化雰囲気中において，温度８００〜１００
０℃により３０分〜２４時間加熱し，上記水素吸蔵合金
粒子とその表面を被覆している金属被膜，該金属被膜と
Ｎｉ粉末，及び上記金属被膜同士を，それぞれその接触
部分で焼結させてなることが好ましい。これにより，電
極の上記各構成物がその接触部において互いに焼結した
強固な電極とすることができ，サイクル寿命特性の優れ
た電極を得ることができる。Further, according to the invention of claim 8, after the compression molding, the temperature is 800 to 100 in a non-oxidizing atmosphere.
By heating at 0 ° C. for 30 minutes to 24 hours, the hydrogen storage alloy particles and the metal coating coating the surface thereof, the metal coating and the Ni powder, and the metal coatings are sintered at their respective contact portions. It is preferable that This makes it possible to form a strong electrode in which the above-mentioned constituents of the electrode are sintered together at their contact portions, and an electrode having excellent cycle life characteristics can be obtained.
【００２６】さらに，上記多孔質の基材を有する電極に
おいては，請求項９の発明のように，上記加熱処理によ
り，上記構成物の焼結に加えて，金属被膜あるいはＮｉ
粉末と上記基材とを，それぞれその接触部分で焼結させ
てなることが好ましい。これにより，電極全体がさらに
強固となり，さらにサイクル寿命特性が向上する。Further, in the electrode having the porous base material, as in the invention of claim 9, by the heat treatment, in addition to the sintering of the constituents, a metal film or Ni is used.
It is preferable to sinter the powder and the base material at their contact portions. As a result, the entire electrode becomes stronger and the cycle life characteristics are further improved.
【００２７】上記非酸化雰囲気としては，真空，還元雰
囲気，不活性雰囲気等がある。また，上記加熱温度が８
００℃未満の場合には，焼結されないという問題があ
る。一方，１３００℃を超える場合には，Ｔｉ及びＮ
ｉ，又はＮｉ，又はＮｉを含むラーベス相を主成分とす
る三次元網目構造の第２相が消滅するという問題があ
り，好ましくは，１０００℃未満で行うのがよい。The non-oxidizing atmosphere includes vacuum, reducing atmosphere, inert atmosphere and the like. The heating temperature is 8
If the temperature is lower than 00 ° C, there is a problem that sintering is not performed. On the other hand, when the temperature exceeds 1300 ° C, Ti and N
There is a problem that the second phase of the three-dimensional network structure containing i, Ni, or the Laves phase containing Ni as the main component disappears, and it is preferably performed at a temperature of less than 1000 ° C.
【００２８】また，上記加熱時間が３０分未満の場合に
は，十分な焼結が得られないという問題がある。一方，
２４時間もあれば，目的とする焼結を達成できる。ま
た，上記加熱は，加熱する電極を１ｋｇ／ｃｍ2 〜１０
ｔｏｎ／ｃｍ2 の加圧力で加圧しながら行うことが好ま
しい。上記加圧力が１ｋｇ／ｃｍ2 未満の場合には電極
が変形するという問題が生じる。一方，１０ｔｏｎ／ｃ
ｍ2 を超える場合には，高密度になり過ぎて良好な電極
特性が得られないという問題がある。When the heating time is less than 30 minutes, there is a problem that sufficient sintering cannot be obtained. on the other hand,
The desired sintering can be achieved in 24 hours. In addition, the heating is performed by heating the electrode to be heated at 1 kg / cm 2 to 10
It is preferable to perform it while applying a pressure of ton / cm 2 . If the applied pressure is less than 1 kg / cm 2 , the electrode may be deformed. On the other hand, 10 ton / c
If it exceeds m 2 , there is a problem that the density becomes too high and good electrode characteristics cannot be obtained.
【００２９】[0029]
実施形態例 本発明の実施形態例にかかる水素吸蔵合金電極につき，
図１〜図３を用いて説明する。本例においては，本発明
にかかる２種類の水素吸蔵合金電極Ｅ１，Ｅ２と，従来
の３種類の水素吸蔵合金電極Ｃ１，Ｃ２，Ｃ３を準備
し，電極特性の比較を行った。Embodiment Example Regarding a hydrogen storage alloy electrode according to an embodiment example of the present invention,
This will be described with reference to FIGS. In this example, two types of hydrogen storage alloy electrodes E1 and E2 according to the present invention and three conventional types of hydrogen storage alloy electrodes C1, C2 and C3 were prepared and the electrode characteristics were compared.
【００３０】上記電極Ｅ１としては，図１に示すごと
く，水素吸蔵合金粒子１１の表面を導電性のＣｕ被膜１
２により被覆した導電性粒子１と，触媒活性なＮｉ粉末
２とを所定量混合し圧縮成形してなる電極１０を用い
た。上記水素吸蔵合金粒子１１は，図２に示すごとく，
水素吸蔵機能を有するマトリックス１１１中に，三次元
網目構造の第２相１１２を析出してなる。As the electrode E1, as shown in FIG. 1, the surface of the hydrogen storage alloy particles 11 is made of a conductive Cu coating 1
A conductive particle 1 coated with 2 and a catalytically active Ni powder 2 were mixed in a predetermined amount and compression-molded into an electrode 10. As shown in FIG. 2, the hydrogen storage alloy particles 11 are
A second phase 112 having a three-dimensional network structure is deposited in a matrix 111 having a hydrogen storage function.
【００３１】この電極Ｅ１は，次の手順により作製し
た。まず，Ｖ4 ＴｉＮｉ0.56Ｃｏ0.14の組成になるよう
に合金作製用元素を秤量した後，アーク溶解法を用いて
ボタン状の合金を作製した。得られた合金は，その断面
をＥＰＭＡ分析した結果，Ｖ7 ＴｉＮｉ0.4 Ｃｏ0.05の
マトリックス１１１中に，ＴｉＮｉ1.05Ｖ0.08Ｃｏ0.08
の三次元網目構造の第２相１１２を析出してなる水素吸
蔵合金であった。なお，この水素吸蔵合金は，後述する
電極Ｅ２，Ｃ１〜Ｃ３全てにおいて，同じものを用い
た。This electrode E1 was manufactured by the following procedure. First, the elements for alloy production were weighed so that the composition was V 4 TiNi 0.56 Co 0.14 , and then the button-shaped alloy was produced by using the arc melting method. As a result of EPMA analysis of the cross section of the obtained alloy, TiNi 1.05 V 0.08 Co 0.08 in the matrix 111 of V 7 TiNi 0.4 Co 0.05
Was a hydrogen storage alloy formed by precipitating the second phase 112 having a three-dimensional network structure. The same hydrogen storage alloy was used for all electrodes E2, C1 to C3 described later.
【００３２】次いで，ボタン状合金を温度５００℃にお
いて水素化粉砕した後，さらに機械的粉砕を加えること
により，粒径１５０μｍ以下の水素吸蔵合金粒子１１と
した。次いで，この合金粒子１１の表面をフッ酸等を用
いて活性化した後，合金粒子１１の表面に２０重量％の
ＣｕをメッキしてＣｕ被膜１２を形成した。これを上記
導電性粒子１とした。なお，メッキ時には，奥野製薬製
の銅無電解メッキ液（ＭＡＣ−５００Ａ，Ｂ）を用い
た。Next, the button-shaped alloy was hydrogenated and ground at a temperature of 500 ° C., and then mechanically ground to obtain hydrogen storage alloy particles 11 having a particle size of 150 μm or less. Then, after activating the surface of the alloy particle 11 with hydrofluoric acid or the like, 20% by weight of Cu was plated on the surface of the alloy particle 11 to form a Cu coating film 12. This was designated as the conductive particle 1. At the time of plating, a copper electroless plating solution (MAC-500A, B) manufactured by Okuno Seiyaku was used.
【００３３】次いで上記導電性粒子１の重量に対し，２
０重量％のＮｉ粉末と，１０重量％のＦＥＰ（テトラフ
ルオロエチレン−ヘキサフルオロプロピレン共重合体
（ダイキン工業（株）製）とを混合し，１０ｔｏｎ／ｃ
ｍ2 の荷重を加えて第１ペレットを成形した。次いで，
ＦＥＰを溶融させるため，第１ペレットを温度３００℃
において５分間ホットプレスすることにより第２ペレッ
トを得た。なお，この時のプレス圧は，約４００ｋｇ／
ｃｍ2 とした。次いで，得られた第２ペレットを集電体
であるニッケルメッシュに挟み，Ｎｉリード線と共にス
ポット溶接して電極Ｅ１とした。Next, based on the weight of the conductive particles 1, 2
0% by weight of Ni powder and 10% by weight of FEP (tetrafluoroethylene-hexafluoropropylene copolymer (manufactured by Daikin Industries, Ltd.) were mixed to obtain 10 ton / c.
The first pellet was molded by applying a load of m 2 . Then,
In order to melt the FEP, the temperature of the first pellet was 300 ℃.
A second pellet was obtained by hot pressing for 5 minutes. The pressing pressure at this time is about 400 kg /
It was set to cm 2 . Then, the obtained second pellet was sandwiched between nickel meshes serving as a current collector, and spot-welded together with a Ni lead wire to obtain an electrode E1.
【００３４】次に，電極Ｅ２は，電極Ｅ１における上記
第２ペレットを真空中（４×１０-6ｔｏｒｒ）において
８５０℃の温度で１時間焼成させたものである。その他
は，電極Ｅ１と同様の手順により作製した。Next, the electrode E2 is obtained by firing the second pellet of the electrode E1 in vacuum (4 × 10 −6 torr) at a temperature of 850 ° C. for 1 hour. Others were manufactured by the same procedure as the electrode E1.
【００３５】次に，電極Ｃ１は，上記第１ペレット作製
の際にＮｉ粉末を用いていない点において，電極Ｅ１と
異なる。その他は，電極Ｅ１と同様である。また，電極
Ｃ２は，水素吸蔵合金粒子にＣｕ被膜を被覆させず，上
記第１ペレット作製の際にＮｉ粉末を４０重量％混合し
た。その他は，電極Ｅ１と同様である。Next, the electrode C1 is different from the electrode E1 in that Ni powder is not used in the production of the first pellet. Others are the same as the electrode E1. For the electrode C2, the hydrogen-absorbing alloy particles were not coated with the Cu coating, and 40% by weight of Ni powder was mixed during the production of the first pellets. Others are the same as the electrode E1.
【００３６】また，電極Ｃ３は，電極Ｃ２におけるＮｉ
粉末をＣｕ粉末に代えたものである。即ち，電極Ｃ３
は，水素吸蔵合金粒子にＣｕ被膜を被覆させず，上記第
１ペレット作製の際にＣｕ粉末を４０重量％混合した。
その他は，電極Ｅ１と同様である。The electrode C3 is the same as the Ni in the electrode C2.
The powder was replaced with Cu powder. That is, the electrode C3
In the case of, the hydrogen-absorbing alloy particles were not coated with the Cu coating, and 40 wt% of Cu powder was mixed at the time of producing the first pellet.
Others are the same as the electrode E1.
【００３７】次に，上記各電極の電極特性の評価方法に
ついて説明する。電極特性の評価は，Ｈ型の電解セルを
用いて，充放電サイクルに伴う放電容量を測定すること
により行った。まず，Ｈ型セルの対極には水酸化ニッケ
ル，参照極には水銀／酸化水銀電極，電解液には６ｍｏ
ｌ／ｌの水酸化カリウム水溶液を用いた。Next, a method for evaluating the electrode characteristics of each of the above electrodes will be described. The evaluation of the electrode characteristics was performed by using an H-type electrolytic cell and measuring the discharge capacity with charge / discharge cycles. First, the counter electrode of the H-type cell is nickel hydroxide, the reference electrode is a mercury / mercury oxide electrode, and the electrolyte is 6 mo.
A 1 / l potassium hydroxide aqueous solution was used.
【００３８】また，充放電は，５時間の充電後３０分間
休止し，その後５０ｍＡ／ｇの電流密度で０．７５Ｖま
で放電するというサイクルを繰り返した。また，このと
きの充電は，活物質（水素吸蔵合金粒子）の単位重量に
対し１００ｍＡ／ｇの電流密度で行った。そして，上記
充放電サイクル毎に，単位活物質量に対する放電容量
（ｍＡｈ／ｇ）を測定した。The charging / discharging was repeated for 5 hours after the charging was stopped for 30 minutes and then discharged to 0.75 V at a current density of 50 mA / g. The charging at this time was performed at a current density of 100 mA / g per unit weight of the active material (hydrogen storage alloy particles). Then, the discharge capacity (mAh / g) per unit active material amount was measured for each charge / discharge cycle.
【００３９】測定結果を図３に示す。図３は，横軸に充
放電サイクル数，縦軸に放電容量を取った。図３より知
られるごとく，電極Ｅ１は，放電容量が非常に高く，充
放電サイクルを繰り返してもその低下が少なく，サイク
ル寿命に優れている。また，電極Ｅ２は，電極Ｅ１より
も若干放電容量が低いものの，充放電サイクル数の増加
に対する放電容量の低下が電極Ｅ１よりもさらに少な
く，極めて良好なサイクル寿命特性を示した。The measurement results are shown in FIG. In FIG. 3, the horizontal axis represents the number of charge / discharge cycles and the vertical axis represents the discharge capacity. As is known from FIG. 3, the electrode E1 has a very high discharge capacity, has a small decrease even after repeated charge and discharge cycles, and has an excellent cycle life. Further, although the electrode E2 had a slightly lower discharge capacity than the electrode E1, the discharge capacity did not decrease more than the electrode E1 with an increase in the number of charging / discharging cycles, and exhibited extremely good cycle life characteristics.
【００４０】これに対し，電極Ｃ１は，充放電サイクル
数が少ない段階においては，高い放電容量を示したが，
サイクル数が３０回を超えるころから急激に放電容量が
低下し，劣悪なサイクル寿命特性を示した。また，電極
Ｃ２，Ｃ３は，サイクル寿命特性は良好であったが，充
放電サイクルの初期段階から放電容量が低かった。On the other hand, the electrode C1 showed a high discharge capacity in the stage where the number of charge / discharge cycles was small,
When the number of cycles exceeded 30, the discharge capacity decreased sharply and exhibited poor cycle life characteristics. The electrodes C2 and C3 had good cycle life characteristics, but had a low discharge capacity from the initial stage of the charge / discharge cycle.
【００４１】この結果から，水素吸蔵合金粒子の表面に
Ｃｕ被膜を被覆させた場合（Ｅ１，Ｅ２，Ｃ１）には高
い放電容量が得られるが，さらにＮｉ粉末を混合して電
極を作製した場合（Ｅ１，Ｅ２）のみ，充放電サイクル
を繰り返しても，その状態を長く維持することができる
ことがわかる。From these results, a high discharge capacity is obtained when the surface of the hydrogen storage alloy particles is coated with a Cu coating (E1, E2, C1), but when Ni powder is further mixed to form an electrode. It can be seen that only (E1, E2) can maintain that state for a long time even if the charge / discharge cycle is repeated.
【００４２】一方，上記Ｃｕ被膜を形成せずに，Ｃｕ粉
末もしくはＮｉ粉末を水素吸蔵合金粒子に混合させただ
けでは（Ｃ２，Ｃ３），高い放電容量が得られないこと
がわかる。On the other hand, it is understood that a high discharge capacity cannot be obtained only by mixing Cu powder or Ni powder with the hydrogen storage alloy particles without forming the Cu coating (C2, C3).
【００４３】[0043]
【発明の効果】上記のごとく，本発明によれば，ＶＴｉ
Ｎｉ固溶体系合金の持つ高水素吸蔵量の特性を十分生か
した，高放電容量でサイクル寿命に優れた水素吸蔵合金
電極を提供することができる。As described above, according to the present invention, VTi
It is possible to provide a hydrogen storage alloy electrode having a high discharge capacity and an excellent cycle life, which takes full advantage of the high hydrogen storage capacity of the Ni solid solution alloy.
【図１】実施形態例の水素吸蔵合金電極の断面を示す説
明図。FIG. 1 is an explanatory view showing a cross section of a hydrogen storage alloy electrode of an embodiment example.
【図２】実施形態例における，導電性粒子の断面を示す
説明図。FIG. 2 is an explanatory view showing a cross section of conductive particles in the embodiment.
【図３】実施形態例における，充放電サイクル数に対す
る放電容量の推移を示す説明図。FIG. 3 is an explanatory diagram showing a transition of discharge capacity with respect to the number of charge / discharge cycles in the embodiment example.
１０．．．水素吸蔵合金電極， １．．．導電性粒子， １１．．．水素吸蔵合金粒子， １１１．．．マトリックス， １１２．．．三次元網目構造の第２相， １２．．．金属被膜（Ｃｕ被膜）， ２．．．Ｎｉ粉末， 10. . . Hydrogen storage alloy electrode, 1. . . Conductive particles, 11. . . Hydrogen storage alloy particles, 111. . . Matrix, 112. . . Second phase of three-dimensional network structure, 12. . . Metal coating (Cu coating), 2. . . Ni powder,
───────────────────────────────────────────────────── フロントページの続き (72)発明者 磯村 秋人 愛知県刈谷市八軒町５丁目50番地 株式会 社イムラ材料開発研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akito Isomura 5-50, Hachikencho, Kariya city, Aichi Prefecture Imla Material Development Laboratory
Claims (9)
被膜により被覆した導電性粒子と，Ｎｉ粉末とを所定量
混合し圧縮成形してなると共に，上記水素吸蔵合金粒子
は，水素吸蔵機能を有するマトリックス中に，Ｔｉ及び
Ｎｉ，又はＮｉ，又はＮｉを含むラーベス相を主成分と
する三次元網目構造の第２相を析出してなることを特徴
とする水素吸蔵合金電極。1. The hydrogen-absorbing alloy particles are formed by mixing a predetermined amount of conductive particles in which the surface of the hydrogen-absorbing alloy particles is coated with a conductive metal film and Ni powder, and compression-molding the hydrogen-absorbing alloy particles. A hydrogen storage alloy electrode, characterized in that a second phase having a three-dimensional network structure containing Ti and Ni or Ni or a Laves phase containing Ni as a main component is deposited in a matrix having
被膜により被覆した導電性粒子と，Ｎｉ粉末とを所定量
混合して導電性の多孔質の基材の空孔中に充填し，圧縮
成形してなると共に，上記水素吸蔵合金粒子は，水素吸
蔵機能を有するマトリックス中に，Ｔｉ及びＮｉ，又は
Ｎｉ，又はＮｉを含むラーベス相を主成分とする三次元
網目構造の第２相を析出してなることを特徴とする水素
吸蔵合金電極。2. A predetermined amount of electrically conductive particles obtained by coating the surface of hydrogen storage alloy particles with an electrically conductive metal coating, and Ni powder are filled into the pores of an electrically conductive porous substrate, The hydrogen storage alloy particles are formed by compression molding, and the second phase having a three-dimensional network structure containing Ti and Ni, or Ni or a Laves phase containing Ni as a main component is formed in a matrix having a hydrogen storage function. A hydrogen storage alloy electrode characterized by being deposited.
は，ニッケルメッシュ，パンチングメタル，又は発泡ニ
ッケルであることを特徴とする水素吸蔵合金電極。3. The hydrogen storage alloy electrode according to claim 2, wherein the porous substrate is nickel mesh, punching metal, or nickel foam.
上記マトリックスは，（β−Ｔｉ，Ｖ）系の固溶体型の
合金であることを特徴とする水素吸蔵合金電極。4. The method according to claim 1, wherein:
A hydrogen storage alloy electrode, wherein the matrix is a (β-Ti, V) -based solid solution type alloy.
上記導電性の金属被膜は，Ｃｕ，Ｎｉもしくはそれらの
合金であり，上記水素吸蔵合金粒子に対して１５〜４０
重量％被覆してあることを特徴とする水素吸蔵合金電
極。5. The method according to claim 1, wherein:
The conductive metal coating is Cu, Ni or an alloy thereof, and is 15 to 40 relative to the hydrogen storage alloy particles.
A hydrogen storage alloy electrode characterized by being coated by weight%.
上記触媒活性なＮｉ粉末は，その粒径が１〜１５０μｍ
であり，上記導電性粒子に対して５〜３０重量％混合し
てなることを特徴とする水素吸蔵合金電極。6. The method according to any one of claims 1 to 5,
The catalytically active Ni powder has a particle size of 1 to 150 μm.
The hydrogen storage alloy electrode is characterized by being mixed in an amount of 5 to 30% by weight with respect to the conductive particles.
上記導電性粒子及びＮｉ粉末に対して，結着剤としての
有機系バインダを０〜１０重量％混合してなることを特
徴とする水素吸蔵合金電極。7. The method according to any one of claims 1 to 6,
A hydrogen storage alloy electrode, characterized in that 0 to 10% by weight of an organic binder as a binder is mixed with the conductive particles and Ni powder.
上記圧縮成形後，非酸化雰囲気中において，温度８００
〜１０００℃により３０分〜２４時間加熱し，上記水素
吸蔵合金粒子とその表面を被覆している金属被膜，該金
属被膜とＮｉ粉末，及び上記金属被膜同士を，それぞれ
その接触部分で焼結させてなることを特徴とする水素吸
蔵合金電極。8. The method according to any one of claims 1 to 7,
After the compression molding, the temperature is 800 in a non-oxidizing atmosphere.
By heating at ˜1000 ° C. for 30 minutes to 24 hours, the hydrogen storage alloy particles and the metal coating covering the surface thereof, the metal coating and Ni powder, and the metal coatings are sintered at their respective contact portions. A hydrogen storage alloy electrode characterized by the following.
上記圧縮成形後，非酸化雰囲気中において，温度８００
〜１０００℃により３０分〜２４時間加熱し，上記水素
吸蔵合金粒子とその表面を被覆している金属被膜，該金
属被膜とＮｉ粉末，上記金属被膜同士，及び該金属被膜
或は上記Ｎｉ粉末と上記多孔質の基材とを，それぞれそ
の接触部分で焼結させてなることを特徴とする水素吸蔵
合金電極。9. The method according to claim 2, wherein
After the compression molding, the temperature is 800 in a non-oxidizing atmosphere.
By heating at ~ 1000 ° C for 30 minutes to 24 hours, the hydrogen storage alloy particles and the metal coating coating the surface thereof, the metal coating and the Ni powder, the metal coatings, and the metal coating or the Ni powder. A hydrogen storage alloy electrode, characterized in that it is formed by sintering the porous base material at each of its contact portions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7274763A JPH0992271A (en) | 1995-09-27 | 1995-09-27 | Hydrogen storage alloy electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7274763A JPH0992271A (en) | 1995-09-27 | 1995-09-27 | Hydrogen storage alloy electrode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0992271A true JPH0992271A (en) | 1997-04-04 |
Family
ID=17546243
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7274763A Pending JPH0992271A (en) | 1995-09-27 | 1995-09-27 | Hydrogen storage alloy electrode |
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| Country | Link |
|---|---|
| JP (1) | JPH0992271A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000062359A1 (en) * | 1999-04-14 | 2000-10-19 | Matsushita Electric Industrial Co., Ltd. | Hydrogen storage alloy electrode, battery including the same and method for producing the both |
| KR100599763B1 (en) * | 2005-04-18 | 2006-07-12 | 삼성에스디아이 주식회사 | Plasma display device and driving method thereof |
| JP2015111502A (en) * | 2013-12-06 | 2015-06-18 | トヨタ自動車株式会社 | Hydrogen storage alloy particle, electrode for alkaline storage battery, and alkaline storage battery |
-
1995
- 1995-09-27 JP JP7274763A patent/JPH0992271A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000062359A1 (en) * | 1999-04-14 | 2000-10-19 | Matsushita Electric Industrial Co., Ltd. | Hydrogen storage alloy electrode, battery including the same and method for producing the both |
| US6610445B1 (en) | 1999-04-14 | 2003-08-26 | Matsushita Electric Industrial Co., Ltd. | Hydrogen storage alloy electrode, battery including the same and method for producing the both |
| KR100599763B1 (en) * | 2005-04-18 | 2006-07-12 | 삼성에스디아이 주식회사 | Plasma display device and driving method thereof |
| JP2015111502A (en) * | 2013-12-06 | 2015-06-18 | トヨタ自動車株式会社 | Hydrogen storage alloy particle, electrode for alkaline storage battery, and alkaline storage battery |
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