JPH11297321A - Hydrogen storage alloy electrode material for nickel-hydrogen battery and its manufacture, and hydrogen storage alloy electrode thereof - Google Patents
Hydrogen storage alloy electrode material for nickel-hydrogen battery and its manufacture, and hydrogen storage alloy electrode thereofInfo
- Publication number
- JPH11297321A JPH11297321A JP10116141A JP11614198A JPH11297321A JP H11297321 A JPH11297321 A JP H11297321A JP 10116141 A JP10116141 A JP 10116141A JP 11614198 A JP11614198 A JP 11614198A JP H11297321 A JPH11297321 A JP H11297321A
- Authority
- JP
- Japan
- Prior art keywords
- storage alloy
- hydrogen storage
- nickel
- carbon
- hydrogen
- 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
- 239000000956 alloy Substances 0.000 title claims abstract description 131
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 129
- 239000001257 hydrogen Substances 0.000 title claims abstract description 90
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 90
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 238000003860 storage Methods 0.000 title claims abstract description 83
- 239000007772 electrode material Substances 0.000 title claims description 16
- 238000004519 manufacturing process Methods 0.000 title description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 80
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 74
- 229910052751 metal Inorganic materials 0.000 claims abstract description 44
- 239000002184 metal Substances 0.000 claims abstract description 44
- 239000002245 particle Substances 0.000 claims description 64
- 239000004005 microsphere Substances 0.000 claims description 42
- 239000011248 coating agent Substances 0.000 claims description 26
- 238000000576 coating method Methods 0.000 claims description 26
- 229910052987 metal hydride Inorganic materials 0.000 claims description 21
- 239000000843 powder Substances 0.000 claims description 11
- 238000007747 plating Methods 0.000 claims description 10
- 239000011149 active material Substances 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 8
- 238000002441 X-ray diffraction Methods 0.000 claims description 6
- 239000012298 atmosphere Substances 0.000 claims description 6
- 239000008151 electrolyte solution Substances 0.000 claims description 6
- OSOVKCSKTAIGGF-UHFFFAOYSA-N [Ni].OOO Chemical compound [Ni].OOO OSOVKCSKTAIGGF-UHFFFAOYSA-N 0.000 claims description 4
- 229910052783 alkali metal Inorganic materials 0.000 claims description 4
- 150000001340 alkali metals Chemical class 0.000 claims description 4
- 229910000483 nickel oxide hydroxide Inorganic materials 0.000 claims description 4
- 239000000243 solution Substances 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 2
- 239000013078 crystal Substances 0.000 claims 3
- 239000003792 electrolyte Substances 0.000 claims 1
- 239000003575 carbonaceous material Substances 0.000 abstract description 14
- 238000009792 diffusion process Methods 0.000 abstract description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 34
- 239000010949 copper Substances 0.000 description 17
- 230000007423 decrease Effects 0.000 description 9
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 8
- 229910000990 Ni alloy Inorganic materials 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 239000011325 microbead Substances 0.000 description 7
- 230000001351 cycling effect Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 238000003795 desorption Methods 0.000 description 5
- 239000006185 dispersion Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000005484 gravity Effects 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000002931 mesocarbon microbead Substances 0.000 description 4
- 239000002923 metal particle Substances 0.000 description 4
- 230000035882 stress Effects 0.000 description 4
- 239000004698 Polyethylene Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- -1 polyethylene Polymers 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 229910001068 laves phase Inorganic materials 0.000 description 2
- HEPLMSKRHVKCAQ-UHFFFAOYSA-N lead nickel Chemical compound [Ni].[Pb] HEPLMSKRHVKCAQ-UHFFFAOYSA-N 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 238000005551 mechanical alloying Methods 0.000 description 2
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 2
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910001122 Mischmetal Inorganic materials 0.000 description 1
- 229910018007 MmNi Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 229910000366 copper(II) sulfate Inorganic materials 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 229910001325 element alloy Inorganic materials 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 description 1
- 239000012811 non-conductive material Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
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]
【発明の属する技術分野】本発明はニッケル水素電池用
水素吸蔵合金電極材料およびその製造方法、ならびに水
素吸蔵合金電極、更に詳細にはニッケル水素電池の負極
に使用される水素吸蔵合金電極の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen storage alloy electrode material for a nickel-metal hydride battery and a method for producing the same, and more particularly to an improvement in a hydrogen storage alloy electrode used for a negative electrode of a nickel-metal hydride battery. .
【０００２】[0002]
【従来技術】近年、電子機器、携帯機器の小型、軽量化
が進行し、その電源として電池がより重要視されるとと
もに一層の高エネルギー密度化が求められている。この
高エネルギー密度電池の一つとして負極に水素吸蔵合金
を用いたニッケル水素電池が注目され、実用化されてい
る。2. Description of the Related Art In recent years, as electronic devices and portable devices have become smaller and lighter, batteries have become more important as power sources, and higher energy densities have been demanded. As one of such high energy density batteries, a nickel-metal hydride battery using a hydrogen storage alloy for a negative electrode has attracted attention and has been put to practical use.
【０００３】上記ニッケル水素電池の負極は、常温付近
で水素を可逆的、かつ速やかに吸蔵、放出しうることが
必要である。現在、実用化されている合金は、高率放電
（レイト）特性、保存特性などに優れているミッシュメ
タル（Ｍｍ）−Ｎｉ系のＡＢ5型多元素合金（ＭｍＮｉ
3.4Ｃｏ0.8Ｍｎ0.6Ａｌ0.2など）が主流である。[0003] The negative electrode of the nickel-metal hydride battery needs to be able to occlude and release hydrogen reversibly and quickly at around normal temperature. Currently, alloys in practical use are high-rate discharge (Rate) characteristic, AB 5 type multi-element alloys of mischmetal (Mm) -Ni system has excellent and saving characteristics (MmNi
3.4 Co 0.8 Mn 0.6 Al 0.2 ).
【０００４】これに対して、近年更なる高エネルギー密
度化と長寿命（あるいはサイクル長寿命）化が求められ
ており、従来より放電容量の大きい水素吸蔵合金材料が
望まれる。理論水素吸蔵量が上記Ｍｍ−Ｎｉ系ＡＢ5型
合金より大きく、大容量化が期待できる水素吸蔵合金と
して、ＣａＮｉ5合金、ＡＢ2型ラーベス相合金、Ｔｉ−
Ｖ−Ｎｉ系などのＢＣＣ（体心立方構造）固溶体型合
金、Ｍｇ2ＮｉなどのＡ2Ｂ型合金が検討されている。On the other hand, in recent years, higher energy density and longer life (or longer cycle life) have been demanded, and a hydrogen storage alloy material having a larger discharge capacity than before has been desired. Large theoretical hydrogen storage capacity is higher than the Mm-Ni system AB 5 type alloys, as the hydrogen storage alloy can be expected capacity, CaNi 5 alloy, AB 2 type Laves phase alloys, Ti-
BCC (body-centered cubic structure) solid solution type alloys such as V-Ni and A 2 B type alloys such as Mg 2 Ni are being studied.
【０００５】しかしながら、これら大容量が期待される
合金材料は、Ｍｍ−Ｎｉ系ＡＢ5型合金に比べて初期放
電容量は大きいものの、サイクル経過による容量の減衰
が大きく、数十サイクルで容量が半減、あるいはそれ以
下になったり、電気化学的活性度が小さく大電流が取得
できない欠点を有していた。However, an alloy material of these high capacity are expected, although compared to the Mm-Ni system AB 5 type alloys initial discharge capacity is large, large attenuation capacity by cycles elapsed, the capacity of several tens of cycles half , Or less, or the electrochemical activity was so small that a large current could not be obtained.
【０００６】これらの対策として、合金表面へ、導電性
を有する金属であるＮｉ、あるいはＣｕのメッキ、メカ
ニカルアロイングによるＮｉ微粉末や炭素系材料の合金
表面被覆などが試みられてきた。しかし、導電性を有す
る金属であるＮｉやＣｕによる水素吸蔵合金表面の被覆
は、サイクル経過による容量の減衰抑制やレイト特性改
善には一定の効果があるものの、比重が大きいため、添
加量を多くすると容量自体の低下を招いた。一方、炭素
材料による水素吸蔵合金表面の被覆は、炭素材料の比重
が小さいため、逆に合金と炭素との比重差が大きくな
り、十分な混合を行う上での障害となって、完全な表面
被覆が達成されなかったり、また、一部の炭素は合金化
せずに単に表面に吸着されているのみであったりして、
サイクル経過による容量減衰抑制が十分でなく、レイト
特性も改善されなかった。[0006] As a countermeasure, attempts have been made to coat the alloy surface with Ni or Cu, which is a conductive metal, or to coat the alloy surface with fine nickel powder or carbon-based material by mechanical alloying. However, coating of the surface of the hydrogen storage alloy with conductive metals such as Ni and Cu has a certain effect on suppressing the decay of capacity and improving the rate characteristics over the course of the cycle, but the specific gravity is large, so the amount of addition is large. Then, the capacity itself was reduced. On the other hand, when the hydrogen storage alloy surface is coated with a carbon material, the specific gravity of the carbon material is small, and consequently, the specific gravity difference between the alloy and carbon becomes large. No coating was achieved, and some carbon was simply adsorbed on the surface without alloying,
The capacity decay was not sufficiently suppressed due to the cycling, and the rate characteristics were not improved.
【０００７】さらに、炭素材料による水素吸蔵合金表面
被覆については、ＮｉやＣｕなどの金属による被覆の場
合と比較して多量を要するため（例えば特開平９−２５
９８７０号では最大３０重量部の炭素が必要）、十分な
粒子の分散が達成されないと、絶対量としての水素吸蔵
・脱離量が減少し（炭素材料には水素の吸蔵・脱離能力
がないため）、金属による被覆の場合より容量の低下が
深刻となる場合も起こった。Further, a large amount of surface coating of a hydrogen storage alloy with a carbon material is required as compared with the case of coating with a metal such as Ni or Cu (for example, see JP-A-9-25).
No. 9870 requires a maximum of 30 parts by weight of carbon. Unless sufficient dispersion of particles is achieved, the absolute amount of hydrogen absorption / desorption decreases (the carbon material has no hydrogen storage / desorption capability). Therefore, there was a case where the capacity was more seriously reduced than in the case of coating with metal.
【０００８】これに対して、両者の特徴を加味した形
で、導電性を有する金属と導電性を有する炭素材料とを
併せて水素吸蔵合金粉末と混合、メカニカルアロイング
することによって、上記の課題を解決する試みも考えら
れるが、該金属と該炭素材料との比重差による分散不良
は依然解決されず、かえって混合量の増大による電池容
量の低下を招く恐れが大きく、この方法による効果は期
待できなかった。[0008] On the other hand, by taking into account the characteristics of both, a metal having conductivity and a carbon material having conductivity are mixed together with a hydrogen storage alloy powder and subjected to mechanical alloying, whereby the above-mentioned problem is solved. However, the dispersion failure due to the difference in specific gravity between the metal and the carbon material is still not solved, and the battery capacity is more likely to be reduced due to an increase in the mixing amount, and the effect of this method is expected. could not.
【０００９】[0009]
【発明の目的】本発明の目的は、上記現状を解決するた
め、導電性を有する金属を表面上にあらかじめ被覆した
結晶性微小球炭素を用いて、これを可能な限り少量で、
水素吸蔵合金の表面に均一高分散で、かつ強固に付着
（一部金属と一部炭素が合金中に拡散）させ、サイクル
経過による容量の減衰を抑制し、かつレイト特性を改善
したニッケル水素電池用水素吸蔵合金電極材料およびそ
の製造方法、ならびに水素吸蔵合金電極を提供すること
にある。SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems by using crystalline microsphere carbon in which a conductive metal is coated on the surface in advance, and using as small a quantity as possible.
Nickel-metal hydride battery with uniform and high dispersion and strong adhesion (partially metal and part of carbon diffuses into the alloy) on the surface of the hydrogen storage alloy, suppressing capacity decay due to cycling and improving late characteristics It is an object of the present invention to provide a hydrogen storage alloy electrode material for use, a method for producing the same, and a hydrogen storage alloy electrode.
【００１０】[0010]
【課題を解決するための手段】上記目的を達成するた
め、本発明によるニッケル水素電池用水素吸蔵合金電極
材料は、オキシ水酸化ニッケルを活物質とする正極と、
水素を活物質として吸蔵脱離する水素吸蔵合金からなる
負極と、アルカリ金属水溶液の電解液とで構成されるニ
ッケル水素電池の負極を作製するための水素吸蔵合金電
極材料において、表面を導電性の金属被膜で被覆した結
晶性微小球炭素を、水素吸蔵合金粒子の表面上に均一に
分散付着しかつ前記金属被膜で被覆した結晶性微小球炭
素の一部が前記水素吸蔵合金粒子の表面に拡散している
ことを特徴とする。In order to achieve the above object, a hydrogen storage alloy electrode material for a nickel-metal hydride battery according to the present invention comprises a positive electrode comprising nickel oxyhydroxide as an active material,
A negative electrode made of a hydrogen storage alloy that absorbs and desorbs hydrogen as an active material, and a hydrogen storage alloy electrode material for producing a negative electrode of a nickel-metal hydride battery composed of an aqueous solution of an alkali metal aqueous solution. The crystalline microsphere carbon coated with the metal coating is uniformly dispersed and adhered on the surface of the hydrogen storage alloy particles, and a part of the crystalline microsphere carbon coated with the metal coating diffuses to the surface of the hydrogen storage alloy particles. It is characterized by doing.
【００１１】更に本発明によるニッケル水素電池用水素
吸蔵合金電極材料の製造方法は、メッキにより結晶性微
小球炭素粉末の表面に導電性の金属被膜を被覆する工程
と、表面に導電性の金属被膜を被覆した前記結晶性微小
球炭素粉末と水素吸蔵合金粉末とを混合して不活性ガス
雰囲気下で機械的な応力を加える工程とを含むことを特
徴とする。Further, the method for producing a hydrogen storage alloy electrode material for a nickel-metal hydride battery according to the present invention comprises the steps of: coating a surface of a crystalline microsphere carbon powder with a conductive metal film by plating; Mixing the crystalline microsphere carbon powder coated with and the hydrogen storage alloy powder and applying a mechanical stress under an inert gas atmosphere.
【００１２】また本発明は上述のニッケル水素電池用水
素吸蔵合金電極材料を使用した電極を提供するものであ
り、オキシ水酸化ニッケルを活物質とする正極と、水素
を活物質として吸蔵脱離する水素吸蔵合金からなる負極
と、アルカリ金属水溶液の電解液とで構成されるニッケ
ル水素電池の水素吸蔵合金電極において、表面を導電性
の金属被膜で被覆した結晶性微小球炭素を、水素吸蔵合
金粒子の表面上に均一に分散付着しかつ前記金属被膜で
被覆した結晶性微小球炭素の一部が前記水素吸蔵合金粒
子の表面に拡散している材料を成形してなることを特徴
とする。The present invention also provides an electrode using the above-mentioned hydrogen storage alloy electrode material for a nickel-metal hydride battery. The positive electrode uses nickel oxyhydroxide as an active material, and the storage and desorption uses hydrogen as an active material. In a hydrogen-absorbing alloy electrode of a nickel-metal hydride battery composed of a negative electrode made of a hydrogen-absorbing alloy and an aqueous solution of an alkali metal aqueous solution, crystalline microsphere carbon whose surface is coated with a conductive metal film is treated with hydrogen-absorbing alloy particles. A material in which a part of the crystalline microsphere carbon which is uniformly dispersed and adhered on the surface of the metal particles and which is covered with the metal film is diffused on the surface of the hydrogen storage alloy particles.
【００１３】本発明によれば、導電性を有する金属をあ
らかじめ表面上に被覆した結晶性微小球炭素を用い、こ
れを水素吸蔵合金とともに混合し、機械的な応力を加え
ることによって、導電性を有する金属とカーボンの拡散
層を合金表面に高分散、均一に付与し、かつ金属を被覆
した炭素を物理的あるいは化学的に表面に吸着させた水
素吸蔵合金からなる電極を提案する。According to the present invention, crystalline microsphere carbon having a conductive metal coated on the surface in advance is used, mixed with a hydrogen storage alloy, and subjected to mechanical stress to thereby increase conductivity. The present invention proposes an electrode made of a hydrogen storage alloy in which a diffusion layer of a metal and carbon having high diffusion and uniformity is applied to the surface of an alloy, and metal-coated carbon is physically or chemically adsorbed on the surface.
【００１４】本発明になる水素吸蔵合金電極が、これを
搭載した電池において、大容量で優れた経時安定性と優
れたレイト特性を示す理由はかならずしも完全に明らか
ではないが、導電性を有する金属をあらかじめ結晶性微
小球炭素粒子表面上に被覆したために、水素吸蔵合金粒
子と該炭素粒子との比重差が縮小されて、従来の金属を
被覆しなかった結晶性微小球炭素粒子を用いた場合に比
べてより均一に混合することか可能となり、分散性が向
上したことと、かつ、結晶性微小球炭素粉末とこの炭素
粉末表面上にあらかじめ被覆してある導電性を有する金
属とが、高分散、均一に水素吸蔵合金表面上に付着させ
ることができ、効果的、かつ均一な金属とカーボンの拡
散層を水素吸蔵合金表面に形成可能となったためと、さ
らに、導電性を有する金属をあらかじめ結晶性微小球炭
素粒子の表面上に被覆したことによって、従来の金属粒
子と炭素粒子を個々に混合した方法に比べて、大幅に金
属材料と炭素材料の混合量を低減して効果的かつ均一に
合金粒子表面に分散させることが可能となり、相対的に
水素吸蔵合金の割合を高めることによって電極の水素吸
蔵・脱離量を増加させたためと考えられる。The reason why the hydrogen storage alloy electrode according to the present invention exhibits a large capacity, excellent aging stability and excellent late characteristics in a battery equipped with the electrode is not necessarily completely clear, but it is not always clear. When previously coated on the surface of the crystalline microsphere carbon particles, the difference in specific gravity between the hydrogen storage alloy particles and the carbon particles is reduced, and conventional microsphere carbon particles not coated with metal are used. It is possible to mix more uniformly than in the case of, and that the dispersibility has been improved, and that the crystalline microsphere carbon powder and the conductive metal previously coated on the surface of the carbon powder have high performance. Dispersion and uniform deposition on the surface of the hydrogen storage alloy, and effective and uniform diffusion layer of metal and carbon can be formed on the surface of the hydrogen storage alloy. Metal is coated on the surface of the crystalline microsphere carbon particles in advance, so that the mixing amount of the metal material and the carbon material is greatly reduced compared to the conventional method of individually mixing the metal particles and the carbon particles. This is probably because the particles can be effectively and uniformly dispersed on the surface of the alloy particles, and the amount of hydrogen storage / desorption of the electrode was increased by relatively increasing the ratio of the hydrogen storage alloy.
【００１５】本発明をさらに詳しく説明する。The present invention will be described in more detail.
【００１６】本発明になる、導電性を有する金属をあら
かじめ表面に被覆してある結晶性微小球炭素を表面上に
担持させた水素吸蔵合金では、該炭素材料の一部によっ
て合金表面に金属とカーボンとで構成される拡散層を形
成しており、かつ、該炭素材料の一部によって該水素吸
蔵合金粒子の表面上に細かく拡散吸着されていることを
特徴としている。In the hydrogen storage alloy according to the present invention, in which crystalline microsphere carbon whose surface is coated in advance with a conductive metal is supported on the surface, a part of the carbon material causes the metal surface to be mixed with the metal. It is characterized in that a diffusion layer composed of carbon and carbon is formed, and the diffusion layer is finely diffused and adsorbed on the surface of the hydrogen storage alloy particles by a part of the carbon material.
【００１７】導電性を有する金属であらかじめ表面を被
覆した結晶性微小球炭素は、水素吸蔵合金に対して４重
量部以上３０重量部以下が有効である。その理由は、機
械的応力を加えた結果として水素吸蔵合金表面に形成さ
れる拡散層が有効に形成され、かつ、該水素吸蔵合金粒
子の表面上に均一に拡散されるのに最適な量であるから
である。The content of the crystalline microsphere carbon whose surface is previously coated with a conductive metal is preferably 4 to 30 parts by weight based on the hydrogen storage alloy. The reason is that a diffusion layer formed on the surface of the hydrogen storage alloy as a result of applying mechanical stress is effectively formed, and in an optimum amount to be uniformly diffused on the surface of the hydrogen storage alloy particles. Because there is.
【００１８】該微小球炭素の割合が４重量部未満である
と、金属とカーボンとの拡散層が水素吸蔵合金表面に完
全に形成されず、かつ、水素吸蔵合金粒子間の導電性を
十分に確保できない。一方、該微小球炭素の割合が３０
重量部を越えた場合には、上記合金表面上に形成される
拡散層や、水素吸蔵合金粒子間の導電性は確保されるも
のの、水素吸蔵合金の相対割合が減少するために、容量
低下が著しく、上記微小球炭素を担持した効果が損なわ
れる。When the proportion of the microsphere carbon is less than 4 parts by weight, a diffusion layer of metal and carbon is not completely formed on the surface of the hydrogen storage alloy, and the conductivity between the hydrogen storage alloy particles is not sufficiently improved. I can't secure it. On the other hand, when the ratio of the microsphere carbon is 30
When the amount exceeds the weight part, although the conductivity between the diffusion layer formed on the alloy surface and the hydrogen storage alloy particles is ensured, the relative decrease of the hydrogen storage alloy is reduced, so that the capacity is reduced. Significantly, the effect of supporting the microsphere carbon is impaired.
【００１９】導電性を有する金属であらかじめ表面を被
覆した結晶性微小球炭素は、平均粒径範囲が５μｍ以上
６０μｍ以下であることが有効である。その理由は、機
械的応力を加えた結果として水素吸蔵合金表面に形成さ
れる拡散層が有効に形成され、かつ、該水素吸蔵合金粒
子の表面上に均一に拡散されるからである。It is effective that the crystalline microsphere carbon whose surface is coated in advance with a conductive metal has an average particle size range of 5 μm or more and 60 μm or less. The reason is that the diffusion layer formed on the surface of the hydrogen storage alloy as a result of applying the mechanical stress is effectively formed and is uniformly diffused on the surface of the hydrogen storage alloy particles.
【００２０】平均粒径が５μｍ未満の結晶性微小球炭素
は、その粒径が小さすぎて合金表面に吸着されるのみな
らず合金粒子間の空隙を埋め、電池に供した場合に電解
液の浸透が不十分となってイオン導電率を低下させ、逆
に、平均粒径６０μｍを越える結晶性微小球炭素を用い
ると水素吸蔵合金粒子間の導電性を確保するために要す
る炭素粒子が多量となり、相対的に水素吸蔵合金の含有
比率が低下して電池容量の減少につながり好ましくな
い。The crystalline microsphere carbon having an average particle size of less than 5 μm is not only adsorbed on the alloy surface due to its small particle size, but also fills the voids between the alloy particles, and when used for a battery, the electrolytic solution has Insufficient infiltration lowers the ionic conductivity. Conversely, if crystalline microsphere carbon having an average particle size of more than 60 μm is used, the amount of carbon particles required to secure conductivity between the hydrogen storage alloy particles increases. However, the content ratio of the hydrogen storage alloy relatively decreases, which leads to a reduction in battery capacity, which is not preferable.
【００２１】該結晶性微小球炭素粒子の表面上を被覆す
るための、導電性を有する金属は、それぞれの原子量が
異なるため、該炭素粒子と該金属との重量比率では規定
できないが、被覆して形成される表面上の被膜の膜厚が
１μｍ以下であることが好ましい。Since the metal having conductivity for coating the surface of the crystalline microsphere carbon particles has a different atomic weight, the weight ratio between the carbon particles and the metal cannot be specified. It is preferable that the thickness of the coating on the surface to be formed is 1 μm or less.
【００２２】１μｍ以上の膜厚を有する被膜が該微小球
炭素に形成された場合、金属粒子をそのまま用いた場合
とほぼ同程度の混合量（重量当たり）となり、炭素材料
を用いた場合の軽量化の利点が損なわれ、かつ、粒子が
大きくなる分だけ、水素吸蔵合金粒子間相互の導電性を
確保するために金属粒子をそのまま用いた場合より大量
を必要として、その結果、水素吸蔵合金の相対的含有量
を低下させ電池容量低下をきたして好ましくない。When a coating having a film thickness of 1 μm or more is formed on the microsphere carbon, the mixing amount (per weight) is almost the same as when the metal particles are used as they are, and the weight is reduced when the carbon material is used. The advantage of the hydrogen storage alloy is impaired, and the larger the particles, the larger the amount required to secure mutual conductivity between the hydrogen storage alloy particles than if the metal particles were used as they were. It is not preferable because the relative content is reduced and the battery capacity is reduced.
【００２３】該結晶性微小球炭素を担持させた水素吸蔵
合金の電極が大容量、かつ優れた容量の経時安定性、高
レイト特性を示すためには、該水素吸蔵合金粉末のＸ線
回折測定において、カーボンのピークが存在し、かつ、
そのカーボンピークの水素吸蔵合金メインピークに対す
る強度比が１／１０になることが好ましい。カーボンの
ピークが消滅するような強すぎる機械強度を加えると、
該合金への水素吸蔵・脱離量が大幅に減少し、かつその
速度も低下することになって好ましくない。一方、該強
度比が１／１０を越えるような場合は、水素吸蔵合金表
面上に不均一で、局部的な拡散層しか形成されず、かつ
粒子表面への吸着分散も不均一で、十分な効果が得られ
ず、同様に好ましくない。In order for the electrode of the hydrogen storage alloy carrying the crystalline microsphere carbon to exhibit a large capacity, excellent storage stability with time and high rate characteristics, X-ray diffraction measurement of the hydrogen storage alloy powder is required. , There is a carbon peak, and
Preferably, the intensity ratio of the carbon peak to the hydrogen storage alloy main peak is 1/10. If you add too strong mechanical strength that the carbon peak disappears,
Undesirably, the amount of hydrogen absorption / desorption to the alloy is greatly reduced, and the speed is also lowered. On the other hand, when the strength ratio exceeds 1/10, only a non-uniform and localized diffusion layer is formed on the surface of the hydrogen storage alloy, and the adsorption and dispersion on the surface of the particles are also non-uniform. No effect is obtained, which is similarly unfavorable.
【００２４】本特許請求に関わる水素吸蔵合金は、Ｍｍ
−Ｎｉ系ＡＢ5型、ＣａＮｉ5合金、ＡＢ2型ラーベス相
合金、ＢＣＣ（体心立方構造）固溶体型合金、Ａ2Ｂ型
合金など、電気化学的に水素の吸蔵・脱離が可能であ
り、電池用負極に応用されうる材料がその対象として考
えられるが、電池用負極の材料と成りうる合金ならこれ
に限定されることはない。[0024] The hydrogen storage alloy according to the present invention has Mm
-Ni-based AB 5 type, CaNi 5 alloy, AB 2 type Laves phase alloys, BCC (body-centered cubic structure) solid solution alloy, such as A 2 B type alloy is electrochemically capable of absorbing and desorbing hydrogen A material that can be applied to a negative electrode for a battery can be considered as an object thereof, but is not limited to an alloy that can be a material for a negative electrode for a battery.
【００２５】また、結晶性微小球炭素としては、コール
タール、石油系重質油、熱硬化性樹脂を出発原料として
加熱して生成したメソフェーズ小球体を焼成したカーボ
ンマイクロビーズ（ＭＣ）、メソフェーズカーボンマイ
クロビーズ（ＭＣＭＢ）などが有効であるが、上述の諸
条件を満たす材料であればよく、これに限定されない。Examples of the crystalline microsphere carbon include carbon microbeads (MC) obtained by calcining mesophase microspheres produced by heating coal tar, petroleum heavy oil, and thermosetting resin as starting materials, and mesophase carbon. Although microbeads (MCMB) and the like are effective, any material can be used as long as it satisfies the above-described conditions, and is not limited thereto.
【００２６】さらに、上記結晶性微小球炭素粒子の表面
上を被覆するための導電性を有する金属としてはＮｉ，
Ｃｕ，Ｃｏ，Ｆｅなどが有効であるが、該微小球炭素粒
子上に上述した膜厚の条件で被覆でき、かつ十分な導電
性を示すことができる金属であれば、何らこれに限定さ
れることはない。Further, as the conductive metal for coating the surface of the crystalline microsphere carbon particles, Ni, Ni,
Cu, Co, Fe, etc. are effective, but are not limited to any metal as long as it can be coated on the microsphere carbon particles under the above-mentioned film thickness conditions and can exhibit sufficient conductivity. Never.
【００２７】上記、導電性を有する金属を結晶性微小球
炭素粒子表面上に被覆する方法としては、電気化学メッ
キや、該金属化合物を微小球炭素粒子とともに混合し焼
成する方法などが有効であるが、均一で上記膜厚、導電
性の条件を満たす方法であれば、何らこれらに限定はさ
れない。As a method for coating the surface of the crystalline microsphere carbon particles with a conductive metal, electrochemical plating, a method in which the metal compound is mixed with the microsphere carbon particles and firing is effective. However, the method is not particularly limited as long as it is a method that is uniform and satisfies the above-mentioned film thickness and conductivity conditions.
【００２８】以下に、本特許請求になる水素吸蔵合金電
極について実施例を用いて説明するが、本発明は何らこ
れに限定されることはない。Hereinafter, the hydrogen storage alloy electrode according to the present invention will be described with reference to examples, but the present invention is not limited to these examples.
【００２９】[0029]
【実施例１】平均粒径約５０μｍのカーボンマイクロビ
ーズＭＣ（日本力一ボン製）粒子の表面上に、平均膜厚
０．５μｍの厚さでＮｉを被覆した。Ｎｉの被覆は、図
１に示す構造のメッキ浴を用いて行った。Example 1 Ni was coated on the surface of carbon microbead MC (manufactured by Nippon Rika Bon Co., Ltd.) particles having an average particle diameter of about 50 μm with an average thickness of 0.5 μm. The Ni coating was performed using a plating bath having the structure shown in FIG.
【００３０】すなわち、図１において、導電性炭素棒
（５ｍｍφ）１を中心に配置した全網２中に、ＭＣ粒子
３を粒子間の導電性パスが損なわれないように空隙をな
くして充填し、被メッキ電極とし、対極には導電性炭素
板（３０ｍｍ×１００ｍｍ）４を配して浴槽７に設置
し、これに硫酸ニッケルを溶解させた水溶液系電解液５
を両極が完全に浸漬するよう十分な量を浴槽に満たす。
このメッキ浴に、樹脂などで表面を被覆し、両極に連結
された非導電性材料で被覆されたリード線６を定電流電
源に結線して電気化学メッキを実施したものである。That is, in FIG. 1, MC particles 3 are filled in a whole net 2 centered on a conductive carbon rod (5 mmφ) 1 without voids so that a conductive path between the particles is not impaired. A conductive carbon plate (30 mm × 100 mm) 4 is disposed on the counter electrode and placed in a bath 7, and an aqueous electrolyte solution 5 in which nickel sulfate is dissolved is placed in the bath 7.
Fill the bath tub in a sufficient amount so that both electrodes are completely immersed.
In this plating bath, the surface is coated with a resin or the like, and a lead wire 6 connected to both electrodes and coated with a non-conductive material is connected to a constant current power supply to perform electrochemical plating.
【００３１】粗粉砕したＭｇ2Ｎｉ合金（粒径５３μｍ
以下）と、上記方法によって表面上にＮｉを被覆した該
ＭＣ（Ｎｉ＋ＭＣ）とを表１に示す割合で、アルゴンガ
ス雰囲気下で１０時間遊星ボールミル混合を行った。Coarsely pulverized Mg 2 Ni alloy (particle size 53 μm
The following) and the MC (Ni + MC) whose surface was coated with Ni by the above method were mixed in a planetary ball mill for 10 hours in an argon gas atmosphere at a ratio shown in Table 1.
【００３２】得られた水素吸蔵合金粉体に結着剤として
ポリエチレン粉末を重量部にして９７／３の割合で加
え、これにさらにエタノールを適量加えてぺースト状に
して、あらかじめニッケルリード線をスポット溶接した
厚さ０．６ｍｍ、縦横が２ｃｍの発砲状ニッケルに充
填、乾燥後加圧し、これを真空中１３０℃で１時間加熱
して試験用電極を作製した。To the obtained hydrogen storage alloy powder, polyethylene powder was added as a binder at a ratio of 97/3 by weight, and an appropriate amount of ethanol was further added thereto to form a paste, and a nickel lead wire was previously prepared. A spot-welded nickel foam having a thickness of 0.6 mm and a length and width of 2 cm was filled, dried and pressurized, and heated at 130 ° C. for 1 hour in a vacuum to prepare a test electrode.
【００３３】 [0033]
【００３４】この電極を負極にし、ニッケルリード線を
溶接した縦横２ｃｍの水酸化ニッケル正極とともに８Ｎ
ＫＯＨ水溶液５０ｃｃを入れたビーカー中に浸漬して
試験電池とした。充放電サイクル試験は、室温中、充電
０．１Ａ、１２時間、放電０．１Ａ、終止電圧０．８
Ｖ、休止１０分の条件で行った。This electrode was used as a negative electrode, and a nickel lead wire was welded to a nickel hydroxide positive electrode having a length of 2 cm and a width of 8 cm.
A test battery was immersed in a beaker containing 50 cc of an aqueous KOH solution. The charge / discharge cycle test was performed at room temperature, at a charge of 0.1 A, for 12 hours, at a discharge of 0.1 A, and at a final voltage of 0.8.
V, 10 minutes of rest.
【００３５】比較例として、表面上にＮｉを被覆した平
均粒径約５０μｍのＭＣ（Ｎｉ＋ＭＣ）の替わりに、Ｎ
ｉを被覆しない平均粒径約５０μｍのＭＣを用いて、こ
の炭素粒子をＭｇ2Ｎｉ合金に対して２０重量部加えて
本実施例の方法と同様の方法によってＭＣ担持Ｍｇ2Ｎ
ｉ合金を作製し、電極を作製し、試験電池を構成して、
本実施例と同様の条件で試験を行った。As a comparative example, instead of MC (Ni + MC) having an average particle size of about 50 μm and having Ni coated on the surface, N
Using MC having an average particle size of about 50 μm that does not cover i, 20 parts by weight of the carbon particles are added to the Mg 2 Ni alloy, and the MC-supported Mg 2 N
i-alloy, electrode, test battery,
A test was performed under the same conditions as in this example.
【００３６】図２ａに結果を示す。FIG. 2a shows the results.
【００３７】図２ａは、表１の各試料と、比較例として
作製したＭＣ担持合金に対応する試験負極を用いた電池
のサイクルに伴う調製合金重量当たりの容量の変化を比
較した図であり、図中１は、試料１に対応したＮｉ＋Ｍ
ＣをＭｇ2Ｎｉ出発合金に対し１重量部加えた合金の電
極の特性を、２は試料２に対応したＮｉ＋ＭＣを５重量
部加えた合金の電極の特性を、３は試料３に対応したＮ
ｉ＋ＭＣを１０重量部加えた合金の電極の特性を、４は
試料４に対応したＮｉ＋ＭＣを２０重量部加えた合金の
電極の特性を、５は試料５に対応したＮｉ＋ＭＣを３０
重量部加えた合金の電極と、比較例で作製したＭＣ担持
Ｍｇ2Ｎｉ合金電極との特性を示す曲線である。FIG. 2A is a diagram comparing the change in capacity per weight of the prepared alloy with each cycle of the battery using the test negative electrode corresponding to the MC-supported alloy prepared as a comparative example with each sample of Table 1. In the figure, 1 is Ni + M corresponding to sample 1.
The characteristics of the electrode of the alloy in which C was added by 1 part by weight to the Mg 2 Ni starting alloy, the characteristics of the electrode of the alloy in which 5% by weight of Ni + MC corresponding to Sample 2 were added, and the characteristics of N in which the electrode of Sample 3 was added.
The characteristics of the electrode of the alloy to which 10% by weight of i + MC were added, 4 were the characteristics of the electrode of the alloy to which 20% by weight of Ni + MC corresponding to Sample 4, and 5 were 30 to 30% of the Ni + MC corresponding to Sample 5.
And the electrode of the parts by weight of the alloy, is a curve showing the characteristics of the MC-bearing Mg 2 Ni alloy electrode prepared in Comparative Example.
【００３８】また、また図２ｂはＮｉ被覆結晶性微小球
炭素の添加量に対する放電容量を示したものであり、符
号１から５は図２ａと同様、試料番号に対応している。FIG. 2B shows the discharge capacity with respect to the amount of Ni-coated crystalline microsphere carbon added. Reference numerals 1 to 5 correspond to the sample numbers as in FIG. 2A.
【００３９】図２ａ、図２ｂから明らかなように、Ｎｉ
＋ＭＣを４重量部以上、３０重量部以下の範囲で加えて
調製された合金からなる電極を用いた電池の容量は大き
く、かつサイクルに伴う容量の低下も小さくなってい
る。As is clear from FIGS. 2A and 2B, Ni
The capacity of a battery using an electrode made of an alloy prepared by adding + MC in a range of not less than 4 parts by weight and not more than 30 parts by weight is large, and the decrease in capacity due to cycling is small.
【００４０】これに対し、Ｎｉ＋ＭＣを１重量部加えて
調製された合金電極の場合では、調製合金重量当たりの
容量は低く、かつ、サイクルに伴う容量減少が大きかっ
た。On the other hand, in the case of the alloy electrode prepared by adding 1 part by weight of Ni + MC, the capacity per the weight of the prepared alloy was low, and the capacity decrease accompanying the cycle was large.
【００４１】また、Ｎｉ＋ＭＣを、３０重量部加えて調
製された合金電極の場合、サイクルに伴う低下はＮｉ＋
ＭＣを５重量部以上、２０重量部以下の範囲で加えて調
製された合金の場合とほぽ同等であるものの、容量自体
は低下してしまい、あまり好ましくはなかった。したが
ってＮｉ＋ＭＣは好ましくは４重量部以上、３０重量部
以下、更に好ましくは５〜２０ 重量部、最も好ましく
は１０〜２０重量部である。In the case of an alloy electrode prepared by adding 30 parts by weight of Ni + MC, the decrease accompanying the cycle was Ni + MC.
Although almost the same as the alloy prepared by adding MC in a range of 5 parts by weight or more and 20 parts by weight or less, the capacity itself was reduced, which was not so preferable. Therefore, Ni + MC is preferably at least 4 parts by weight and at most 30 parts by weight, more preferably 5 to 20 parts by weight, most preferably 10 to 20 parts by weight.
【００４２】さらに、従来法によるＮｉメッキを施さな
いＭＣを２０重量部担持したＭｇ2Ｎｉ合金電極では初
期容量も低く、かつサイクルに伴う容量減少も大きく、
いずれも好ましくなかった。Furthermore, in the case of a Mg 2 Ni alloy electrode carrying 20 parts by weight of MC not subjected to Ni plating according to the conventional method, the initial capacity is low, and the capacity decrease accompanying the cycle is large.
Neither was preferred.
【００４３】[0043]
【実施例２】実施例１に用いた合金と同様の粗粉砕した
Ｍｇ2Ｎｉ合金（粒径５３μｍ以下）１００ｇと、硫酸
ニッケルを溶解した電解液の替わりに硫酸第二銅を溶解
した電解液を用いた以外は実施例１に示した方法と同様
の方法によって表面上に平均膜厚約０．３５μｍでＣｕ
を被覆した平均粒径約２０μｍのカーボンマイクロビー
ズＭＣ（Ｃｕ＋ＭＣ）２０ｇとを、アルゴンガス雰囲気
下で表２に示した時間遊星ボールミル混合を行った。Embodiment 2 100 g of a coarsely pulverized Mg 2 Ni alloy (particle diameter: 53 μm or less) similar to the alloy used in Embodiment 1 and an electrolytic solution in which cupric sulfate is dissolved in place of the electrolytic solution in which nickel sulfate is dissolved Was formed on the surface with an average film thickness of about 0.35 μm except that Cu was used.
Was mixed with 20 g of carbon microbeads MC (Cu + MC) having an average particle size of about 20 μm and mixed with a planetary ball mill in an argon gas atmosphere for the time shown in Table 2.
【００４４】得られた試料についてＸ線回折測定を行っ
た。また、実施例１と同様な方法で試験用電極、試験用
電池を作製し、実施例１と同様な条件でサイクル試験を
行った。An X-ray diffraction measurement was performed on the obtained sample. Further, a test electrode and a test battery were prepared in the same manner as in Example 1, and a cycle test was performed under the same conditions as in Example 1.
【００４５】表２に、Ｘ線回折測定による合金のメイン
ピークに対するカーボンの（００２）面のピークの強度
比とサイクル試験による最大放電容量を示す。また、図
３には試料８と、比較例として粗粉砕Ｍｇ2Ｎｉ合金１
００ｇと、平均粒径約２０μｍのＭＣ２０ｇとをアルゴ
ン雰囲気中にてシェイカーミキサーで単純混合した粉体
のＸ線回折図を示す。Table 2 shows the intensity ratio of the peak of the (002) plane of carbon to the main peak of the alloy by X-ray diffraction measurement and the maximum discharge capacity by a cycle test. FIG. 3 shows sample 8 and coarsely pulverized Mg 2 Ni alloy 1 as a comparative example.
FIG. 4 shows an X-ray diffraction diagram of a powder obtained by simply mixing 00 g and 20 g of MC having an average particle size of about 20 μm in an argon atmosphere using a shaker mixer.
【００４６】 [0046]
【００４７】表２と図３より明らかなように、ピーク強
度比が１／１０より大きいと最大容量が大幅に低下し、
好ましくない。As is clear from Table 2 and FIG. 3, when the peak intensity ratio is larger than 1/10, the maximum capacity is greatly reduced,
Not preferred.
【００４８】[0048]
【実施例３】実施例２と同様な方法によって、平均粒径
約２０μｍのカーボンマイクロビーズＭＣ粒子表面上に
表３に示す膜厚のＣｕの被覆を行ってＣｕ＋ＭＣを作製
した。Example 3 In the same manner as in Example 2, Cu + MC was produced by coating the surface of the carbon microbead MC particles having an average particle diameter of about 20 μm with Cu having a film thickness shown in Table 3.
【００４９】粗粉砕したＭｇ2Ｎｉ合金（粒径５３μｍ
以下）と作製したＣｕ＋ＭＣとを、実施例１と同様の方
法でアルゴンガス雰囲気下で１０時間遊星ボールミル混
合を行った。A coarsely pulverized Mg 2 Ni alloy (particle size: 53 μm
Then, the prepared Cu + MC was mixed with a planetary ball mill in an argon gas atmosphere for 10 hours in the same manner as in Example 1.
【００５０】得られた水素吸蔵合金粉体と結着剤として
ポリエチレン粉末とから実施例１と同様の方法によって
試験用電極を作製した。A test electrode was produced in the same manner as in Example 1 from the obtained hydrogen storage alloy powder and polyethylene powder as a binder.
【００５１】 [0051]
【００５２】この電極を負極にし、実施例１と同様の試
験電極を作製し、さらに実施例１と同様の条件でサイク
ル試験を行った。Using this electrode as a negative electrode, a test electrode similar to that of Example 1 was prepared, and a cycle test was performed under the same conditions as in Example 1.
【００５３】図４ａに結果を示す。FIG. 4a shows the results.
【００５４】図４ａは、表３の各試料に対応する試験負
極を用いた電池の、サイクルに伴う調製合金重量当たり
の容量の変化を示した図であり、図中１１は、参考例と
して作製した試料１１を使用した電極の特性を、１２は
本発明になる試料１２を使用した電極の特性を、１３は
同じく本発明になる試料１３を使用した電極の特性を、
１４は試料１４を使用した電極の特性を示した曲線であ
る。FIG. 4A is a diagram showing the change in capacity per weight of the prepared alloy with cycling of the battery using the test anode corresponding to each sample in Table 3, and 11 in FIG. 12 shows the characteristics of the electrode using the sample 11 according to the present invention, 12 shows the characteristics of the electrode using the sample 13 according to the present invention,
Reference numeral 14 denotes a curve showing characteristics of an electrode using the sample 14.
【００５５】図４ｂはＣｕ被覆の厚さと放電容量の関係
を示す図である。FIG. 4B is a diagram showing the relationship between the thickness of the Cu coating and the discharge capacity.
【００５６】図４ａ、図４ｂから明らかなように、表面
上に被覆したＣｕの膜厚が、１．２μｍ以下の結晶性微
小球炭素粒子からなる電極を用いた電池の容量は大き
く、かつサイクルに伴う容量の低下も小さく優れた特性
を示した。更に好ましくは１μｍ以下、最も好ましくは
０．２〜１μｍである。As is clear from FIGS. 4A and 4B, the capacity of the battery using the electrode made of crystalline microsphere carbon particles having a thickness of Cu of 1.2 μm or less coated on the surface is large and the cycle is large. The decrease in capacity due to the above was small and excellent characteristics were exhibited. More preferably, it is 1 μm or less, most preferably 0.2 to 1 μm.
【００５７】これに対し、Ｃｕの膜厚が１．２μｍを越
える炭素粒子の電極の場合では、調製合金重量当たりの
容量は低かった。On the other hand, in the case of an electrode of carbon particles having a Cu film thickness exceeding 1.2 μm, the capacity per weight of the prepared alloy was low.
【００５８】また、Ｃｕを表面に被覆せず、そのままで
微小球炭素を用いた電極の場合も容量が低下し、かつ、
サイクル経過に伴う容量減少も大きくなり好ましくなか
った。Also, in the case of an electrode using microsphere carbon as it is without coating the surface with Cu, the capacity is reduced, and
The decrease in capacity with the passage of cycles was also large, which was not preferable.
【００５９】[0059]
【実施例４】Ｔｉ0.3Ｖ0.45Ｃｒ0.10Ｌａ0.05Ｎｉ0.1の
組成になるＢＣＣ型合金（粒径４０μｍ以下）１００ｇ
と、実施例２と同様の方法でＣｕを平均膜厚０．３４μ
ｍで表面を被覆した異なる平均粒径を持つメソフェーズ
カーボンマイクロビーズ（Ｃｕ＋ＭＣＭＢ）２０ｇを、
アルゴンガス雰囲気下で１０時間遊星ボールミル混合を
行った。Embodiment 4 100 g of a BCC type alloy (particle size of 40 μm or less) having a composition of Ti 0.3 V 0.45 Cr 0.10 La 0.05 Ni 0.1
And an average film thickness of 0.34 μm in the same manner as in Example 2.
20 g of mesophase carbon microbeads (Cu + MCMB) having different average particle diameters coated on the surface with m
Planetary ball mill mixing was performed for 10 hours under an argon gas atmosphere.
【００６０】得られた水素吸蔵合金粉体と、結着剤とし
てポリエチレン粉末とから、実施例１と同様の方法によ
って試験用電極を作製した。From the obtained hydrogen storage alloy powder and polyethylene powder as a binder, a test electrode was produced in the same manner as in Example 1.
【００６１】この電極を負極にし、実施例１と同様の試
験電極を作製し、さらに実施例１と同様の条件でサイク
ル試験を行った。Using this electrode as a negative electrode, a test electrode similar to that of Example 1 was prepared, and a cycle test was performed under the same conditions as in Example 1.
【００６２】図５に結果を示す。FIG. 5 shows the results.
【００６３】図５は、Ｃｕ＋ＭＣＭＢの平均粒径と第１
回目の放電容量（合金重量当たり）との関係を示した図
である。ＭＣＭＢの平均粒径が５μｍ以上６０μｍ以下
の場合、これを用いた電極の電池容量はいずれも４００
ｍＡｈ／ｇより大きく良好な特性を示した。FIG. 5 shows the average particle size of Cu + MCMB and the first particle size.
It is a figure showing the relation with the discharge capacity (per alloy weight) of the time. When the average particle size of MCMB is 5 μm or more and 60 μm or less, the battery capacity of each electrode using the same is 400 μm.
It showed good characteristics larger than mAh / g.
【００６４】[0064]
【発明の効果】以上述べたように、本発明になるニッケ
ル水素電池用水素吸蔵合金電極材料およびその製造方
法、ならびに水素吸蔵合金電極によれば、該電極を負極
として用いたニッケル水素電池において、サイクル経過
による容量の減衰の抑制と、レイト特性の改善が期待で
き、優れた電池を提供できる。As described above, according to the hydrogen-absorbing alloy electrode material for a nickel-metal hydride battery according to the present invention, the method for producing the same, and the hydrogen-absorbing alloy electrode, in a nickel-metal hydride battery using the electrode as a negative electrode, It is possible to suppress the attenuation of the capacity due to the passage of the cycle and to improve the rate characteristics, thereby providing an excellent battery.
【図１】実施例１において使用した、導電性を有する金
属を電気化学メッキにより結晶性微小球炭素粒子表面に
被覆するためのメッキ浴の概念を示した図。FIG. 1 is a view showing the concept of a plating bath used in Example 1 for coating a surface of a crystalline microsphere carbon particle with a metal having conductivity by electrochemical plating.
【図２ａ】実施例１において試験した電池の結果であ
り、合金重量当たりの容量のサイクルに伴う変化の様子
を示した図。FIG. 2A is a diagram showing the result of the battery tested in Example 1, and showing how the capacity per alloy weight changes with cycling.
【図２ｂ】実施例１における放電容量とＮｉ被覆結晶性
炭素の添加量重量比（重量部）の関係を示す図。FIG. 2B is a graph showing the relationship between the discharge capacity and the weight ratio (parts by weight) of Ni-coated crystalline carbon in Example 1.
【図３】実施例２におけるＸ線回折測定の結果であり、
本発明になる合金と、比較例として表面未処理の出発物
質である合金との回折ピークを示した図。FIG. 3 shows the results of X-ray diffraction measurement in Example 2,
The figure which showed the diffraction peak of the alloy which becomes this invention, and the alloy which is a surface untreated starting material as a comparative example.
【図４ａ】実施例３において試験した電池の結果であ
り、合金重量当たりの容量のサイクルに伴う変化の様子
を示した図。FIG. 4a is a diagram showing the results of the battery tested in Example 3, and showing how the capacity per alloy weight changes with cycling.
【図４ｂ】実施例３における放電容量と銅の被覆厚みと
の関係を示す図。FIG. 4B is a diagram showing the relationship between the discharge capacity and the copper coating thickness in Example 3.
【図５】実施例４において試験した電池の結果であり、
表面をＣｕで被覆したメソフェーズカーボンマイクロビ
ーズの平均粒径と合金重量当たりの最大容量の関係を示
した図。FIG. 5 shows the results of the battery tested in Example 4,
The figure which showed the relationship between the average particle diameter of the mesophase carbon microbead whose surface was covered with Cu, and the maximum capacity per alloy weight.
１ 導電性炭素棒 ２ 金属網 ３ 結晶性微小球炭素粒子 ４ 導電性炭素板 ５ 電解液 ６ リード線 ７ メッキ浴槽 REFERENCE SIGNS LIST 1 conductive carbon rod 2 metal net 3 crystalline microsphere carbon particles 4 conductive carbon plate 5 electrolytic solution 6 lead wire 7 plating bath
Claims (7)
と、水素を活物質として吸蔵脱離する水素吸蔵合金から
なる負極と、アルカリ金属水溶液の電解液とで構成され
るニッケル水素電池の負極を作製するための水素吸蔵合
金電極材料において、 表面を導電性の金属被膜で被覆した結晶性微小球炭素
を、水素吸蔵合金粒子の表面上に均一に分散付着しかつ
前記金属被膜で被覆した結晶性微小球炭素の一部が前記
水素吸蔵合金粒子の表面に拡散していることを特徴とす
るニッケル水素電池用水素吸蔵合金電極材料。1. A negative electrode of a nickel-metal hydride battery comprising a positive electrode using nickel oxyhydroxide as an active material, a negative electrode made of a hydrogen storage alloy that absorbs and desorbs hydrogen as an active material, and an electrolyte of an aqueous alkali metal solution. In the hydrogen storage alloy electrode material for producing the crystal, the crystalline microsphere carbon whose surface is coated with a conductive metal coating is uniformly dispersed and adhered on the surface of the hydrogen storage alloy particles and the crystal coated with the metal coating A hydrogen storage alloy electrode material for a nickel-metal hydride battery, wherein a part of the conductive microsphere carbon is diffused on the surface of the hydrogen storage alloy particles.
以上６０μｍ以下であることを特徴とする請求項１記載
のニッケル水素電池用水素吸蔵合金電極材料。2. The crystalline microsphere carbon has an average particle size of 5 μm.
2. The hydrogen storage alloy electrode material for a nickel-metal hydride battery according to claim 1, wherein the thickness is not less than 60 μm.
以下であることを特徴とする請求項１または２記載のニ
ッケル水素電池用水素吸蔵合金電極材料。3. The conductive metal coating has a thickness of 1.2 μm.
The hydrogen storage alloy electrode material for a nickel-metal hydride battery according to claim 1 or 2, wherein:
る前記結晶性微小球炭素の割合が４重量部以上３０重量
部以下であることを特徴とする請求項１から３記載のニ
ッケル水素電池用水素吸蔵合金電極材料。4. The hydrogen for a nickel-metal hydride battery according to claim 1, wherein the ratio of the crystalline microsphere carbon to 100 parts by weight of the hydrogen storage alloy particles is 4 parts by weight or more and 30 parts by weight or less. Storage alloy electrode material.
ーク強度に対する炭素の回折ピーク強度の比が１０分の
１以下であることを特徴とする請求項１から４記載のニ
ッケル水素電池用水素吸蔵合金電極材料。5. The hydrogen for a nickel-metal hydride battery according to claim 1, wherein a ratio of a diffraction peak intensity of carbon to a main diffraction peak intensity of the hydrogen storage alloy in X-ray diffraction is 1/10 or less. Storage alloy electrode material.
に導電性の金属被膜を被覆する工程と、表面に導電性の
金属被膜を被覆した前記結晶性微小球炭素粉末と水素吸
蔵合金粉末とを混合して不活性ガス雰囲気下で機械的な
応力を加える工程とを含むことを特徴とするニッケル水
素電池用水素吸蔵合金電極材料の製造方法。6. A step of coating the surface of the crystalline microsphere carbon powder with a conductive metal film by plating, and the step of coating said crystalline microsphere carbon powder having a surface coated with a conductive metal film with a hydrogen storage alloy powder. And applying a mechanical stress in an inert gas atmosphere by mixing the hydrogen storage alloy electrode material for a nickel-metal hydride battery.
と、水素を活物質として吸蔵脱離する水素吸蔵合金から
なる負極と、アルカリ金属水溶液の電解液とで構成され
るニッケル水素電池の水素吸蔵合金電極において、表面
を導電性の金属被膜で被覆した結晶性微小球炭素を、水
素吸蔵合金粒子の表面上に均一に分散付着しかつ前記金
属被膜で被覆した結晶性微小球炭素の一部が前記水素吸
蔵合金粒子の表面に拡散しているニッケル水素電池用水
素吸蔵合金電極材料を成形してなることを特徴とする水
素吸蔵合金電極。7. A hydrogen battery for a nickel-metal hydride battery comprising a positive electrode using nickel oxyhydroxide as an active material, a negative electrode made of a hydrogen storage alloy that absorbs and desorbs hydrogen as an active material, and an electrolytic solution of an aqueous alkali metal solution. In the storage alloy electrode, the crystalline microsphere carbon whose surface is coated with a conductive metal coating is uniformly dispersed and attached on the surface of the hydrogen storage alloy particles, and a part of the crystal microsphere carbon coated with the metal coating. Formed from a hydrogen storage alloy electrode material for a nickel-metal hydride battery which is diffused on the surface of the hydrogen storage alloy particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10116141A JPH11297321A (en) | 1998-04-10 | 1998-04-10 | Hydrogen storage alloy electrode material for nickel-hydrogen battery and its manufacture, and hydrogen storage alloy electrode thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10116141A JPH11297321A (en) | 1998-04-10 | 1998-04-10 | Hydrogen storage alloy electrode material for nickel-hydrogen battery and its manufacture, and hydrogen storage alloy electrode thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11297321A true JPH11297321A (en) | 1999-10-29 |
Family
ID=14679768
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10116141A Pending JPH11297321A (en) | 1998-04-10 | 1998-04-10 | Hydrogen storage alloy electrode material for nickel-hydrogen battery and its manufacture, and hydrogen storage alloy electrode thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11297321A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100347882C (en) * | 2004-07-30 | 2007-11-07 | 松下电器产业株式会社 | Negative electrode and nickel-metal hydride storage battery using the same |
| CN113764698A (en) * | 2020-12-31 | 2021-12-07 | 厦门大学 | Hydrogen storage fuel and preparation method thereof |
-
1998
- 1998-04-10 JP JP10116141A patent/JPH11297321A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100347882C (en) * | 2004-07-30 | 2007-11-07 | 松下电器产业株式会社 | Negative electrode and nickel-metal hydride storage battery using the same |
| CN113764698A (en) * | 2020-12-31 | 2021-12-07 | 厦门大学 | Hydrogen storage fuel and preparation method thereof |
| CN113764698B (en) * | 2020-12-31 | 2024-01-09 | 厦门大学 | Hydrogen storage fuel and preparation method thereof |
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