JPH07153462A - Metal oxide-hydrogen secondary battery - Google Patents
Metal oxide-hydrogen secondary batteryInfo
- Publication number
- JPH07153462A JPH07153462A JP5301494A JP30149493A JPH07153462A JP H07153462 A JPH07153462 A JP H07153462A JP 5301494 A JP5301494 A JP 5301494A JP 30149493 A JP30149493 A JP 30149493A JP H07153462 A JPH07153462 A JP H07153462A
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen storage
- negative electrode
- storage alloy
- secondary battery
- metal oxide
- 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.)
- Granted
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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Secondary Cells (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は金属酸化物を正極活物質
とし、水素を負極活物質とする金属酸化物・水素二次電
池に関し、特に負極を改良した金属酸化物・水素二次電
池に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal oxide / hydrogen secondary battery using a metal oxide as a positive electrode active material and hydrogen as a negative electrode active material, and more particularly to a metal oxide / hydrogen secondary battery with an improved negative electrode. It is a thing.
【０００２】[0002]
【従来の技術】現在、金属酸化物・水素二次電池におい
て、水素負極を水素吸蔵合金で構成した形式のものが注
目を集めている。その理由は、この電池系が元来、高エ
ネルギ−密度を有するために容積効率的に有利であり、
しかも安全作動が可能であって、特性的にも信頼度の点
でも優れているからである。前記負極は、前記水素吸蔵
合金の粉末を含むペーストを調製し、前記ペーストを網
状焼結金属繊維などの導電性芯体に充填することにより
製造される。2. Description of the Related Art At present, a metal oxide / hydrogen secondary battery of a type in which a hydrogen negative electrode is composed of a hydrogen storage alloy is drawing attention. The reason is that this battery system originally has a high energy-density and thus is advantageous in volumetric efficiency.
Moreover, it is possible to operate safely and is excellent in terms of characteristics and reliability. The negative electrode is manufactured by preparing a paste containing the powder of the hydrogen storage alloy and filling the paste into a conductive core body such as reticulated sintered metal fibers.
【０００３】前記水素吸蔵合金としては、従来から、Ｌ
ａＮｉ5 が多用されている。また、Ｌａ，Ｃｅ，Ｐｒ，
Ｎｄ，Ｓｍなどのランタン系元素の混合物であるミッシ
ュメタル（以下、Ｍｍという）とＮｉとの合金、すなわ
ちＭｍＮｉ5 も広く用いられている。ＭｍＮｉ5 は希土
類成分としてＭｍを用いるために、希土類成分として高
価なＬａ元素のみを用いるＬａＮｉ5 に比べて安価であ
り、実用的である。Conventionally, the hydrogen storage alloy has been L
aNi 5 is often used. In addition, La, Ce, Pr,
An alloy of misch metal (hereinafter referred to as Mm), which is a mixture of lanthanum-based elements such as Nd and Sm, and Ni, that is, MmNi 5 is also widely used. Since MmNi 5 uses Mm as a rare earth component, it is cheaper and more practical than LaNi 5 that uses only expensive La element as a rare earth component.
【０００４】また、ＬａＮｉ5 及びＭｍＮｉ5 に関して
は、Ｎｉの一部をＡｌ，Ｍｎ，Ｆｅ，Ｃｏ，Ｔｉ，Ｃ
ｕ，Ｚｎ，Ｚｒ，Ｃｒ，Ｖ，Ｂのような元素で置換した
多元素系のものも使用されている。Regarding LaNi 5 and MmNi 5 , a part of Ni is Al, Mn, Fe, Co, Ti, C.
A multi-element system in which elements such as u, Zn, Zr, Cr, V and B are substituted is also used.
【０００５】しかしながら、前述した組成の水素吸蔵合
金の粉末から作製された負極は、充放電サイクルの進行
に伴って前記水素吸蔵合金粉末が水素化粉砕されて微粉
化され、劣化を生じるため、前記負極を備えた二次電池
は充放電サイクル寿命が短くなるという問題点があっ
た。また、前記水素吸蔵合金粉末の微粉化の進行度合が
合金ロットによって異なるため、前記二次電池の充放電
サイクル寿命がばらつくという問題点があった。この微
粉化の進行度合の差異は、水素吸蔵合金中に含まれる不
純物や、合金製造条件の変動による合金の均質性のばら
つき、あるいは合金製造時に各合金成分の歩留りが変動
することによる合金の組成比のばらつきなどの影響と考
えられるが、現段階では明らかでない。However, in the negative electrode prepared from the powder of the hydrogen storage alloy having the above-mentioned composition, the hydrogen storage alloy powder is hydro-pulverized and pulverized as the charge / discharge cycle progresses, and deteriorates. The secondary battery having the negative electrode has a problem that the charge / discharge cycle life is shortened. In addition, since the degree of progress of pulverization of the hydrogen storage alloy powder varies depending on the alloy lot, there is a problem that the charge / discharge cycle life of the secondary battery varies. This difference in the degree of pulverization is due to impurities contained in the hydrogen storage alloy, variations in the homogeneity of the alloy due to changes in the alloy manufacturing conditions, or the composition of the alloy due to changes in the yield of each alloy component during alloy production. This may be due to the variation in the ratio, but it is not clear at this stage.
【０００６】[0006]
【発明が解決しようとする課題】本発明は従来の問題を
解決するためになされたもので、充放電サイクルの進行
に伴って微粉化されるのを抑制することができ、かつ前
記微粉化の進行度合を一定にすることが可能な負極を備
えた金属酸化物・水素二次電池を提供しようとするもの
である。DISCLOSURE OF THE INVENTION The present invention has been made to solve the conventional problems, and it is possible to suppress pulverization with the progress of charge / discharge cycles, and further An object of the present invention is to provide a metal oxide / hydrogen secondary battery provided with a negative electrode capable of maintaining a constant degree of progress.
【０００７】[0007]
【課題を解決するための手段】本発明は、容器内に金属
酸化物を含む正極とアルカリ電解液と水素吸蔵合金を含
む負極とを収納した構造を有する金属酸化物・水素二次
電池において、前記負極は、一般式ＬｍＮｉw Ｃｏx Ｍ
ｎy Ａｌz （但し、ＬｍはＬａを含む希土類元素から選
ばれる少なくとも一種からなり、原子比の合計値が４．
８≦ｗ＋ｘ＋ｙ＋ｚ≦５．５を示す）で表され、かつＸ
線回折により得られる結晶格子定数ａ，ｃそれぞれが
０．４９５ｎｍ≦ａ≦０．５１０ｎｍ，０．４００ｎｍ
≦ｃ≦０．４１０ｎｍである六方晶構造を有する水素吸
蔵合金を含むことを特徴とする金属酸化物・水素二次電
池である。The present invention provides a metal oxide / hydrogen secondary battery having a structure in which a positive electrode containing a metal oxide, a negative electrode containing an alkaline electrolyte and a hydrogen storage alloy are housed in a container. The negative electrode has a general formula of LmNi w Co x M
n y Al z (where Lm is at least one selected from La-containing rare earth elements, and the total atomic ratio is 4.
8 ≦ w + x + y + z ≦ 5.5), and X
The crystal lattice constants a and c obtained by line diffraction are 0.495 nm ≦ a ≦ 0.510 nm and 0.400 nm, respectively.
A metal oxide / hydrogen secondary battery comprising a hydrogen storage alloy having a hexagonal crystal structure with ≦ c ≦ 0.410 nm.
【０００８】前記水素吸蔵合金に配合されるＬｍ，Ｎ
ｉ，Ｃｏ，Ｍｎ，Ａｌの５成分について詳細に説明す
る。 （１）Ｌｍ ＬｍはＬａを含む希土類元素から選ばれる少なくとも一
種からなり、水素を吸蔵する働きを有する。Lm, N blended with the hydrogen storage alloy
The five components of i, Co, Mn, and Al will be described in detail. (1) Lm Lm is made of at least one selected from rare earth elements including La and has a function of storing hydrogen.
【０００９】（２）Ｎｉ Ｎｉは、前記水素吸蔵合金に吸蔵された水素を放出させ
る働きを有する。前記水素吸蔵合金に配合されるＮｉの
原子比は、３．９０〜４．５０の範囲にすることが望ま
しい。これは次のような理由によるものである。前記原
子比を３．９０未満にすると、前記水素吸蔵合金の水素
吸蔵量が目的とする量から外れる恐れがある。一方、前
記原子比が４．５０を越えると、前記水素吸蔵合金の水
素吸蔵量の低下が起こりやすく、前記二次電池のサイク
ル寿命が低下する恐れがある。より好ましい原子比は、
４．００〜４．３０の範囲である。(2) Ni Ni has a function of releasing hydrogen stored in the hydrogen storage alloy. The atomic ratio of Ni blended in the hydrogen storage alloy is preferably in the range of 3.90 to 4.50. This is due to the following reasons. When the atomic ratio is less than 3.90, the hydrogen storage amount of the hydrogen storage alloy may deviate from the target amount. On the other hand, when the atomic ratio exceeds 4.50, the hydrogen storage amount of the hydrogen storage alloy is likely to decrease, and the cycle life of the secondary battery may decrease. A more preferable atomic ratio is
It is in the range of 4.00 to 4.30.
【００１０】（３）Ｃｏ Ｃｏは、前記二次電池のサイクル寿命を向上させる働き
を有する。前記水素吸蔵合金に配合されるＣｏの原子比
は、０．３８〜０．５０の範囲にすることが望ましい。
これは次のような理由によるものである。前記原子比を
０．３８未満にすると、前記負極の微粉化の抑制が困難
になる恐れがある。一方、前記原子比が０．５０を越え
ると、前記水素吸蔵合金の水素吸蔵量の低下が起こりや
すく、前記二次電池のサイクル寿命が低下する恐れがあ
る。より好ましい原子比は、０．４０〜０．４５の範囲
である。(3) Co Co has a function of improving the cycle life of the secondary battery. The atomic ratio of Co compounded in the hydrogen storage alloy is preferably in the range of 0.38 to 0.50.
This is due to the following reasons. If the atomic ratio is less than 0.38, it may be difficult to suppress pulverization of the negative electrode. On the other hand, when the atomic ratio exceeds 0.50, the hydrogen storage amount of the hydrogen storage alloy is likely to decrease, and the cycle life of the secondary battery may decrease. A more preferable atomic ratio is in the range of 0.40 to 0.45.
【００１１】（４）Ｍｎ Ｍｎは、前記負極を高容量化し、前記負極の微粉化を抑
制する働きを有する。前記水素吸蔵合金に配合されるＭ
ｎの原子比は、０．２８〜０．５０の範囲にすることが
望ましい。これは次のような理由によるものである。前
記原子比を０．２８未満にすると、前記水素吸蔵合金の
平衡水素圧を適正化することが困難になり、前記負極の
容量が低下する恐れがある。一方、前記原子比が０．５
０を越えると、前記水素吸蔵合金の水素吸蔵量の低下及
び前記水素吸蔵合金の腐食が起こりやすく、前記二次電
池のサイクル寿命が低下する恐れがある。より好ましい
原子比は、０．３０〜０．４０の範囲である。(4) Mn Mn has a function of increasing the capacity of the negative electrode and suppressing pulverization of the negative electrode. M mixed with the hydrogen storage alloy
The atomic ratio of n is preferably in the range of 0.28 to 0.50. This is due to the following reasons. When the atomic ratio is less than 0.28, it becomes difficult to optimize the equilibrium hydrogen pressure of the hydrogen storage alloy, and the capacity of the negative electrode may decrease. On the other hand, the atomic ratio is 0.5
When it exceeds 0, the hydrogen storage amount of the hydrogen storage alloy is likely to be reduced and the hydrogen storage alloy is likely to be corroded, which may reduce the cycle life of the secondary battery. A more preferable atomic ratio is in the range of 0.30 to 0.40.
【００１２】（５）Ａｌ Ａｌは、前記負極を高容量化し、前記二次電池のサイク
ル寿命を向上させる働きを有する。前記水素吸蔵合金に
配合されるＡｌの原子比は、０．２８〜０．５０の範囲
にすることが望ましい。これは次のような理由によるも
のである。前記原子比を０．２８未満にすると、前記水
素吸蔵合金の平衡水素圧を適正化し前記負極の高容量化
を図ることが困難になる恐れがあると共に前記負極の微
粉化の抑制が困難になる恐れがある。一方、前記原子比
が０．５０を越えると、前記水素吸蔵合金の水素吸蔵量
の低下及び前記水素吸蔵合金の腐食が起こりやすく、前
記二次電池のサイクル寿命が低下する恐れがある。より
好ましい原子比は、０．３０〜０．４０の範囲である。(5) Al Al has a function of increasing the capacity of the negative electrode and improving the cycle life of the secondary battery. The atomic ratio of Al compounded in the hydrogen storage alloy is preferably in the range of 0.28 to 0.50. This is due to the following reasons. If the atomic ratio is less than 0.28, it may be difficult to optimize the equilibrium hydrogen pressure of the hydrogen storage alloy to increase the capacity of the negative electrode, and it may be difficult to suppress atomization of the negative electrode. There is a fear. On the other hand, when the atomic ratio exceeds 0.50, the hydrogen storage amount of the hydrogen storage alloy is reduced and the hydrogen storage alloy is likely to be corroded, which may reduce the cycle life of the secondary battery. A more preferable atomic ratio is in the range of 0.30 to 0.40.
【００１３】前記Ｎｉ，前記Ｃｏ，前記Ｍｎ，前記Ａｌ
の原子比ｗ，ｘ，ｙ，ｚの合計値を４．８〜５．５の範
囲に限定したのは次のような理由によるものである。前
記合計値を４．８未満にすると、前記負極の微粉化を抑
制することが困難になる。一方、前記合計値が５．５を
越えると、前記水素吸蔵合金の平衡水素圧が高くなり水
素吸蔵量が低下するため、前記二次電池の容量が低下す
る。より好ましい合計値は、５．００〜５．４０の範囲
である。Ni, Co, Mn, Al
The reason for limiting the total value of the atomic ratios w, x, y, z in the range of 4.8 to 5.5 is as follows. When the total value is less than 4.8, it becomes difficult to suppress pulverization of the negative electrode. On the other hand, when the total value exceeds 5.5, the equilibrium hydrogen pressure of the hydrogen storage alloy increases and the hydrogen storage amount decreases, so that the capacity of the secondary battery decreases. A more preferable total value is in the range of 5.00 to 5.40.
【００１４】前記水素吸蔵合金の結晶格子定数ａ，ｃを
それぞれ規定したのは、次のような理由によるものであ
る。前記結晶格子定数ａが０．４９５ｎｍ未満になる
と、前記負極の水素吸蔵合金の平衡水素圧が高くなり水
素吸蔵量が低下するため、前記二次電池の容量が低下す
る。一方、前記結晶格子定数ａが０．５１０ｎｍを越え
ると、前記負極の微粉化を抑制することが困難になる。
また、前記結晶格子定数ｃが０．４００ｎｍ未満になる
と、前記負極の水素吸蔵合金の平衡水素圧が高くなり水
素吸蔵量が低下するため、前記二次電池の容量が低下す
る。一方、前記結晶格子定数ｃが０．４１０ｎｍを越え
ると、前記負極の微粉化を抑制することが困難になる。
より望ましい結晶格子定数ａ，ｃはそれぞれ、０．４９
９ｎｍ≦ａ≦０．５０５ｎｍ，０．４０３ｎｍ≦ｃ≦
０．４０７ｎｍである。The crystal lattice constants a and c of the hydrogen storage alloy are defined for the following reasons. When the crystal lattice constant a is less than 0.495 nm, the equilibrium hydrogen pressure of the hydrogen storage alloy of the negative electrode increases and the hydrogen storage amount decreases, so the capacity of the secondary battery decreases. On the other hand, when the crystal lattice constant a exceeds 0.510 nm, it becomes difficult to suppress pulverization of the negative electrode.
Further, when the crystal lattice constant c is less than 0.400 nm, the equilibrium hydrogen pressure of the hydrogen storage alloy of the negative electrode increases and the hydrogen storage amount decreases, so the capacity of the secondary battery decreases. On the other hand, when the crystal lattice constant c exceeds 0.410 nm, it becomes difficult to suppress pulverization of the negative electrode.
More desirable crystal lattice constants a and c are 0.49, respectively.
9 nm ≦ a ≦ 0.505 nm, 0.403 nm ≦ c ≦
It is 0.407 nm.
【００１５】前記負極は、前記水素吸蔵合金の粉末に、
好ましくは高分子結着剤を配合し、必要に応じて導電性
粉末を配合してペーストを調製し、前記ペーストを導電
性芯体に充填することにより製造される。The negative electrode is made of the hydrogen storage alloy powder,
Preferably, a polymer binder is mixed, and if necessary, conductive powder is mixed to prepare a paste, and the paste is filled in a conductive core body.
【００１６】前記高分子結着剤としては、例えばポリア
クリル酸ナトリウム、ポリテトラフルオロエチレン（Ｐ
ＴＦＥ）、カルボキシメチルセルロース及びその塩（Ｃ
ＭＣ）などを挙げることができる。かかる高分子結着剤
の配合割合は、前記水素吸蔵合金粉末１００重量部に対
して０．５〜５重量部の範囲にすることが望ましい。Examples of the polymer binder include sodium polyacrylate and polytetrafluoroethylene (P
TFE), carboxymethyl cellulose and salts thereof (C
MC) and the like. The blending ratio of the polymer binder is preferably in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of the hydrogen storage alloy powder.
【００１７】前記導電性粉末としては、例えばカーボン
ブラック、黒鉛等を挙げることができる。かかる導電性
粉末の配合割合は、前記水素吸蔵合金粉末１００重量部
に対して４重量部以下であることが望ましい。Examples of the conductive powder include carbon black and graphite. The blending ratio of the conductive powder is preferably 4 parts by weight or less with respect to 100 parts by weight of the hydrogen storage alloy powder.
【００１８】前記導電性芯体としては、例えばパンチド
メタル、エキスパンドメタル、金網等の二次元構造のも
の、発泡メタル、網状焼結金属繊維などの三次元構造の
もの等を挙げることができる。Examples of the conductive core include those having a two-dimensional structure such as punched metal, expanded metal, and wire mesh, and those having a three-dimensional structure such as foam metal and reticulated sintered metal fiber.
【００１９】前記正極は、例えば水酸化ニッケルなどの
金属酸化物の他に酸化コバルト、高分子結着剤などを含
有するペーストを、例えば焼結繊維基板、発泡メタル、
不織布メッキ基板又はパンチドメタル基板などの導電性
芯体に充填することにより製造される。この高分子結着
剤としては、前記負極における高分子結着剤と同様のも
のを挙げることができる。前記アルカリ電解液として
は、例えば１５〜５０ｇ／ｌの水酸化リチウムが添加さ
れた２５〜３１重量％の水酸化カリウム水溶液を挙げる
ことができる。For the positive electrode, for example, a paste containing cobalt oxide, a polymer binder, etc. in addition to a metal oxide such as nickel hydroxide, for example, a sintered fiber substrate, a foam metal,
It is manufactured by filling a conductive core body such as a non-woven fabric plated substrate or a punched metal substrate. Examples of the polymer binder include those similar to the polymer binder in the negative electrode. Examples of the alkaline electrolyte include 25 to 31 wt% potassium hydroxide aqueous solution to which 15 to 50 g / l of lithium hydroxide is added.
【００２０】[0020]
【作用】本発明者らは、前述した一般式ＬｍＮｉw Ｃｏ
x Ｍｎy Ａｌz で表される水素吸蔵合金において、その
結晶構造及びＸ線回折により測定された結晶格子定数と
充放電サイクル寿命とが相関することを見出した。すな
わち、結晶構造が六方晶でかつその結晶格子定数ａ，ｃ
が小さい水素吸蔵合金は、結晶が強固であるために充放
電サイクル中の水素の吸蔵・放出により粉砕され難く、
充放電サイクル寿命を長くできるが、前記結晶格子定数
ａ，ｃが小さすぎると、水素吸蔵量の低下を招き、かえ
って充放電サイクル寿命が短くなることがわかった。The present inventors have found that the above-mentioned general formula LmNi w Co
In the hydrogen-absorbing alloy represented by x Mn y Al z, its crystal structured and measured by X-ray diffraction was a crystal lattice constant and the charge-discharge cycle life was found to be correlated. That is, the crystal structure is hexagonal and its crystal lattice constants a and c are
A hydrogen storage alloy with a small size is hard to be crushed due to storage and release of hydrogen during charge / discharge cycles because the crystal is strong,
It was found that the charge / discharge cycle life can be extended, but if the crystal lattice constants a and c are too small, the hydrogen storage amount is reduced, and the charge / discharge cycle life is shortened.
【００２１】このようなことから、本発明者らは前記結
晶格子定数ａ，ｃをそれぞれ０．４９５ｎｍ≦ａ≦０．
５１０ｎｍ，０．４００ｎｍ≦ｃ≦０．４１０ｎｍに規
定することによって、十分な水素吸蔵性能を有すると共
に結晶強度の高い水素吸蔵合金が得られることを見出し
た。その結果、前記水素吸蔵合金を含む負極は十分な水
素吸蔵量を有し、かつ充放電サイクルの進行に伴ない微
粉化されるのを抑制して劣化を抑制できる。さらに、前
記結晶格子定数ａ，ｃを前記範囲に規定することによっ
て、前記水素吸蔵合金の結晶の強度が揃うため、前記負
極は前記微粉化の進行度合を一定にできる。From the above, the present inventors set the crystal lattice constants a and c to 0.495 nm ≦ a ≦ 0.
It has been found that a hydrogen storage alloy having sufficient hydrogen storage performance and high crystal strength can be obtained by defining 510 nm and 0.400 nm ≦ c ≦ 0.410 nm. As a result, the negative electrode containing the hydrogen storage alloy has a sufficient hydrogen storage capacity, and can be suppressed from being pulverized with the progress of charge / discharge cycles to suppress deterioration. Furthermore, by defining the crystal lattice constants a and c within the above ranges, the crystal strengths of the hydrogen storage alloy are made uniform, so that the negative electrode can have a constant degree of pulverization.
【００２２】従って、前述した一般式ＬｍＮｉw Ｃｏx
Ｍｎy Ａｌz で表され、かつＸ線回折により得られる結
晶格子定数ａ，ｃがそれぞれ０．４９５ｎｍ≦ａ≦０．
５１０ｎｍ，０．４００ｎｍ≦ｃ≦０．４１０ｎｍであ
る六方晶構造を有する水素吸蔵合金を含む負極を備えた
二次電池は、充放電サイクル寿命を長くすることがで
き、かつその寿命のばらつきを低減することができる。Therefore, the above-mentioned general formula LmNi w Co x
Mn y Al z , and the crystal lattice constants a and c obtained by X-ray diffraction are 0.495 nm ≦ a ≦ 0.
A secondary battery including a negative electrode containing a hydrogen storage alloy having a hexagonal crystal structure with 510 nm and 0.400 nm ≦ c ≦ 0.410 nm can have a long charge / discharge cycle life and reduce variations in the life. can do.
【００２３】[0023]
【実施例】以下、本発明の実施例を詳細に説明する。 実施例１〜３ まず、純度９９．９％の希土類元素Ｌｍ（Ｌｍは、Ｌａ
が４５．１％，Ｃｅが４．６％，Ｐｒが１２．１％，Ｎ
ｄが３７．０％，その他の希土類元素及び不可避不純物
が１．１％からなる）、Ｎｉ、Ｃｏ、Ｍｎ、及びＡｌを
構成成分とし、高周波溶解によって、組成がＬｍＮｉ
4.0 Ｃｏ0.4 Ｍｎ0.3 Ａｌ0.3 （原子比の合計値は５．
０）で表される水素吸蔵合金インゴットを３０個作製し
た。つづいて、これらの水素吸蔵合金インゴットを機械
粉砕した。EXAMPLES Examples of the present invention will be described in detail below. Examples 1 to 3 First, the rare earth element Lm having a purity of 99.9% (Lm is La
45.1%, Ce 4.6%, Pr 12.1%, N
d is 37.0%, other rare earth elements and unavoidable impurities are 1.1%), Ni, Co, Mn, and Al are constituent components, and the composition is LmNi by high frequency melting.
4.0 Co 0.4 Mn 0.3 Al 0.3 (The total atomic ratio is 5.
30 hydrogen storage alloy ingots represented by 0) were produced. Subsequently, these hydrogen storage alloy ingots were mechanically crushed.
【００２４】得られた各水素吸蔵合金粉末の結晶格子定
数をＸ線回折法（管球；Ｃｕ）により測定し、六方晶で
かつその結晶格子定数ａ，ｃが下記表１に示す値である
５種類の水素吸蔵合金粉末を選び出した。The crystal lattice constants of the obtained hydrogen storage alloy powders were measured by X-ray diffractometry (tube; Cu). Hexagonal crystal lattice constants a and c are the values shown in Table 1 below. Five kinds of hydrogen storage alloy powder were selected.
【００２５】次いで、前記５種類の水素吸蔵合金粉末
に、高分子結着剤として、ポリテトラフルオロエチレ
ン、ポリアクリル酸ナトリウム及びカルボキシメチルセ
ルロースナトリウム塩を併用し、導電性粉末としてのカ
ーボンブラック並びに水とを添加し、混練して５種類の
ペーストを調製した。つづいて、前記各ペーストを導電
性芯体であるパンチドメタルに塗布し、乾燥、プレスし
た後、裁断することにより、５種類の負極を作製した。Then, polytetrafluoroethylene, sodium polyacrylate and sodium carboxymethyl cellulose are used as a polymer binder in combination with the above-mentioned five kinds of hydrogen storage alloy powders, and carbon black and water as conductive powders are added. Was added and kneaded to prepare 5 kinds of pastes. Subsequently, each of the above-mentioned pastes was applied to a punched metal which is a conductive core, dried, pressed, and then cut into five types of negative electrodes.
【００２６】また、水酸化ニッケル及び酸化コバルトを
含有するペーストを調製した。このペーストをニッケル
焼結繊維基板に充填し、更に乾燥後、全体にプレスし、
裁断することにより、非焼結式ニッケル正極を作製し
た。A paste containing nickel hydroxide and cobalt oxide was prepared. This paste was filled into a nickel sintered fiber substrate, further dried, and then pressed all over,
A non-sintered nickel positive electrode was produced by cutting.
【００２７】前記５種類の負極と前記非焼結式ニッケル
正極とを用いて図１に示す容量が１０００ｍＡｈの５種
類の試験セルを組立てた。すなわち、前記負極１は、前
記正極２との間にセパレータ３を介在してスパイラル状
に捲回され、ＡＡサイズの円筒形容器４内に収納されて
いる。前記負極１は作製された電極群の最外周に配置さ
れて前記容器４と電気的に接触している。７規定の水酸
化カリウム及び１規定の水酸化リチウムからなるアルカ
リ電解液は、前記容器４内に収容されている。中央に穴
５を有する円形の封口板６は、前記容器４の上部開口部
に配置されている。リング状の絶縁性ガスケット７は、
前記封口板６の周縁と前記容器４の上部開口部内面の間
に配置され、前記上部開口部を内側に縮径するカシメ加
工により前記容器４に前記封口板６を前記ガスケット７
を介して気密に固定している。鍔部を有する正極端子８
はその鍔部の下面が前記封口板６にリング状のスペーサ
９を介して溶接されている。正極リード１０は、一端が
前記正極２に接続され、他端が前記正極端子８に接続さ
れている。Using the five types of negative electrodes and the non-sintered nickel positive electrode, five types of test cells having a capacity of 1000 mAh shown in FIG. 1 were assembled. That is, the negative electrode 1 is spirally wound with the separator 3 interposed between the negative electrode 1 and the positive electrode 2, and is housed in the AA size cylindrical container 4. The negative electrode 1 is arranged on the outermost periphery of the prepared electrode group and is in electrical contact with the container 4. An alkaline electrolyte composed of 7N potassium hydroxide and 1N lithium hydroxide is contained in the container 4. A circular sealing plate 6 having a hole 5 in the center is arranged in the upper opening of the container 4. The ring-shaped insulating gasket 7 is
The sealing plate 6 is attached to the container 4 by caulking, which is disposed between the peripheral edge of the sealing plate 6 and the inner surface of the upper opening of the container 4, and is caulked to reduce the diameter of the upper opening inward.
It is fixed airtightly through. Positive electrode terminal 8 having a collar portion
The lower surface of the collar portion is welded to the sealing plate 6 via a ring-shaped spacer 9. The positive electrode lead 10 has one end connected to the positive electrode 2 and the other end connected to the positive electrode terminal 8.
【００２８】次いで、前記５種類の試験セルそれぞれ１
０個ずつについて、１０００ｍＡｈで９０分間充電した
後、終止電圧を１Ｖにして１０００ｍＡｈで放電する充
放電サイクルを繰り返し、電池容量が充放電サイクル初
期の１／２になるまでに要したサイクル数を測定し、平
均サイクル数を求め、その結果を下記表１に示す。Then, one of each of the five types of test cells is provided.
For 0 cells each, charge the battery for 1000 minutes at 1000 mAh for 90 minutes, then set the final voltage to 1 V and discharge at 1000 mAh. Repeat the charge-discharge cycle to measure the number of cycles required until the battery capacity becomes half of the initial charge-discharge cycle. Then, the average number of cycles was determined, and the results are shown in Table 1 below.
【００２９】また、前記５種類の水素吸蔵合金粉末につ
いて、ＪＩＳ Ｈ ７２０１に従い、６０±５℃で圧力
−組成等温線を測定し、この結果から水素吸蔵量（１０
ａｔｍ時のＨ／Ｍ（水素と水素吸蔵合金の原子比））を
求め、その結果を下記表１に併記する。The pressure-composition isotherms of the above-mentioned 5 kinds of hydrogen storage alloy powders were measured at 60 ± 5 ° C. according to JIS H7201, and the hydrogen storage capacity (10
H / M (atomic ratio of hydrogen and hydrogen storage alloy) at atm was determined, and the results are also shown in Table 1 below.
【００３０】[0030]
【表１】 [Table 1]
【００３１】表１から明らかなように、組成が前述した
式ＬｍＮｉ4.0 Ｃｏ0.4 Ｍｎ0.3 Ａｌ0.3 で表され、結
晶格子定数ａ，ｃがそれぞれ０．４９５ｎｍ≦ａ≦０．
５１０ｎｍ，０．４００ｎｍ≦ｃ≦０．４１０ｎｍであ
る六方晶構造を有する水素吸蔵合金を備えた実施例１〜
３の二次電池はサイクル寿命を長くすることができ、か
つその寿命のばらつきを低減することができることがわ
かる。これは、前記負極が充放電サイクルの進行に伴い
微粉化されるのを抑制することができ、かつ前記微粉化
の進行度合を一定にできるためであると考えられる。こ
れに対し、組成は実施例１〜３と同様であるが、結晶格
子定数ａが０．４９５ｎｍ未満で、ｃが０．４００ｎｍ
未満である六方晶構造を有する水素吸蔵合金を含む負極
を備えた比較例１の二次電池は、前記負極の水素吸蔵量
が低いため、サイクル寿命が短くなることがわかる。一
方、組成は実施例１〜３と同様であるが、結晶格子定数
ａが０．５１０ｎｍを越え、ｃが０．４１０ｎｍを越え
る六方晶構造を有する水素吸蔵合金を含む負極を備えた
比較例２の二次電池は、前記負極の水素吸蔵量が実施例
１〜３と同様に高いにもかかわらず、サイクル寿命が短
くなることがわかる。これは、前記負極が実施例１〜３
よりも微粉化の進行が速いためであると考えられる。As is apparent from Table 1, the composition is represented by the above-mentioned formula LmNi 4.0 Co 0.4 Mn 0.3 Al 0.3 , and the crystal lattice constants a and c are 0.495 nm ≦ a ≦ 0.
Examples 1 to 10 provided with a hydrogen storage alloy having a hexagonal crystal structure of 510 nm and 0.400 nm ≤ c ≤ 0.410 nm.
It can be seen that the secondary battery of No. 3 can have a long cycle life and can reduce variations in the life. It is considered that this is because the negative electrode can be suppressed from being pulverized as the charge / discharge cycle progresses, and the degree of pulverization can be made constant. On the other hand, the composition is the same as in Examples 1 to 3, but the crystal lattice constant a is less than 0.495 nm and c is 0.400 nm.
It can be seen that the secondary battery of Comparative Example 1 including the negative electrode containing the hydrogen storage alloy having the hexagonal crystal structure of less than 1 has a short cycle life because the hydrogen storage amount of the negative electrode is low. On the other hand, Comparative Example 2 having the same composition as in Examples 1 to 3, but including a negative electrode containing a hydrogen storage alloy having a hexagonal crystal structure in which the crystal lattice constant a exceeds 0.510 nm and c exceeds 0.410 nm. It can be seen that, in the secondary battery of No. 3, although the hydrogen storage amount of the negative electrode is high as in Examples 1 to 3, the cycle life is shortened. This is because the negative electrode is one of Examples 1-3.
It is considered that this is because the pulverization progresses faster than that.
【００３２】[0032]
【発明の効果】以上詳述したように本発明によれば、充
放電サイクルの進行に伴って微粉化されるのを抑制する
ことができ、前記微粉化の進行度合を一定にすることが
可能な負極を備え、サイクル寿命を長くすることがで
き、かつそのばらつきが低減された金属酸化物・水素二
次電池を提供することができる。As described above in detail, according to the present invention, it is possible to suppress pulverization with the progress of charge / discharge cycles, and to make the degree of pulverization constant. It is possible to provide a metal oxide / hydrogen secondary battery that includes such a negative electrode, has a long cycle life, and has reduced variations.
【図１】本発明の実施例で用いた試験セルの断面図。FIG. 1 is a cross-sectional view of a test cell used in an example of the present invention.
１…負極、２…正極、３…セパレータ、４…有底円筒形
容器。1 ... Negative electrode, 2 ... Positive electrode, 3 ... Separator, 4 ... Cylindrical container with a bottom.
Claims (1)
リ電解液と水素吸蔵合金を含む負極とを収納した構造を
有する金属酸化物・水素二次電池において、前記負極
は、一般式ＬｍＮｉw Ｃｏx Ｍｎy Ａｌz （但し、Ｌｍ
はＬａを含む希土類元素から選ばれる少なくとも一種か
らなり、原子比の合計値が４．８≦ｗ＋ｘ＋ｙ＋ｚ≦
５．５を示す）で表され、かつＸ線回折により得られる
結晶格子定数ａ，ｃそれぞれが０．４９５ｎｍ≦ａ≦
０．５１０ｎｍ，０．４００ｎｍ≦ｃ≦０．４１０ｎｍ
である六方晶構造を有する水素吸蔵合金を含むことを特
徴とする金属酸化物・水素二次電池。1. In a metal oxide / hydrogen secondary battery having a structure in which a positive electrode containing a metal oxide, a negative electrode containing an alkaline electrolyte and a hydrogen storage alloy are housed in a container, the negative electrode is of the general formula LmNi w. Co x Mn y Al z (where, Lm
Is at least one selected from rare earth elements including La, and the total atomic ratio is 4.8 ≦ w + x + y + z ≦
5.5) and the crystal lattice constants a and c obtained by X-ray diffraction are 0.495 nm ≦ a ≦.
0.510 nm, 0.400 nm ≦ c ≦ 0.410 nm
A metal oxide / hydrogen secondary battery comprising a hydrogen storage alloy having a hexagonal crystal structure of
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30149493A JP3727360B2 (en) | 1993-12-01 | 1993-12-01 | Method for producing metal oxide / hydrogen secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30149493A JP3727360B2 (en) | 1993-12-01 | 1993-12-01 | Method for producing metal oxide / hydrogen secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07153462A true JPH07153462A (en) | 1995-06-16 |
| JP3727360B2 JP3727360B2 (en) | 2005-12-14 |
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ID=17897596
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30149493A Expired - Lifetime JP3727360B2 (en) | 1993-12-01 | 1993-12-01 | Method for producing metal oxide / hydrogen secondary battery |
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| Country | Link |
|---|---|
| JP (1) | JP3727360B2 (en) |
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- 1993-12-01 JP JP30149493A patent/JP3727360B2/en not_active Expired - Lifetime
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