JP3071003B2 - Hydrogen storage alloy electrode and method for producing the same - Google Patents
Hydrogen storage alloy electrode and method for producing the sameInfo
- Publication number
- JP3071003B2 JP3071003B2 JP3277530A JP27753091A JP3071003B2 JP 3071003 B2 JP3071003 B2 JP 3071003B2 JP 3277530 A JP3277530 A JP 3277530A JP 27753091 A JP27753091 A JP 27753091A JP 3071003 B2 JP3071003 B2 JP 3071003B2
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen storage
- storage alloy
- battery
- value
- 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.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/383—Hydrogen absorbing alloys
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、可逆的に水素を吸蔵，
放出する水素吸蔵合金を含む水素吸蔵合金電極の製造方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reversibly stores hydrogen,
The present invention relates to a method for manufacturing a hydrogen storage alloy electrode including a hydrogen storage alloy to be released.
【０００２】[0002]
【従来の技術】従来からよく用いられる蓄電池として
は、鉛電池及びニッケル−カドミウム電池がある。しか
し、近年、これら電池より軽量で且つ高容量となる可能
性があるということで、特に常圧で負極活物質である水
素を可逆的に吸蔵及び放出することのできる水素吸蔵合
金を備えた電極を負極に用い、水酸化ニッケルなどの金
属酸化物を正極活物質とする電極を正極に用いた金属−
水素アルカリ蓄電池が注目されている。2. Description of the Related Art Conventionally, storage batteries which are often used include a lead battery and a nickel-cadmium battery. However, in recent years, since these batteries may be lighter and have higher capacity than those batteries, an electrode provided with a hydrogen storage alloy capable of reversibly storing and releasing hydrogen, which is a negative electrode active material, particularly at normal pressure. Using a metal oxide such as nickel hydroxide as a positive electrode active material and a positive electrode as a negative electrode;
Attention has been paid to hydrogen-alkaline storage batteries.
【０００３】ところで、上記水素吸蔵合金としては、電
池特性を向上させるべく、合金の平衡圧を低下させる必
要がある。そこで、一般に、水素吸蔵合金にマンガンを
添加するような構成がとられていた。[0003] Incidentally, as the above-mentioned hydrogen storage alloy, it is necessary to lower the equilibrium pressure of the alloy in order to improve the battery characteristics. Therefore, a configuration is generally adopted in which manganese is added to the hydrogen storage alloy.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記マ
ンガンを多量に含む水素吸蔵合金は、充放電時に著しい
微粉化を生じるため、水素吸蔵合金の酸化量が多くな
る。この結果、このような構成の水素吸蔵合金を用いた
金属−水素アルカリ蓄電池のサイクル特性が低下すると
いう課題を有していた。However, the hydrogen storage alloy containing a large amount of manganese causes remarkable pulverization at the time of charge / discharge, so that the oxidation amount of the hydrogen storage alloy increases. As a result, there is a problem that the cycle characteristics of the metal-hydrogen alkaline storage battery using the hydrogen storage alloy having such a configuration are deteriorated.
【０００５】本発明は係る現状を考慮してなされたもの
であって、充放電時における水素吸蔵合金の微粉化を抑
制して、金属−水素アルカリ蓄電池のサイクル特性を飛
躍的に向上させることができる水素吸蔵合金電極の製造
方法を提供することを目的としている。SUMMARY OF THE INVENTION The present invention has been made in view of the present situation, and it is an object of the present invention to suppress the pulverization of a hydrogen storage alloy during charging and discharging and to dramatically improve the cycle characteristics of a metal-hydrogen alkaline storage battery. It is an object of the present invention to provide a method for manufacturing a hydrogen storage alloy electrode that can be used.
【０００６】[0006]
【発明を解決するための手段】上記目的を達成するため
に、本発明の水素吸蔵合金電極の製造方法は、少なくと
も希土類とＮｉ，Ｃｏ，Ｍｎ，Ａｌを含有し、Ｍｎの量
が水素吸蔵合金１molに対して１０mol％以下となるよう
に、水素吸蔵合金を構成する元素を溶融させ、溶湯を作
製する第１ステップと、溶湯を０．４℃／ｍｉｎ以下の
速度で冷却させる第２ステップと、を有することを特徴
とする。In order to achieve the above object, a method for producing a hydrogen storage alloy electrode according to the present invention comprises a method for producing a hydrogen storage alloy electrode comprising at least a rare earth element, Ni, Co, Mn, and Al, wherein the amount of Mn is reduced. A first step of melting the elements constituting the hydrogen storage alloy so as to be 10 mol% or less with respect to 1 mol to prepare a molten metal, and a second step of cooling the molten metal at a rate of 0.4 ° C./min or less. , Is characterized by having.
【０００７】[0007]
【作用】上記製造方法によれば、第１ステップで溶湯を
作る際に、溶湯中のＭｎの量が水素吸蔵合金１molに対
して１０mol％以下となるように規定している。また、
第２ステップで溶湯を０．４℃／ｍｉｎ以下のゆっくり
した冷却速度で冷却させる。このように製造された水素
吸蔵合金電極では、充放電時における水素吸蔵合金の微
粉化が抑制されて水素吸蔵合金の酸化量が低減するの
で、金属−水素アルカリ蓄電池のサイクル特性を飛躍的
に向上させることができる。水素吸蔵合金中のマンガン
含有量を規定することにより効果が生じる理由は以下の
とおりである。According to the above manufacturing method, when the molten metal is produced in the first step, the amount of Mn in the molten metal is specified to be 10 mol% or less based on 1 mol of the hydrogen storage alloy. Also,
In the second step, the molten metal is cooled at a slow cooling rate of 0.4 ° C./min or less. In the hydrogen storage alloy electrode manufactured in this way, since the pulverization of the hydrogen storage alloy during charging and discharging is suppressed and the amount of oxidation of the hydrogen storage alloy is reduced, the cycle characteristics of the metal-hydrogen alkaline storage battery are dramatically improved. Can be done. The reason why the effect is obtained by defining the manganese content in the hydrogen storage alloy is as follows.
【０００８】即ち、マンガンは、水素吸蔵合金の平衡圧
を下げるという効果を有しているので、水素吸蔵合金作
製時には不可欠な元素ではあるが、希土類を固溶しない
ため、ＣａＣｕ5型結晶格子中には入り難い。従って、
水素吸蔵合金にマンガンを含有させると、水素吸蔵合金
内でマンガンが偏析し易く、その結果この水素吸蔵合金
を用いた電池の充放電を繰り返すと、上記の偏析してい
る部分より割れが生じて、新たな反応面が出現しやす
い。そして、このように新たな反応面が出現すると、反
応面積が増大して、充放電効率が向上するようにも考え
られるが、マンガンはアルカリ電解液で溶解、酸化し易
い元素であるため、上記の如く新たな反応面が出現して
も、この反応面においてマンガンが溶解、酸化して、表
面が不活性となる。この結果、反応面積の増大を図るこ
とができず、充放電効率が低下して、サイクル特性が低
下することになる。しかし、Ｍｎは少量でも含有されて
いれば水素吸蔵合金の平衡圧を低下する効果を奏するの
で、水素吸蔵合金におけるＭｎの含有量を上記のように
小さく規定すれば、マンガンによる水素吸蔵合金の微粉
化を抑制してサイクル特性の低下を抑えながら、水素吸
蔵合金の平衡圧を下げることができる。Namely, manganese, since it has the effect of lowering the equilibrium pressure of hydrogen storage alloy, but at the time of making the hydrogen storage alloy is an essential element, because it does not form a solid solution of rare earth, CaCu 5 type crystal lattice It is hard to enter. Therefore,
When manganese is contained in the hydrogen storage alloy, manganese is easily segregated in the hydrogen storage alloy, and as a result, when charging and discharging of the battery using this hydrogen storage alloy are repeated, cracks are generated from the segregated portions described above. , A new reaction surface is likely to appear. Then, when such a new reaction surface appears, it is considered that the reaction area is increased and the charge / discharge efficiency is improved. However, since manganese is an element which is easily dissolved and oxidized in an alkaline electrolyte, Even when a new reaction surface appears, manganese dissolves and oxidizes on this reaction surface, and the surface becomes inactive. As a result, the reaction area cannot be increased, the charge / discharge efficiency is reduced, and the cycle characteristics are reduced. However, since the effect of lowering the equilibrium pressure of the hydrogen storage alloy is exhibited if Mn is contained even in a small amount, if the content of Mn in the hydrogen storage alloy is specified as small as described above, the fine powder of the hydrogen storage alloy by manganese is obtained. Thus, the equilibrium pressure of the hydrogen storage alloy can be reduced while suppressing the deterioration of the cycle characteristics by suppressing the formation of the alloy.
【０００９】また、第２ステップで溶湯を冷却した後、
水素吸蔵合金塊にアニール処理を施せば、水素吸蔵合金
の不均一歪みを更に小さくすることができる。そして、
アニール処理を施す場合、下記の実施例に示すように、
アニール時間は２時間以上とし、アニール温度は８００
〜１１００℃の範囲で行うことが望ましい。After cooling the molten metal in the second step,
If the hydrogen storage alloy ingot is subjected to an annealing treatment, the uneven strain of the hydrogen storage alloy can be further reduced. And
When performing the annealing treatment, as shown in the following example,
Annealing time is 2 hours or more and annealing temperature is 800
It is desirable to carry out in the range of １1100 ° C.
【００１０】[0010]
【実施例】本発明の一実施例を、図１〜図６に基づい
て、以下に説明する。 〔実施例〕図１は本発明の電極を用いた密閉円筒型ニッ
ケル−水素アルカリ蓄電池の断面図であり、焼結式ニッ
ケルから成る正極１と、水素吸蔵合金を含む負極２と、
これら正負両極１・２間に介挿されたセパレータ３とか
ら成る電極群４は渦巻状に巻回されている。この電極群
４は負極端子兼用の外装罐６内に配置されており、この
外装罐６と上記負極２とは負極用導電タブ５により接続
されている。上記外装罐６の上部開口にはパッキング７
を介して封口体８が装着されており、この封口体８の内
部にはコイルスプリング９が設けられている。このコイ
ルスプリング９は電池内部の内圧が異常上昇したときに
矢印Ａ方向に押圧されて内部のガスが大気中に放出され
るように構成されている。また、上記封口体８と前記正
極１とは正極用導電タブ１０にて接続されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view of a sealed cylindrical nickel-hydrogen alkaline storage battery using an electrode of the present invention, in which a positive electrode 1 made of sintered nickel, a negative electrode 2 containing a hydrogen storage alloy,
An electrode group 4 composed of the separator 3 interposed between the positive and negative electrodes 1 and 2 is spirally wound. The electrode group 4 is disposed in an outer can 6 also serving as a negative electrode terminal. The outer can 6 and the negative electrode 2 are connected by a negative electrode conductive tab 5. A packing 7 is provided at the upper opening of the outer can 6.
A sealing member 8 is mounted through the opening, and a coil spring 9 is provided inside the sealing member 8. The coil spring 9 is configured such that when the internal pressure inside the battery rises abnormally, it is pressed in the direction of arrow A and the gas inside is released to the atmosphere. The sealing body 8 and the positive electrode 1 are connected by a positive electrode conductive tab 10.
【００１１】ここで、上記構造の密閉円筒型ニッケル−
水素アルカリ蓄電池を、以下のようにして作製した。先
ず、市販のＭｍ（ミッシュメタルであって、希土類元素
の混合物）とＮｉとＣｏとＭｎとＡｌとを元素比で１：
３．４：０．９：０．３：０．４の割合となるように秤
量した後、高周波溶解炉内で溶解して溶湯を作成する。
次に、上記溶湯を０．４℃／min の速度で徐冷すること
により、ＭｍＮｉ3.4 Ｃｏ0.9 Ｍｎ0. 3 Ａｌ0.4 で示さ
れる水素吸蔵合金鋳塊を作成した。次に、この水素吸蔵
合金鋳塊の粒径が５０μｍ以下となるように粉砕した
後、この水素吸蔵合金粉末に結着剤を加えて混練し、更
にこの混合物に圧力を加えることにより負極２を作製し
た。Here, the sealed cylindrical nickel-
A hydrogen-alkaline storage battery was produced as follows. First, commercially available Mm (a misch metal, a mixture of rare earth elements), Ni, Co, Mn, and Al in an element ratio of 1:
After being weighed so as to have a ratio of 3.4: 0.9: 0.3: 0.4, it is melted in a high-frequency melting furnace to prepare a molten metal.
Next, the molten metal by slow cooling at a rate of 0.4 ° C. / min, to create a hydrogen storage alloy ingot represented by MmNi 3.4 Co 0.9 Mn 0. 3 Al 0.4. Next, after pulverizing the ingot of the hydrogen storage alloy so as to have a particle size of 50 μm or less, a binder is added to the hydrogen storage alloy powder, the mixture is kneaded, and pressure is applied to the mixture to form the negative electrode 2. Produced.
【００１２】次に、この負極２と、理論容量１０００mA
h の焼結式ニッケル正極１とを、不織布からなるセパレ
ータ３を介して巻回し、電極群４を作製した。しかる
後、この電極群４を外装罐６内に挿入し、更に３０重量
％のＫＯＨ水溶液を上記外装罐６内に注液した後、外装
罐６を密閉することにより理論容量１０００mAh の密閉
円筒型ニッケル−水素蓄電池を作製した。Next, the negative electrode 2 and a theoretical capacity of 1000 mA
h and the sintered nickel positive electrode 1 were wound through a nonwoven fabric separator 3 to form an electrode group 4. Thereafter, the electrode group 4 is inserted into the outer can 6, and a 30% by weight aqueous solution of KOH is injected into the outer can 6. Then, the outer can 6 is closed to form a closed cylindrical type having a theoretical capacity of 1000 mAh. A nickel-hydrogen storage battery was manufactured.
【００１３】このようにして作製した電池を、以下
（Ａ）電池と称する。 〔比較例〕市販のＭｍとＮｉとＣｏとＭｎとＡｌとを元
素比で１：３．２：０．７：０．９：０．２の割合とな
るように秤量する他は、上記実施例１と同様にして電池
を作製した。このようにして作製した電池を、以下
（Ｘ）電池と称する。 〔実験１〕上記本発明の（Ａ）電池及び比較例の（Ｘ）
電池におけるサイクル特性を調べたので、その結果を下
記表１に示す。尚、実験条件は、充電電流１Ｃで１．２
時間充電した後、１Ｃの電流で電池電圧が１Ｖまで放電
するという条件であり、電池容量が５００mAh （初期容
量の１／２）となったときを電池寿命とした。The battery fabricated in this manner is hereinafter referred to as (A) battery. [Comparative Example] The above procedure was followed except that commercially available Mm, Ni, Co, Mn, and Al were weighed in an elemental ratio of 1: 3.2: 0.7: 0.9: 0.2. A battery was produced in the same manner as in Example 1. The battery fabricated in this manner is hereinafter referred to as (X) battery. [Experiment 1] The battery (A) of the present invention and the battery (X) of the comparative example
The cycle characteristics of the battery were examined, and the results are shown in Table 1 below. The experimental conditions were as follows: charge current 1C, 1.2
After the battery was charged for 1 hour, the battery voltage was discharged to 1 V at a current of 1 C. The battery life was defined as when the battery capacity reached 500 mAh (1/2 of the initial capacity).
【００１４】[0014]
【表１】 上記表１より明らかなように、比較例の（Ｘ）電池で
は、サイクル寿命が８００回であるのに対して、本発明
の（Ａ）電池では、サイクル寿命１７５０回となってい
ることが認められる。そこで、本願出願人は、本発明の
（Ａ）電池が比較例の（Ｘ）電池に比べて優れていると
いう理由を検討すべく、以下のような実験を行った。 〔実験２〕上記本発明の（Ａ）電池に用いる水素吸蔵合
金及び比較例の（Ｘ）電池に用いられる水素吸蔵合金の
不均一歪の値について調べたので、その結果を表２に示
す。尚、不均一歪とは、以下のように定義される。 ・不均一歪の定義 ラウエカメラ等でデバイ環を測定した際、このデバイ環
がブロードになるという現象の原因の一つであって、下
記数１により定義される。[Table 1] As is clear from Table 1 above, the battery of the comparative example (X) had a cycle life of 800 times, whereas the battery (A) of the present invention had a cycle life of 1750 times. Can be Therefore, the applicant of the present application conducted the following experiment in order to examine the reason that the battery (A) of the present invention is superior to the battery (X) of the comparative example. [Experiment 2] The non-uniform strain values of the hydrogen storage alloy used for the battery (A) of the present invention and the hydrogen storage alloy used for the battery (X) of the comparative example were examined. The results are shown in Table 2. The non-uniform strain is defined as follows. -Definition of non-uniform distortion This is one of the causes of the phenomenon that the Debye ring becomes broad when the Debye ring is measured by a Laue camera or the like, and is defined by the following equation 1.
【００１５】[0015]
【数１】 (Equation 1)
【００１６】[0016]
【表２】 上記表２から明らかなように、本発明の（Ａ）電池に用
いる水素吸蔵合金は、比較例の（Ｘ）電池に用いられる
水素吸蔵合金より不均一歪の値が小さくなっていること
が認められる。このように、本発明の電池に用いる水素
吸蔵合金の不均一歪の値が小さくなるのは、希土類と固
溶しないＭｎ量が少ないということに起因しているもの
と考えられる。[Table 2] As is clear from Table 2 above, the hydrogen storage alloy used for the battery (A) of the present invention has a smaller value of the non-uniform strain than the hydrogen storage alloy used for the battery (X) of the comparative example. Can be The reason why the value of the non-uniform strain of the hydrogen storage alloy used for the battery of the present invention is small is considered to be due to the fact that the amount of Mn that does not form a solid solution with the rare earth is small.
【００１７】そして、このように水素吸蔵合金の不均一
歪の値が小さくなれば、充放電を繰り返し行う場合にお
ける微粉化が抑制されるので、実験１に示す如くサイク
ル特性が向上するものと考えられる。 〔実験３〕 水素吸蔵合金の不均一歪の値と水素吸蔵合金を用いた電
池のサイクル特性との関係を調べたので、その結果を図
２に示す。尚、充放電条件は前記実験１で示す条件と同
様の条件である。It is considered that when the value of the non-uniform strain of the hydrogen storage alloy is reduced as described above, the pulverization during repeated charging and discharging is suppressed, and the cycle characteristics are improved as shown in Experiment 1. Can be [Experiment 3] The relationship between the value of the non-uniform strain of the hydrogen storage alloy and the cycle characteristics of the battery using the hydrogen storage alloy was examined, and the results are shown in FIG. The charge and discharge conditions were the same as those shown in Experiment 1.
【００１８】図２より明らかなように、不均一歪の値が
５．４×１０-3未満であるとサイクル特性が向上し、特
に３．０×１０-3以下であると飛躍的に向上することが
認められる。したがって、不均一歪の値は５．４×１０
-3未満であることが必要であり、特に３．０×１０-3以
下であることが望ましい。 〔実験４〕前記実験１で示す如く、水素吸蔵合金の不均
一歪の値を小さくするには、水素吸蔵合金中のＭｎ量の
割合を減少させればよいということが判明した。そこ
で、水素吸蔵合金中のＭｎ量の割合と水素吸蔵合金の不
均一歪の値との関係を調べたので、その結果を図３に示
す。尚、この場合の水素吸蔵合金鋳塊の冷却速度は０．
４℃／min で行った。As is apparent from FIG. 2, the cycle characteristics are improved when the value of the non-uniform strain is less than 5.4 × 10 −3 , and particularly, when the value is 3.0 × 10 −3 or less, the cycle characteristics are dramatically improved. Is allowed to do so. Therefore, the value of the non-uniform distortion is 5.4 × 10
It is necessary to be less than -3 , particularly desirably 3.0 × 10 -3 or less. [Experiment 4] As shown in Experiment 1, it was found that the value of the Mn content in the hydrogen storage alloy should be reduced in order to reduce the value of the non-uniform strain of the hydrogen storage alloy. Then, the relationship between the ratio of the amount of Mn in the hydrogen storage alloy and the value of the non-uniform strain of the hydrogen storage alloy was examined, and the results are shown in FIG. In this case, the cooling rate of the hydrogen-absorbing alloy ingot was set at 0.1.
The test was performed at 4 ° C./min.
【００１９】図３より明らかなように、Ｍｎの割合が水
素吸蔵合金１molに対して１０mol％以下であれば不均一
歪の値が小さくなることが認められる。 〔実験５〕 本願出願人は、Ｍｎの割合を減少させる以外に不均一歪
の値を小さくする方法を調べるべく、各種の実験を行っ
たところ、以下に示す２つの方法により、不均一歪みを
小さくすることができることを見出した。水素吸蔵合
金溶湯の冷却速度を小さくする。水素吸蔵合金金塊に
アニール処理を施す。As is apparent from FIG. 3, when the ratio of Mn is 10 mol% or less with respect to 1 mol of the hydrogen storage alloy, the value of the non-uniform strain is reduced. [Experiment 5] The present applicant conducted various experiments in order to investigate a method of reducing the value of the non-uniform strain in addition to reducing the ratio of Mn, and found that the non-uniform strain was reduced by the following two methods. I found that it can be made smaller. Reduce the cooling rate of the hydrogen storage alloy melt. Anneal the hydrogen storage alloy ingot.
【００２０】そこで、本実験５においては水素吸蔵合金
溶湯の冷却速度と不均一歪の値との関係を調べ、下記実
験６及び実験７においては、それぞれ、アニール処理の
温度と不均一歪の値との関係及びアニール処理の時間と
不均一歪の値との関係を調べた。尚、本実験では、水素
吸蔵合金としてＭｍＮｉ3.4 Ｃｏ0.8 Ｍｎ0.6 Ａｌ0.2
（即ち、Ｍｎの割合は10mol%のもの）を用い、且つその
結果を図４に示す。Therefore, in Experiment 5, the relationship between the cooling rate of the hydrogen-absorbing alloy melt and the value of the non-uniform strain was examined. In Experiments 6 and 7, the annealing temperature and the value of the non-uniform strain were measured, respectively. And the relationship between the annealing time and the value of the non-uniform strain were examined. In this experiment, MmNi 3.4 Co 0.8 Mn 0.6 Al 0.2 was used as the hydrogen storage alloy.
(That is, the ratio of Mn is 10 mol%), and the results are shown in FIG.
【００２１】図４より明らかなように、冷却速度が０．
４℃／min 以下であれば、不均一歪の値が５．４×１０
-3未満となっていることが認められ、特に冷却速度が
０．２℃／min 以下であれば、不均一歪の値が極めて小
さくなることが認められる。したがって、水素吸蔵合金
鋳塊の冷却速度は０．４℃／min 以下であることが必要
であり、特に０．２℃／min 以下であることが望まし
い。 〔実験６〕アニール処理の温度と不均一歪の値との関係
を調べたので、その結果を図５に示す。尚、その他の条
件は以下の通りである。 ・水素吸蔵合金：ＭｍＮｉ3.4 Ｃｏ0.8 Ｍｎ0.6 Ａｌ
0.2 ・水素吸蔵合金溶湯の冷却速度：０．４℃／min ・アニール時間：２４ｈｒ 図５から明らかなように、アニール処理の温度が８００
〜１１００℃の間で不均一歪の値が極めて小さくなって
いることが認められる。したがって、水素吸蔵合金鋳塊
にアニール処理を施す場合には、８００〜１１００℃の
間で処理するのが好ましい。 〔実験７〕アニール処理の時間と不均一歪の値との関係
を調べたので、その結果を図６に示す。尚、その他の条
件は以下の通りである。 ・水素吸蔵合金：ＭｍＮｉ3.4 Ｃｏ0.8 Ｍｎ0.6 Ａｌ
0.2 ・水素吸蔵合金溶湯の冷却速度：０．４℃／min ・アニール温度：１０００℃ 図６から明らかなように、アニール処理の時間が２時間
以上であれば不均一歪の値が極めて小さくなっているこ
とが認められる。したがって、水素吸蔵合金鋳塊にアニ
ール処理を施す場合には、２時間以上処理するのが好ま
しい。 〔その他の事項〕上記実施例においては、水素吸蔵合
金としてＭｍＮｉ3.4 Ｃｏ0.9 Ｍｎ0.3 Ａｌ0.4 等を用
いているが、これに限定するものではなく、その他の希
土類系水素吸蔵合金、Ｔｉ系水素吸蔵合金、アルカリ土
類系水素吸蔵合金等であっても同様の効果を有すること
を確認している。 本発明は上記円筒型の蓄電池に限定するものではな
く、偏平型の蓄電池であっても同様の効果を有する。As is apparent from FIG.
If it is 4 ° C./min or less, the value of the non-uniform strain is 5.4 × 10
It is recognized that the value is less than −3 , and particularly when the cooling rate is 0.2 ° C./min or less, the value of the non-uniform strain becomes extremely small. Therefore, the cooling rate of the hydrogen storage alloy ingot needs to be 0.4 ° C./min or less, particularly preferably 0.2 ° C./min or less. [Experiment 6] The relationship between the annealing temperature and the value of the non-uniform strain was examined, and the results are shown in FIG. The other conditions are as follows.・ Hydrogen storage alloy: MmNi 3.4 Co 0.8 Mn 0.6 Al
0.2. Cooling rate of hydrogen storage alloy melt: 0.4 ° C./min. Annealing time: 24 hr. As is clear from FIG.
It is recognized that the value of the non-uniform strain is extremely small between 〜1100 ° C. Therefore, when performing an annealing treatment on the hydrogen storage alloy ingot, it is preferable to perform the treatment at a temperature of 800 to 1100 ° C. [Experiment 7] The relationship between the annealing time and the value of the non-uniform strain was examined, and the results are shown in FIG. The other conditions are as follows.・ Hydrogen storage alloy: MmNi 3.4 Co 0.8 Mn 0.6 Al
0.2. Cooling rate of hydrogen storage alloy: 0.4 ° C./min. Annealing temperature: 1000 ° C. As is clear from FIG. 6, if the annealing time is 2 hours or more, the value of the non-uniform strain becomes extremely small. Is recognized. Therefore, when performing an annealing treatment on the hydrogen storage alloy ingot, the treatment is preferably performed for 2 hours or more. [Other Matters] In the above embodiment, MmNi 3.4 Co 0.9 Mn 0.3 Al 0.4 or the like is used as the hydrogen storage alloy. However, the present invention is not limited to this. Other rare earth hydrogen storage alloys, Ti based hydrogen storage It has been confirmed that alloys, alkaline earth hydrogen storage alloys and the like have the same effect. The present invention is not limited to the cylindrical storage battery, and the same effect can be obtained even with a flat storage battery.
【００２２】[0022]
【発明の効果】以上説明したように本発明によれば、水
素吸蔵合金の微粉化が抑制されて、水素吸蔵合金の酸化
量が低減するので、このような水素吸蔵合金を用いた電
池のサイクル特性を飛躍的に向上させることができると
いった効果を奏する。As described above, according to the present invention, since the pulverization of the hydrogen storage alloy is suppressed and the oxidation amount of the hydrogen storage alloy is reduced, the cycle of the battery using such a hydrogen storage alloy is reduced. This has the effect of dramatically improving the characteristics.
【図１】本発明の一実施例に係る水素吸蔵合金電極を用
いた金属−水素アルカリ蓄電池の断面図である。FIG. 1 is a cross-sectional view of a metal-hydrogen alkaline storage battery using a hydrogen storage alloy electrode according to one embodiment of the present invention.
【図２】不均一歪の値とサイクル数との関係を示すグラ
フである。FIG. 2 is a graph showing a relationship between a value of a non-uniform strain and the number of cycles.
【図３】ＭＨ中のＭｎの割合と不均一歪の値との関係を
示すグラフである。FIG. 3 is a graph showing the relationship between the ratio of Mn in MH and the value of non-uniform strain.
【図４】水素吸蔵合金の冷却速度と不均一歪の値との関
係を示すグラフである。FIG. 4 is a graph showing a relationship between a cooling rate of a hydrogen storage alloy and a value of non-uniform strain.
【図５】アニール温度と不均一歪の値との関係を示すグ
ラフである。FIG. 5 is a graph showing a relationship between an annealing temperature and a value of non-uniform strain.
【図６】アニール時間と不均一歪の値との関係を示すグ
ラフである。FIG. 6 is a graph showing a relationship between an annealing time and a value of non-uniform strain.
１ 正極 ２ 負極 ３ セパレータ 1 positive electrode 2 negative electrode 3 separator
───────────────────────────────────────────────────── フロントページの続き (72)発明者 近野 義人 守口市京阪本通２丁目18番地 三洋電機 株式会社内 (72)発明者 松浦 義典 守口市京阪本通２丁目18番地 三洋電機 株式会社内 (72)発明者 西尾 晃治 守口市京阪本通２丁目18番地 三洋電機 株式会社内 (72)発明者 古川 修弘 守口市京阪本通２丁目18番地 三洋電機 株式会社内 (56)参考文献 特開 昭57−63670（ＪＰ，Ａ) 特開 昭57−101631（ＪＰ，Ａ) 特開 平２−223150（ＪＰ，Ａ) 特開 昭61−19062（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/24 - 4/26 H01M 4/38 C22C 1/00 C22C 19/00 - 19/03 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshito Chino 2-18-18 Keihanhondori Moriguchi City Sanyo Electric Co., Ltd. (72) Inventor Yoshinori Matsuura 2-18-18 Keihanhondori Moriguchi City Sanyo Electric Co., Ltd. ( 72) Inventor Koji Nishio 2--18 Keihanhondori, Moriguchi-shi Sanyo Electric Co., Ltd. (72) Inventor Nobuhiro Furukawa 2-18-18 Keihanhondori, Moriguchi-shi Sanyo Electric Co., Ltd. (56) References JP Sho 57 JP-A-63670 (JP, A) JP-A-57-101631 (JP, A) JP-A-2-223150 (JP, A) JP-A-61-19062 (JP, A) (58) Fields investigated (Int. . 7, DB name) H01M 4/24 - 4/26 H01M 4/38 C22C 1/00 C22C 19/00 - 19/03
Claims (2)
Ａｌとを含有し、前記Ｍｎの量が水素吸蔵合金１molに
対して１０mol％以下となるように、水素吸蔵合金を構
成する元素を溶融させ、溶湯を作製する第１ステップ
と、 上記溶湯を０．４℃／ｍｉｎ以下の速度で冷却させる第
２ステップと、 を有することを特徴とする水素吸蔵合金電極の製造方
法。 (1) at least a rare earth and Ni, Co, Mn,
A first step of melting an element constituting the hydrogen storage alloy so that the amount of the Mn is 10 mol% or less with respect to 1 mol of the hydrogen storage alloy, the first step of preparing a molten metal; A second step of cooling at a rate of 4 ° C./min or less, and a method for producing a hydrogen storage alloy electrode.
合金をアニール処理する第３ステップを有することを特
徴とする請求項１記載の水素吸蔵合金電極の製造方法。 2. The method for producing a hydrogen storage alloy electrode according to claim 1, further comprising a third step of annealing the hydrogen storage alloy cooled in the second step.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3277530A JP3071003B2 (en) | 1991-10-24 | 1991-10-24 | Hydrogen storage alloy electrode and method for producing the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3277530A JP3071003B2 (en) | 1991-10-24 | 1991-10-24 | Hydrogen storage alloy electrode and method for producing the same |
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| Publication Number | Publication Date |
|---|---|
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| JP3071003B2 true JP3071003B2 (en) | 2000-07-31 |
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| JP4183959B2 (en) | 2002-03-22 | 2008-11-19 | 株式会社日本製鋼所 | Method for producing hydrogen storage alloy |
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