JPH09283174A - Alkaline storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alkaline storage battery in which preservation characteristics are superior, and battery characteristics are stable for a long period by suppressing the elution of the negative electrode hydrogen storage alloy into alkaline electrolyte, and also suppressing the elution of metal compounds. SOLUTION: An alkaline storage battery is composed of a positive electrode mainly composed of metal oxide, a negative electrode mainly composed of hydrogen storage alloy, a separator, and alkaline electrolyte. In the alkaline storage battery at least one among ions mainly composed of Ti, Nb, Cr, Al and/or their complexes is contained in the alkaline electrolyte, or at least one among the above mentioned ones and/or compounds mainly composed of them is contained in battery constituting elements.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an alkaline storage battery,
In particular, the present invention relates to a metal oxide / hydrogen alkaline storage battery using a hydrogen storage alloy for the negative electrode.

[0002]

2. Description of the Related Art Alkaline storage batteries having a hydrogen storage alloy as a negative electrode and a metal oxide such as nickel oxide as a positive electrode have already been proposed. Compared with the conventional sealed nickel-cadmium storage battery, etc., this battery was mainly found to have a deterioration in life characteristics such as a decrease in capacity when used for a long time at high temperature. In order to improve this life characteristic, for example, JP-A-3-
Various proposals have been made in Japanese Patent No. 155049.

[0003]

However, in addition to the life characteristics, the conventional alkaline storage battery described above has a problem that the capacity of the battery decreases when it is stored for a long time in an unused state, particularly when stored at high temperature for a long time. was there.

This is because the constituent elements in the hydrogen storage alloy of the negative electrode are eluted in the alkaline electrolyte and the metallic compounds such as Co added to the positive electrode for the purpose of improving the utilization rate are eluted. It was found from the analysis of the storage-aged battery that the elution reaction was positive and hindered the electrode reaction of the negative electrode, resulting in a decrease in battery capacity. Therefore, in order to improve the characteristics such as the capacity maintenance of the battery during storage, it is necessary to suppress not only elution from the negative electrode but also elution from the positive electrode.

The present invention solves the above-mentioned problems and provides an alkaline storage battery capable of exhibiting stable battery characteristics over a long period of time by suppressing a decrease in capacity during battery storage.

[0006]

To achieve this object, the present invention provides a positive electrode containing a metal oxide as a main constituent material,
A negative electrode containing a hydrogen storage alloy as a main constituent material, a separator, and an alkaline electrolyte. At least one kind of ions of Ti, Nb, Cr, and Al and / or a complex thereof is contained in the alkaline electrolyte. Is included. In addition, Ti, Nb, Cr,
It contains at least one of Al and / or at least one of compounds mainly containing them.

[0007] As a result, it is possible to prevent the components in the hydrogen storage alloy of the negative electrode and the metal compounds added to the positive electrode from being eluted in the alkaline electrolyte, which was not sufficient in the conventional method, so It is possible to obtain a metal oxide / hydrogen alkaline storage battery having excellent characteristics and exhibiting stable battery characteristics over a long period of time.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is one in which at least one kind of ions of Ti, Nb, Cr and Al and / or their complexes is contained in an alkaline electrolyte. It is an object of the present invention to provide an alkaline storage battery capable of exhibiting stable battery characteristics over a long period of time by suppressing the elution of electrode constituent components into an alkaline electrolyte and suppressing the capacity decrease during battery storage.

Further, the invention according to claim 2 of the present invention provides:
Ti, Nb, Cr, Al is contained in a battery constituent member including a positive electrode containing a metal oxide as a main constituent material, a negative electrode containing a hydrogen storage alloy as a main constituent material, a separator, and an alkaline electrolyte.
At least one and / or this Ti, N
It contains at least one of compounds containing b, Cr, or Al as a main component, and also suppresses a decrease in capacity during battery storage, and can exhibit stable battery characteristics over a long period of time. It provides an alkaline storage battery.

[0010]

Next, specific examples of the present invention will be described.

(Example 1) As a hydrogen storage alloy, Mm
Using Ni ₅ based hydrogen storage alloy. Mm (Mm is La, C
mixture of rare earth elements including e, Nd, Sm) and N
i, Mn, Al and Co are weighed and mixed at a constant composition ratio,
The composition formula MmNi3.9Mn0.3Al0.
An alloy of 3Co0.5 was prepared. After finely pulverizing the hydrogen storage alloy to an average particle size of 30 μm, the alloy powder is kneaded with an aqueous solution of polyvinyl alcohol (PVA) which is a binder to form a paste, which is then filled in a foamed nickel porous body to obtain an AA size Battery dimensions (39 mm x 75 mm x 0.7 mm)
Then, it was pressed and cut to obtain a hydrogen storage alloy electrode.

Then, this hydrogen storage alloy electrode was combined with a known foam metal type nickel positive electrode to prepare an AA size sealed nickel-hydrogen alkaline storage battery having a nominal capacity of 1200 mAh according to the positive electrode capacity regulation.

Here, the negative electrode containing 2% by weight of Ti powder was in the battery A, the Ti powder dispersed in alcohol was sprayed on the separator, and 2% by weight of the Ti powder was attached to the battery B, the positive electrode. Battery C contained 2% by weight of Ti powder, and battery D contained 0.1% by weight of ionized Ti in the electrolytic solution.

Further, except that Ti is not added to the battery,
A battery having the same structure as that of the present invention was manufactured and used as a comparative battery E.

Next, a storage test was conducted using each of these batteries. In the storage test, the battery in a discharged state was stored for one month at a high temperature of 65 ° C., and the change in the battery capacity before and after storage was evaluated. Battery capacity is evaluated at a constant temperature of 20 ° C.
Charged at 0.1 CmA for 15 hours and discharged at 0.2 Cm
The final voltage was raised to 0.8 V with A, and the discharge capacity at this time was measured and taken as the battery capacity.

FIG. 1 shows the storage test results as the capacity recovery rate (recovery rate (%) = capacity after storage / capacity before storage × 100).

As can be seen from the results of FIG. 1, the battery A of the present invention is 93%, the battery B is 91%, the battery C is 94%, and the battery D is
Shows a recovery rate of 90% or more, which is 95%.

On the other hand, the comparative battery E had a recovery rate of 80%. As a result of analyzing the storage characteristics of the nickel-metal hydride storage battery, the negative electrode capacity decreases due to the elution of the metal elements that compose the negative electrode alloy, and the negative electrode eluate reaching the positive electrode inhibits the positive electrode reaction, and also improves the positive electrode utilization rate. Therefore, it was found that the added compound containing Co as a main component was eluted in the electrolytic solution and the initial utilization ratio could not be maintained, which was the main cause of the capacity decrease after storage. That is, in any case, it was found that the chemical dissolution reaction from the positive and negative electrodes was the main factor of the deterioration of the storage characteristics.

In the batteries containing Ti as in the batteries A to D of the present invention, the Ti ions present in the alkaline electrolyte are positive,
It is thought that the dissolution reaction of the negative electrode was suppressed more effectively than the comparative battery, and as a result, the storage characteristics of the battery were improved.

(Example 2) In this example, a battery F containing 2% by weight of Nb powder in a negative electrode alloy electrode was sprayed with a liquid in which alcohol of Nb powder was dispersed on a separator to deposit 2% by weight of Nb powder. Battery G, 2 Nb powder in the positive electrode
Battery H containing wt%, N ionized with respect to the electrolytic solution
A battery I containing b in an amount of 0.1% by weight was prepared in the same manner as in Example 1, except that the AA having a nominal capacity of 1200 mAh regulated by the positive electrode capacity.
A size sealed nickel-hydrogen alkaline storage battery was created.

FIG. 2 shows the results of a storage test conducted on the batteries F to I prepared in this example and the conventional example E in the same manner as in Example 1.

From the results shown in FIG. 2, the battery F of this embodiment is 92
%, G was 96%, H was 95%, and I was 95%, all showing excellent recoverability of 90% or more.

As in Example 1, the batteries containing Nb of the batteries F to I of this example were stored because the Nb ions in the alkaline electrolyte can effectively suppress the dissolution reaction from the positive and negative electrodes. It is considered that the characteristics have improved.

(Embodiment 3) In this embodiment, battery J containing 2 wt% of Cr powder in the negative electrode alloy electrode and a liquid in which Cr powder was dispersed in alcohol were sprayed on the separator to deposit 2 wt% of Cr powder. Battery K, 2 Cr powder in the positive electrode
Battery L containing wt%, C ionized with respect to the electrolytic solution
A battery M containing 0.1% by weight of r was prepared in the same manner as in Example 1, except that an AA having a nominal capacity of 1200 mAh regulated by the positive electrode capacity was obtained.
A size sealed nickel-hydrogen alkaline storage battery was created.

FIG. 3 shows the results of a storage test conducted on the batteries J to M prepared in this example and the conventional example E in the same manner as in the example 1.

From the result of FIG. 3, the battery J of this embodiment is 97
%, K was 94%, L was 96%, and M was 93%, all showing a recoverability of 90% or more.

Also in this case, as in the previous embodiment, in the batteries containing Cr of the batteries J to M of this embodiment, the Cr ion in the alkaline electrolyte can effectively suppress the dissolution reaction from the positive and negative electrodes. It is thought that the storage characteristics have improved.

Example 4 In this example, a battery N containing 2% by weight of Al powder in a negative electrode alloy electrode and a liquid in which Al powder was dispersed in alcohol were sprayed on a separator to deposit 2% by weight of Al powder. Battery O, 2 Al powder in the positive electrode
Battery P containing wt%, A ionized with respect to the electrolyte
A battery Q containing 0.1% by weight of 1 was used for each of AA having a nominal capacity of 1200 mAh regulated by the positive electrode capacity in the same manner as in Example 1.
A size sealed nickel-hydrogen alkaline storage battery was created.

FIG. 4 shows batteries N to Q prepared in this embodiment,
The result of carrying out a storage test on Conventional Example E as in Example 1 is shown.

From the result of FIG. 4, the battery N of this embodiment is 97.
%, O was 94%, P was 94%, and Q was 95%, all showing a recoverability of 90% or more.

Also in this case, as in the previous embodiment, in the batteries containing Al of the batteries N to Q of this embodiment, Al ions in the alkaline electrolyte can effectively suppress the dissolution reaction from the positive and negative electrodes. It is thought that the storage characteristics have improved.

The above is the embodiment of the present invention, but the effect of the present invention can be obtained if the alkaline electrolyte contains at least one of ions mainly containing Ti, Nb, Cr and Al.
Two or more of these ions may be present. With this configuration, specifically, for example, the Ti compound forms at least a part thereof in an alkaline electrolyte to form a titanate ion and / or a titanium complex, and the Nb compound forms at least an alkali electrolyte in the alkaline electrolyte. Part of which forms a niobate ion and / or niobium complex, said Cr compound is at least part of which forms a chromate ion and / or chromium complex in an alkaline electrolyte, and said Al compound is Those that form aluminate ions and / or aluminum complexes at least partially in the alkaline electrolyte have a high effect of improving the storage characteristics.

Ti, Nb, C in the alkaline electrolyte
At least one of r, an ion containing Al as a main component, and / or a complex is 10 to 1000 relative to the alkaline electrolyte.
It is preferable to contain 0 ppm from the viewpoint of improving the characteristics.

It has also been found that the present invention improves the characteristics during high temperature storage and at the same time improves the charging efficiency at high temperatures.

The hydrogen storage alloy has the composition ratio MmNi3.90Mn0.3Al0.3Co0.5 shown in this embodiment.
AB ₅ type alloy having a CaCu ₅ structure as represented by 0 or a composition ratio of ZrMn0.3V0.2Cr
From the characteristics, it is desirable that the material is an AB ₂ alloy having a Laves phase structure represented by 0.2Ni1.3.

Further, in the above embodiment, an example of a sealed alkaline storage battery was shown, but it was found that an open type alkaline storage battery has the same excellent effect.

[0037]

A positive electrode containing a metal oxide as a main constituent material,
In an alkaline storage battery comprising a negative electrode containing a hydrogen storage alloy as a main constituent material, a separator, and an alkaline electrolyte, at least one of ions and / or complexes mainly containing Ti, Nb, Cr, and Al in the alkaline electrolyte. In terms of constitution, at least one of the battery constitutions described above contains at least one of Ti, Nb, Cr, and Al alone, or at least one of compounds mainly containing Ti, Nb, Cr, and Al. Suppressing the elution of the hydrogen storage alloy in the negative electrode and the elution of metal compounds added to the positive electrode, which was not sufficient with the conventional method, by using an alkaline storage battery characterized by having Therefore, a metal oxide / hydrogen alkaline storage battery having excellent storage characteristics and stable battery characteristics for a long period of time can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing storage test results of batteries A to D prepared in this example and a conventional example E.

FIG. 2 is a diagram showing storage test results of batteries F to I prepared in this example and a conventional example E.

FIG. 3 is a diagram showing storage test results of batteries J to M and a conventional example E prepared in this example.

FIG. 4 is a diagram showing storage test results of batteries N to Q and a conventional example E created in this example.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Kaitani 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (12)

[Claims] 1. A positive electrode containing a metal oxide as a main constituent material, a negative electrode containing a hydrogen storage alloy as a main constituent material, and a separator.
An alkaline storage battery comprising an alkaline electrolyte, characterized in that the alkaline electrolyte contains at least one ion of Ti, Nb, Cr, and / or a complex thereof. . 2. A positive electrode containing a metal oxide as a main constituent material, a negative electrode containing a hydrogen storage alloy as a main constituent material, and a separator.
An alkaline storage battery including an alkaline electrolyte, wherein at least one of Ti, Nb, Cr, and Al and / or at least one of compounds containing them as a main component is contained in each of the battery constituent elements. An alkaline storage battery characterized by containing. 3. The alkaline storage battery according to claim 1, wherein the compound of Ti forms an ion, a titanate ion, and / or a titanium complex in an alkaline electrolyte. 4. The alkaline storage battery according to claim 1, wherein the compound of Nb forms an ion, a niobate ion, and / or a niobium complex in an alkaline electrolyte. 5. The alkaline storage battery according to claim 1, wherein the Cr compound forms an ion, a chromate ion, and / or a chromium complex in an alkaline electrolyte. 6. The alkaline storage battery according to claim 1, wherein the Al compound forms an ion, an aluminate ion, and / or an aluminum complex in an alkaline electrolyte. 7. The T contained in each of the battery constituent elements.
The amount of i, Nb, Cr, Al or a compound mainly containing these is 10 to 10,000 p with respect to the alkaline electrolyte.
It is pm, The alkaline storage battery in any one of Claims 2-6. 8. T contained in the alkaline electrolyte
An ion mainly composed of i, Nb, Cr, or Al,
The amount of at least 1 of this and / or its complex is 10-10000 ppm with respect to an alkaline electrolyte, The alkaline storage battery in any one of Claims 1-6. 9. T in the complex of Ti, Nb, Cr, Al or a compound mainly composed of Ti, Nb, Cr, Al.
The alkaline storage battery according to claim 1, wherein the oxidation numbers of i, Nb, Cr, and Al are divalent, trivalent, or tetravalent. 10. The main alloy phase of the hydrogen storage alloy is Ca.
An AB ₅ series alloy having a Cu ₅ structure or an AB ₂ series alloy having a Laves phase structure.
The alkaline storage battery according to any one of 1. 11. The AB ₅ type alloy has a general formula of MmNi.
_XYZ Co _Y M _Z (in the formula, 4.8 ≦ X ≦ 5.2, 0 <Y ≦
2.0,0 <Z ≦ 1.5, M is Mn, Al, C
r, Fe, Cu, Sn, Sb, Mo, V, Nb, Ta,
At least one of Zn, Mg, Zr, and Ti,
Mm represents a mixture of at least three or more rare earth metals), and the La content in the alloy is 5
The alkaline storage battery according to claim 10, which is ˜25 wt%. 12. The AB ₂ -based alloy has the general formula ABα (wherein A is Zr alone or 30 atomic% or less of Ti and H).
f, Ta, Y, Ca, Mg, La, Ce, Nd, Nb,
Zr and B containing Mo, Al and Si are Ni and Mg and C
a, Ti, Hf, V, Nb, Cr, Mo, Mn, Fe,
Co, Pd, Cu, Ag, Zn, Cd, Al, Si, L
a, Ce, Pr, Nd, at least one element selected from the group consisting of α = 15 to 2.5, A and B are different elements, and the alloy phase substantially belongs to the Laves phase of the intermetallic compound. , Its crystal structure is at least one of hexagonal symmetric C14 type and cubic symmetric C15 type, and its lattice constant is C14.
In the case of the mold, a = 4.8 to 5.2Å, c = 7.9 to 8.3
11. The alkaline storage battery according to claim 10, wherein a = 6.92 to 7.30Å in the case of C15 type.