JP2713881B2 - Sealed metal oxide / hydrogen battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention]   The present invention uses a metal oxide as a positive electrode active material and hydrogen as a negative electrode active material.
Materials, so-called metal oxide / hydrogen secondary batteries
More specifically, the hydrogen anode is made of a hydrogen storage alloy.
The internal pressure of the battery is kept low, self-discharge is suppressed,
In addition, gold that exhibits its performance from the beginning and maintains a long life
The present invention relates to a metal oxide-hydrogen battery. [Technical background of the invention and its problems]   Currently, in metal oxide / hydrogen batteries, the hydrogen anode is
Attention has been paid to those made of elemental storage alloys.
The reason is that this battery system originally has a high energy density.
And is advantageous in terms of volumetric efficiency, and safe operation is possible.
This is because it is excellent both in characteristics and reliability.
You.   The hydrogen storage alloy used for the hydrogen anode of this type of battery
Conventionally, LaNi_FiveIs often used. Also, La, C
Missis, which is a mixture of lanthanide elements such as e, Pr, Nd, and Sm
Alloy of nickel (hereinafter referred to as Mm) and Ni,
MmNi_FiveIs also widely used. In addition, LaCo_Five, SmCo_FiveSuch
Alloys of rare earth elements with Co are often used.   When such a hydrogen storage alloy is used, the internal pressure of the battery
Is the internal pressure of the battery not using a hydrogen storage alloy (50kg / cm^TwoLess than
It is true that it is lower than that of (bottom). Only
However, its value is still 2-5 kg /
cm^TwoDegree, for example, nickel cadmium battery
Pressure (0-1kg / cm^Two) Is higher than that of   If the internal pressure of the battery is higher than the atmospheric pressure,
Along with the need to make the structure somewhat robust
Then, the following inconveniences are caused characteristically. No.
The first problem is that the hydrogen molecule in the battery has a small molecular diameter,
Therefore, it is inevitable that the battery leaks gradually from the battery container.
And seriously impairs security: The second problem is
As a result of the phenomenon (1), the stored hydrogen is released from the hydrogen negative electrode.
The battery capacity is reduced and self-discharge is caused.   Therefore, the equilibrium plateau pressure is applied to the hydrogen anode.
It has been proposed to use low hydrogen storage alloys,
Research on gold is underway.   For example, LaNi_Five, MmNi_FiveAs for, at room temperature
Each equilibrium plateau pressure is as high as 3 atm and 15 atm
Therefore, in batteries using these as the negative electrode material,
Inconveniences such as deterioration of integrity and self-discharge occur.   On the other hand, even if this equilibrium plateau pressure is low,
A hydrogen storage alloy with a small amount of hydrogen
The following problems are caused in the battery. First,
In addition, since the hydrogen storage capacity is small, the rechargeable battery capacity is small.
When it comes to: Secondly, because the charging capacity is small, it becomes overcharged
Gaseous hydrogen as a result
That is. Hydrogen generation during overcharge also increases in battery pressure
Because it hurts, it impairs battery safety.   Considering the above points, as a material for the hydrogen anode,
Is water with a low equilibrium plateau pressure and a large hydrogen storage capacity.
It may be desirable to use an elemental storage alloy.   For example, LaCo, a known hydrogen storage alloy_Five, LaNi_1.5Co_3.5
The equilibrium plateau pressure around room temperature was 0.1 atm and 0.2 atm, respectively.
Pressure but low, but can be stored below 3 atm
The quantity is LaNi_Five(H.H.Van Mal, K, H.J.Bus
chow and F.A.Kuijpers, J. Less-Common Metals, 32,289
(1973)). Therefore, in batteries using these as the negative electrode material,
The problem is that the capacity is small and
Occurs.   It has already been used as a material for hydrogen storage alloy electrodes.
La-Ni-Co alloys (J.J.G.Willems, Philps
 J. Res,39, 1 (1984)) and Mm-Ni-Co alloys
Is compared to the previous La-Ni-Mn-based alloy and Mm-Ni-Mn-based alloy.
It is possible to further reduce the equilibrium plateau pressure
However, it is said that this type of alloy does not have sufficient hydrogen storage capacity.
Had problems.   As described above, the electrode material of the battery has a large hydrogen storage capacity.
And low equilibrium plateau pressure are both required
However, there is no conventional electrode with both of these,
Means that the capacity decrease during repeated charge and discharge is small.
Such long life characteristics are also required. This is a large hydrogen storage capacity
Using a hydrogen storage alloy with low equilibrium plateau pressure
Configure the electrodes and charge and discharge in an alkaline aqueous solution that is an electrolyte.
When repeated, initially a large capacity is retained and water
Even if no element generation is observed, the charge
If the life of the pond will be exhausted, there will be significant restrictions on its use
Is added. For example, MmNi_4.5Mn_0.5And Mn
Ni_4.2Mn_0.8Alloys that have been used more than ever
For an electrode made of a negative electrode material, the charge capacity is initially 100%.
% Discharge is possible, but 8 times in about 100 charge / discharge cycles.
The capacity decreases to 0%, and to 50% after about 150 operations. this is
Water as negative electrode material for charge and discharge cycle in electrolyte
Attributed to the fact that elemental storage alloys are not chemically stable.
Therefore, such chemical safety is required to extend the service life.
It is also required to be qualitative.   The chemical stability of the electrode as described above, for example, Al component
Used a small amount of hydrogen storage alloy as material
And the electrode has a long life (Japanese Patent Application No. 59-120826).
issue). In addition, the inclusion of elements such as Al, Cr, Si
The hydrogen storage alloy is corrosion resistant due to the formation of a closed oxide layer
It is said to have corrosiveness (Japanese Patent Laid-Open No. 60-89066).   In addition, the electrodes of the rechargeable battery must be operated as easily as possible.
And exhibit its performance in a short time. example
For example, in a conventional nickel-cadmium battery,
So-called chemical treatment, in which the battery is charged and discharged several times
However, this is a small
Only the amount of discharge is obtained, and the efficiency increases as charging and discharging are repeated
This is because there is a phenomenon of rising. Hydrogen storage
A similar tendency is seen in the case of gold electrodes.
The discharge efficiency is low, and its performance can be improved by charging and discharging several times.
Will be demonstrated. This is due to the water contained inside the electrode.
Electrolyte reaches the surface of element storage alloy particles and the alloy surface becomes electrolyte
More than once to be activated for the storage of hydrogen from
This is because the above charging and discharging are required. Electrode as above
The charge and discharge for the initial activation of the electrode is the theoretical capacity of the electrode
Is performed with a smaller charge amount. like this
If a large capacity charge is suddenly applied without any pre-processing
Is a gas that generates gaseous hydrogen on the surface of the hydrogen storage alloy electrode.
This impedes the penetration of the electrolyte into the electrode,
The exfoliation of alloy particles from the contacted electrode surface is induced,
The disadvantage is that the amount is significantly reduced. Follow
Therefore, a chemical treatment of small capacity charge / discharge is required,
It is said that this process is completed in a small number of times and sufficient performance is achieved
It is self-evident that electrodes with properties are industrially advantageous.
You.   As described above, negative electrode materials for metal oxide / hydrogen batteries
Hydrogen storage alloy has a large hydrogen storage capacity and equilibrium
Low plateau pressure is required, and hydrogen
Alloy electrodes are easier to chemically convert at the initial stage and chemically
Characteristics that are stable and have a long life are required.
A hydrogen storage alloy electrode satisfying the above conditions has not been obtained.
Therefore, the large capacity required for metal oxide / hydrogen batteries
Prevents internal pressure rise and reduces the risk of hydrogen leakage
Excellent stability, low self-discharge and long life
A battery having all of the characteristics described above could not be produced. [Object of the invention]   The present invention relates to the above-described configuration of a conventional hydrogen storage alloy electrode.
Providing a new hydrogen storage alloy electrode that solves various problems
The internal pressure of the battery is maintained at a low level, preventing hydrogen leakage.
Large capacity and long length, ensuring safety and suppressing self-discharge
The purpose is to provide a long-life metal oxide / hydrogen battery. [Summary of the Invention]   The present inventors have developed a hydrogen storage alloy to achieve the above object.
As a result of repeated research on battery anodes used as materials,
La-Ni-Mn alloy, Mm-Ni-Mn alloy, La-Ni
-Co alloy, Mm-Ni-Co alloy compared to M-Ni-Mn
-Co alloys (M is a rare earth element containing yttrium
Represents at least a kind. ) Is an alloy containing each element in a specified ratio
Has large hydrogen storage capacity and low equilibrium plateau pressure, and
When used as an electrode, 100% of the charged electricity can be discharged
Large discharge capacity and discharge efficiency beyond the limit
Does not drop much from 100%, resulting in large capacity
And found the fact that it reduced hydrogen generation.
To develop metal oxide / hydrogen batteries using this alloy as the negative electrode
Reached.   That is, the metal oxide / hydrogen battery of the present invention
That is, metal oxide is used as a positive electrode active material, and hydrogen is used as a negative electrode active material.
Negative electrode in a metal oxide / hydrogen battery Next formula   MNi_xMn_yCO_zA_w (Where M is at least the amount of rare earth elements including yttrium.
A kind: A is at least one of the elements selected from Al, Ti, Si, Cr
One type: x, y, z, w each represent an atomic ratio,   3.5 ≦ x ≦ 4.8 ……   0.01 <y ≦ 1.2 ......   0.01 <z ≦ 1.5 ......   0.01 ≦ w ≦ 0.6 ……   4.8 ≦ x + y + z + w ≦ 5.2 …… Represents a number that satisfies the relationship ) Consisting of a hydrogen storage alloy indicated by
Element is housed in a container and hermetically sealed.
Sealed metal oxide / hydrogen battery.   In the formula, M is any one of rare earth elements including yttrium.
Species or a mixture of several lanthanum elements.
Misch metal (Mm) and La misch metal
Lanthanum-enriched misch metal (hereinafter referred to as Lm)
You. ).   Of the above three types, M is preferably Lm.
No.   By including both Mn and Co in this alloy,
Reduce equilibrium plateau pressure while maintaining hydrogen storage
Is realized. A in the formula is used as an electrode material.
Structure for charge-discharge cycling in electrolyte when immersed
Is a component that contributes to the stabilization of Al, Ti, Si, and Cr.
When at least one of the selected elements is used,
A longer service life is achieved. Formula other than the rare earth element
In terms of the total amount of components,
LaNi, a typical hydrogen storage alloy for gold_FiveLarge from the structure of
Hydrogen storage capacity is reduced due to the highly distorted structure, which is preferable.
Not good.   The amount of element A needs to be within the range of the formula, where w is the atomic ratio.
You. When this becomes 0.6 <w, the hydrogen storage amount decreases.
As a result, the capacity decreased, and sufficient effects were not obtained at w <0.01.
Not. Even if component A is contained, its alloy is used as a material.
The configured hydrogen storage alloy electrode holds a large capacity and is the first
In order not to deteriorate the characteristics of the chemical conversion treatment during
It is necessary to contain a lot of Ni, and 3.5 <x
Appropriate. The upper limit of the equation is the equilibrium plateau pressure at 4.8 <x
Raises the problem. When the amount of Mn is 1.2 <y
If it becomes excessive, the amount of hydrogen storage decreases, while the amount of Mn decreases.
Mn is contained in a very small amount, that is, when y ≦ 0.01
Expression range is needed because the effect of
Become. Also, a hydrogen storage alloy containing Mn in the range of the formula
The electrode made of
Processing becomes easier. Furthermore, if the amount of Co also becomes 1.5 <z, water
When the amount of occluded element decreases, while the amount is very small, that is, when z ≦ 0.01
In the case, the effect of containing Co is effectively utilized
Cause the problem of not being. For the above reasons, the inclusion of each component
The ratio must be within the range that satisfies
Is necessary. Using such a hydrogen storage alloy as a material
Large capacity and long life by using structured electrode
A battery with excellent safety can be obtained.   The present inventors have developed a part of the alloy consisting of Mi-Ni-Mn-Co.
MNi substituted with component A that contributes to stabilization of the alloy structure_xMn_yC
o_zA_wElectrodes made of alloys of different compositions
When an appropriate amount is contained, it is composed of an alloy represented by M-Ni-Mn-Co.
Longer lifespan compared to fabricated electrodes
Was. The inclusion of element A reduces the hydrogen storage capacity of the alloy and reduces
And it tends to induce a decrease in
Of hydrogen storage alloy electrode used in the initialization treatment
Although the properties may be deteriorated, the present inventors
As a result of the research, the large capacity is maintained and the electrode is initialized.
To determine the composition range that facilitates the
Using a negative electrode composed of the alloy as an electrode material
Metal oxide and hydrogen batteries.   These alloys according to the present invention are determined from the target composition.
A predetermined amount of each component element powder is mixed, and the mixed powder is used as an example.
For example, a homogeneous solid solution can be obtained by melting in a vacuum arc melting furnace.
Can be obtained as Furthermore, this solid solution is pulverized.
Or 40kg / cm at room temperature^TwoPlace in a hydrogen atmosphere
It is easy to perform the activation process
A powder can be prepared.   In the metal oxide / hydrogen battery of the present invention,
Is the above-mentioned water that can occlude and release hydrogen as the negative electrode active material.
Powder of a nitrogen storage alloy and, for example, polytetrafluoroethylene.
After mixing with a binder such as ren, it is made into a sheet and configured
The used sheet electrode is used. In addition, the alloy powder and cal
Boxymethylcellulose (CMC), polyvinyl alcohol
(PVA), polyacrylate, polytetrafluoroe
Binder such as styrene and H_TwoMix with O to make a paste
And filling or coating the conductive substrate
A negative electrode may be formed. The hydrogen storage alloy of the negative electrode material is hydrogen
May be used in the state of releasing hydrogen, or partially occlude hydrogen
You may use it in the state where it did. As the positive electrode, for example, gold
Nickel hydroxide nickel (OH) for sintered nickel₂)
Nickel oxide (NiOO) impregnated with an active material
The electrode of H) is used. In addition, non-sintered nickel hydroxide
(Ni (OH)₂) And cobalt compounds (Co, CoO, Co (O
H)₂)), And further mix the mixture with CMC, PVA,
Binder such as acrylate and H_TwoMix with O and paste
After filling or applying to the conductive substrate, dry it
It may be used as a positive electrode. And obtained in this way
The positive and negative electrodes are made of an aqueous alkaline solution such as KOH or NaOH.
Metal oxide-hydrogen battery according to the present invention immersed in an electrolytic solution
Is configured. 〔The invention's effect〕   As described above, according to the present invention, as described above,
With high composition and atomic ratio_xMn_yCo_zA_wIs given by
An electrode made of a hydrogen storage alloy as a negative electrode
And a battery with a positive electrode containing a metal oxide as the active material.
By doing so, large capacity and internal pressure rise are prevented.
Battery that is stopped and has a low risk of hydrogen leakage and excellent safety
Can be provided.   According to the present invention, furthermore, the chemical conversion treatment is made difficult.
And a battery with a longer life can be provided.   Hereinafter, the present invention will be described in more detail based on examples.
I do. (Example of the invention) Reference example 1. (1) Negative electrode formation   Mix predetermined amounts of powders of Lm, Ni, Mn and Co
And the resulting mixed powder is melted in a vacuum arc melting furnace.
The composition is LmNi_4.15Mn_0.8C_0.005Was obtained.
This solid solution is crushed to a diameter of about 5 mm,
Pump and a container connected to a hydrogen cylinder.^-6
kg / cm^TwoAfter maintaining the following vacuum at room temperature for 1 hour, introduce hydrogen
Into, pressure about 35kg / cm^Two1 to several hours at room temperature under hydrogen atmosphere
Micronized by holding for a while. Over an hour again
Ten^-3kg / cm^TwoDegassed at room temperature to 60 ° C, keeping below
Thereafter, the alloy powder was taken out of the container. The obtained alloy powder
The particle size of the powder was 2 to 100 μm. In the above example, hydrogen
Crushing the alloy by absorbing ozone into the alloy
But ball mills, pulperizers, jet mills, etc.
Those crushed by a crusher may be used.   This alloy powder and polytetrafluoroethylene (PTFE)
And kneaded well to form a 0.5mm thick sheet
Molded. Weight ratio of alloy powder to PTFE is 96: 4 in dry state
Met.   The obtained two sheets are put on both sides of one nickel net.
To form a 0.7mm thick electrode.
Was used as a negative electrode. (2) Formation of positive electrode   Porous nickel sintered body Ni (OH)₂And impregnate this
A chemical conversion treatment was performed to form a NiOOH electrode, which was used as a positive electrode. (3) Manufacturing of batteries   The above negative electrode, positive electrode, and 0.3 mm thick polypropylene
8 mol / KOH aqueous solution
The battery shown in FIG. 1 was manufactured as an electrolyte.   In FIG. 1, 1 is a negative electrode, 2 is a separator, and 3 is a positive electrode.
It is a pole. 4 and 5 are terminals of a negative electrode and a positive electrode, respectively.
And is taken out outside independently of the battery container 6.
Have been. 7 is an electrolytic solution. Negative electrode 1 according to the present invention
Wrap the separator in a U-shape with the separator 2 and attach the positive electrode 3 from both sides.
It was arranged and brought into close contact with an acrylic holder 8. Positive
The capacity is set to be sufficiently larger than the capacity of the negative electrode.
The following measurements were made under conditions where the battery performance was dominated by the characteristics of the negative electrode.
became. (4) Battery characteristics   A constant current (1 g of hydrogen storage alloy contained in the negative electrode)
Or 170mA) to change the charging time
After charging the battery with a constant current (hydrogen storage alloy contained in the negative electrode)
Discharge until battery voltage drops to 0.95V at 170mA / g)
The efficiency at the time of this was measured. In addition, 10
0mAhg^-1Charge and discharge several times in the following, and the performance of the negative electrode is sufficient
The experiment was performed in a state where it was exhibited. Co for comparison
LmNi is an alloy that does not contain_4.2Mn_0.8Of the same configuration using
A battery was manufactured and the same measurement was performed. Also does not contain Mn
LmNi alloy_4.15Co_0.8Al_0.05Of the same configuration using
A battery was prepared and the same measurement was performed. Figure 3 shows the results
You. In the figure, the charging capacity is the unit weight of the alloy contained in the negative electrode.
The efficiency is calculated as the charge capacity of the discharge capacity.
Percentage (ie, Indicated by In the figure Is LmNi according to the present invention._4.15MN_0.8Co_0.05Alloy as anode material
The capacity characteristics of the battery used as LmNi is a comparative example_4.2Mn_0.8,-▼-is a comparative example Lm
Ni_4.15Co_0.8Al_0.05Is the case.   By using an Lm-Ni-Mn-Co alloy as a material,
100% higher than Lm-Ni-Mn and Lm-Ni-Co-Al alloys
The range of capacity that can be discharged with the efficiency of
Less gaseous hydrogen is generated even at capacity less than 0%
As can be seen from FIG. That is, LmNi_4.2Mn_0.8Alloy or
LmNi_4.15Co_0.8Al_0.05When using alloys as materials
Is about 160mAhg^-1With a charging capacity exceeding 100%
Electricity is not generated, and the utterance of hydrogen starts. In contrast, the present invention
By LmNi_4.15Mn_0.8Co_0.05Battery with alloy electrode as negative electrode
About 190mAhg^-1Up to 100% efficiency is possible.
The shaded portion in FIG. 3 corresponds to the difference in the amount of generated hydrogen,
It can be seen that the battery according to the present invention is more excellent in safety
You. Example 1   The hydrogen storage alloy used for the negative electrode is LmNi according to the present invention._4.2M
n_0.5Co_0.1Al_0.2Reference Example 1 except that the composition was
A similar battery was manufactured and its capacity characteristics were examined. The result is
In Figure 4 About 200mAhg as shown in^-1Discharge with 100% efficiency up to
High-capacity batteries with a capacity of less than
Was not seen. A value indicating the capacity of this battery
As 300mAhg^-1The discharge capacity for charging was measured
However, 245mAhg^-1Met. Example 2   The hydrogen storage alloy used for the negative electrode is LmNi according to the present invention._4.0M
n_0.6Co_0.2Al_0.2Example 1 except that the composition was
A similar battery was manufactured and its capacity characteristics were examined. The result
In Figure 4 Indicated by In this embodiment, about 200 mAhg^-1Up to 100% efficiency
It became a large capacity battery that could be retained. Hydrogen generation is also 200mAhg
^-1Was not seen until.   As a comparative example, LmNi containing insufficient Ni and excess Co
_2.2Mn_0.6Co_2.0Al_0.2Battery capacity using alloy as anode material
Fig. 4 shows the quantitative characteristics However, as compared with the case of this embodiment,
I did. At this time, the LmNi of the present example and the comparative example_4.0Mn
_0.6Co_0.2Al_0.2, LmNi_2.2Mn_0.6Co_2.0Al_0.2Use each alloy of
300mAhg of used battery^-1Discharge capacity for charging
233 mAhg in the case of this embodiment^-1, 178mAhg for the comparative example
^-1Met. Example 3   The hydrogen storage alloy used for the negative electrode is LmNi according to the present invention._4.2M
n_0.3Co_0.2Al_0.3Example 1 except that the composition was
A similar battery was manufactured. Its 300mAhg^-1Against charging
227 mAhg when measuring discharge capacity^-1Met. Next
Of the battery was examined. Use it as a battery
In order to avoid the danger of hydrogen leakage,
Charge and discharge with a capacity in the range shown. Therefore, the battery according to the present invention
Life test can discharge almost 100% of charged electricity
Performed with volume. Specifically, small capacity
175mAhg for a battery that has been repeatedly charged and discharged several times
^-1To charge for 1 hour, and then the battery voltage with the same current
Discharge was performed until the voltage dropped to 1.0 V, and this was repeated. And
High rate was calculated as a percentage of discharge capacity to charge capacity
Figure 5 shows the results Indicated by   As a comparative example, a conventional product, LmNi_4.2Mn_0.8Pair of
Battery composed of an alloy consisting of
_4.2Mn_0.5Al_0.3An alloy consisting of
Battery and LmNi_4.2Co_0.5Al_0.3Of the composition
A battery composed of gold as a negative electrode material was manufactured in the same manner as in Example 1.
The method was manufactured and its life characteristics were measured. The results are shown in FIG.
LmNi_4.2Mn_0.8The characteristics of the battery using_4.2M
n_0.5Al_0.3Battery characteristics using LmNi_4.2Co_0.5Al_0.3The characteristics of batteries using
Shown. As is apparent from FIG. 5, Lm4.
Batteries using an alloy consisting of 2Mn0.3Co0.2Al0.3
Discharge at an efficiency of 90% or more even after 600 cycles
LmNi maintains 90% for only about 100 cycles_4.2Mn
_0.8Conventional product using an alloy consisting of approximately 200 cycles
LmNi only maintains 90%_4.2Mn_0.5Al_0.3From the composition of
90% only up to about 300 cycles
LmNi not maintained_4.2Co_0.5Al_0.3Use of alloy consisting of
That a significantly longer life has been achieved compared to conventional products.
Recognize. Example 4   The hydrogen storage alloy used for the negative electrode is LmNi according to the present invention._3.7M
n_0.6Co_0.5Al_0.2Example 1 except that the composition was
Produce a similar battery and its 300mAhg^-1Release for charging
The capacitance was measured. The result is 233mAhg^-1Met. Incidentally
The battery life characteristics were examined in the same manner as in Example 4. So
Figure 5 shows the resultsMaintain 90% efficiency over 600 cycles
A long-life battery was obtained. Example 5   Composition LmNi similar to Example 4_4.2Mn_0.3Co_0.2Al_0.3With
A hydrogen storage alloy was prepared in the same manner as in Example 1, and a sheet was prepared.
To form a negative electrode from a 5.5 g section of the sheet
did. Further, the same positive electrode, separator, and electrode as in Example 1 were used.
Using the solution, the battery shown in FIG. 2 was manufactured. sand
That is, the positive electrode, the separator, and the negative electrode are stacked and spirally wound.
This is stored in a battery container together with the electrolyte and
Sealed with ket 9 and O-ring 10. In FIG.
Here, 1 is a negative electrode, 2 is a separator, and 3 is a positive electrode.
The negative electrode 1 is in close contact with the battery case 6. With the battery of this embodiment
Is set so that the capacity of the positive electrode is less than or equal to the capacity of the negative electrode
did. 7 is an electrolytic solution.   To determine the initial characteristics of this battery,
The discharge capacity was measured by the discharge cycle. First
Two cycles with a 100 mAh charge, followed by a 200 mAh charge
Power cycle twice, then 400 mAh charging
Kuru was done. In FIG. Indicates the discharge capacity obtained in each cycle. A,
b and c represent the charging capacity of 100, 200 and 400 mAh respectively, and…
... indicate that the charging capacity has been changed. No.
As can be seen in FIG. 6, the battery of this embodiment has a
On the other hand, it shows almost 100% efficiency in about 2 cycles.   Next, as a comparative example, the hydrogen storage alloy used for the negative electrode was Ni
LmNi with insufficient amount_3.2Mn_0.6Co_1.0Al_0.2The composition of
A battery similar to that of Example 1 was manufactured except for
The characteristics were examined in the same manner as in Example 3. However, this comparison
Example battery is 175mAhg^-1With almost 100% efficiency for charging
Approximately 20 small charges and discharges before discharge is possible
It was necessary to repeat the electricity. The results are shown in FIG. And more than 600 cycles and close to 100%
A long-life battery exhibiting high efficiency was obtained. like this
175mAhg capacity^-1Comparative example shows good results in charge and discharge
But 300 mAhg^-1Discharge capacity is 215 for charging
mAhg^-1And a smaller capacity than the battery according to the present invention.   Further, as another comparative example, LmNi having the same composition as above was used._3.2M
n_0.6CO_1.0Al_0.2As in Example 5 using an alloy having the composition
A battery was manufactured, and its initial characteristics were measured in the same manner as in Example 5.
I checked in. Fig. 6 shows the results. As shown. As can be seen in FIG.
Ponds have poor initial efficiency and charge capacity is as small as 100 mAh.
It reaches only about 60% in three cycles. In this state
When the capacity was increased to 200mAh, the discharge capacity was rather
Diminished. Then repeat the cycle with 400 mAh charging
The discharge capacity gradually increased, but after 10 cycles
However, it did not reach sufficient efficiency. Therefore, this comparative example
Such a battery has a good life even after its manufacture.
Requires multiple charge / discharge cycles before performance
This is industrially disadvantageous.   Set of hydrogen storage alloy in the above Examples and Comparative Examples
The relationship between the formation and the capacitance of the electrode using it is summarized
The results are shown in Table 1. Table 1 shows that the atomic ratio x of Ni is 3.5 or more.
Large capacity is obtained when it is large, and capacity is less than 3.5
It can be seen that it decreases. Also, as shown in FIG.
Since the lack of Ni has a bad effect on the initial characteristics of the pond,
It is necessary that 3.5 <x. Example 6   Composition LmNi similar to Example 4_3.7Mn_0.6Co_0.5Al_0.2With
A hydrogen storage alloy was prepared in the same manner as in Example 1, and
A battery having the same configuration as that of the battery No. 5 was manufactured. However, as a negative electrode
Uses a sheet weighing 7 g, and also transmits the internal pressure of the battery
Then, the pressure was measured on a part of the positive electrode terminal 5 of the battery container shown in FIG.
The vessel was attached.   This battery is charged 3 times with a charge capacity of 600mAh, 800mAh
Cycle twice, then cycle by charging 1Ah
Was done. The charge capacity of 1 Ah is about 1.5 times the capacity of the positive electrode
Hit. This charge / discharge cycle is indicated by-▽-in FIG.
Indicates the maximum value of the battery internal pressure at the end of charging in the middle.   The charging capacity is 600 mAh (part a in FIG. 7), 800 mAh (
7 (b) and 1Ah (c in FIG. 7)
The internal pressure also rises as the
Internal pressure is up to 4.6kgcm even with electricity^-2And normal battery safety
Valve is at least 19kgcm^-2To withstand the internal pressure of
Then, it can be said that the battery of this embodiment is sufficiently safe. Note that
Even after the 8th charge / discharge cycle with charge capacity 1Ah
The pressure is 4.6kgcm^-2Never exceeded.   Next, as a comparative example, the hydrogen storage alloy used for the negative electrode was Ni
LmNi with insufficient amount_3.2Mn_0.6Co_1.0Al_0.2The composition of
A battery similar to that of Example 7 was prepared except for
Was measured. In FIG. As a result, the cycle by charging 600 mAh
Twice (part a in FIG. 7) by charging at 800 mAh.
After applying the wheel three times (part b in FIG. 7), the charging capacity is 1A
Repeat the charge / discharge cycle (h in Fig. 7)
Was.   As is clear from FIG. 7, in this comparative example, the charging capacity was
The internal pressure increases as the current increases to 600 mAh, 800 mAh, and 1 Ah,
10kgcm at eye^-2Reach In addition, when charging 1Ah
Internal pressure 11-12kgcm^-2And the same level after 9th cycle
The internal pressure was indicated. 1.5 times the initial capacity as in this comparative example
Internal pressure is 10kgcm in charge / discharge cycle with degree of charge^-2Cross over
Batteries are dangerous and are not suitable as sealed secondary batteries for consumer use
That's right. Such an increase in internal pressure is due to hydrogen absorption of the anode material.
This is seen when the amount of Ni in the alloy composition is insufficient.
MNi_xMnyCo_zA_wIn an alloy having a composition represented by the general formula of
It is necessary that the amount x of Ni exceeds 3.5. Insufficient amount of Ni
In the case of feet, the internal pressure rises as seen in the comparative example above.
The danger arises.   As shown in the above examples, the alloy according to the present invention was negatively charged.
Metal oxide / hydrogen batteries used as electrode materials are
Therefore, it is a battery having a large capacity, a long life and excellent safety.
In particular, the alloy represented by the composition of MNixMnyCozAw according to the present invention
In the battery using as the negative electrode material, Examples 4 and 5 shown in FIG.
As shown in the figure, the service life is greatly extended compared to the conventional product.
And processing immediately after battery production as shown in FIG.
Is also easy. Further, the alloy having the composition according to the present invention is used as a negative electrode material.
As shown in Fig. 7, a good internal pressure characteristic
Good safety and excellent safety. The composition of these alloys is
Range specified in consideration of the relationship with the desired battery characteristics
Each can be decided within. In addition, according to the present invention,
Gold composition excludes unavoidable impurities that enter during its production
Not something. This inevitable impurity is, for example, iron
And tin.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a battery according to the present invention, FIG. 2 is a schematic sectional view of another structural example of a battery according to the present invention, and FIGS. 5, a battery according to the present invention and a comparative example, FIG. 5 shows a life characteristic diagram of the battery according to the present invention and the comparative example, FIG. 6 shows an initial capacity characteristic diagram of the battery according to the present invention and the comparative example, and FIG. FIG. 9 is a characteristic diagram showing a relationship between the number of charge / discharge cycles and the internal pressure of the battery of the comparative example. DESCRIPTION OF SYMBOLS 1 ... Negative electrode, 2 ... Separator 3 ... Positive electrode, 4 ... Negative electrode terminal, 5 ... Positive electrode terminal 6 ... Battery container, 7 ... Electrolyte solution, 8 ... Holder 9 ... Insulating gasket, 10 …… O-ring

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Yuji Sato               1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi Toshiba Corporation               Within the Research Institute                (56) References JP-A-60-250558 (JP, A)

Claims (1)

(57) [Claims] The metal oxide as the positive electrode active material, the metal oxide-hydrogen batteries using hydrogen as a negative electrode active material, a negative electrode, in the formula _{MNi x Mn y CO z A w} ( Formula, M at least of rare earth elements including yttrium Type: A is at least one type of element selected from Al, Ti, Si, Cr: x, y, z, w each represent an atomic ratio, 3.5 ≦ x ≦ 4.8,
0.01 <y ≦ 1.2, 0.01 <z ≦ 1.5, 0.01 ≦ w ≦ 0.6, 4.8 ≦
Represents a number that satisfies the relationship x + y + z + w ≦ 5.2. A sealed metal oxide-hydrogen battery comprising a hydrogen storage alloy represented by the formula (1), wherein the components of the battery are housed in a container and sealed.