JP3459525B2 - Method for producing hydrogen storage alloy for hydrogen storage alloy electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to a nickel-hydrogen
Used in negative electrodes of alkaline secondary batteries such as secondary batteries.
UsedHydrogen storage alloy for hydrogen storage alloy electrodeManufacturing method
Water used for this hydrogen storage alloy electrode
Reforming the hydrogen storage alloy, and
It is characterized by improved activity and low temperature characteristics.
is there. [0002] 2. Description of the Related Art Conventionally, as one of alkaline secondary batteries,
Thus, nickel-hydrogen secondary batteries are known.
In a Kel-Hydrogen secondary battery, hydrogen is generally
A hydrogen storage alloy electrode using a storage alloy has been used. [0003] Here, the hydrogen storage alloy used for the negative electrode
As misch metal, which is a mixture of rare earth elements
Mm-based hydrogen storage alloy using (Mm) or Laves
(Laves) -based hydrogen storage alloys have been used. However, these hydrogen storage alloys are generally
A film such as an oxide is formed on the surface by natural oxidation or the like.
The hydrogen storage alloy is used to store hydrogen.
A gold electrode is manufactured, and this hydrogen storage alloy electrode is
When used for negative electrodes in elementary rechargeable batteries,
Activity of the hydrogen storage alloy at low
And the battery capacity in the initial stage is low.
Or the pressure inside the battery increases.
Was. For this reason, in recent years, Japanese Patent Laid-Open No.
As shown in US Pat.
Immerse it in an acidic solution such as hydrochloric acid to remove the surface of the hydrogen storage alloy.
To remove the oxide film at
Was. [0006] Here, the hydrogen storage alloy is acid-dissolved as described above.
Immersed in a solution to remove the acid on the surface of the hydrogen storage alloy.
Active coating on the surface of the hydrogen storage alloy
Sites appear to some extent, but active parts on this surface
Is oxidized again and the initial state in the hydrogen storage alloy
Activity is not sufficiently improved,
Hydrogen gas is not absorbed sufficiently and battery capacity is low.
And problems such as high pressure inside the battery
did. Further, in the conventional hydrogen storage alloy electrode,
Has poor electron conductivity at low temperature,
There is also a problem of poor discharge characteristics when used in
There. [0008] SUMMARY OF THE INVENTION The present invention relates to nickel
-Used for negative electrodes of alkaline secondary batteries such as hydrogen secondary batteries
Solving the various problems described above for hydrogen storage alloy electrodes
And at least nickel
Containing hydrogen, cobalt, aluminum and manganese
Used in batteries for hydrogen storage alloy electrodes including storage alloys
The activity in the initial stage of the
When it is sufficiently absorbed and sufficient battery capacity is obtained from the beginning
In both cases, the internal pressure is rarely increased,
Sufficient discharge characteristics are obtained even when used at low temperatures.
The task is to be able to [0009] Means for Solving the Problems According to claim 1 of the present invention.
KickHydrogen storage alloy for hydrogen storage alloy electrodeThe manufacturing method of
In order to solve the above problems,
Nickel, cobalt, aluminum and manganesecontains
The hydrogen storage alloy is added to the weight of the hydrogen storage alloy.chloride
Add aluminum or aluminum hydroxide 1-5% by weight
In the acid solutionSurface treatmentThis water
At a depth of 30 ° from the surface of the elemental storage alloy
Cobalt, aluminum and manganese abundances
Is the sum of a and c in the bulk region inside the hydrogen storage alloy.
Baltic, aluminum, and manganese atoms
When the sum is b, the condition of a / b ≧ 1.20 isFulfill
I did.[0010] Here, add to the acidic solutionAluminum chloride
Or aluminum hydroxideThe amount of hydrogen storage alloy weight
1-5% by weightAluminum chloride or
Is aluminum hydroxideIs small, the hydrogen storage alloy
Cobalt and aluminum at a depth of 30 mm from the surface
Luminium and manganese are reduced and aluminum
Even if the amount of the aluminum compound is too large,
The atoms of manganese and manganese are well treated on the surface of the hydrogen storage alloy.
Will not remain in the
Koval at a depth of 30 mm from the surface of gold
Sum of the abundance ratio of each atom of
Becomes smaller and does not satisfy the condition of a / b ≧ 1.20
It is because it becomes. In the above-mentioned claim 1,Hydrogen storage
Hydrogen storage alloy for alloy electrodesHydrogen storage
Kovar at a depth of 30 mm from the surface of the alloy
Sum of the abundance ratio of each atom of
And cobalt in a bulk region inside the hydrogen storage alloy,
With the sum b of the abundance ratio of each atom of aluminum and manganese
The relationship satisfies the condition of a / b ≧ 1.20If you do,
Cobalt, aluminum and manganese atoms absorb hydrogen
More at the surface than the bulk region inside gold
Then, due to the catalytic action of these atoms, this hydrogen storage
Activity of hydrogen storage alloy electrode using gold is higher than the initial
As well as improved electronic conductivity at low temperatures
It is.[0012] Then, such a hydrogen storage alloy electrode is
When used for nickel-hydrogen secondary batteries, etc.
Gas generation is suppressed, and the initial battery capacity is reduced.
As well as the pressure inside the battery
Discharge even when used at low temperatures.
The characteristics are improved.[0013] Also, as described above, hydrogen storage alloyChloride
Luminium or aluminum hydroxideAcid solution with
PH of this acidic solution is too high for processing in liquid
Then, the coating of oxides etc. on the surface of the hydrogen storage alloy is sufficiently
But the pH of this acidic solution drops.
The active metal in the hydrogen storage alloy is also melted
The active part on the surface of the hydrogen storage alloy also decreases
Therefore, preferably, the initial pH is 0.7-2.0 acidic
Surface treatment of hydrogen storage alloy using solution
You.[0014] Also, the temperature of the above acidic solution is too high
The active metal in the hydrogen storage alloy is also dissolved,
While the active part on the surface of the element storage alloy also decreases,
If the temperature of the acidic solution is too low, the surface of the hydrogen storage alloy will
Coatings such as oxides cannot be sufficiently removed.
The temperature of the acidic solution of
It is preferable to carry out the treatment of the storage alloy.[0015] Furthermore, as described above, hydrogen storage alloy,salt
Aluminum fluoride or aluminum hydroxideAcid added with
When treating in an acidic solution,
When an appropriate amount of quinones such as lahydroquinone is added,
Hydrogen is removed due to removal of dissolved oxygen in the neutral solution
The formation of oxide film again on the surface of the storage alloy is suppressed.
And the initial activity in hydrogen storage alloy is improved
Preferably, quinones in an acidic solution
From 5 ppm to 100 ppm. [0016] Embodiments of the present invention will be described below.Hydrogen storage alloy
Hydrogen storage alloy for electrodesThe method of manufacturing
And a comparative example, as shown in the examples of the present invention.
ManufacturedHydrogen storage alloy electrode using hydrogen storage alloy
ToWhen used for batteries, the internal pressure of the battery
As well as improving discharge characteristics at low temperatures.
Make things clear. In the present invention,Hydrogen absorption
Hydrogen storage alloy for storage alloy electrodeIn particular, the production method of
The present invention is not limited to the examples shown in
Can be implemented with appropriate changes within the scope that does not change
It is.[0017] (Examples 1 to 3 and Comparative Example 1, 2) In these examples and comparative examples, a mixture of rare earth elements was used.
Misch metal (Mm), Ni, Co and Al
And Mn by MmNi_3.1Co_0.8Al_0.4Mn_0.7of
Weigh and mix to achieve the composition ratio, melt this and
After alloying, this is mechanically pulverized to obtain a hydrogen storage alloy powder.
I got the end.[0018] Next, the hydrogen storage alloy powder thus obtained
The surface of the powder should be treated in an acidic solution using hydrochloric acid.
Was.[0019] Here, the table of hydrogen storage alloy powder
When treating the surface in an acidic solution, see Table 1 below.
As shown, the initial pH of the acidic solution was 1 and the solution temperature was 25 ° C.
In addition, in Examples 1 to 3 and Comparative Example 1,
Aluminum chloride in an acidic solution as described above
Aluminum AlCl_ThreeAs shown in the table, and
Raquinone was added in an amount of 50 ppm.
Add only 50 ppm of anthraquinoneLike
Was.[0020] And each acidic solution adjusted as above
Each hydrogen storage alloy is immersed until the pH becomes about 7.
Then, the surface of each hydrogen storage alloy was treated.[0021] Next, each surface treated as described above
Existence of each atom from the surface of the hydrogen storage alloy to a depth of 30mm
The ratio was measured. The measurement of the abundance ratio of each atom is a scanning type
Using a transmission electron microscope and an energy dispersive X-ray analyzer
Measured. Here, the abundance ratio of each atom was measured
In the section, the scanning transmission electron microscope and the energy
Of the total number of metal atoms detected by the diffuse X-ray analyzer
The ratio of the number of existing atoms is calculated. And
By this method, a depth of 30 ° from the surface of each hydrogen storage alloy is obtained.
Abundance ratio of Co, Al, Mn atoms in the previous part
Of the hydrogen storage alloy in the same manner.
Ratio of Co, Al, Mn atoms in the bulk region
The sum b of the ratios is obtained, a / b is calculated, and the result is shown in Table 1.
Also shown.[0022] [Table 1] [0023]As a result, the hydrogen storage capacity of Examples 1 to 3 was determined.
Gold has an a / b value of 1.20 or more.
Although the above conditions were met, AlCl_ThreeTo
Treated with more than 5% by weight of added acidic solution
Hydrogen storage alloy of Comparative Example 1 or AlCl_ThreeIs added
Hydrogen storage compounds of Comparative Example 2 treated with no acidic solution
In gold, the value of a / b is lower than 1.20
I was[0024] Next, the above Examples 1-3 and Comparative Examples 1,
Each hydrogen storage alloy 10 surface-treated as shown in FIG.
0 parts by weight of polyethylene as a binder
20 parts by weight of a 5% by weight aqueous solution of oxide are added and mixed.
Each paste, adjust each paste, and
On both sides of core body made of Kel-plated punching metal
After coating and drying at room temperature, cut to size
The hydrogen storage alloy electrodes of Examples 1 to 3 and Comparative Examples 1 and 2
The pole was made.[0025] Then, each of the hydrogen storage alloys thus produced
While the gold electrode is used for the negative electrode, the positive electrode is
Use a commonly used sintered nickel electrode,
As the separator, an alkali-resistant non-woven fabric was used.
As shown in FIG.
These are spirally wound with the separator 3 interposed.
After being stored in the battery can 4, the battery
30% by weight potassium hydroxide aqueous solution as potassium electrolyte
Pouring and sealing the positive electrode 1 through the positive electrode lead 5
6 and the negative electrode 2 is connected via the negative electrode lead 7.
The battery can 4 is connected to the battery can 4, and the battery can 4 and the positive electrode lid 6 are insulated from each other.
The kin 8 was used for electrical separation.[0026] Also, between the positive electrode lid 6 and the positive electrode external terminal 9
The coil spring 10 is installed, and the internal pressure of the battery rises abnormally.
In this case, the coil spring 10 is compressed
Gas inside the battery was released to the atmosphere.[0027] Then, each nick made as described above
At room temperature (normal temperature) with respect to the Kel-hydrogen secondary battery,
After charging each with a charging current of 0.2 C for 6 hours,
Discharge with a discharge current of 0.2 C at low temperature.
The initial discharge capacity of each of these nickel-hydrogen secondary batteries was
And the results are shown in Table 2 below.[0028] [Table 2] [0029]As is clear from this result, the above a /
A hydrogen storage alloy having a value of b of 1.20 or more was used.
Nickel using the hydrogen storage alloy electrodes of Examples 1 to 3 as a negative electrode
For the Kel-hydrogen secondary battery, the value of a / b is 1.20 or less.
Comparative Example 1 using a lower hydrogen storage alloy, 2Hydrogen storage
Compared to nickel-hydrogen secondary batteries that use alloy electrodes for the negative electrode
In all, the initial discharge capacity at a low temperature of 0 ° C.
As a result, the discharge characteristics at low temperatures were improved.[0030] (Examples 4 to 6 and Comparative Example3,4) Examples 4 to 6 and Comparative Examples3,4In the upper
Examples 1 to 3 and Comparative Example 1, 2Grinding as in the case of
Surface treatment of the obtained hydrogen storage alloy in an acidic solution
When the temperature of the acidic solution is set to 25 ° C,
AlCl added to this acidic solution_ThreeAnd anthrax
In Example 4, as shown in Table 3 below, the amount of non
Example 1, Example 5, Example 2 and Example 6
Example 3 and Comparative Example3Then a comparative example1And a comparative example4Then a comparative example
While the same as 2, The initial p in the above acidic solution
The H value was changed as shown in the table,
An alloy surface treatment was performed.[0031] Here, as described above, the initial
A / b, even when the pH value of the
Value hardly changes, and the value of Example 4 is that of Example 1.
And those of Example 5 are those of Example 2 and those of Example 6
What is in Example 3 and Comparative Example3Is a comparative example1Nomo
And a comparative example4Is a comparative exampleTwo thingsAlmost the same a /
The value of b was shown.[0032] Next, each hydrogen storage compound obtained as described above was used.
In the case of the above Examples 1-3 and Comparative Examples 1 and 2 using gold
In the same manner as above, while preparing each hydrogen storage alloy electrode,
Each of the hydrogen storage alloy electrodes is used as a negative electrode to form a nickel-
A hydrogen secondary battery was manufactured.[0033] Then, each nickel produced in this way
The internal pressure of each battery was measured for each
While charging at 1000mA (1C) at room temperature
No, internal pressure of battery is 10kgf / cm^TwoUntil you reach
Measure the charging time, and apply this to each nickel-hydrogen secondary battery.
Table 3 below shows the initial internal pressure characteristics in the test. What
In determining the internal pressure characteristics, four
Of nickel-hydrogen secondary batteries
The average value was shown.[0034] [Table 3] [0035]As is clear from this result, the acid solution
Even when the initial pH was changed, the above-mentioned Example 1 was used.
Examples in which the value of a / b was 1.20 or more as in the cases of Nos. 1 to 3.
4 to 6 are Comparative Examples 1, 2The value of a / b is
Comparative example that was lower than 1.203,4Compared to
The charging time, which indicates the internal pressure characteristics of the battery, is longer,
Gas generation is suppressed and the discharge capacity is
The quantity was obtained.[0036] Also, as described above, the hydrogen storage alloy
When performing surface treatment in liquid, the initial pH
When treated with an acidic solution in the range of 0.7 to 2.0
In addition, the internal pressure characteristics of each nickel-hydrogen secondary battery have been improved
Was done.[0037] (Examples 7 to 9 and Comparative Example5,6) Examples 7 to 9 and Comparative Example5,6In the upper
Examples 1 to 3 and Comparative Example 1, 2Grinding as in the case of
Surface treatment of the obtained hydrogen storage alloy in an acidic solution
When the initial pH of the acidic solution is set to 1,
AlCl added to this acidic solution_ThreeAnd anthrax
The amount of non was determined in Example 7 as shown in Table 4 below.
Example 1, Example 8, Example 2 and Example 9
Example 3 and Comparative Example5Now, Comparative Example 1 and Comparative Example6Then a comparative example
2Same asOn the other hand, the temperature of the acidic solution
Change as shown in the table, and change the table
Surface treatment was performed.[0038] Here, the liquid in the acidic solution as described above
Even when the temperature is changed, the value of a / b is almost unchanged.
No change, the thing of Example 7 is the same as that of Example 1,
Example 8 is the example 2 and Example 9 is the example
Example 3 and comparative example5Of Comparative Example 1
Comparative example6Is Comparative Example 2StuffThe value of a / b which is almost the same as
Indicated.[0039] Next, each hydrogen storage compound obtained as described above was used.
In the case of the above Examples 1-3 and Comparative Examples 1 and 2 using gold
In the same manner as above, while preparing each hydrogen storage alloy electrode,
Each of the hydrogen storage alloy electrodes is used as a negative electrode to form a nickel-
Hydrogen rechargeable batteries were fabricated, and each nickel-hydrogen rechargeable battery was
Initial pressure characteristics are measured in the same manner as above,
The results are shown in Table 4 below.[0040] [Table 4] [0041]As is clear from this result, the acid solution
When the liquid temperature is in the range of 25.0 ° C to 70.0 ° C,
Examples 7 to 7 in which the value of a / b became 1.20 or more as in
9 is a comparative example in which the value of a / b is lower than 1.20.5,
6The charging time, which indicates the internal pressure characteristics of the battery, is longer than that of
Gas generation is suppressed in the initial stage,
Sufficient discharge capacity was obtained.[0042] (Examples 10 to 12 and Comparative Example7,8) These Examples 10 to 12 and Comparative Examples7,8At
Are the above Examples 1 to 3 and Comparative Example 1., 2As in
In a acidic solution
For surface treatment, adjust the initial pH of the acidic solution to 1, acidic
The solution temperature was adjusted to 25 ° C and the solution was added to this acidic solution.
AlCl to be added_ThreeAs shown in Table 5 below.
Example 10 is Example 1 and Example 11 is Example 2.
Example 12 includes Example 3 and Comparative Example7Then, with Comparative Example 1,
Comparative example8Then, while making the same as Comparative Example 2,
The amount of anthraquinone added to the liquid is shown in the table.
Change the surface treatment of the hydrogen storage alloy.
Was.[0043] Where it is added to the acidic solution as described above.
Even if the amount of anthraquinone is changed
The value of a / b described above hardly changed, and that of Example 10 was actual.
Example 1 and Example 11 are those of Example 2.
Example 12 is the same as Example 3 and Comparative Example7of
These are those of Comparative Example 1 and Comparative Example8Of Comparative Example 2
The value of a / b was almost the same as that of the above.[0044] Next, each hydrogen storage compound obtained as described above was used.
In the case of the above Examples 1-3 and Comparative Examples 1 and 2 using gold
In the same manner as above, while preparing each hydrogen storage alloy electrode,
Each of the hydrogen storage alloy electrodes is used as a negative electrode to form a nickel-
Hydrogen rechargeable batteries were fabricated, and each nickel-hydrogen rechargeable battery was
The internal pressure characteristics at the initial stage are measured in the same manner as above.
The results are shown in Table 5 below.[0045] [Table 5] [0046]As is evident from the results,
5.0 ppm to 100.0 ppm of anthraquinone
When added in the range, the value of a / b is 1.2 as described above.
In Examples 10 to 12 in which the value was 0 or more, the value of a / b
Comparative example where is lower than 1.207,8Batteries compared to those of
Charging time, which shows the internal pressure characteristics of
Gas generation is suppressed, and a sufficient discharge capacity is provided from the beginning.
Obtained.[0047] (Examples 13 to 15 and Comparative Example9) Examples 13 to 15 and Comparative Example9In the upper
Examples 1 to 3 and Comparative Example 1, 2Grinding as in the case of
Surface treatment of the obtained hydrogen storage alloy in an acidic solution
In processing, the above Examples 1 to 3 and Comparative Example 1, 2
As in the case of the above, the initial pH of the acidic solution is set to 1 and the liquid temperature is set to 25.
° C and add 50 ppm of anthraquinone
On the other hand, as shown in Table 6 below,
Aluminum hydroxide Al (OH) as minium compound
_ThreeWas added as shown in the table.[0048] Next, each water surface treated as described above
Existence of each atom at a depth of 30mm from the surface of element storage alloy
The ratio was measured. The measurement of the abundance ratio of each atom is performed by scanning transparency.
Using a scanning electron microscope and an energy dispersive X-ray analyzer
It was measured. Here, the abundance ratio of each atom is the measured part
Minute, scanning transmission electron microscope and energy dispersion
The total number of metal atoms detected by the X-ray spectrometer
It is the ratio of the number of existing atoms. And this
30 ° depth from the surface of each hydrogen storage alloy
Of the existence ratio of Co, Al, and Mn atoms
The sum a is obtained, and the inside of each hydrogen storage alloy is similarly calculated.
Ratio of Co, Al, Mn atoms in the bulk region of
A / b is calculated, and the result is shown in Table 6.
Also shown.[0049] [Table 6] [0050]As a result, the hydrogen storage capacity of Examples 13 to 15 was
Gold has an a / b value of 1.20 or more.
Although the above conditions were met, Al (OH)
_ThreeWith more than 5% by weight of 7% by weight
Comparative example processed9Of the hydrogen storage alloy of
The value of b was lower than 1.20.[0051] (Examples 16 to 18 and Comparative Example10) These Examples 16 to 18 and Comparative Example10In
For surface treatment of hydrogen storage alloy in acidic solution
The above Examples 13 to 15 and Comparative Example8As in
Then, the temperature of the acidic solution was adjusted to 25 ° C, and anthraquinone was added to 5
0 ppm, and as shown in Table 7 below,
Aluminum hydroxide Al (O
H)_ThreeIn Example 16, Example 13 was compared with Example 13
7 and Example 18 and Example 18
Comparative example10Then a comparative example9While the above acidic solution
Change the initial pH value of the solution as shown in the table.
The surface treatment of each of the hydrogen storage alloys was performed.[0052] Here, as described above, the initial
A / b, even when the pH value of the
Is almost unchanged, and the value of Example 16 is different from that of Example 13.
The thing of Example 17 is the same as that of Example 14,
Example 18 is the same as Example 15 and Comparative Example10Stuff
Is a comparative example9The values of a / b were almost the same as those of the above.[0053] Next, each hydrogen storage compound obtained as described above was used.
In the case of Examples 1 to 3 and Comparative Examples 1 and 2 using gold
In the same manner as above, while preparing each hydrogen storage alloy electrode,
Each of the hydrogen storage alloy electrodes is used as a negative electrode to form a nickel-
A hydrogen secondary battery was manufactured, and each nickel thus manufactured was manufactured.
-Initial internal pressure characteristics of the hydrogen secondary battery in each of the above cases
And the results are shown in Table 7.
Was.[0054] [Table 7] [0055]As is clear from this result, the acid solution
Even when the initial pH is changed, the value of a / b
In Examples 16 to 18 in which 1.20 or more, a /
Comparative example in which the value of b was lower than 1.2010Ratio of
In all cases, the charging time, which indicates the internal pressure characteristics of the battery, becomes longer.
Gas generation in the initial stage is suppressed,
High discharge capacity was obtained.[0056] Also, as described above, the hydrogen storage alloy
When performing surface treatment in liquid, the initial pH
When treated with an acidic solution in the range of 0.7 to 2.0
The internal pressure characteristics of each nickel-hydrogen secondary battery are
Was raised.[0057] (Examples 19 to 21 and Comparative Example11) Examples 19 to 21 and Comparative Examples11In
For surface treatment of hydrogen storage alloy in acidic solution
The above Examples 13 to 15 and Comparative Example9As in
The initial pH of the acidic solution was set to 1 and the
As shown in Table 8 below, with addition of 50 ppm of quinone.
Aluminum hydroxide added to the above acidic solution
Al (OH)_ThreeIn Example 19, the amount of
Example 20 is Example 14 and Example 21 is Example 1
5 and Comparative Example11Then a comparative example9While the same as above
The temperature of the acidic solution was changed as shown in the table.
Each of the hydrogen storage alloys was subjected to a surface treatment.[0058] Here, the liquid in the acidic solution as described above
Even when the temperature is changed, the value of a / b is almost unchanged.
No change, the thing of Example 19 is the same as that of Example 13,
The twentieth embodiment differs from the fourteenth embodiment in the fourteenth embodiment and the twenty-first embodiment.
The thing of Example 15 and the comparative example11Is a comparative example
9The values of a / b were almost the same as those of the above.[0059] Next, each hydrogen storage compound obtained as described above was used.
In the case of Examples 1 to 3 and Comparative Examples 1 and 2 using gold
In the same manner as above, while preparing each hydrogen storage alloy electrode,
Each of the hydrogen storage alloy electrodes is used as a negative electrode to form a nickel-
A hydrogen secondary battery was manufactured, and each nickel thus manufactured was manufactured.
-Initial internal pressure characteristics of the hydrogen secondary battery in each of the above cases
And the results are shown in Table 8.
Was.[0060] [Table 8] [0061]As is clear from this result, the acid solution
When the liquid temperature is in the range of 25.0 ° C to 70.0 ° C,
Example 19 in which the value of a / b became 1.20 or more as in
21 are comparative examples in which the value of a / b is lower than 1.20.
11The charging time, which indicates the internal pressure characteristics of the battery, is
It is longer, the generation of gas in the initial stage is suppressed,
Sufficient discharge capacity was obtained from the beginning.[0062] (Examples 22 to 24 and Comparative Example12) Examples 22 to 24 and Comparative Examples12In
For surface treatment of hydrogen storage alloy in acidic solution
The above Examples 13 to 15 and Comparative Example9As in
The initial pH of the acidic solution is set to 1 and the temperature of the solution is set to 25 ° C.
In addition, as shown in Table 9 below, in the above acidic solution
Aluminum hydroxide to be added Al (OH)_ThreeThe amount of
Example 22 is Example 13 and Example 23 is Example 14.
In Example 24, Example 15 and Comparative Example12Then compare
An example9While adding to the above acidic solution
By changing the amount of nthraquinone as shown in the table,
Each of the hydrogen storage alloys was subjected to a surface treatment.[0063] Where it is added to the acidic solution as described above.
Even if the amount of anthraquinone is changed
The value of a / b described above hardly changed, and that of Example 22 was actual.
The thirteenth embodiment and the twenty-third embodiment are the same as the fourteenth embodiment.
No., Example 24 is the same as Example 15 and Comparative Example
12Is a comparative example9Shows almost the same a / b value as
did.[0064] Next, each hydrogen storage compound obtained as described above was used.
In the case of Examples 1 to 3 and Comparative Examples 1 and 2 using gold
In the same manner as above, while preparing each hydrogen storage alloy electrode,
Each of the hydrogen storage alloy electrodes is used as a negative electrode to form a nickel-
A hydrogen secondary battery was manufactured, and each nickel thus manufactured was manufactured.
-Initial internal pressure characteristics of the hydrogen secondary battery in each of the above cases
And the results are shown in Table 9.
Was.[0065] [Table 9] [0066]As is evident from the results,
Anthraquinone in the range of 5 ppm to 100 ppm
In this case, the value of a / b becomes 1.20 or more as described above.
In Examples 12 to 24, the value of a / b was 1.2.
Comparative example lower than 012Pressure characteristics of the battery
The charging time, which indicates
Generation was suppressed, and a sufficient discharge capacity was obtained from the beginning. [0067] As described in detail above, the claims of the present invention are described below.
Described in 1Hydrogen storage alloy for hydrogen storage alloy electrodeHow to make
At least nickel, cobalt, aluminum
Um, manganeseContaining hydrogen storage alloy
Against the weight of the storage alloyAluminum chloride or aluminum hydroxide
In an acidic solution containing 1-5% by weight of miniumIn
Perform surface treatment30 ° from the surface of this hydrogen storage alloy
Cobalt, aluminum,
A is the sum of the abundance ratios of each atom in the hydrogen storage alloy,
Cobalt, aluminum and man in some bulk regions
When the sum of the abundance ratio of each atom of the gun is b, a / b
When satisfying the condition of ≧ 1.20, the hydrogen storage alloy
, Aluminum and manganese on the surface of
The proportion of atoms increases, and these atomic catalysis
The hydrogen storage alloy electrode using this hydrogen storage alloy.
Activity is improved from the beginning, and at low temperatures
Electronic conductivity has been improved. As a result, the first aspect of the present invention is described.
Manufactured by the methodHydrogen storage alloy for hydrogen storage alloy electrodes
Hydrogen storage alloy electrode using goldNickel-hydrogen secondary battery
Suppress gas generation in the initial stage when used for
As the battery capacity in the initial stage increases,
The rise in pressure inside the chamber is also suppressed, and
The discharge characteristics were also improved when used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a nickel-hydrogen secondary battery produced in an example of the present invention and a comparative example. [Description of Signs] 1 positive electrode 2 negative electrode (hydrogen storage alloy electrode)

────────────────────────────────────────────────── ─── Continuing on the front page (72) Nobuyuki Higashiyama, 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Prefecture Inside Sanyo Electric Co., Ltd. (72) Inventor Mamoru Kimoto 2-5-5, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Shin Fujitani 2-5-5 Keihanhondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Koji Nishio 2-5, Keihanhondori, Moriguchi City, Osaka Prefecture No. 5 Sanyo Electric Co., Ltd. (56) References JP-A-7-296846 (JP, A) WO 95/023435 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/14-4/62 B22F 1/00

Claims (1)

(57) [Claims 1] A hydrogen storage alloy containing at least nickel, cobalt, aluminum, and manganese,
Placed in an acidic solution of aluminum or aluminum hydroxide chloride was added to 5% by weight relative to the weight of the storage alloy
Surface treatment to remove 30% from the surface of this hydrogen storage alloy.
Cobalt, aluminum, up to the depth of Å
When the sum of the abundance ratios of the respective atoms of manganese is a and the sum of the abundance ratios of the respective atoms of cobalt, aluminum and manganese in the bulk region inside the hydrogen storage alloy is b, a /
The condition that b ≧ 1.20 is satisfied .
For producing a hydrogen storage alloy for a hydrogen storage alloy electrode .