JP2001035489A - Sealed alkaline storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the external leakage of an electrolyte over a long period and enhance the strength of a positive electrode molded body by solid dissolving Mn in γ-type nickel oxyhydroxide in a specified ratio, and adding cement to a positive electrode. SOLUTION: In γ-type nickel oxyhydroxide that is a positive electrode active material, Mn is solid dissolved as in 5-50 wt.% to the total quantity of Ni and Mn. According to this, the oxygen overvoltage can be increased. However, when the solid solution quantity is too small, the oxygen overvoltage is not sufficiently improved, so that repeated charge and discharge cause a leakage of electrolyte. When the solid solution quantity is too large, the quantity of γ-type nickel oxyhydroxide is relatively reduced, so that a sufficient discharge capacity cannot be obtained. When cement is added to a positive electrode, the strength of the positive electrode molded body can be enhanced. As the cement, portland cement is particularly preferred, and the mixing ratio is preferably set to 99.9:0.1-90:10 as the weight ratio of γ-type nickel oxyhydroxide: cement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed alkaline storage battery with a discharge start. The discharge-started storage battery is a storage battery that can be discharged for the first time without being charged in advance.

[0002]

2. Description of the Related Art
Manganese dioxide has been proposed as a positive electrode active material for a sealed alkaline storage battery using zinc as a negative electrode active material (see Japanese Patent Publication No. 45-3570). A mixture of nickel oxide and manganese dioxide has been proposed as a positive electrode active material of an alkaline storage battery using zinc as a negative electrode active material (see Japanese Patent Publication No. 49-114471).

However, manganese dioxide has poor reversibility in the charge / discharge cycle, and does not return to the original manganese dioxide even if charged after the first discharge, so that the discharge capacity sharply decreases in the charge / discharge cycle. In addition, since the oxygen overvoltage of manganese dioxide is low, oxygen gas (due to electrolysis of water) is generated on the positive electrode side during charging, and the internal pressure of the battery increases, and accordingly, the adhesion at the junction of the battery exterior member decreases. Therefore, the electrolyte is easily leaked to the outside. Also, when a mixture of nickel oxide and manganese dioxide is used for a storage battery, the internal pressure of the battery is likely to rise, as in the case of using manganese dioxide alone, because the oxygen overvoltage of nickel oxide, which is the active material, is low. Liquid is likely to occur.

As a positive electrode active material that can solve such a problem, the present applicant has proposed γ-type nickel oxyhydroxide in which manganese is dissolved (see JP-A-10-214621). By using γ-type nickel oxyhydroxide in which manganese is dissolved as a positive electrode active material, it is possible to obtain a highly reliable discharge-starting sealed alkaline storage battery in which the electrolyte is unlikely to leak out for a long period of the charge / discharge cycle. be able to.

In such a sealed alkaline storage battery, when zinc is used as a negative electrode active material, a so-called inside-out type structure in which a negative electrode is arranged at the center of a battery can and a positive electrode is arranged around the center is generally adopted. . That is, a hollow positive electrode is disposed inside a battery can serving as a positive electrode current collector so as to be electrically connected to the battery can, and the negative electrode is disposed inside the positive electrode. Since the positive electrode molded body is inserted into the battery can so as to be electrically connected to the battery can as described above, if the strength of the positive electrode molded body is low, cracks occur in the positive electrode molded body, and the positive electrode molded body is inserted into the battery can. Can not be done. For this reason, there has been a demand for a method for increasing the strength of the positive electrode molded body.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable sealed alkaline storage battery with a discharge start, in which electrolyte does not easily leak to the outside over a long period of charge / discharge cycles, wherein the strength of the positive electrode molded body is enhanced. It is to provide an alkaline storage battery.

[0007]

The sealed alkaline storage battery according to the present invention comprises a battery can and a γ-type nickel oxyhydroxide disposed in the battery can so as to make electrical contact with the battery can. A hollow positive electrode, a negative electrode disposed inside the positive electrode, using zinc as a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and a negative electrode disposed in the negative electrode A sealed alkaline storage battery comprising a current collector, a positive electrode, a negative electrode, and an electrolytic solution impregnated in a separator, wherein the γ-type nickel oxyhydroxide contains manganese in an amount of 5 to 50% by weight based on the total amount of nickel and manganese. % Solid solution and cement is added to the positive electrode.

Γ used as a positive electrode active material in the present invention
The type nickel oxyhydroxide has manganese (Mn) of 5 to 5
0% by weight solid solution. The manganese solid solution amount in the present invention is defined by the following equation.

Amount of solid solution of manganese (% by weight) = (amount of manganese in γ-type nickel oxyhydroxide) / (total amount of nickel and manganese in γ-type nickel oxyhydroxide) × 10
O Oxygen overpotential can be increased by dissolving manganese in γ-type nickel oxyhydroxide according to the present invention. When the solid solution amount of manganese is less than 5% by weight, the oxygen overvoltage cannot be sufficiently improved, so that leakage of the electrolyte occurs when charge and discharge are repeated. If the solid solution amount of manganese exceeds 50% by weight, the amount of γ-type nickel oxyhydroxide, which is an active material, relatively decreases, so that a sufficient discharge capacity cannot be obtained.

[0010] In the present invention, cement is added to the positive electrode. By adding cement, the strength of the positive electrode molded body can be increased. Specifically, as a method for adding cement, a positive electrode active material is mixed with a γ-type nickel oxyhydroxide, a conductive agent such as graphite powder, and an electrolytic solution to prepare a positive electrode mixture by adding cement. Method. The positive electrode mixture obtained in this manner is subjected to pressure molding to obtain a positive electrode molded body.

As the cement, hydraulic cement is preferably used, and among them, Portland cement, slag cement, alumina cement and the like are particularly preferably used.

The mixing ratio of cement is γ in the positive electrode.
Weight ratio of nickel oxyhydroxide to cement (γ-nickel oxyhydroxide: cement) is 99.9: 0.1 to
It is preferably 90:10. That is, the amount of cement defined by the following formula is preferably 0.1 to 10% by weight.

Addition amount of cement (% by weight) = Cement amount /
(Amount of manganese solid solution γ-type nickel oxyhydroxide + amount of cement) × 100 If the amount of cement is less than 0.1% by weight, the strength of the positive electrode molded body may not be sufficiently increased. If the amount of cement exceeds 10% by weight, the active material γ
Since the amount of the nickel oxyhydroxide becomes relatively small, a sufficient battery capacity may not be obtained.

In the present invention, the valence of the nickel atom in the γ-type nickel oxyhydroxide is preferably 3.4 to 3.8 before the first discharge, that is, in a fully charged state. If the valence of the nickel atom is less than 3.4, it is difficult to obtain a sufficient discharge capacity, and the electrolyte may leak during charging due to a low oxygen overvoltage. In general, there is no nickel oxyhydroxide having a valence of nickel atom larger than 3.8. Therefore, even if the charging is further continued after the fully charged state, only the water is decomposed and oxygen gas is generated, and the valence of the nickel atom does not exceed 3.8.

The γ-type nickel oxyhydroxide used in the present invention is obtained, for example, by oxidizing nickel hydroxide with an oxidizing agent such as sodium hypochlorite (NaClO). The valence of nickel can be adjusted by the amount of the oxidizing agent to be reacted.

The γ-type nickel oxyhydroxide used in the present invention further includes zinc, cobalt,
Bismuth, aluminum, yttrium, erbium,
At least one element selected from the group consisting of ytterbium and gadolinium may be dissolved. By using γ-type nickel oxyhydroxide in which these elements are dissolved, the oxygen overvoltage of the positive electrode can be further increased. The solid solution amount of these elements is preferably about 0.5 to 5% by weight. The solid solution amount is defined by the following equation.

Solid solution amount of other elements (% by weight) = (amount of other elements in γ-type nickel oxyhydroxide) / (total amount of nickel and other elements in γ-type nickel oxyhydroxide) × 1
Further, in the present invention, the positive electrode, the negative electrode, the separator, the negative electrode current collector, and the electrolyte are 75% by volume of the volume in the battery can.
It is preferable to occupy the above. Thereby, the filling amount of the active material in the battery can can be increased, and a sealed alkaline storage battery having a high discharge capacity can be obtained. Also,
In such a sealed alkaline storage battery having a high discharge capacity, it is possible to suppress an increase in the internal pressure of the battery and to prevent the electrolyte from leaking out when charging and discharging are repeated.

[0018]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

(Experiment 1) In this experiment, batteries A1 to A6 in which cement was added to γ-type nickel oxyhydroxide in which manganese was dissolved, and batteries X in which cement was not added,
Discharge capacity at the first cycle, discharge capacity retention rate at the 25th cycle, and leakage battery of comparative battery Y using manganese dioxide as the positive electrode active material and comparative battery Z using a mixture of nickel oxide and manganese dioxide as the positive electrode active material The number of occurrences was examined.

[Preparation of positive electrode] 40.4 g of manganese sulfate,
Dissolve 154.8 g of nickel sulfate in water to make the total amount 5000
ml. 10% by weight ammonia and 1%
A 0% by weight aqueous solution of sodium hydroxide was added dropwise,
Was maintained at 9.5 ± 0.3. When the pH dropped, the mixed aqueous solution was dropped, and after the pH became constant, it was mixed for 1 hour. Then, after filtration and washing with water, drying was performed at 80 ° C. to obtain nickel hydroxide in which manganese was dissolved.

To a mixture of 500 ml of a 10 mol / l aqueous sodium hydroxide solution and 1500 ml of a 10% by weight aqueous sodium hypochlorite solution, 100 g of the above-obtained nickel hydroxide powder in which manganese was dissolved was added with stirring. After stirring and mixing for 1 hour, the precipitate is filtered, washed with water,
Drying at 60 ° C. gave γ-type nickel oxyhydroxide.
At this time, it was confirmed by atomic absorption spectrometry that manganese was dissolved in a solid solution at 20% by weight based on the total amount of nickel and manganese in the γ-type nickel oxyhydroxide. The valence of the nickel atom at this time was 3.6 as a result of measurement by divalent / trivalent redox titration of iron.

The thus obtained γ-type nickel oxyhydroxide (cathode active material) and Portland cement (Denka ordinary Portland cement, manufactured by Denki Kagaku Kogyo Co., Ltd.)
100 parts by weight of a powder mixed in a weight ratio of 9: 1, 10 parts by weight of graphite powder and 10 parts by weight of a 30% by weight aqueous solution of potassium hydroxide were mixed for 30 minutes by a rapier, and pressed and molded.
1.3cm outside diameter, 0.95cm inside diameter, 1.15cm height
Was produced. This means that 1% by weight of cement was added to the total amount of γ-type nickel oxyhydroxide and cement. In addition, the positive electrode was manufactured under the condition that the pressing pressure at the time of forming the positive electrode was set to 2.8 ton / cm ² lower than usual and cracks were easily generated. In the production of the battery, this cylindrical hollow positive electrode was
They were stacked in series and used as a single cylindrical hollow body as a whole.

[Preparation of Negative Electrode] 65 parts by weight of zinc powder as a negative electrode active material, 34 parts by weight of a 40% by weight aqueous solution of potassium hydroxide containing a saturated amount of zinc oxide (ZnO), and acrylic resin as a gelling agent (Japan) (Junron PW150, manufactured by Junyaku Co., Ltd.) was mixed with 1 part by weight to prepare a gelled negative electrode.

[Preparation of Battery] Using the above-mentioned positive electrode and negative electrode, a structure commonly called “inside-out type” (the battery can side is the positive electrode side, the battery lid side is the negative electrode side: both “outside / positive type”) AA size sealed alkaline storage battery (battery of the present invention) A1 was manufactured. In addition, in order to define the discharge capacity by the positive electrode capacity, the electrochemical capacity between the positive electrode and the negative electrode was set to 1: 1.2 (all the following batteries had the same capacity ratio). Further, the volume occupied by the power generating element body composed of the negative electrode, the positive electrode, the electrolytic solution, the separator, the negative electrode current collector, and the electrolytic solution is 80% with respect to the volume in the battery can.
% By volume (all of the following batteries had the same filling rate).

FIG. 1 is a partial cross-sectional view showing the manufactured sealed alkaline storage battery. The illustrated sealed alkaline storage battery includes a cylindrical bottomed positive electrode can (positive electrode external terminal) 1, a negative electrode cover (negative electrode external terminal) 2, an insulating packing 3, a negative electrode current collector rod 4 made of brass, and a cylindrical positive electrode (nickel negative electrode). Electrode 5, a cylindrical film-shaped separator 6 mainly composed of vinylon, a gelled negative electrode (zinc electrode) 7, and the like.

In the positive electrode can 1, a positive electrode 5 is accommodated in contact with the inner peripheral surface of the cylindrical portion of the positive electrode can 1, and a separator 6 has an outer peripheral surface on the inner peripheral surface of the cylindrical hollow positive electrode 5. The separator 6 is filled with a gelled negative electrode 7 inside the separator 6. A negative electrode current collector rod (negative electrode current collector) 4 whose one end is supported by an insulating packing 3 that electrically insulates the positive electrode can 1 and the negative electrode lid 2 is inserted into the center of the negative electrode 7. The opening of the positive electrode can 1 is closed by a negative electrode lid 2. The inside of the battery is sealed by inserting an insulating packing 3 into the opening of the positive electrode can 1, placing the negative electrode cover 2 thereon, and caulking the closed end of the positive electrode can 1 inside. In the sealed alkaline storage battery according to the present embodiment, the electrode can includes a positive electrode can 1, a negative electrode lid 2, and an insulating packing 3.

In the sealed alkaline storage battery of the above embodiment, a cylindrical positive electrode is used as the hollow positive electrode. However, the present invention is not limited to this.
It may be a hollow positive electrode such as a rectangular tube.

(Experiment 2) Battery A2 was produced in the same manner as in the production of the positive electrode except that the amount of manganese sulfate was changed to 5.1 g. At this time, it was confirmed by an atomic absorption method that the manganese solid solution amount was 2.5% by weight. The valence of the nickel atom was 3.6.

(Experiment 3) Battery A3 was produced in the same manner as in the production of the positive electrode except that the amount of manganese sulfate was changed to 10.2 g. At this time, the manganese solid solution amount was confirmed to be 5% by weight by an atomic absorption method. The valence of the nickel atom was 3.6.

(Experiment 4) Battery A4 was produced in the same manner as in the production of the positive electrode except that the amount of manganese sulfate was changed to 20.2 g. At this time, the manganese solid solution amount was confirmed to be 10% by weight by an atomic absorption method. The valence of the nickel atom was 3.6.

(Experiment 5) Battery A5 was produced in the same manner as in the production of the positive electrode except that the amount of manganese sulfate was changed to 101 g. At this time, it was confirmed by an atomic absorption method that the manganese solid solution amount was 50% by weight. The valence of the nickel atom was 3.6.

(Experiment 6) Battery A6 was produced in the same manner as in the production of the positive electrode except that the amount of manganese sulfate was changed to 121 g. At this time, it was confirmed by an atomic absorption method that the manganese solid solution amount was 60% by weight. The valence of the nickel atom was 3.6.

Comparative Example 1 A battery X was produced in the same manner as in the production of the positive electrode except that no cement was added.

Comparative Example 2 100 g of manganese dioxide powder
And 15 g of graphite powder and 5 g of polyethylene resin, and further mixed with 20 ml of a 7 mol / l aqueous solution of potassium hydroxide, followed by pressure molding to produce a positive electrode. A sealed alkaline storage battery Y was produced in the same manner except that this positive electrode was used.

(Comparative Example 3) 500 ml of a 2 mol / l aqueous solution of nickel nitrate and 1500 ml of a 10% by weight aqueous solution of sodium hypochlorite were dropped and mixed into 2000 ml of a 14 mol / l aqueous solution of potassium hydroxide. The mixture was gradually cooled for 1 hour. Next, the generated precipitate was filtered, washed with water, and dried at 90 ° C. to prepare a nickel oxide powder as a positive electrode active material.

The above nickel oxide powder 50 g, manganese dioxide powder 30 g, graphite 15 g and polyethylene resin 5
g, and then mixed with 20 ml of a 7 mol / l aqueous solution of potassium hydroxide, followed by pressure molding.
A positive electrode was produced.

A sealed alkaline storage battery Z was produced in the same manner except that this positive electrode was used.

(Crack Generation Rate of Positive Electrode) The crack generation rate generated when the molded positive electrode was inserted into a battery can was determined by the following equation. Crack generation rate (%) = (number of positive electrodes with cracks)
Table 1 shows the results.

(Capacity Retention Rate and Number of Generated Leakage Batteries in Various Charge and Discharge Cycles of Each Battery) The above nine types of sealed alkaline storage batteries differing only in the positive electrode active material were 100 m
After discharging until the battery voltage becomes 1 V at 100 A, 100 mA
A charge / discharge cycle test was performed in which the charge step was performed until the battery voltage reached 1.95 V (1.65 V in Comparative Example 2). The capacity retention ratio and the number of leaked batteries generated were examined.

Incidentally, ten batteries were manufactured for each. Table 1 shows the results. The discharge capacity at the first cycle in Table 1 is an index with the capacity at the first cycle of the battery A1 as 100. The capacity retention rate at the 25th cycle is a ratio (%) to the discharge capacity at the first cycle of each battery, and is an average value of the capacity retention rates of the batteries in which the electrolyte did not leak.

[0041]

[Table 1]

As is clear from the results shown in Table 1, a battery A1 using a positive electrode prepared by adding cement to γ-type nickel oxyhydroxide in which manganese is solid-dissolved in an amount of 5 to 50% by weight is added.
In addition, A3 to A5 have no cracks in the positive electrode, and are excellent in cycle characteristics and leakage resistance.

It is considered that the reason why the number of leaked batteries generated in the battery A2 is large is that the oxygen overvoltage cannot be sufficiently improved due to the small amount of solid solution of manganese. Battery A6
It is considered that the reason why the discharge capacity in the first cycle is small is that the amount of γ-type nickel oxyhydroxide, which is an active material, is relatively reduced due to the large amount of solid solution of manganese.

The reason why the positive electrode crack generation rate of the comparative battery X is high is considered to be that the strength of the positive electrode molded product was insufficient because no cement was added. The reason why the discharge capacity of the comparative battery Y is low is considered to be that the crystal structure has changed. In addition, it is considered that the liquid leakage resistance is poor because the oxygen overvoltage of the positive electrode is low.

The reason why the discharge capacity of the comparative battery Z is low is that oxygen overvoltage is low because manganese is not dissolved in the positive electrode active material, the charge acceptability is low, and as a result, the active material utilization rate is low. It is thought that it became. It is considered that the liquid leakage resistance is poor because the oxygen overvoltage of the positive electrode is low.

(Experiment 2) In this experiment, the amount of cement to be added was examined. In the preparation of the positive electrode, the mixing ratio of γ-type nickel oxyhydroxide containing 20% by weight of manganese in solid solution and cement was 99.95: 0.05, 99.9: 0.
Batteries B1 to B6 were produced in the same manner, except that 1, 97: 3, 95: 5, 90:10, and 88:12. At this time, the valence of the nickel atom was 3.6.

Experiment 1 for each of these batteries B1 to B6
A charge / discharge cycle test was performed under the same conditions as
The battery capacity at the cycle, the battery capacity at the 25th cycle, and the number of leaked batteries were examined. The crack generation rate of the positive electrode molded body was measured in the same manner as in Experiment 1.

Table 2 shows the results. The discharge capacity at the first cycle in Table 2 is 100% of the capacity at the first cycle of the battery A1.
Is an index. The capacity retention rate at the 25th cycle is a ratio (%) to the discharge capacity at the 1st cycle of each battery. A1 is the same battery as A1 in Table 1.

[0049]

[Table 2]

From the results shown in Table 2, it can be seen that in order to prevent cracks from occurring in the positive electrode and obtain a high discharge capacity, it is preferable to add 0.1 to 10% by weight of cement in the positive electrode. It is considered that the reason why the crack generation rate of the comparative battery B1 is high is that the strength of the positive electrode molded body could not be sufficiently increased due to the small amount of cement added. Further, it is considered that the reason why the discharge capacity of the comparative battery B6 is low is that the amount of the cement added was increased and the amount of the γ-type nickel oxyhydroxide as the active material was reduced.

(Experiment 3) In this experiment, the relationship between the valence of nickel atoms in γ-type nickel oxyhydroxide, the battery capacity, and the liquid leakage was examined.

In "Preparation of the positive electrode" of Experiment 1, the amount of the 10% by weight aqueous solution of sodium hypochlorite mixed with 500 ml of the aqueous sodium hydroxide solution was changed to 1500 ml.
The sealed alkaline storage batteries D1 to D3 were produced in the same manner as the production of the battery A1, except that 1350 ml, 1400 ml, or 1600 ml was used. The valence of the nickel atom at this time is 3.3, 3.4, 3.8.
The manganese in the active material had a solid solution amount of 20% by weight. The mixing ratio of manganese solid solution γ-type nickel oxyhydroxide and cement was 99: 1. These D1 to D
A charge / discharge cycle test was performed on each of the batteries No. 3 under the same conditions as those used in Experiment 1, and the battery capacity in the first cycle, the battery capacity in the 25th cycle, and the number of leaked batteries were examined. The crack generation rate of the positive electrode was measured in the same manner as in Experiment 1.

Table 3 shows the results. The discharge capacity at the first cycle in Table 3 is 100% of the capacity at the first cycle of the battery A1.
Is an index. The capacity retention rate at the 25th cycle is a ratio (%) to the discharge capacity at the first cycle of each battery, and is an average value of the capacity retention rates of the batteries in which the electrolyte did not leak. A1 is the same battery as A1 in Table 1. The crack generation rate of the positive electrode was 0% in each case.
Met.

[0054]

[Table 3]

As apparent from the results shown in Table 3, in order to obtain a battery having a large battery capacity, γ-type nickel oxyhydroxide having a valence of nickel atom of 3.4 to 3.8 was used as a positive electrode active material. It turns out that it is preferable to use.

(Experiment 4) In this experiment, the effect of elements dissolved in solid solution other than manganese was examined. The definition of the amount of solid solution is shown below. Solid solution amount (% by weight) = (amount of solid solution element other than manganese in γ-type nickel oxyhydroxide) / (amount of nickel in γ-type nickel oxyhydroxide + amount of solid solution element other than manganese) × 10
0

(Experiment 4-1) In the preparation of the positive electrode of Experiment 1, zinc sulfate was used in addition to manganese sulfate and nickel sulfate at 1.4.
A battery E1 was made in the same manner except that 6 g was dissolved. At this time, it was confirmed by an atomic absorption method that the solid solution amount of zinc was 1% by weight and the solid solution amount of manganese was 20% by weight.
The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. The mixing ratio between the active material and the cement was 99: 1.

(Experiment 4-2) Battery E2 was produced in the same manner as in Experiment 1, except that 1.55 g of cobalt sulfate was dissolved in addition to manganese sulfate and nickel sulfate. At this time, it was confirmed by atomic absorption spectroscopy that the solid solution amount of cobalt was 1% by weight and the solid solution amount of manganese was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. The mixing ratio between the active material and the cement was 99: 1.

(Experiment 4-3) Battery E3 was produced in the same manner as in Experiment 1, except that 0.86 g of bismuth sulfate was dissolved in addition to manganese sulfate and nickel sulfate. At this time, it was confirmed by an atomic absorption method that the amount of bismuth in the solid solution was 1% by weight and the amount of manganese in the solution was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. The mixing ratio between the active material and the cement was 99: 1.

(Experiment 4-4) Battery E4 was produced in the same manner as in Experiment 1 except that 3.74 g of aluminum sulfate was dissolved in addition to manganese sulfate and nickel sulfate.
Was prepared. At this time, it was confirmed by an atomic absorption method that the solid solution amount of aluminum was 1% by weight and the solid solution amount of manganese was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. In addition,
The mixing ratio of the active material and the cement was 99: 1.

(Experiment 4-5) Battery E5 was produced in the same manner as in Experiment 1 except that 1.55 g of yttrium sulfate was dissolved in addition to manganese sulfate and nickel sulfate.
Was prepared. At this time, it was confirmed by emission spectroscopy (ICP) that the amount of yttrium dissolved in solid was 1% by weight. Further, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. In addition,
The mixing ratio of the active material and the cement was 99: 1.

(Experiment 4-6) Battery E6 was produced in the same manner as in Experiment 1 except that 1.10 g of erbium sulfate was dissolved in addition to manganese sulfate and nickel sulfate. At this time, it was confirmed by luminescence analysis (ICP) that the solid solution amount of erbium was 1% by weight. Further, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. The mixing ratio between the active material and the cement was 99: 1.

(Experiment 4-7) Battery E was produced in the same manner as in Experiment 1 except that 1.08 g of ytterbium sulfate was dissolved in addition to manganese sulfate and nickel sulfate.
7 was produced. At this time, the solid solution amount of ytterbium is 1
The weight% was confirmed by emission spectrometry (ICP).
Further, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. The mixing ratio between the active material and the cement was 99: 1.

(Experiment 4-8) Battery E8 was manufactured in the same manner as in Experiment 1, except that 1.13 g of gadolinium sulfate was dissolved in addition to manganese sulfate and nickel sulfate in the preparation of the positive electrode.
Was prepared. At this time, it was confirmed by an emission spectrometry (ICP) that the solid solution amount of gadolinium was 1% by weight. Further, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 20% by weight. The valence of nickel was determined by iron bivalent / trivalent redox titration to be 3.6. In addition,
The mixing ratio of the active material and the cement was 99: 1.

(Experiment 4-9) A battery E9 was produced in the same manner as in the experiment 1 except that 1.10 g of erbium sulfate and 3.74 g of aluminum sulfate were dissolved in addition to manganese sulfate and nickel sulfate. . At this time,
It was confirmed by emission spectrometry (ICP) that the solid solution amount of erbium was 1% by weight. Further, it was confirmed by an atomic absorption method that the amount of solid solution of aluminum was 1% by weight and the amount of solid solution of manganese was 20% by weight. The valence of nickel is 2/3 of iron
As a result of quantification by titration redox titration, it was 3.6.
The mixing ratio between the active material and the cement was 99: 1.

Experiment 1 on each of these batteries E1 to E9
A charge / discharge cycle test was performed under the same conditions as
The battery capacity at the cycle, the battery capacity at the 25th cycle, and the number of leaked batteries were examined. Further, the crack generation rate of the molded positive electrode was measured in the same manner as in Experiment 1.

Table 4 shows the results. The discharge capacity at the first cycle in Table 4 is 100 times the capacity at the first cycle of the battery A1.
Is an index. The capacity retention rate at the 25th cycle is a ratio (%) to the discharge capacity at the first cycle of each battery, and is an average value of the capacity retention rates of the batteries in which the electrolyte did not leak. A1 is the same battery as A1 in Table 1.

[0068]

[Table 4]

As is clear from the results shown in Table 4, in addition to manganese, zinc, cobalt, bismuth, aluminum,
It can be seen that excellent properties can be obtained even when at least one element selected from the group consisting of yttrium, erbium, ytterbium, and gadolinium is dissolved.

[0070]

According to the present invention, there is provided a sealed alkaline storage battery having a highly reliable discharge start, in which the electrolyte is unlikely to leak to the outside over a long period of the charge / discharge cycle, in which the strength of the molded positive electrode is increased. A sealed alkaline storage battery can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a sealed alkaline storage battery of one embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Positive electrode can 2 ... Negative electrode cover 3 ... Insulating packing 4 ... Negative current collector rod 5 ... Positive electrode 6 ... Separator 7 ... Gelled negative electrode

Continuing from the front page (72) Inventor Mamoru Kimoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Yasuhiko Ito 2-5-25 Keihanhondori, Moriguchi-shi, Osaka No. Sanyo Electric Co., Ltd. F-term (reference) 5H003 AA04 BB02 BB04 BB11 BD00 BD04 5H016 AA03 AA08 AA10 EE01 EE05 HH00 HH01 5H028 AA01 AA05 AA07 CC17 EE01 EE05 EE08 HH00 HH01

Claims (4)

[Claims] 1. A battery can, a hollow positive electrode using gamma-type nickel oxyhydroxide as a positive electrode active material, and a hollow positive electrode disposed in the battery can so as to be in electrical contact with the battery can. A negative electrode, which is disposed on the inside and has zinc as a negative electrode active material,
A separator disposed between the positive electrode and the negative electrode, a negative electrode current collector disposed in a state inserted in the negative electrode,
A sealed alkaline storage battery comprising the positive electrode, the negative electrode, and an electrolyte impregnated in the separator, wherein the γ-type nickel oxyhydroxide contains manganese in an amount of 5 to 50% by weight based on the total amount of nickel and manganese. Solid solution,
A sealed alkaline storage battery characterized in that cement is added to the positive electrode. 2. The weight ratio of γ-type nickel oxyhydroxide to cement in the positive electrode is 99.9: 0.1-9.
2. The sealed alkaline storage battery according to claim 1, wherein the ratio is 0:10. 3. The sealed alkali according to claim 1, wherein the valence of the nickel atom in the γ-type nickel oxyhydroxide before the first discharge is 3.4 to 3.8. Storage battery. 4. The γ-type nickel oxyhydroxide further comprises at least one element selected from the group consisting of zinc, cobalt, bismuth, aluminum, yttrium, erbium, ytterbium and gadolinium in addition to manganese. The sealed alkaline storage battery according to any one of claims 1 to 3, wherein: