JP3092222B2 - Nickel hydroxide active material and nickel positive electrode and alkaline storage battery using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline storage battery using nickel oxide for a positive electrode, a hydrogen storage alloy capable of electrochemically storing and releasing hydrogen, cadmium or zinc for a negative electrode. (Nickel hydroxide) and the improvement of the positive electrode characteristics.

[0002]

2. Description of the Related Art Lead-acid batteries and nickel-cadmium batteries (hereinafter referred to as nickel-cadmium batteries) that are currently in practical use are:
Widely used in portable equipment. Although lead-acid batteries are inexpensive, they generally have low energy density per unit weight (Wh / kg) and have problems in cycle life, etc., and are not suitable as a power source for small and lightweight portable devices.

On the other hand, nickel-cadmium batteries have a higher energy density per unit weight and volume than lead-acid batteries, and are superior in reliability such as cycle life. Therefore, nickel-cadmium batteries are widely used as power sources for various portable devices. ing. However, since the load on the battery increases with the added value of the portable device, a secondary battery with a higher energy density has been desired as a power source for the portable device. In the field of nickel-cadmium batteries, nickel-cadmium batteries having 30 to 60% higher capacity than conventional nickel-cadmium batteries using sintered nickel positive electrodes have been developed. A nickel-hydrogen storage battery using a hydrogen storage alloy for a negative electrode having a higher capacity than a nickel-cadmium battery (more than twice as large as a nickel-cadmium battery using a sintered nickel positive electrode) has been developed. In order to improve the energy density of the positive electrode, these high-capacity alkaline storage batteries have a high density (more than 90%) of a three-dimensional porous nickel foam or nickel fiber porous body filled with nickel hydroxide powder at a high density. doing. As a result, the energy of a conventional sintered nickel positive electrode - whereas density of 400~450mAh / cm ^3, it said nickel positive electrode is 500~630mAh / cm ^3.

However, a positive electrode in which nickel hydroxide powder is densely filled in foamed nickel or a porous nickel fiber has a problem that the cycle life characteristic is deteriorated although the energy density is high. This is due to the high volume of γ-
NiOOH is formed on the positive electrode to expand the positive electrode,
This is because the battery absorbs the electrolyte present in the battery, increases the internal resistance of the battery, and decreases the discharge capacity. In order to solve this problem, the following methods have been proposed. (1) A method of adding cadmium oxide powder to nickel hydroxide powder to suppress generation of γ-NiOOH. (2) A method of adding zinc, zinc oxide, and zinc compound powder to nickel hydroxide powder to suppress γ-NiOOH generated during charging (JP-A-59-112574). (3) A method of containing cadmium oxide inside nickel hydroxide powder, or a method of using zinc or cadmium as a solid solution to form
The addition of 10 wt% prevents the development of internal fiber pores with a pore radius of 30 mm or more, and further reduces the total pore volume to 0.05 cm ³ /
g or less to suppress γ-NiOOH generated during charging (Japanese Patent Application Laid-Open No. 61-104565,
0061, USP-4844999).

[0005]

According to the above-mentioned methods (1) and (2), cadmium oxide and zinc oxide powders are added to nickel hydroxide powder to obtain γ-NiOOH. Although the generation is suppressed and the cycle life characteristics are improved, the life characteristics are not dramatically improved. In particular, as the battery capacity increases, that is, as the energy density of the positive electrode increases, the effect of adding cadmium oxide or zinc oxide powder decreases. Under a low temperature (0 ° C.) atmosphere, the cycle life of an alkaline storage battery using a positive electrode having an energy density of 600 mAh / cm ³ is about 200 cycles. This suggests that it is difficult to suppress the generation of γ-NiOOH only by adding cadmium oxide or zinc oxide powder with increasing energy density. Therefore, it is necessary to improve the particle structure or crystal structure of the active material powder.

In the method (3), cadmium oxide, zinc or cadmium is present as a solid solution inside the crystal of the nickel hydroxide powder, as in the conventionally proposed method. Γ-NiOOH generated during charging is suppressed as compared with the case where zinc oxide powder is mixed with nickel hydroxide, and the cycle life is improved. However, since the development of internal fiber pores of 30 ° or more is prevented, the electrolyte does not easily enter the inside of the nickel hydroxide particles, and the active material utilization rate at the initial stage of charge / discharge is as low as about 70%.

In addition, since the electrolyte does not easily enter the inside of the nickel hydroxide particles, the electrolyte becomes uneven inside the nickel hydroxide particles, and the current density locally increases, and the γ-N
iOOH is easily generated. As a result, low temperature (0 ° C)
The cycle life under an atmosphere is about 300 cycles.

Further, in the process of producing such nickel hydroxide, ammonium sulfate is used, so that ammonium is present as an impurity in the nickel hydroxide powder, and this ammonium promotes self-discharge of the battery.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. A nickel hydroxide active material having a simple structure, having a high utilization rate of active materials at the initial stage of charge and discharge, and having excellent cycle life characteristics and self-discharge characteristics at low temperatures. It is an object of the present invention to provide a substance, a nickel positive electrode, and an alkaline storage battery using the same.

[0010]

According to the present invention, a nickel hydroxide active material powder used for a nickel positive electrode is selected from the group consisting of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese. 1 to 7 wt% of nickel hydroxide active material powder
% Of the primary particles are particles in which countless primary particles of 0.1 μm or less are aggregated, and a space volume having a pore radius of 30 ° or more accounts for 20 to 70% of the total space volume.

[0011] At least one member selected from the group consisting of cobalt, cobalt hydroxide, zinc oxide, zinc, cadmium and cadmium oxide is added to the nickel hydroxide powder.
It is a nickel positive electrode filled or coated on a three-dimensional porous body or a flat plate.

Further, a nickel positive electrode mainly composed of nickel oxide, a negative electrode mainly composed of a hydrogen storage alloy or cadmium oxide capable of electrochemically storing and releasing hydrogen, and an alkaline electrolyte And before the first charge and discharge, the nickel positive electrode contains at least one member selected from the group consisting of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese in a nickel hydroxide active material powder. 1-7
A nickel hydroxide powder containing 0.1% or less by mass of primary particles having a pore radius of 30 ° or more with respect to a total volume of 20 to 70% of the total space volume. , Cobalt hydroxide, zinc oxide, zinc,
A nickel positive electrode mainly composed of a three-dimensional porous body or a flat plate that supports a powder to which at least one of the group consisting of cadmium and cadmium oxide is added and imparts conductivity is used, and the specific gravity of the alkaline electrolyte is 1. 23-1.4
And the amount of electrolyte per 1 Ah of battery capacity is 1.0 to
The configuration was maintained at 2.0 cm ³ / Ah.

[0013]

According to this structure, a space volume having a pore radius of 30 ° or more is added to the entire space volume by 20 to 70%.
%, It is easy for the electrolyte to enter the inside of the particles, and γ-NiOO due to uneven distribution of the electrolyte inside the particles.
H generation is suppressed.

Furthermore, since the primary particles having a particle size of 0.1 μm or less are innumerably aggregated and the electrolyte can easily enter the inside of the particles, the utilization rate of the active material at the initial stage of charge / discharge is improved. In addition, as a nickel positive electrode, by adding cobalt and cobalt hydroxide to the nickel hydroxide powder of the present invention, the utilization rate of the active material is improved, and any one of zinc oxide, zinc, cadmium and cadmium oxide is added. By doing so, the expansion of the nickel positive electrode is suppressed, and the charge / discharge cycle life is improved. Therefore, by filling or applying the nickel hydroxide powder of the present invention and the additive to a three-dimensional porous body or a flat plate, the energy density is high,
A positive electrode having excellent cycle life characteristics can be obtained.

The positive electrode of the present invention comprises a negative electrode mainly composed of a hydrogen storage alloy or cadmium oxide capable of electrochemically storing and releasing hydrogen, an alkaline electrolyte, and a separator. In alkaline storage batteries,
By setting the specific gravity of the alkaline electrolyte to 1.23 to 1.4, the supply of protons to nickel hydroxide becomes easy,
The initial charge / discharge efficiency is improved. When the amount of the electrolyte is 1.0
By setting it to 2.0 cm ³ / Ah, the electrolyte can be appropriately distributed in the positive electrode, the negative electrode and the separator, and an alkaline storage battery having an excellent cycle life can be obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

Example 1 The nickel hydroxide powder used in this example was prepared as follows. The nickel hydroxide powder contains 0.3 wt% and 3.5 wt% of cobalt and zinc in nickel hydroxide, respectively.
The composition was contained as a wt% solid solution. Nickel sulfate, cobalt sulfate and zinc sulfate were dissolved in water at a predetermined ratio to prepare a mixed aqueous solution in which ions of nickel, cobalt and zinc were dissolved. Next, while supplying a fixed amount of this mixed aqueous solution and sodium hydroxide to the reaction vessel, the temperature was increased to 35 ° C.
The pH was kept constant at 11.3, and the mixture was vigorously stirred.
Primary particles having a particle size of 1 μm or less were prepared, and nickel hydroxide in which the primary particles were innumerably aggregated was continuously formed using the particles as nuclei.

The nickel hydroxide powder is heated at 50 ° C. to remove metal salts such as sodium hydroxide and nickel sulfate.
Was washed with water and dried at 80 ° C. to prepare a nickel hydroxide powder.

According to this method, nickel hydroxide can be produced continuously without forming a complex with ammonium. Next, only the pH of the reaction tank was adjusted to 11.0, 11.1, 11.5 and 1 in the same manner as described above.
It changed to 1.6 and the nickel hydroxide powder was produced continuously.

As shown in FIG. 1, these prepared nickel hydroxide powders have a primary particle diameter of 0.1 μm or less. Next, the physical properties of nickel hydroxide prepared under various pH conditions are shown in (Table 1).

[0021]

[Table 1]

The spatial volume ratio in Table 1 is such that the pore radius is 10
The ratio of the space volume of 30 ° or more to the total space volume of 200 °. In addition, No. 1 was determined by atomic absorption analysis. As a result of analyzing Zn and Co contained in the nickel hydroxide powders of A to E, 3.45 wt% of Zn was contained and 0.32 wt% of Co was contained. In addition, it is difficult to measure the pore distribution of 10 ° or less by the method using adsorption of nitrogen gas.
It is considered that a space having the following pores exists.
The tap density is a 20cc graduated cylinder with a weight of Ag.
Was charged with nickel hydroxide powder, and after tapping 200 times, the weight (including nickel hydroxide powder) Bg of the graduated cylinder and the volume Dcc of nickel hydroxide were measured and determined by the following equation. Tap density = (BA) / D A positive electrode was prepared by the following method using five types of nickel hydroxide powders A to E. Nickel hydroxide powder, cobalt powder and cobalt hydroxide powder in a weight ratio of 100:
After mixing at a ratio of 7: 5, water was added to the mixture and kneaded to form a paste. The support had a porosity of 95% and an areal density of 30.
The foamed nickel porous body of 0 g / m ² was filled, dried, pressurized, and immersed in an aqueous solution in which a fluororesin powder was dispersed. Then, after drying again, it was cut into a predetermined size to prepare a nickel positive electrode having a capacity of 1400 mAh. The negative electrode was prepared by the following method. The alloy composition is MmNi3.6Co0.7Mn
0.4 Al0.3 (Mm is a misch metal and a mixture of rare earth elements). The misch metal Mm, which is a mixture of rare earth elements, and each sample of Ni, Co, Mn, and Al are put in an arc furnace, evacuated to 10 ^-4 to 10 ^-5 torr, and then decompressed in an argon gas atmosphere. Arc discharge in the state,
It was dissolved by heating. In vacuum to homogenize the sample, 1
Heat treatment was performed at 050 ° C. for 6 hours. After coarsely pulverizing the obtained alloy ingot, a powder having an average particle diameter of 20 μm was obtained using a wet ball mill. This powder was treated while being stirred for 1 hour in a 7.2 mol aqueous potassium hydroxide solution at 80 ° C.
The powder was washed with water to remove potassium hydroxide from the alloy powder, and dried to obtain a hydrogen storage alloy powder used for the negative electrode. Water and carboxymethyl cellulose (CMC) are added to the hydrogen storage alloy powder to form a paste, which is filled into a foamed nickel porous body having a porosity of 95%, dried, pressurized.
The resultant was cut into a predetermined size to prepare a hydrogen storage alloy negative electrode. As the separator, a sulfonated separator obtained by sulfonating a nonwoven fabric made of polypropylene and polyethylene was used.

The negative electrode 1 and the positive electrode 2 formed as described above were swirled through a separator 3 and inserted into a case 4 also serving as a negative electrode terminal. Then, 20 g / l of lithium hydroxide was added to an aqueous solution of potassium hydroxide having a specific gravity of 1.30.
2.4 cm ^{3 of the} dissolved alkaline electrolyte was injected, the case 4 was sealed with a sealing plate 7 provided with a positive electrode terminal 5 and a safety valve 6, and a battery having a capacity of 1400 mAh in which the battery capacity was regulated by the positive electrode. A 5 A size sealed nickel-metal hydride storage battery was constructed. FIG. 2 shows the structure of the prepared battery. In the drawing, 8 is an insulating gasket, 9 is a positive electrode current collector for electrically connecting the positive electrode 2 and the sealing plate 7. Five types of batteries (corresponding to the above A to E) having different nickel hydroxides of the positive electrode were prepared with the same configuration as in FIG. Using these batteries, an active material utilization test of nickel hydroxide, which was a positive electrode active material, was performed under the following conditions. In a 20 ° C. environment, the battery was charged at a charging current of 0.1 CmA at a charging current of 0.1 CmA, that is, 150% of the theoretical capacity calculated from the nickel hydroxide active material, paused for 1 hour, and then stopped at 0.
Continuous discharge was performed up to 1.0 V at a constant discharge current of 2 CmA. Charge / discharge was repeated 5 times by this method, and the active material utilization rate in each cycle was calculated. The active material utilization was calculated by the following equation. Active material utilization rate = (discharge capacity up to 1.0 V / theoretical nickel hydroxide capacity) × 100 (Table 2)
9 shows the results of examining the active material utilization rates in the batteries using the nickel hydroxides of Nos. To E.

[0024]

[Table 2]

As apparent from (Table 2), no. The utilization rate of nickel hydroxide of A is 80% in the first cycle, and the utilization rate after repeating 5 cycles of charge / discharge is 85%.
It is. This is because the space volume having a pore radius of 30 ° or more is 17% of the total space volume. This correlates with a specific surface area of 8.6 m ² / g and a small total space volume of 0.01 cm ³ / g. Therefore, it is difficult for the electrolyte solution to penetrate into the inside of the pores of the nickel hydroxide particles, and as a result, the effective nickel hydroxide involved in the charge / discharge reaction decreases. Low. Further, even if the charge / discharge cycle is repeated, the utilization rate is improved only by about 5%. No. The nickel hydroxide powder of E has a space volume ratio of 78%, a specific surface area of 25.6 m ² / g and a total space volume of 0.06 cm ³ / g. Therefore, the nickel hydroxide powder can sufficiently contain an electrolytic solution, and the utilization rate in the first cycle is as high as 95%. But,
Since the tap density is as low as 1.8 g / cm ³ , the filling property is reduced, and the packing density, that is, the capacity density is reduced.

From the above, it is apparent that nickel hydroxide is
Has a pore radius of 200 ° and a space volume ratio of 20 to 70%
Indicates an excellent active material utilization rate. Spherical nickel hydroxide having such properties has a reaction pH of 11.3 ± 0.3.
It can be obtained by controlling in the range of 2. The BET specific surface area and the space volume of the pores have a correlation with the space volume ratio.
o. 10 to 20 m ² / g shown in B, C and D and 0.015 to
It is preferable to control so as to be 0.04 cm ³ / g.
In addition, the tap density and average particle size of the nickel hydroxide powder are important for the filling property of the electrode. If the tap density is low, the filling density of the nickel hydroxide in the electrode, that is, the capacity density, is reduced, and the actual battery capacity is reduced. Decrease. The average particle size is related to the viscosity of the paste containing nickel hydroxide. By controlling the average particle size to an appropriate value, it becomes possible to fill or coat the support. Therefore, the tap density and the average particle diameter are preferably 1.9 g / cm ³ or more and 7 to 20 μm, respectively.

Example 2 When ammonia remained in nickel hydroxide, no.
In order to examine how the self-discharge characteristics of a battery having the same configuration as that of battery No. C change, in the battery containing no.
C-1 and C-2 batteries were prepared, respectively. Other than the above, No. 1 of Example 1 was used. Battery configuration conditions similar to C were set. The self-discharge characteristics were tested under the following conditions. In an atmosphere of 20 ° C., charging was performed at 0.1 CmA for 15 hours, and after resting for 1 hour, discharging was performed to 1.0 V with a discharging current of 0.2 CmA, and the discharge capacity (A) was calculated. Next, at 20 ° C
Under an atmosphere of 0.1 CmA for 15 hours, and left in a charged state at 45 ° C. for 14 days.
The battery was discharged to 1.0 V at a discharge current of 0.2 CmA in an atmosphere of ° C., and the discharge capacity (B) was calculated. Next, a capacity retention ratio representing a self-discharge characteristic was obtained by the following equation. Capacity maintenance rate (%) = discharge capacity (B) / discharge capacity (A) × 100 (Table 3) C and the comparative example No. 5 shows the self-discharge characteristics of the batteries C-1 and C-2.

[0028]

[Table 3]

As is evident from the results in Table 3, when ammonia is contained, the capacity retention rate when left at a high temperature decreases. Therefore, in the case of producing nickel hydroxide by forming a complex of ammonia, the self-discharge characteristic is lowered because ammonia remains in the nickel hydroxide powder even if washing is performed sufficiently. On the other hand, the nickel hydroxide powder of the present invention does not contain ammonia in the production process, and thus exhibits excellent self-discharge characteristics.

(Embodiment 3) Using the same nickel hydroxide powder as in C, a positive electrode having the composition (weight ratio) shown in Table 4 was prepared.
The positive electrode was prepared in the same manner as in Example 1.

[0031]

[Table 4]

Next, No. Example 1 using positive electrodes F to I
The same battery as in Example 1 was produced in combination with the negative electrode used in Example 1. Using these batteries, a test of the active material utilization rate and the charge / discharge cycle life of nickel hydroxide as a positive electrode active material was performed under the following conditions. The active material utilization rate was set to a constant current of 0.2 CmA at a charging current of 0.1 CmA under an environment of 20 ° C., charging 150% of the positive electrode capacity, that is, the theoretical capacity calculated from the nickel hydroxide active material, performing a 1-hour pause. Continuous discharge was performed to a discharge current of 1.0 V. Charge and discharge by this method
Repeated times, the active material utilization rate in the second cycle was calculated. The active material utilization was calculated by the following equation. Active material utilization rate =
(Discharge capacity up to 1.0 V / nickel hydroxide theoretical capacity)
× 100 charge / discharge cycle life is 1 Cm under 0 ° C environment
The battery was charged for 1.3 hours with a charging current of A, and then continuously discharged to 1.0 V with a discharging current of 1 CmA.

The charge and discharge were repeated under these conditions, and the point at which the discharge time was reduced to 60% of the initial continuous discharge time was defined as the cycle life. No. in “Table 5” The results of the active material utilization rates and the cycle life of FI are shown.

[0034]

[Table 5]

Even when the nickel hydroxide powder of the present invention shown in Example 1 was used, the active material utilization and the charge / discharge cycle life characteristics differed depending on the positive electrode composition shown in (Table 4). No. When the positive electrode is composed only of the nickel hydroxide powder of the present invention F, the utilization ratio of the active material is as low as 82.3%. On the other hand, the positive electrode No. When G to I are used, the active material utilization is 94.8 to 95.5%, which indicates excellent characteristics. When the nickel hydroxide of the present invention is used, it is necessary to make cobalt or cobalt hydroxide coexist with nickel hydroxide in order to improve the utilization factor. The addition amounts of cobalt and cobalt hydroxide are preferably in the range of 4 to 18 parts by weight and 0 to 10 parts by weight, respectively, with respect to 100 parts by weight of nickel hydroxide powder from the viewpoint of substantial discharge capacity. That is, when the cobalt content is less than 4 parts by weight, the utilization rate decreases, and the actual discharge capacity decreases. Also,
When the addition amount of cobalt is more than 18 parts by weight, the utilization rate of the active material is as good as 95% or more, but the packing density is reduced, so that the substantial discharge capacity is reduced. The above range is preferable since the amount of cobalt hydroxide added shows a similar tendency.

The charge / discharge cycle life was No. With a positive electrode composition of F to I, 500 or more charge / discharge cycles are possible even in an atmosphere at 0 ° C. N containing zinc oxide
o. When the positive electrode of I was used, the cycle life characteristic was 750.
Very good with the cycle. Therefore, it is necessary to make zinc oxide coexist with nickel hydroxide powder in order to have better life characteristics. The addition amount is suitably from 0 to 10 parts by weight with respect to 100 parts by weight of nickel hydroxide.
It falls below. In addition, cadmium oxide, cadmium,
Zinc and the like also show a similar effect of improving cycle life,
These addition amounts are preferably in the range of 0 to 10 parts by weight.

In this embodiment, the support has a surface density of 300 g /
m ² foamed nickel porous material was used, but the area density was 200
The same effect is exhibited in the range of up to 700 g / m ² . Also,
Similar effects can be obtained by using a punched metal or a flat plate, which is a kind of three-dimensional porous body, in addition to the foamed nickel porous body. (Example 4) C and the nickel hydroxide powder of Example 2 Using the positive electrode of I and changing the specific gravity and amount of the electrolytic solution, a battery similar to that of Example 1 was produced. No. of the created battery The relationship between the specific gravity of the electrolyte and the electrolyte and the amount of the electrolyte is shown in (Table 6). The results obtained by performing a utilization factor and a cycle life test under the same conditions as in Example 3 using these batteries are also shown in (Table 6).

[0038]

[Table 6]

No. In the case of the battery of J, when the specific gravity of the electrolyte is as low as 1.20, the utilization factor is 88.2%, and the battery capacity is reduced. In addition, the electrolyte having a specific gravity of 1.43, which is high, had a specific gravity of 1.43. In the case of N, the cycle life is reduced to 450 cycles. On the other hand, N
o. In the case of K to M, the utilization rate is 93.5 to 96%,
The cycle life is 650 to 770, which indicates excellent characteristics. Accordingly, the specific gravity of the electrolyte solution was No. The range of 1.23 to 1.40 for batteries KM is optimal. No. 1 having an electrolyte volume of 1.3 cc. Since the O battery is insufficient for the nickel hydroxide of the present invention, both the utilization factor and the cycle life decrease. In addition, in the case of No. 3 in which the amount of the electrolytic solution was 3.0 cc. The S battery has a good utilization rate of 95%, but has a lower cycle life than the case of 2.8 cc. This is because when the battery is charged with a current value of 1 CmA because of the large amount of electrolyte, the absorption reaction of oxygen gas generated from the cathode during overcharge at the anode decreases at the anode, and the gas and electrolyte leak from the safety valve. The life is shortened. No. The battery capacity of P to R is 1.4
Since it is Ah, the amount of electrolyte per Ah is 1.
0, 1.43, and 2.0. From the above, it is preferable that the specific gravity of the alkaline electrolyte is 1.23 to 1.40 and the amount of the electrolyte is 1.0 to 2.0 cm ^{3 /} Ah. In addition,
The lithium hydroxide (LiOH) contained in the electrolyte is 10%.
When the content is not more than g / l, the discharge voltage is significantly reduced. In this embodiment,
Although the case where an AB ₅ -based hydrogen storage alloy is used for the negative electrode is shown, similar effects can be obtained by using an AB or AB ₂ -based hydrogen storage alloy such as titanium, a cadmium negative electrode, or a zinc negative electrode.

[0040]

As described above, according to the present invention, the nickel hydroxide active material powder used for the nickel positive electrode contains at least one of the group consisting of cadmium, zinc, calcium, magnesium, iron, cobalt and manganese. Nickel hydroxide active material powder contains 1 to 7 wt%,
Particles in which primary particles of 1 μm or less are innumerably aggregated.
The space volume having a pore radius of 0 ° or more is 20 to 70% of the total space volume.

Further, in a nickel positive electrode comprising a nickel hydroxide powder as a main component, a three-dimensional porous body or a flat plate which supports the nickel hydroxide powder and imparts conductivity, cadmium, calcium, zinc, magnesium,
1 to 7 wt% of at least one selected from the group consisting of iron, cobalt and manganese is contained in the nickel hydroxide active material powder. It is composed of a nickel hydroxide powder having a space volume having a radius of 20 to 70% of the total space volume and at least one member of the group consisting of cobalt, cobalt hydroxide, zinc oxide, zinc, cadmium and cadmium oxide. Nickel positive electrode.

A nickel positive electrode mainly composed of nickel oxide, a negative electrode mainly composed of a hydrogen storage alloy capable of electrochemically storing and releasing hydrogen or a negative electrode mainly composed of cadmium oxide, and an alkaline electrolyte And an alkaline storage battery comprising a separator, a case into which these are inserted, and a sealing plate provided with a safety valve, the nickel positive electrode is made of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese before the first charge and discharge. At least one of the group consisting of 1 to 7 wt.
% Nickel particles having a pore volume of 30 ° or more are 20 to 70% of the total space volume, and cobalt is Using a nickel positive electrode mainly composed of a three-dimensional porous body or a flat plate that supports at least one of cobalt hydroxide, zinc oxide, zinc, cadmium and cadmium oxide and these powders and imparts conductivity, Specific gravity 1.23 to 1.4, battery capacity 1Ah
This is an alkaline storage battery in which the amount of electrolyte per unit is 1.0 to 2.0 cm ³ / Ah.

With the simple structure as described above, it is possible to provide a nickel hydroxide, a nickel positive electrode and an alkaline storage battery having improved capacity and reliability of a nickel hydroxide active material and a low cycle life, and having excellent capacity and reliability. Will be possible.
Further, since ammonia or the like is not used at the time of preparing the powder, it is possible to provide an alkaline storage battery having excellent self-discharge characteristics.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the particle structure of a spherical nickel hydroxide powder prepared according to the present invention.

FIG. 2 is a cross-sectional view of a nickel-metal hydride storage battery prepared according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative electrode 2 Positive electrode 3 Separator 4 Case 6 Safety valve 7 Sealing plate

Continuing on the front page (72) Inventor Fumihiko Yoshii 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Inventor Shingo Tsuda 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 4/52

Claims (27)

(57) [Claims] The nickel hydroxide active material powder as a battery active material contains at least one selected from the group consisting of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese in the nickel hydroxide active material powder in an amount of 1 to 4. 7
wt%, and particles in which primary particles of 0.1 μm or less are aggregated innumerably, and a space volume having a pore radius of 30 ° or more is 20 to 70 % with respect to a total space volume having a pore radius of 10 to 200 °. % Of the nickel hydroxide active material. 2. The nickel hydroxide active material according to claim 1, wherein the nickel hydroxide active material powder is spherical. 3. The nickel hydroxide active material according to claim 1, wherein the active material powder has a BET specific surface area of 10 to 20 m ² / g measured by nitrogen gas adsorption. 4. The active material powder has an average particle diameter of 7 to 20 μm.
2. The nickel hydroxide active material according to claim 1, wherein the nickel hydroxide active material has a tap density of 1.9 g / cm ³ or more. 5. A method according to claim 1 wherein the pore radius of the total pore volume 10~200Å is 0.015~0.04cm ³ / g
The nickel hydroxide active material as described. 6. An active material powder is prepared by reacting a mixed aqueous solution of nickel sulfate, zinc sulfate and cobalt sulfate with an aqueous sodium hydroxide solution to form a reaction pH in the production of nickel hydroxide.
The nickel hydroxide active material according to claim 1, wherein the particles are particles obtained by controlling the following. 7. The nickel hydroxide active material according to claim 6, wherein the reaction pH is 11.3 ± 0.2. 8. A nickel positive electrode comprising a nickel hydroxide powder as a main component, a three-dimensional porous body or a flat plate which supports the nickel hydroxide powder and imparts conductivity, wherein cadmium, calcium, zinc, magnesium, iron, At least one of the group consisting of cobalt and manganese is contained in the nickel hydroxide active material powder in an amount of 1 to 7 wt%,
0.1 μm or less primary particles are innumerably aggregated particles, and a space volume having a pore radius of 30 °
20-70 % of the total space volume with a diameter of 10-200mm
A nickel positive electrode comprising: nickel hydroxide powder, and at least one selected from the group consisting of cobalt, cobalt hydroxide, zinc oxide, zinc, cadmium, and cadmium oxide. 9. Nickel hydroxide: cobalt: cobalt hydroxide: zinc oxide and / or cadmium oxide by weight ratio:
Cadmium and / or zinc = 100: 4-18: 0-0
The nickel positive electrode according to claim 8, wherein the ratio is 10: 0 to 10: 0 to 10. 10. The nickel positive electrode according to claim 8, wherein the three-dimensional porous body is a foamed nickel porous body or a punched metal. 11. The nickel hydroxide active material powder has a BET specific surface area of 10 to 20 measured by adsorption of nitrogen gas.
The nickel positive electrode according to claim 8, wherein m ² / g. 12. The nickel hydroxide active material powder has an average particle diameter of 7 to 20 μm and a tap density of 1.9 g / c.
m ³ or more nickel positive electrode according to claim 8, wherein the spherical particles. 13. The nickel positive electrode according to claim 8, wherein the total volume of the space having a pore radius of 10 to 200 ° is 0.015 to 0.04 cm ³ / g. 14. The nickel positive electrode according to claim 8, wherein the foamed porous nickel body has an areal density of 200 to 700 g / m ² . 15. The reaction pH in the production of nickel hydroxide, wherein the active material powder is made of a mixed aqueous solution of nickel sulfate, zinc sulfate and cobalt sulfate and an aqueous sodium hydroxide solution.
The nickel positive electrode according to claim 8, wherein the nickel positive electrode is a particle obtained by controlling the following. 16. The nickel positive electrode according to claim 15 , wherein the reaction pH is 11.3 ± 0.2. 17. A nickel positive electrode mainly composed of nickel oxide, a negative electrode mainly composed of a hydrogen storage alloy capable of electrochemically storing and releasing hydrogen or a negative electrode mainly composed of cadmium oxide, and an alkaline electrolysis. Liquid, a separator and a case for inserting these power generating elements, and an alkaline storage battery comprising a sealing plate provided with a safety valve, the nickel positive electrode before the first charge and discharge, cadmium, calcium, zinc, magnesium, iron, cobalt and A space in which at least one member of the group consisting of manganese is contained in the nickel hydroxide active material powder in an amount of 1 to 7 wt%, in which primary particles of 0.1 μm or less are aggregated innumerably, and have a pore radius of 30 ° or more. volume cobalt nickel hydroxide powder is 20% to 70% pore radius of the total pore volume 10～200A, hydroxide cobaltite Alkaline electrolysis using a nickel positive electrode mainly composed of a three-dimensional porous body or a flat plate that supports at least one of the group consisting of zinc oxide, zinc, cadmium and cadmium oxide and provides these powders and imparts conductivity. The specific gravity of the liquid is 1.23 to 1.4,
The amount of electrolyte per 1 Ah of battery capacity is 1.0 to 2.0 cm
³ / Ah. 18. The nickel positive electrode has a weight ratio of nickel hydroxide: cobalt: cobalt hydroxide: zinc oxide and / or cadmium oxide: cadmium and / or zinc = 10.
The alkaline storage battery according to claim 17 , wherein the ratio is 0: 4 to 18: 0 to 10: 0 to 10: 0 to 10. 19. The alkaline storage battery according to claim 17 , wherein the three-dimensional porous body is a foamed nickel porous body or a punched metal. 20. The alkaline storage battery according to claim 17 , wherein the foamed nickel porous body has an areal density of 200 to 700 g / m ² . 21. The nickel hydroxide active material powder has an average particle size of 7 to 20 μm and a tap density of 1.9 g / c.
alkaline storage battery according to claim 17 wherein m is ³ or more particles. 22. The nickel hydroxide active material powder has a BET specific surface area of 10 to 20 as measured by adsorption of nitrogen gas.
The alkaline storage battery according to claim 17 , wherein m ² / g. 23. The alkaline storage battery according to claim 17 , wherein the total volume of the space having a pore radius of 10 to 200 ° is 0.015 to 0.04 cm ³ / g. 24. Nickel hydroxide is a particle produced by a mixed aqueous solution of nickel sulfate, zinc sulfate and cobalt sulfate and an aqueous sodium hydroxide solution, and obtained by controlling a reaction pH in a nickel hydroxide production reaction. The alkaline storage battery according to claim 17 . 25. The alkaline storage battery according to claim 24 , wherein the reaction pH in the nickel hydroxide production reaction is 11.3 ± 0.2. 26. The alkaline storage battery according to claim 17 , wherein the alkaline electrolyte comprises at least one of potassium hydroxide and sodium hydroxide and lithium hydroxide. 27. The alkaline storage battery according to claim 26, wherein lithium hydroxide (LiOH) is contained in the electrolytic solution in an amount of 10 g / l or more.