JP3136668B2 - Nickel hydroxide active material powder, 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 and the like.
It is 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 these high-capacity alkaline storage batteries, in order to improve the energy density of the positive electrode, nickel hydroxide powder is filled in a three-dimensional porous nickel foam or nickel fiber porous body having a high porosity (90% or more). .

As a result, the energy density of the conventional sintered nickel positive electrode is 400 to 450 mAh / cm ³ , whereas that of the nickel positive electrode is 500 mAh / cm 3.
³ or more . As the nickel hydroxide powder to be filled in the three-dimensional porous body, nickel hydroxide fine powder precipitated and precipitated with nickel sulfate and an alkali is dried and solidified, and then a crushed powder is used. However, such a positive electrode has a higher energy density than a sintered nickel positive electrode, but has a problem in that cycle life characteristics are deteriorated. This is because a large volume of γ-NiOOH is generated on the positive electrode during charging to expand the positive electrode, absorb the electrolyte present in the separator, increase the internal resistance of the battery, and decrease the discharge capacity. is there. 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) zinc nickel hydroxide powder, zinc oxide powder method was added to suppress the gamma-NiOOH generated during charging (JP 59-112574 JP) zinc compounds. (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
Internal transition with 10wt% addition and pore radius of 30mm or more
Prevents the development of transfer pores, further 0.05c all pore volume
γ-NiOO controlled at m ³ / g or less and generated during charging
Method of inhibiting H (JP 61-104565, JP-
JP 2-30061 discloses, USP-4844999
No. ).

[0005]

In such a conventionally proposed method, since the nickel hydroxide powder in the angular state is used, it is impossible to further increase the packing density in the three-dimensional porous body. It is.

As a result, the energy density of the positive electrode has reached its limit. In the method of (1) and (2), to suppress the formation of gamma-NiOOH by adding cadmium oxide and zinc oxide powder to nickel hydroxide powder, but to improve the cycle life characteristics greatly not improve in. 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. This is because cadmium oxide or zinc oxide powder alone can cause γ-Ni
This suggests that it is difficult to suppress the generation of OOH. 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 packing density in the positive electrode is improved by preventing the development of internal transition pores of 30 ° or more, 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 and discharge is increased. 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, the current density locally increases, and γ-NiOOH is easily generated. As a result, the cycle life in a low temperature (0 ° C.) 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 and a nickel hydroxide having a high energy density and an excellent cycle life characteristic are provided with a simple structure to improve the packing density of the active material. It is an object to provide a positive electrode and an alkaline storage battery using the same.

It is another object of the present invention to provide a nickel hydroxide active material and a nickel positive electrode which are excellent in nickel hydroxide active material utilization and self-discharge characteristics at the initial stage of charge and discharge, and an alkaline storage battery using the same.

[0011]

According to the present invention, there is provided a nickel hydroxide active material powder for use in a nickel positive electrode, which comprises at least one of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese. containing 1～7Wt% of nickel hydroxide powder, the particle size
Spherical or spherical-like particles and particle size of 10-30 μm
This is a mixture of non-spherical particles of 10 μm or less . This nickel hydroxide powder is a nickel positive electrode in which at least one of cobalt, cobalt oxide, zinc oxide, zinc, cadmium and cadmium oxide is 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 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, before the first charge / discharge, the nickel positive electrode contains at least one of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese in an amount of 1 to 7 wt% in the nickel hydroxide active material powder. Contains
Spherical or spherical-like particles with a particle size of 10-30 μm
At least one of cobalt, cobalt oxide, zinc oxide, zinc, cadmium, and cadmium oxide is added to nickel hydroxide powder, which is a mixture of non-spherical particles having a particle diameter of 10 μm or less, and these powders are supported to impart conductivity. A nickel positive electrode mainly composed of a two-dimensional porous body or a flat plate is used, and the specific gravity of the alkaline electrolyte 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.

[0013]

By the action This arrangement, i.e., Seikyokusaku made sometimes cadmium, calcium, zinc, magnesium, iron, at least one of cobalt and manganese is contained 1～7Wt% to the nickel hydroxide active material powder, the particle size 10~30μ
m or spherical-like particles with a particle size of 10 μm or less
By using a mixture with the above non-spherical particles, the packing density and cycle life characteristics can be improved.

That is, by mixing spherical or spherical-like particles having a particle size of 10 to 30 μm with non-spherical particles having a particle size of 10 μm or less, the nickel hydroxide powder can be efficiently present in the gaps between the particles. it is possible, when created made a positive electrode using a mixed powder as described above, and thus to improve filling density of nickel hydroxide.
By including at least one of cadmium, calcium, zinc, magnesium, iron, cobalt, and manganese in the nickel hydroxide active material powder as a 1 to 7 wt% solid solution, γ having a larger volume than β-NiOOH during overcharge -The generation of NiOOH is suppressed. As a result, expansion of the active material and the positive electrode is suppressed, and the cycle life characteristics are improved.

Further, the nickel positive electrode has a problem that even if the packing density is improved by using the nickel hydroxide powder of the present invention, the substantial energy density is low. For this purpose, cobalt and cobalt hydroxide are added to the positive electrode to improve the utilization of the nickel hydroxide active material. as a result,
Even when a positive electrode with an increased packing density is used, the utilization rate of the nickel hydroxide active material is improved, so that a substantial energy density can be obtained corresponding to the packing density.

Further, by adding zinc oxide, zinc, cadmium and cadmium oxide, the generation of high volume γ-NiOOH during overcharge is further suppressed. as a result,
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 above-mentioned additive to a three-dimensional porous body or a flat plate, a positive electrode having a high energy density and excellent cycle life characteristics can be obtained. . In an alkaline storage battery comprising the positive electrode of the present invention and 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, an alkaline electrolyte, and a separator. , The specific gravity of the alkaline electrolyte is 1.2
By setting the ratio to 3 to 1.4, the supply of protons to nickel hydroxide is facilitated, and the utilization rate of the nickel hydroxide active material is improved. The amount of the electrolyte was (per positive electrode capacity) 1.
By setting the concentration to 0 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 excellent cycle life can be obtained.

[0018]

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

[0019] (Example 1) Nickel hydroxide powder used in this example was <br/> work made as follows. The nickel hydroxide powder contains 3.7 wt% and 0.5 wt% of zinc and cobalt in nickel hydroxide, respectively.
The composition contained wt%. Nickel sulfate, cobalt sulfate, and zinc sulfate are dissolved in water at a predetermined ratio to form a mixed aqueous solution in which nickel, cobalt, and zinc ions are dissolved.
Made . Next, while supplying the mixed aqueous solution and sodium hydroxide to the reaction tank in a fixed amount, the residence time in the reaction tank was set to 20 times.
1 / hr, the temperature was 35 ° C., the pH was kept constant at 11.3 and an aqueous sodium hydroxide solution, and the mixture was vigorously stirred.
Primary particles of 0.1 μm or less are generated, and nickel hydroxide composed of a mixture of spherical particles and non-spherical particles containing 3.7 wt% and 0.5 wt% of zinc and cobalt, respectively, is continuously formed while using these particles as nuclei. It was made of work. The work made grain structure of nickel hydroxide powder in the present invention shown in FIG. As can be seen from FIG. 1, powder having a particle size of about 10 to 30 μm is spherical, and powder having a particle size of about 10 μm or less is non-spherical. The production conditions as described above, ie, the reaction temperature was relatively low at 35 ° C., and the reaction pH was as low as 11.3.
reacted at pH conditions, it is possible to create made spherical and mixed powder of non-spherical, such as the by controlling the residence time in the stirring conditions reaction vessel. As a comparative example, nickel hydroxide fine powder precipitated and precipitated with nickel sulfate and a high-concentration alkaline aqueous solution shown in FIG. 2 was dried and solidified, and then ground and used in the form of angular powder. The average particle diameter of both the nickel hydroxide powder of the present invention and the comparative example is about 12 μm. Next, the results of measuring the tap density in order to examine the filling properties of the nickel hydroxide powder of the present invention and the nickel hydroxide powder of the conventional example into the positive electrode are shown in Table 1 below. The tap density is measured by filling a 20 cc graduated cylinder of nickel hydroxide powder with nickel hydroxide powder and tapping 200 times, then measuring the weight (including nickel hydroxide powder) Bg of the graduated cylinder and the volume Dcc of nickel hydroxide, It was determined by the following equation.

Tap density = (BA) / D The packing density was determined by filling each nickel hydroxide powder into a foamed nickel porous material having a porosity of 95% and a basis weight of 350 g / m ² , and pressing the same. After pressing under the conditions, it was cut into a predetermined size, and the thickness was measured to obtain the packing density by calculation. Table 1 shows a comparison between the tap density and the packing density of the nickel hydroxide of the present invention and the nickel hydroxide of the conventional example.

[0021]

[Table 1]

As is clear from the comparison between the tap density and the packing density in Table 1, the nickel hydroxide powder of the present invention has a higher tap density and a better packing density than the nickel hydroxide powder of the comparative example. You can see that. This is because the nickel hydroxide powder of the comparative example has a square shape, so that there are more gaps between the powders than the spherical particles, so that the tap density and the packing density are not improved. On the other hand, since the nickel hydroxide powder of the present invention is a mixture of spherical and non-spherical particles, gaps between the spherical particles are filled with non-spherical particles. As a result, it can be seen that the tap density is 2.01 g / cc and the packing density is 630 mAh / cc, exhibiting excellent characteristics.

Next, in order to examine the charge-discharge cycle life characteristics of the nickel hydroxide active material powder was manufactured create the nickel-hydrogen storage battery in the following manner. The positive electrode was prepared by mixing the nickel hydroxide powder, cobalt powder, and cobalt hydroxide powder of the present invention in a weight ratio of 100: 7: 5, adding water thereto, kneading the mixture, and forming a paste. Porosity 95 as support
%, A foamed nickel porous body having a surface density of 300 g / m ² , dried, pressurized, and then immersed in an aqueous solution in which a fluororesin powder was dispersed. After again after drying this was cut into predetermined dimensions to create made a nickel positive electrode having a capacity of 1400mAh <br/>. It was created made of nickel positive electrode in a similar manner using the angle-shaped nickel hydroxide powder as a comparative example.

The negative electrode was manufactured by the following method. The alloy composition MmNi3.6 Co0.7Mn0.4Al0.3 (Mm
Is misch metal and a mixture of rare earth elements). Misch metal Mm which is a mixture of rare earth elements and Ni, C
Each sample of o, Mn, and Al was put in an arc furnace, and 10 ^-4 ~
After reducing the pressure to 10 ^-5 torr, arc discharge was performed under reduced pressure in an argon gas atmosphere, and the mixture was heated and dissolved. In order to homogenize the sample, heat treatment was performed at 1050 ° C. for 6 hours in vacuum. 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 placed in a 7.2 mol aqueous potassium hydroxide solution at 80 ° C. for 1 hour.
After performing the treatment while stirring for a time, the alloy powder was washed with water to remove potassium hydroxide, and dried to obtain a hydrogen storage alloy powder used for the negative electrode. Water and carboxymethyl cellulose (CM) are added to this hydrogen storage alloy powder.
C) and the like to form a paste, filled into a foamed nickel porous body having a porosity of 95%, dried, pressurized, and cut into predetermined dimensions to produce 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.

As shown in FIG . 3, the negative electrode 1 and the positive electrode 2 prepared as described above were swirled through a separator 3 and inserted into a case 4 also serving as a negative electrode terminal. Thereafter, 2.8 cm ^{3 of} an alkaline electrolyte obtained by dissolving 20 g / l of lithium hydroxide in an aqueous solution of potassium hydroxide having a specific gravity of 1.30 was used.
And it poured, Quai by sealing plate 7 provided with a safety valve 6 - was sealed to scan 4, public 1400mAh that regulate battery capacity at the positive electrode
A 4/5 A size sealed nickel-metal hydride storage battery having a nominal capacity was constructed.

In FIG . 3, reference numeral 8 denotes an insulating gasket, and 9 denotes a positive electrode current collector for electrically connecting the positive electrode 2 and the sealing plate 7. Battery using a positive electrode made of nickel hydroxide in the prior art was also created manufactured in the same configuration as FIG. The conventional positive electrode made of nickel hydroxide has a low packing density and thus has a battery capacity of 12
90 mAh. Using these batteries, a charge / discharge cycle life test was performed under the following conditions. Charge is 1/3
The charge / discharge cycle was performed at CmA for 4.5 hours, and then the discharge was performed at 1 CmA up to 1.0 V as one cycle, and the charge / discharge cycle was repeated in an atmosphere of 0 ° C. The result is shown in FIG. It can be seen that the battery using the nickel hydroxide positive electrode of the present invention has a higher capacity level than that of the comparative example, and the capacity hardly decreases even after repeated charge and discharge of 500 cycles. On the other hand, in the battery using the positive electrode made of nickel hydroxide of the comparative example, the capacity level at the initial stage of charge / discharge is lower by about 8%, and the capacity decreases when the charge / discharge cycle is repeated 200 times. This is because the nickel hydroxide powder of the present invention is composed of a mixture of spherical and non-spherical particles and therefore has a high capacity density, and contains 3.7 wt% and 0.5 wt% of zinc and cobalt, respectively, in the nickel hydroxide powder. and due to the fact that not.

[0027] (Example 2) cadmium contained in the nickel hydroxide powder, calcium, zinc, magnesium, iron, create manufactured nickel hydroxide powder in the same manner as in Example 1 to examine the effect of cobalt and manganese did. Created manufactured powder is a mixture of similar particles with non-spherical particles spherical or spherical as shown in FIG. The composition of the work made by powder shown in (Table 2) and (Table 3).

[0028]

[Table 2]

[0029]

[Table 3]

The tap densities of the nickel hydroxide powders Nos. 1 to 11 in the table are 1.92 to 2.15 g / cm ³ ,
The average particle size is 9 to 15 μm. When manufactured create the positive electrode, in order to improve the packing density, tap density 1.
9 g / cm ³ or more is required. The average particle diameter of the nickel hydroxide Bae when mixed with nickel hydroxide and water and the filling of the case of steel work the cathode - range in terms of strike flowable 7~20μm is preferred. Next, in order to examine the life characteristics of these nickel hydroxides, a positive electrode and a battery were constructed in the same manner as in Example 1, and the results of tests were shown in FIGS. 5 and 6.

As shown in FIGS. 5 and 6, a battery No. using the nickel hydroxide of the present invention was used. 2 to 11 show that the capacity hardly decreases even if the charge / discharge cycle is repeated 500 times. On the other hand, No. It can be seen that the battery No. 1 does not contain zinc or cobalt, and its capacity is reduced by repeating charging and discharging 250 times.

From FIG. Battery No. 2 contained 1.3 wt% of zinc and cobalt, but the capacity was reduced to about 75% of the initial capacity by repeating charge and discharge 500 times. Therefore, it is considered that the addition amount of zinc or the like is required to be 1 wt% or more. When the addition amount is 7 wt% or more, the capacity density is reduced. Therefore, the addition amount of 7 wt% or less is preferable. Further, when the addition amount of cobalt is 1 wt% or more, the voltage drop at the time of high rate discharge is remarkable.
The following addition amounts are preferred. Cadmium, calcium, zinc, magnesium, iron, cobalt and manganese in nickel hydroxide are considered to exist as a solid solution or a hydroxide in which nickel hydroxide has been partially substituted for nickel.

(Example 3) In the same manner as in Example 1, the reaction pH of the reaction for producing nickel hydroxide powder was changed from 11.0 to 11.6.
Zinc was made create a mixture of similar particles and non-spherical particles in the various spherical or spherical 3.7 wt% and cobalt contained 0.5 wt%. Table 4 shows the physical properties of the nickel hydroxide powders prepared under various pH conditions.

[0034]

[Table 4]

The spatial volume ratio in Table 4 is such that the pore radius is 10
It is the ratio of the space volume of 30 ° or more to the total space volume of 200 ° (calculated from the adsorption isotherm on the nitrogen gas adsorption side). Note that it is difficult to measure the pore distribution of 10 ° or less by a method using nitrogen gas, and it is considered that a space having pores of 10 ° or less actually exists.

Next, a 4/5 A size sealed nickel-hydrogen storage battery having a nominal capacity of 1400 mAh similar to that of Example 1 using the nickel hydroxide powders A to E in Table 4 was used. , Respectively. 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 discharged at a constant discharging current of 0.2 CmA at 1.0 V. Until a continuous discharge. 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 The results of examining the active material utilization rate in the batteries using nickel hydroxides A to E in Table 5 Is shown.

[0038]

[Table 5]

As is clear from (Table 5), no. The utilization rate of nickel hydroxide of A is 80% in the first cycle, and the utilization rate after repeated charge and discharge of 5 cycles is 85%.
%. This is because the space volume having a pore radius of 30 ° or more is 17% of the total space volume. This is 0.01m is the total spatial volume with a specific surface area of 8.6m ² / g ² /
It is correlated with g and small. Therefore, it is difficult for the electrolytic solution to penetrate the inside of the pores of the nickel hydroxide particles, and as a result, the effective nickel hydroxide involved in the charge / discharge reaction is reduced, and the utilization factor is as low as 80 to 85%. No. E
Nickel hydroxide powder has a tap density of 1.8 g / cm ³
And low. The reason why the tap density is low is that the specific surface area and the total space volume are large and the average particle size is small. Although this nickel hydroxide has an excellent utilization factor, it is difficult to fill it at high density due to its low tap density. No. of the present invention. B,
The utilization rate of C and D nickel hydroxide was 9 in the first cycle.
0 to 93%, which is an excellent value of 95 to 98% even after 5 cycles.

From the above, the reaction pH was adjusted to 11.3 ±
By controlling the ratio to 0.2, it is possible to obtain a nickel hydroxide powder having an excellent utilization factor. In addition, the total space volume is 0.015 to 0.0 from the viewpoint of the utilization rate and the tap density.
It is preferably in the range of 4 cm ³ / g. A space volume having a pore radius of 30 ° or more is 20% of the total space volume.
% Is preferable. The specific surface area is preferably in the range of 10 to 20 m ² / g from the viewpoint of utilization and filling.

Next, when ammonia remains in the nickel hydroxide, no. In order to examine how the self-discharge characteristic of a battery having the same configuration as that of C changes, ammonia was added to nickel hydroxide in the battery in an amount of 0.05 wt% and 0.1 wt%.
No. 1 containing 0.1% by weight. C-1 and C-2 of the battery were each work made. 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. Charge at 0.1 CmA under 20 ° C atmosphere
After performing for 5 hours and suspending for 1 hour, discharging was performed to 1.0 V with a discharging current of 0.2 CmA, and the discharging capacity (A) was obtained by calculation. Next, charge at 0.1C in an atmosphere of 20 ° C.
15 hours at 45 mA in a charged state.
Let stand for 20 days, then 0.2CmA under 20 ° C atmosphere
At a discharge current of 1.0 V to 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 6) C and No. of Comparative Example. C-1,
4 shows the self-discharge characteristics of C-2.

[0043]

[Table 6]

As is evident from the results in Table 6, when ammonia is contained, the capacity retention rate when left at a high temperature decreases. Therefore, in the case of producing nickel hydroxide by preparing 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.

Example 4 Using the same nickel hydroxide powder of the present invention as in Example 1,
The positive electrode was created Ltd. <br/> each additive compositions shown in Table 7 (weight ratio). The positive electrode was also created manufactured in the same manner as in Example 1.

[0046]

[Table 7]

Next, No. Example 1 using positive electrodes F to I
In the negative electrode and the combination used, the same battery as in Example 1 was then created made <br/>. Using these batteries, a test of the active material utilization rate and the charge / discharge cycle life of nickel hydroxide powder as a positive electrode active material was performed under the following conditions. The active material utilization rate is 150% of the positive electrode capacity, that is, the theoretical capacity calculated from the nickel hydroxide active material, at a charging current of 0.1 CmA in an environment of 20 ° C.
The battery was charged, suspended for 1 hour, and continuously discharged to 1.0 V at a constant discharge current of 0.2 CmA. The charge / discharge was repeated twice by this method, and 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 / theoretical nickel hydroxide capacity) × 100 The charge / discharge cycle life was 1.3 hours at a charge current of 1 CmA in an environment of 0 ° C. Continuous discharge was performed up to 1.0 V at a discharge current of 1 CmA. The charge / discharge was 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. (Table 8) shows N
o. The results of the active material utilization rates and the cycle life of FI are shown.

[0049]

[Table 8]

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 7). 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 powder 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 content of cobalt is less than 4 parts by weight, the utilization rate is reduced, and the substantial discharge capacity is reduced. When the added 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 and 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 of 0 ° C. No. 1 containing zinc oxide When the positive electrode of I was used, the cycle life characteristics were as good as 750 cycles.

Therefore, it is necessary to make zinc oxide coexist with the nickel hydroxide powder according to the present invention in order to have more excellent 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 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 an areal density of 300 g.
/ M ² of was used foamed nickel porous body, showing a similar effect so long as the surface density of 200 to 700 g / m ^2. Similar effects can be obtained by using punched metal or a flat plate, which is a kind of three-dimensional porous body, in addition to the foamed nickel porous body.

[0054] (Example 5) real施例4 No. Using the positive electrode of the I, by changing the specific gravity and the amount of the electrolytic solution was manufactured create the same cell as in Example 1. No. of work made by <br/> was battery Table 9 shows the relationship between specific gravity and amount of electrolyte
Shown in 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 9).

[0055]

[Table 9]

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,
No. In the case of K to M, the utilization rate is 93.5 to 96%, and the cycle life is 650 to 770 cycles, indicating excellent characteristics. Therefore, the specific gravity of the electrolyte is N
o. The range of 1.23 to 1.40 for batteries KM is optimal. No. 1 having an electrolyte volume of 1.3 cc. O battery is
Since the amount of the nickel hydroxide of the present invention is insufficient, 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 battery of S has a good utilization rate of 95%, but has a lower cycle life than that 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. P to R
Is 1.4 Ah, and the amount of electrolyte per Ah is 1.0, 1.43, and 2.0, respectively. From the above, the specific gravity of the alkaline electrolyte is 1.23 to 1.40.
, And the amount of the electrolytic solution is preferably 1.0 to 2.0 cm ³ / Ah. In addition, when the amount of lithium hydroxide (LiOH) contained in the electrolytic solution is 10 g / l or less, the discharge voltage is significantly reduced. Therefore, it is preferable to contain 10 g / l or more. In this embodiment, the case where an AB ₅ -based hydrogen storage alloy is used for the negative electrode is shown. However, 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.

[0057]

As described above, according to the present invention, the nickel hydroxide active material powder used for the nickel positive electrode comprises at least one of cadmium, zinc, calcium, magnesium, iron, cobalt and manganese. 1 to 7 wt% contained in powder, particle size 10 to 30 μm
<br/> follows spherical or spherical similar particles with a particle size 10μm of is obtained by a mixture of non-spherical particles.

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,
At least one of iron, cobalt and manganese is contained in the nickel hydroxide active material powder in an amount of 1 to 7% by weight, and the particle size is 10 %.
Similar to spherical or spherical ~30μm particles and particle size 10
This is a nickel positive electrode composed of nickel hydroxide powder, which is a mixture with non-spherical particles of μm or less, and at least one of cobalt, cobalt hydroxide, zinc oxide, zinc, cadmium and cadmium oxide. Also,
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, an alkaline electrolyte, and a separator And an alkaline storage battery comprising a case into which these are inserted and a sealing plate provided with a safety valve, the nickel positive electrode hydrates at least one of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese before the first charge and discharge. Nickel hydroxide powder which is a mixture of spherical or spherical particles having a particle diameter of 10 to 30 μm and non-spherical particles having a particle diameter of 10 μm or less, which is contained in a nickel active material powder at 1 to 7 wt%. Provides conductivity by supporting at least one of cobalt, cobalt hydroxide, zinc oxide, zinc, cadmium and cadmium oxide and their powder That mainly using nickel positive electrode composed of a three-dimensional porous body or a flat plate, the specific gravity of the alkaline electrolyte is from 1.23 to 1.4, the amount of electrolyte per battery capacity 1Ah is 1.0~2.0cm ³ / Ah. With the simple configuration as described above, it is possible to provide a nickel hydroxide, a nickel positive electrode, and an alkaline storage battery having a high nickel hydroxide active material filling density, excellent energy density, and improved utilization and low-temperature cycle life. become. Further, since ammonia or the like is not used at the time of powder production, an alkaline storage battery having excellent self-discharge characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the particle structure of a nickel hydroxide powder which is a mixture of spherical and non-spherical particles produced in the present invention.

FIG. 2 is an electron micrograph showing a particle structure of a square nickel hydroxide of a comparative example.

FIG. 3 is a cross-sectional view of a nickel-metal hydride storage battery manufactured by the present invention.

FIG. 4 is a diagram showing the results of cycle life of batteries using nickel hydroxide of the present invention and a comparative example.

FIG. 5 is a diagram showing the results of the cycle life of batteries using nickel hydroxide of various compositions.

FIG. 6 is a diagram showing the results of cycle life of batteries using nickel hydroxide of various compositions.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumihiko Yoshii 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Shingo Tsuda 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-78965 (JP, A) JP-A-2-30061 (JP, A) JP-A-2-109261 (JP, A) JP-A-1-267957 (JP, A) JP-A-1-260762 (JP, A) JP-A-1-187768 (JP, A) JP-A-4-368777 (JP, A) JP-A-4-167364 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/36-4/62

Claims (41)

(57) [Claims] 1. A nickel hydroxide active material powder used in the battery, the nickel hydroxide active at least one of the group consisting of cadmium, calcium, zinc, magnesium, iron, cobalt Contact and manganese at the cathode prepared Nickel hydroxide containing 1 to 7 wt% in a material powder, and a mixture of spherical or spherical-like particles having a particle size of 10 to 30 µm and non-spherical particles having a particle size of 10 µm or less. Active material powder. 2. The nickel hydroxide active material powder has a particle size of 0.1 μm.
nickel hydroxide active material powder according to claim 1, wherein m or less of the primary particles is that combined current. 3. At least one of the group consisting of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese is a solid solution in the crystal of the nickel hydroxide active material powder (solid solution is cadmium, calcium, zinc, magnesium, Iron, cobalt and manganese in which at least one of nickel hydroxide is replaced by a part of nickel, or hydroxide and water of at least one of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese The nickel hydroxide active material powder according to claim 1, which means a mixed crystal with nickel oxide). 4. The active material powder contains zinc in an amount of 3 to 6.9 wt.
The nickel hydroxide active material powder according to claim 1, which contains 1.0 to 0.1 wt% of cobalt. 5. The active material powder has an average particle diameter of 7 to 20 μm.
2. The nickel hydroxide active material powder according to claim 1, wherein the powder has a tap density of 1.9 g / cm ³ or more. 6. The nickel hydroxide active material powder 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. 7. The active material powder has a pore volume of 0.0
15~0.04cm ³ / g nickel hydroxide active material powder according to claim 1, wherein the (nitrogen determined by gas adsorption). 8. The active material powder according to claim 1, wherein a space volume having a pore radius of 30 ° or more is at least 20% of the total space volume (calculated from an adsorption isotherm on the nitrogen gas adsorption side). Nickel hydroxide active material powder. 9. In the production of a nickel hydroxide active material,
Nickel sulfate and cadmium, calcium, zinc, magnesium, iron, and controls the cobalt and at least one reaction temperature and pH while supplying into the reaction vessel mixture aqueous solution with sodium hydroxide and sulfate or nitrate of manganese The nickel hydroxide active material powder according to claim 1, which is obtained by stirring . 10. The nickel hydroxide active material powder according to claim 9, wherein the reaction pH is 11.3 ± 0.2 and the reaction temperature is 30 to 40 ° C. 11. A nickel positive electrode comprising a nickel hydroxide powder as a main component, a three-dimensional porous body or a flat plate supporting the nickel hydroxide powder and imparting conductivity.
Particle diameter 10 containing at least one of cadmium, calcium, zinc, magnesium, iron, cobalt and manganese in a nickel hydroxide powder as a 1 to 7 wt% solid solution
Similar to spherical or spherical ~30μm particles and particle size 10
a nickel hydroxide powder comprising a mixture of a μm or less of non-spherical particles, cobalt, cobalt oxide, nickel positive electrode which is characterized by being composed of zinc oxide, zinc, and at least one of cadmium and cadmium oxide. 12. The nickel positive electrode has a weight ratio of nickel hydroxide: cobalt: cobalt hydroxide: zinc oxide and / or cadmium oxide: cadmium and / or zinc = 1.
The nickel positive electrode according to claim 11, wherein the ratio is from 00: 4 to 18: 0 to 10: 0 to 10: 0-10. 13. The nickel positive electrode according to claim 11, wherein the three-dimensional porous body is a foamed nickel porous body or a punching metal. 14. Nickel hydroxide powders, nickel positive electrode according to claim 11, wherein 0.1μm or less of the primary particles is that combined current. 15. The nickel positive electrode according to claim 11, wherein the nickel hydroxide active material powder contains 3 to 6.9 wt% of zinc and 1 to 0.1 wt% of cobalt. 16. The nickel positive electrode according to claim 11, wherein the nickel hydroxide powder has an average particle diameter of 7 to 20 μm and a tap density of 1.9 g / cm ³ or more. 17. The nickel hydroxide powder has a BET specific surface area of 10 to 20 m ² / s measured by adsorption of nitrogen gas.
The nickel positive electrode according to claim 11, which is g. 18. The nickel hydroxide powder, the nickel positive electrode according to claim 11 wherein the space volume of the pores is 0.015~0.04cm ³ / g (measured by adsorption of nitrogen gas). 19. The nickel hydroxide powder has a space volume having a pore radius of 30 ° or more of 20% of the total space volume.
The nickel positive electrode according to claim 11, which is the above (calculated from the adsorption isotherm on the nitrogen gas adsorption side). 20. In the production of a nickel hydroxide active material, nickel sulfate, cadmium, calcium, zinc,
The nickel positive electrode according to claim 11, which is obtained by controlling a reaction pH and a reaction temperature with a supply amount of a mixed aqueous solution of at least one sulfate or nitrate of magnesium, iron, cobalt and manganese and sodium hydroxide. . 21. The nickel positive electrode according to claim 20 , wherein the reaction pH is 11.3 ± 0.2 and the reaction temperature is 30 to 40 ° C. 22. The nickel positive electrode according to claim 11, containing a powder having water repellency. 23. 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, wherein the nickel positive electrode is made of cadmium, calcium, zinc, magnesium, before the first charge and discharge.
Particles containing at least one of iron, cobalt and manganese as a 1 to 7 wt% solid solution in nickel hydroxide powder
Spherical or spherical-like particles having a diameter of 10 to 30 μm and 1
Nickel hydroxide powder , which is a mixture of non-spherical particles of 0 μm or less, and at least one of cobalt, cobalt oxide, zinc oxide, zinc, cadmium and cadmium oxide, and a support for these powders and imparting conductivity 3 Medical use mainly composed of nickel positive electrode of dimensional porous body or a flat plate
Alkaline storage battery, characterized in that those were. 24. The specific gravity of the alkaline electrolyte is from 1.23 to
1.4, and the amount of electrolyte per 1 Ah of battery capacity was 1.
0-2.0cm ^Three 24. The alka according to claim 23, which is / Ah.
Rechargeable battery. 25. The nickel positive electrode has a weight ratio of nickel hydroxide: cobalt: cobalt hydroxide: zinc oxide and / or cadmium oxide: cadmium and / or zinc = 1.
The alkaline storage battery according to claim 23 , wherein the ratio is 00: 4 to 18: 0 to 10: 0 to 10: 0 to 10. 26. The alkaline storage battery according to claim 23, wherein the three-dimensional porous body is a foamed nickel porous body or a punched metal. 27. The nickel hydroxide powder, an alkaline storage battery according to claim 23, wherein 0.1μm or less of the primary particles is that combined current. 28. A nickel positive electrode comprising a powder having water repellency.
The alkaline storage battery according to claim 23, comprising: 29. The alkaline storage battery according to claim 23 , wherein the nickel hydroxide active material powder contains 3 to 6.9 wt% of zinc and 1 to 0.1 wt% of cobalt. 30. The alkaline storage battery according to claim 23 , wherein the nickel hydroxide powder has an average particle diameter of 7 to 20 μm and a tap density of 1.9 g / cm ³ or more. 31. The nickel hydroxide powder has a BET specific surface area of 10 to 20 m ² / m ² measured by adsorption of nitrogen gas.
The alkaline storage battery according to claim 23, wherein g is g. 32. The alkaline storage battery according to claim 23 , wherein the nickel hydroxide powder has a pore volume of 0.015 to 0.04 cm ³ / g (measured by adsorption of nitrogen gas). 33. The nickel hydroxide powder has a space volume having a pore radius of 30 ° or more of 20% of the total space volume.
24. The alkaline storage battery according to claim 23, which is the above (calculated from the adsorption isotherm on the nitrogen gas adsorption side). 34. A product of the nickel hydroxide active material, at least one of cadmium, calcium, zinc, magnesium, iron, reaction vessel and sodium hydroxide mixed aqueous solution of cobalt and manganese sulfate or nitrate and nickel sulfate controlling the reaction pH and reaction temperature while supplying the alkaline storage battery of claim 23 is obtained by stirring. 35. The alkaline storage battery according to claim 34 , wherein the reaction pH is 11.3 ± 0.2 and the reaction temperature is 30 to 40 ° C. 36. The alkaline storage battery according to claim 23 , wherein the alkaline electrolyte comprises at least one of potassium hydroxide and sodium hydroxide and lithium hydroxide. 37. Lithium hydroxide contained in the electrolyte at a rate of 10 g /
The alkaline storage battery according to claim 23 , wherein the alkaline storage battery contains 1 or more. 38. The alkaline storage battery according to claim 23 , wherein zincate ions are present in the alkaline electrolyte. 39. The alkaline storage battery according to claim 23, wherein the separator is a non-woven fabric subjected to a sulfonation treatment. 40. Cadmium and calcium in the preparation of the positive electrode
, Zinc, magnesium, iron, cobalt and manganese
At least one of the group consisting of
1 to 7 wt% in the active material powder, and the particle size is 10
30 μm spherical or spherical-like particles and a particle size of 10
Hydroxidation for batteries to obtain a mixture with non-spherical particles smaller than μm
A method for producing a nickel active material powder, comprising:
Nickel sulfate and cadmium
Calcium, zinc, magnesium, iron, cobalt
At least one sulfate or nitrate of manganese
Aqueous solution mixed with acid salt and sodium hydroxide are supplied to the reaction tank
While the reaction pH was 11.3 ± 0.2 and the reaction temperature was 3
Hydroxidation characterized by stirring at a controlled temperature of 0 to 40 ° C
Method for producing nickel active material powder. 41. The nickel hydroxide active material powder has a content of 0.1%.
41. The primary particle according to claim 40, wherein the primary particles are not larger than μm.
Production method of nickel hydroxide active material powder described above.