JPH10154525A - Manufacture of alkaline storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an initial active material utilization factor, prevent an internal short circuit during storage, and restrain reduction in discharge capacity by making an electrode group through a separator between a positive electrode and a negative electrode having a structure that a positive electrode material containing an Ni hydroxide, an Ni oxyhydroxide and a Co compound is carried by a current collector, arranging alkaline electrolyte in this, and performing ageing and initial charge. SOLUTION: A separator composed of polypropylene-made nonwoven fabric is interposed between a positive electrode and a negative electrode, and is wound in a spiral shape, and electrode groups are made. These electrode groups and alkaline electrolyte are housed in a vessel, and a nonactive cylindrical Ni hydrogen storage battery is assembled. Next, after ageing is performed for 72 hours in an atmosphere of 25 deg.C, initial charge to charge 200% in 0.1C is performed, and discharge is performed up to 1.0v in 0.2C. Afterwards, after 200% charge is performed in 0.1C at a room temperature, a cycle to perform discharge up to 1.0v in 0.2C is performed by five cycles, and a battery is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an alkaline storage battery having a non-sintered nickel positive electrode.

[0002]

2. Description of the Related Art The positive electrode of an alkaline storage battery is roughly classified into a sintered type and a paste type. From the viewpoint of increasing the capacity, a current collector is filled or coated with a paste containing nickel hydroxide particles as an active material. The paste type to be applied is often used. In this paste-type positive electrode, it is essential that a sufficient electrical connection between the particulate active material and the current collector be taken to improve the utilization factor. Addition of compounds has been performed.

[0003] Japanese Patent Publication No. 2-47824 discloses a nickel hydroxide powder containing nickel oxyhydroxide, a nickel powder and a metal powder exhibiting a lower oxidation potential than nickel hydroxide in an alkaline aqueous solution, such as cobalt or manganese. A method for producing a positive electrode plate for an alkaline storage battery, characterized in that a mixture of a sponge-like nickel porous body having a three-dimensionally continuous structure and a mixed powder thereof is brought into contact with an alkaline aqueous solution for a certain period of time. .

Japanese Patent Application Laid-Open No. 6-52857 discloses that
It contains metallic cobalt powder and nickel oxyhydroxide, and nickel oxyhydroxide is 6 parts relative to the metallic cobalt powder.
In an alkaline storage battery using a non-sintered nickel electrode of 0% by weight or less as a positive electrode, the positive electrode potential becomes C after the storage battery is assembled.
A method for activating an alkaline storage battery is disclosed in which the storage battery is left for a first time to charge and discharge after the storage battery has reached a potential corresponding to the equilibrium potential of o / Co (OH) ₂ .

[0005] However, since the metallic cobalt powder is not easily oxidized, a part thereof remains in the positive electrode. The remaining metallic cobalt powder dissolves in the alkaline electrolyte and precipitates on the separator disposed between the positive electrode and the negative electrode. If such a storage battery is left for a long time or used for a long period of time, the positive electrode swells and the distance between the negative electrode and the negative electrode decreases, so that the positive electrode and the negative electrode intervene through metallic cobalt precipitated in the separator. There is a problem that the contact may cause an internal short circuit, resulting in a decrease in discharge capacity.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high utilization rate of an active material in an early stage, to prevent an internal short circuit during storage for a long period of time, and to suppress a decrease in discharge capacity after storage. An object of the present invention is to provide a method for manufacturing an alkaline storage battery.

[0007]

According to the present invention, there is provided a method of manufacturing an alkaline storage battery comprising the steps of: providing a positive electrode comprising nickel hydroxide, nickel oxyhydroxide and a cobalt compound on a current collector; And a step of assembling an inactive alkaline storage battery provided with an alkaline electrolyte, a step of aging the inactive storage battery, and a step of performing initial charging. It is characterized by the following.

Further, the method for manufacturing an alkaline storage battery according to the present invention has a structure in which a positive electrode material containing nickel hydroxide particles having at least a part of a nickel oxyhydroxide layer and cobalt compound particles is supported on a current collector. An electrode group produced by interposing a separator between the positive electrode and the negative electrode, a step of assembling an inactive alkaline storage battery provided with an alkaline electrolyte, a step of aging the inactive storage battery, and an initial charge And applying step.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an alkaline storage battery according to the present invention will be described. (1) A positive electrode material containing nickel hydroxide {Ni (OH) ₂ }, nickel oxyhydroxide (NiOOH) and a cobalt compound is produced by interposing a separator between a positive electrode and a negative electrode having a structure in which the positive electrode material is supported on a current collector. The inactive alkaline storage battery is assembled by storing the sealed electrode group and the alkaline electrolyte in a container and closing the container.

Hereinafter, the positive electrode, the negative electrode, the separator, and the electrolyte will be described. <1> Positive electrode As the positive electrode, for example, a first positive electrode to a third positive electrode described below can be used.

<First Positive Electrode> A positive electrode material comprising nickel oxyhydroxide particles and composite nickel hydroxide particles having a cobalt compound layer (hereinafter, referred to as particles A) is supported on a current collector. It has a structure.

In the particles A, from the viewpoint of improving the charge / discharge efficiency of the alkaline storage battery, the peak half-value width of the (101) plane of nickel hydroxide by the X-ray powder diffraction method is 0.8.
゜ / 2θ (Cu-Kα) or more is preferable.
More preferable peak half width is 0.9 to 1.0 ° / 2θ.
(Cu-Kα).

As the cobalt compound, a cobalt compound having two or more valences is preferably used. For example, cobalt monoxide (CoO), cobalt hydroxide {Co (OH) ₂ },
At least one type of cobalt compound selected from dicobalt trioxide (Co ₂ O ₃ ) and tricobalt tetroxide (Co ₃ O ₄ ) can be mentioned. In particular, cobalt monoxide and cobalt hydroxide are preferred.

Examples of the current collector include those having a sponge-like, fibrous, or felt-like porous structure made of a metal such as nickel or stainless steel, a nickel-plated resin, or the like.

The content of the nickel oxyhydroxide particles in the positive electrode is 5 to the nickel hydroxide component of the particles A.
It is preferable that the content be 0% by weight or less. Since the nickel oxyhydroxide other than that used for the reaction with the cobalt compound remains in a high order even after aging, when the content exceeds 50% by weight, such an excessive nickel oxyhydroxide amount is reduced. There is a risk of increasing. As a result, the positive electrode may be overcharged at an early stage at the time of initial charging, and the activation of the storage battery may be insufficient. If the activation is insufficient, the initial capacity of the storage battery may decrease. In addition, in order to sufficiently achieve the effect of improving the active material utilization rate by adding the nickel oxyhydroxide particles, the content of the nickel oxyhydroxide particles is preferably 3% by weight or more.
A more preferred content is in the range of 5% to 20% by weight.

Preferably, a binder is added to the positive electrode material in order to improve the adhesion to the current collector. Examples of the binder include polytetrafluoroethylene, carboxymethyl cellulose, methyl cellulose, sodium polyacrylate, and polyvinyl alcohol.

The first positive electrode is prepared, for example, by preparing a paste containing the nickel oxyhydroxide particles, the particles A, the binder and water, filling the paste into the current collector, and drying the paste. It can be manufactured by cutting into a desired size after pressure molding.

<Second Positive Electrode> This positive electrode has a structure in which a positive electrode material containing nickel oxyhydroxide particles, nickel hydroxide particles and cobalt compound particles is supported on a current collector.

In the nickel hydroxide particles, from the viewpoint of improving the charge / discharge efficiency of the alkaline storage battery, the peak half-value width of the (101) plane of the nickel hydroxide by the X-ray powder diffraction method is 0.8 ゜ / 2θ ( Cu-Kα) or more. A more preferable peak half width is 0.9 to 0.9.
1.0 ° / 2θ (Cu-Kα).

As the cobalt compound, the same compounds as those described for the first positive electrode can be used. Examples of the current collector include those similar to those described for the first positive electrode.

The content of the nickel oxyhydroxide particles in the positive electrode is preferably set to 50% by weight or less based on the nickel hydroxide particles for the same reason as described above. In addition, in order to sufficiently achieve the effect of improving the active material utilization rate by adding the nickel oxyhydroxide particles, the content of the nickel oxyhydroxide particles is preferably 3% by weight or more. A more preferred content is in the range of 5% to 20% by weight.

It is preferable to add a binder to the positive electrode material in order to improve the adhesion to the current collector. Examples of the binder include those similar to those described for the first positive electrode.

For the second positive electrode, for example, a paste containing the nickel oxyhydroxide particles, the nickel hydroxide particles, the cobalt compound particles, the binder and water is prepared, and the paste is mixed with the current collector. , Dried and press-molded, and then cut into a desired size.

<Third Positive Electrode> This positive electrode comprises a positive electrode material containing nickel hydroxide particles (hereinafter, referred to as particles B) having a nickel oxyhydroxide layer on at least a part of the surface thereof and cobalt compound particles. It has a structure supported on.

The particles B may be those having a nickel oxyhydroxide layer on only part of the surface or those having a nickel oxyhydroxide layer on the entire surface. The particles B may also have a nickel oxyhydroxide layer inside. However, the particles B do not entirely consist of nickel oxyhydroxide.

As the cobalt compound and the current collector, the same compounds as described in the first positive electrode can be used. The content of the nickel oxyhydroxide layer of the particles B is preferably set to 50% by weight or less based on the nickel hydroxide particles for the same reason as described above. Further, in order to sufficiently achieve the effect of improving the active material utilization rate by forming the nickel oxyhydroxide layer, the content of the nickel oxyhydroxide layer is preferably 3% by weight or more. A more preferred content is from 5% by weight to 20% by weight.
% By weight.

It is preferable to add a binder to the positive electrode material in order to improve the adhesion to the current collector. Examples of the binder include those similar to those described for the first positive electrode.

The third positive electrode includes, for example, the particles B,
Preparing a paste containing the cobalt compound particles, the binder and water, filling the paste into the current collector,
This can be manufactured by drying and press-molding this, and then cutting it into a desired size.

<2> Negative Electrode This negative electrode is kneaded with a negative electrode active material, a conductive material, a binder and water to prepare a paste,
The paste is filled in a conductive substrate, dried, and then molded.

Examples of the negative electrode active material include cadmium compounds such as metal cadmium and cadmium hydroxide, and hydrogen. Examples of the host matrix of hydrogen include a hydrogen storage alloy.

Above all, the hydrogen storage alloy is preferable because the capacity of the storage battery can be improved as compared with the case where the cadmium compound is used. The hydrogen storage alloy is not particularly limited, and may be any as long as it can store hydrogen electrochemically generated in an electrolytic solution and can easily release the stored hydrogen during discharge. For example, LaNi ₅ , MmN
i ₅ (Mm is misch metal), LmNi ₅ (Lm is L
at least one selected from rare earth elements including a), and a part of Ni of these alloys is Al, Mn, Co, Ti, C
Examples thereof include a multi-element-based material substituted with an element such as u, Zn, Zr, Cr, and B, or a TiNi-based or TiFe-based material. In particular, the general formula LmNi _w Co _x Mn
_y Al _z (the total value of atomic ratios w, x, y, and z is 5.00 ≦
(W + x + y + z ≦ 5.50) The hydrogen storage alloy having the composition represented by the formula (1) is suitable because it can suppress the pulverization accompanying the progress of the charge / discharge cycle and improve the charge / discharge cycle life.

Examples of the conductive material include carbon black and graphite. Examples of the binder include polyacrylates such as sodium polyacrylate and potassium polyacrylate, fluorine-based resins such as polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC).

Examples of the conductive substrate include a two-dimensional substrate such as a punched metal, an expanded metal, a perforated rigid plate, and a nickel net; a felt-like metal porous material;
Examples include a three-dimensional substrate such as a sponge-like porous metal body.

<3> Separator Examples of the separator include a nonwoven fabric made of a polyamide fiber and a nonwoven fabric made of a polyolefin fiber such as polyethylene and polypropylene provided with a hydrophilic functional group.

<4> Alkaline Electrolyte Examples of the alkaline electrolyte include an aqueous solution of sodium hydroxide (NaOH), an aqueous solution of lithium hydroxide (LiOH), an aqueous solution of potassium hydroxide (KOH), and a mixture of NaOH and LiOH. Solution, a mixed solution of KOH and LiOH, KOH, LiOH and N
A mixed solution of aOH or the like can be used.

As the alkaline electrolyte, 0.5M
It is preferable to use one containing (mol / l) or more LiOH. The storage battery provided with such an alkaline electrolyte can further improve the cycle life. In such an electrolytic solution, the upper limit of LiOH is preferably set to 1.5M. If the concentration of LiOH exceeds 1.5M, the conductivity of the electrolytic solution may decrease, and the cycle life may decrease. Furthermore, LiOH has relatively low solubility,
Dissolution exceeding 1.5 M is difficult, and precipitation may occur in a low temperature range. More preferred LiOH concentration (M)
Is 0.5 to 1.2.

In order to further improve both the high-temperature charging efficiency and the cycle life of the alkaline storage battery, 2.0 to 6.0 M KO of the electrolyte solution is required.
H, 2.0-5.0 M NaOH and 0.5-1.5.
It is preferable to use an electrolyte having a composition of M LiOH.

(2) Aging is performed on the inactive storage battery. In addition, from the viewpoint of causing the reaction between the nickel oxyhydroxide and the cobalt compound at a higher rate, the aging is preferably performed for a long time so as not to affect the negative electrode.

(3) Initial charging is performed. (1)-
The alkaline storage battery is manufactured by the process (3). The method for manufacturing an alkaline storage battery according to the present invention described above includes a separator interposed between a positive electrode and a negative electrode having a structure in which a positive electrode material containing nickel hydroxide, nickel oxyhydroxide and a cobalt compound is supported on a current collector. The method includes a step of assembling an inactive alkaline storage battery provided with the prepared electrode group and an alkaline electrolyte, a step of aging the inactive storage battery, and a step of performing initial charging. According to such a manufacturing method, the utilization rate of the active material (nickel hydroxide) at the beginning of the charge / discharge cycle is improved, and an internal short circuit when stored for a long time or in a high temperature environment is prevented. In this case, it is possible to provide an alkaline storage battery in which a reduction in capacity is suppressed.

According to the present invention, it is presumed that the storage battery having the above-mentioned excellent characteristics can be provided for the following reasons. First, an experiment described below was performed to estimate the effect of the present invention. That is, a paste composed of nickel hydroxide particles, a binder and water was prepared, filled in a nickel fiber substrate, and dried to produce a nickel hydroxide electrode. The nickel hydroxide particles in this electrode were electrochemically oxidized and converted to nickel oxyhydroxide particles. The obtained electrode is immersed in an alkaline aqueous solution in which a cobalt compound (for example, cobalt hydroxide) is dissolved,
When the potential change of the electrode was measured, the potential gradually decreased and showed a constant potential. When the electrode surface after immersion was observed, black particles different from nickel oxyhydroxide were densely adhered to the surface. An electrode containing metal nickel particles instead of the nickel oxyhydroxide particles,
No change due to such immersion was observed in the electrode containing nickel hydroxide particles before the oxidation treatment.

In consideration of the above facts, according to the present invention, in the aging step, the cobalt compound of the positive electrode is attracted to the nickel oxyhydroxide having a higher potential, and the cobalt compound and the oxyhydroxide are mixed. An oxidation-reduction reaction occurs with nickel, and gradually takes a higher potential, resulting in a highly reactive state in which proton diffusion is very likely to occur. In such a reaction, part of the cobalt compound is converted to conductive cobalt oxyhydroxide. When a positive charge is applied to the positive electrode in such a state, the cobalt compound added to the positive electrode can be converted into cobalt oxyhydroxide at a high ratio, and a dense conductive matrix is formed on the surface of the active material, nickel hydroxide. It becomes possible to do. Therefore, the utilization rate of the active material (nickel hydroxide) at the beginning of the charge / discharge cycle can be improved. In addition, the dense conductive matrix is not easily reduced when the alkaline storage battery is stored in a high-temperature environment or when stored for a long period of time. Moreover, since the positive electrode contains a cobalt compound instead of metal cobalt as a precursor of cobalt oxyhydroxide, it is possible to prevent the metal cobalt remaining in the separator from being deposited after the first charge. Therefore, when the alkaline storage battery is stored in a high-temperature environment or when stored for a long period of time, it is possible to avoid the occurrence of an internal short circuit and to suppress the reduction reaction of the conductive matrix. The subsequent decrease in discharge capacity can be kept low.

In the manufacturing method of the present invention, the positive electrode having a structure in which a positive electrode material containing nickel oxyhydroxide particles and composite nickel hydroxide particles having a cobalt compound layer on the surface is supported on a current collector is used. Thereby, the cobalt compound can be uniformly dispersed in the positive electrode, so that the conductive matrix can be more uniformly formed in the positive electrode. Therefore, the active material utilization and storage characteristics at the beginning of the charge / discharge cycle can be dramatically improved.

The positive electrode has a structure in which a positive electrode material containing nickel hydroxide particles and a cobalt compound particle having a nickel oxyhydroxide layer on at least a part of the surface is supported on a current collector. In the step, the cobalt compound particles are attracted to the nickel hydroxide particles, an oxidation-reduction reaction occurs between the nickel oxyhydroxide and the cobalt compound, and the cobalt compound particles adhere to the nickel hydroxide particles as a result of this reaction. be able to. By performing the initial charge after this aging, a conductive matrix having many portions in contact with the surface of the nickel hydroxide particles can be formed, that is, a denser conductive matrix can be formed. It is possible to further improve the initial active material utilization rate and the storage characteristics.

Further, in a positive electrode having a structure in which a positive electrode material containing nickel hydroxide, nickel oxyhydroxide and a cobalt compound is supported on a current collector, the content of the cobalt oxyhydroxide is set to 50 By setting the weight percent or less, the amount of cobalt oxyhydroxide remaining without reacting with the cobalt compound during the aging step can be reduced, so that the positive electrode quickly reaches an overcharged state during the first charging step. Can be avoided, and activation can be sufficiently performed.

[0045]

Embodiments of the present invention will be described below in detail with reference to the drawings. Example 1 <Preparation of Positive Electrode> First, 1 liter of a 2 mol / l aqueous solution of nickel sulfate, 2 liters of a 14 mol / l aqueous solution of potassium hydroxide and 5 liters of a 12% aqueous solution of sodium hypochlorite were mixed and heated to 85 ° C. To precipitate. The obtained precipitate was sufficiently washed, dried, and pulverized to prepare nickel oxyhydroxide particles.

Carboxymethylcellulose was mixed with 80 parts by weight of nickel hydroxide particles and 10 parts by weight of cobalt hydroxide particles as cobalt compound particles.
5 parts by weight, 0.25 parts by weight of sodium polyacrylate,
3.0 parts by weight of polytetrafluoroethylene and 10 parts by weight of the above nickel oxyhydroxide particles were added, and 30 parts by weight of water was further added to the mixture, followed by kneading to prepare a paste. This paste has a thickness of 1.1 m as a current collector.
m, a nickel-plated fiber substrate having a porosity of 95% is filled, dried, roll-pressed and roll-formed to collect a positive electrode material containing nickel hydroxide particles, nickel oxyhydroxide particles and cobalt hydroxide particles. A positive electrode having a structure supported by an electric body was produced. <Preparation of Negative Electrode> LaNi _4.0 Co _0.4 Mn _0.3 Al _0.3
3 parts by weight of polytetrafluoroethylene powder, 1 part by weight of carbon powder, and 1 part by weight of carboxymethyl cellulose as a binder
A paste was prepared by adding parts by weight and mixing with 50 parts by weight of water. This paste was applied to a nickel net, dried, and then press molded to produce a hydrogen storage alloy negative electrode.

Next, a separator made of a nonwoven fabric made of polypropylene was interposed between the positive electrode and the negative electrode, and spirally wound to form an electrode group. 7. These electrode groups and
An alkaline electrolyte composed of 0 M KOH was housed in a cylindrical container having a bottom, and an inactive cylindrical nickel-metal hydride battery having an AA size (theoretical capacity; 1200 mAh) having the structure shown in FIG. 1 was assembled. Next, after aging was performed for 72 hours in an atmosphere of 25 ° C., an initial charge of 200% charging at 0.1 C was performed in an atmosphere of 25 ° C., and the battery was discharged to 1.0 V at 0.2 C. Then 200% at room temperature at 0.1C
After charging, the battery was subjected to five charge / discharge cycles of discharging at 0.2 C to 1.0 V to produce a cylindrical nickel-metal hydride storage battery.

That is, in FIG. 1, an electrode group 5 produced by laminating a positive electrode 2, a separator 3, and a negative electrode 4 and spirally winding them is accommodated in a bottomed cylindrical container 1. ing. The negative electrode 4 is arranged at the outermost periphery of the electrode group 5 and is in electrical contact with the container 1.
The alkaline electrolyte is contained in the container 1. A circular first sealing plate 7 having a hole 6 in the center is
Is arranged in the upper opening. The ring-shaped insulating gasket 8 is disposed between the peripheral edge of the sealing plate 7 and the inner surface of the upper opening of the container 1, and the sealing plate is formed on the container 1 by caulking to reduce the diameter of the upper opening inward. 7 is hermetically fixed via the gasket 8. One end of the positive electrode lead 9 is connected to the positive electrode 2, and the other end is connected to the lower surface of the sealing plate 7. Hat-shaped positive electrode terminal 10
Is mounted on the sealing plate 7 so as to cover the hole 6. A rubber safety valve 11 is disposed so as to close the hole 6 in a space surrounded by the sealing plate 7 and the positive electrode terminal 10. A circular holding plate 12 made of an insulating material having a hole in the center is arranged on the positive electrode terminal 10 such that a projection of the positive electrode terminal 10 projects from the hole of the holding plate 12. The outer tube 13 covers the periphery of the holding plate 12, the side surface of the container 1, and the periphery of the bottom of the container 1. (Example 2) Example 1 was added to 90 parts by weight of composite nickel hydroxide particles having a cobalt hydroxide layer on the surface (the adhesion amount of the cobalt hydroxide layer was 5% based on the composite nickel hydroxide particles).
10 parts by weight of nickel oxyhydroxide particles obtained in the same manner as described above, 0.25 parts by weight of carboxymethylcellulose, 0.25 parts by weight of sodium polyacrylate, and 3.0 parts by weight of polytetrafluoroethylene, and the mixture was further added. Was mixed with 30 parts by weight of water and kneaded to prepare a paste. This paste has a thickness of 1.1 mm as a current collector.
Then, fill a 95% porosity nickel-plated fiber substrate,
After drying, a positive electrode having a structure in which the positive electrode material containing the composite nickel hydroxide particles and the nickel oxyhydroxide particles was supported on the current collector by rolling and rolling with a roller press was used. Similarly, a cylindrical nickel-metal hydride storage battery was manufactured. (Example 3) In the method for producing nickel oxyhydroxide particles of Example 1, nickel hydroxide particles having a nickel oxyhydroxide layer formed on the entire surface were produced by changing the volume of the aqueous solution of sodium hypochlorite. . In the obtained particles, the content of the nickel oxyhydroxide layer was 10% by weight based on nickel hydroxide.

To 90 parts by weight of the particles, 10 parts by weight of cobalt hydroxide particles as cobalt compound particles, 0.25 parts by weight of carboxymethyl cellulose, 0.25 parts by weight of sodium polyacrylate and 3.0 parts by weight of polytetrafluoroethylene Was added, and 30 parts by weight of water was further added to the mixture and kneaded to prepare a paste. This paste has a thickness of 1.1 mm as a current collector and a porosity of 95%.
After being filled into a nickel-plated fiber substrate, dried, and then roll-pressed and roll-formed, the positive electrode material containing nickel hydroxide particles and cobalt hydroxide particles having a nickel oxyhydroxide layer on the entire surface becomes a current collector. A positive electrode having a supported structure was produced.

A cylindrical nickel-metal hydride storage battery was manufactured in the same manner as in Example 1 except that the positive electrode was thus manufactured. (Example 4) 60 parts by weight of nickel oxyhydroxide particles obtained in the same manner as in Example 1 were added to a mixed powder comprising 30 parts by weight of nickel hydroxide particles and 10 parts by weight of cobalt hydroxide particles as cobalt compound particles; 0.25 parts by weight of carboxymethylcellulose, 0.25 parts by weight of sodium polyacrylate and polytetrafluoroethylene
0 parts by weight was added, and 30 parts by weight of water was further added to the mixture and kneaded to prepare a paste. This paste was filled into a nickel-plated fiber substrate having a thickness of 1.1 mm as a current collector and having a porosity of 95%, dried, and then roll-pressed to form nickel hydroxide particles and oxyhydroxide. A cylindrical nickel-metal hydride storage battery was manufactured in the same manner as in Example 1, except that a positive electrode having a structure in which a positive electrode material containing nickel particles and cobalt hydroxide particles was supported on a current collector was manufactured. (Comparative Example 1) A cylindrical nickel-metal hydride battery was manufactured in the same manner as in Example 1 except that nickel oxyhydroxide particles were not added to the positive electrode but 90 parts by weight of nickel hydroxide particles were added. (Comparative Example 2) A cylindrical nickel-metal hydride storage battery was manufactured in the same manner as in Example 1, except that the same amount of metal cobalt particles as the cobalt compound was added to the positive electrode instead of the cobalt compound.

After charging the obtained storage batteries of Examples 1 to 4 and Comparative Examples 1 and 2 at 0.1 C for 16 hours,
The battery was discharged at 0 C until the terminal voltage became 1.0 V, and the initial capacity was calculated from the discharge duration, and the initial utilization rate [{(initial capacity) / (theoretical capacity of the storage battery)} × 100] was obtained.
The result is shown in FIG.

Further, these storage batteries were discharged for 6 months per month.
After storing in 5 ° C., charging at 0.1 C for 16 hours,
The charge / discharge of discharging until the terminal voltage becomes 1.0 V at 0 C is repeated three times, and the discharge capacity (recovery capacity) is measured. (Capacity)｝ × 100]. The result is shown in FIG. In FIG. 3, the recovery utilization rate of the storage battery of Example 4 is 83%, and the recovery utilization rate of the storage battery of Comparative Example 1 is 80%.
It is.

As is apparent from FIG. 2, an inactive storage battery is assembled using a positive electrode having a structure in which a current collector is filled with a positive electrode material containing nickel hydroxide, nickel oxyhydroxide and a cobalt compound, and subjected to aging. After that, the storage batteries of Examples 1 to 4 manufactured by performing the initial charge have a higher initial utilization rate than the storage battery of Comparative Example 1 manufactured using the positive electrode to which cobalt oxyhydroxide is not added. I understand. In addition, the storage battery of Comparative Example 2 manufactured using the positive electrode containing metal cobalt instead of the cobalt compound had an initial utilization rate as high as the storage batteries of Examples 1 to 4.

Further, as is apparent from FIG.
It can be understood that the storage batteries of Nos. To 4 have higher utilization rates at the time of recharging after high-temperature storage than the storage batteries of Comparative Examples 1 and 2. Therefore,
From the initial utilization rate in FIG. 2 and the recovery utilization rate after high-temperature storage in FIG. 3, the storage batteries of Examples 1 to 4 can improve the initial charge capacity and serve as a conductive auxiliary material that contributes to the formation of a conductive matrix. It can be seen that a practical capacity can be obtained even under severe conditions such as storage for a long period of time and storage under a high temperature environment because metal cobalt is not used.

The initial activation method (initial charge) of the above-described embodiment is based on the formation of a conductive matrix of cobalt and Ni (O
H) The _two active materials are charged at the same time, and when the main focus is on the formation of the cobalt conductive matrix, the charge is carried out at the same rate and in the same atmosphere so as to be 100% of the added amount of the cobalt compound. The same effect can be obtained by charging under arbitrary conditions.

In the above-described embodiment, a cylindrical nickel-metal hydride having a structure in which a separator is interposed between a positive electrode and a negative electrode, and an electrode group produced by spirally winding the separator is accommodated in a container. Although an example in which the present invention is applied to a secondary battery has been described, a prismatic structure having a structure in which a positive electrode and a negative electrode are alternately overlapped with a separator interposed therebetween, and the laminate is housed in a bottomed rectangular cylindrical container. The present invention can be similarly applied to a nickel hydride secondary battery.

[0057]

As described above in detail, according to the present invention, while maintaining the active material utilization rate at the initial stage of the charge / discharge cycle at a high value, a decrease in the capacity when left for a long time or when left at a high temperature is suppressed. And a method for manufacturing an alkaline storage battery.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an alkaline storage battery (for example, a cylindrical alkaline storage battery) according to the present invention.

FIG. 2 is a characteristic diagram showing initial utilization rates of the alkaline storage batteries of Examples 1 to 4 and Comparative Examples 1 and 2 according to the present invention.

FIG. 3 is a characteristic diagram showing the recovery utilization rates of the alkaline storage batteries of Examples 1 to 4 and Comparative Examples 1 and 2 according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... container, 2 ... positive electrode, 3 ... separator, 4 ... negative electrode, 7 ...
Sealing plate.

Claims (4)

[Claims] An electrode group formed by interposing a separator between a positive electrode and a negative electrode having a structure in which a positive electrode material containing nickel hydroxide, nickel oxyhydroxide and a cobalt compound is supported on a current collector, A method of manufacturing an alkaline storage battery, comprising: assembling an inactive alkaline storage battery including a liquid; aging the inactive storage battery; and performing a first charge. 2. A separator is interposed between a positive electrode and a negative electrode having a structure in which a positive electrode material containing nickel hydroxide particles and a cobalt compound particle having a nickel oxyhydroxide layer on at least a part of the surface is supported on a current collector. An electrode group produced by
A method for manufacturing an alkaline storage battery, comprising: assembling an inactive alkaline storage battery provided with an alkaline electrolyte; aging the inactive storage battery; and performing a first charge. 3. The method according to claim 1, wherein the cobalt compound is cobalt hydroxide. 4. The method according to claim 1, wherein the content of the nickel oxyhydroxide in the positive electrode is 50% by weight or less based on the nickel hydroxide.