JPH117960A - Electrode for alkaline secondary battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode, which achieves the maximum discharge capacity with the small number of cycle and which has a large maximum charge capacity, at a low cost by mixing a specified quantity of scale-like nickel alloy powder in the powder, which includes the battery active material, and fixing this mixture powder to a collector, and pressing it for molding. SOLUTION: As a powder for electrode, the mixture powder, which includes the scale-like nickel alloy powder at 5-30 pts.wt. to the powder, which includes the electrode active material, at 100 pts.wt. is used. The scale-like nickel alloy powder, which has the mean granular diameter at about 5-20 μm and the mean thickness at 0.9 μm or less in usual, is desirably used. The scaly nickel alloy powder, which has a peculiar shape having a large aspect ratio, is arranged with a large orientation. Namely, in the case of press molding the scale-like nickel alloy powder, the scale-like nickel alloy powder is arranged vertically relative to the pressing direction and in layer. As a nickel alloy, binary alloy such as Ni-Co group, Ni-Cu group, Ni-Al group and Ni-B group and ternary alloy such as a Ni-Cu-P group is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an alkaline battery (N
The present invention relates to an electrode used for a positive electrode, a negative electrode, or a current collector of an i-Cd storage battery, a Ni-Zn storage battery, a Ni-metal hydride storage battery, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Recently, notebook computers, which are portable devices,
With the widespread use of mobile phones, PHS, VTR cameras and the like, high performance and environmentally friendly secondary batteries are required as power supplies for these devices. In this connection, there is a need on a global scale for secondary batteries for electric vehicles that are safe and contain no pollutants. As a battery that meets such requirements, a Ni-metal hydride battery belonging to an alkaline secondary battery has attracted attention.

A nickel-metal hydride battery uses a nickel hydroxide electrode as a positive electrode, a hydrogen electrode filled with a hydrogen storage alloy powder for reversibly storing and releasing hydrogen as a negative electrode, and an alkaline aqueous solution as an electrolyte. And a structure in which both electrodes are sandwiched one on top of the other via a separator made of an electrically insulating non-woven fabric that holds the liquid and has liquid permeability.

[0004] The above-mentioned electrodes to be incorporated in this type of battery are conventionally manufactured as follows. First, a conductive powder such as a nickel powder and a cobalt powder is mixed with each battery active material (hereinafter, also simply referred to as “active material”) powder, and then a carboxymethyl cellulose resin (CMC resin) and water are blended and kneaded. To prepare a water-soluble active material paint. Next, the active material paint is filled in a three-dimensional porous foamed nickel sheet current collector together with a binder such as a tetrafluoroethylene resin (PTFE resin). Finally, in the current collector filled with these, after removing water in the air or in a vacuum, a current collector which is rolled and controlled to a predetermined thickness is finally obtained as an electrode.

[0005]

By the way, this Ni-
The discharge capacity of a metal hydride battery is determined to some extent by the electrode powder used for the electrode. It is said that it is desirable to lower the internal resistance of the electrode as much as possible in order to exhibit the original characteristics of a battery manufactured by combining them.

The nickel hydroxide powder used for the positive electrode is
Unlike metal, there is almost no conductivity. Therefore, in order to lower the internal resistance of the positive electrode, generally, a predetermined amount of carbonyl nickel powder and cobalt powder are mixed as conductive powder with nickel hydroxide powder, and this mixed powder is filled in a foamed nickel sheet current collector. It is manufactured. Similarly, the negative electrode is manufactured using a conductive powder.

However, in the above method, the number of steps for producing the electrode is large, and quality control is complicated. Not only that, if the conductive powder is used in such a large amount, the content of the active material in the electrode is relatively reduced, and a satisfactory capacity density is secured in a battery manufactured using the electrode. You will not be able to do it.

For this reason, there is a need for the development of an electrode which can be produced relatively easily and which can be filled with more active material. On the other hand, as devices become lighter and smaller, thinner electrodes are required.

As a method of manufacturing such an electrode, the hydrogen storage alloy powder and the flaky Cu powder are mixed, and the mixed powder is press-molded so that the flaky Cu powder is parallel to the electrode surface in the sectional structure of the electrode. Alternatively, there is a method of forming a micro current collector by continuously orienting the micro current collector substantially in parallel (Japanese Patent Laid-Open No. 7-307154). According to this method, the internal resistance of the electrode made of the hydrogen storage alloy can be reduced, and the discharge capacity of the battery can be improved.

However, even with the above method, there is still room for improvement in terms of easily and inexpensively manufacturing a battery having a high discharge capacity.

Accordingly, it is a main object of the present invention to provide an electrode which provides excellent discharge capacity at low cost.

[0012]

Means for Solving the Problems As a result of intensive studies in view of the problems of the prior art, the present inventor has achieved the above object by producing an electrode by using a specific alloy powder together with a battery active material. They have found that this can be achieved and have completed the present invention.

That is, the present invention relates to the following electrode for an alkaline secondary battery and a method for producing the same.

1. As the electrode powder, flaky nickel alloy powder 5 to 100 parts by weight of the powder containing the battery active material
An electrode for an alkaline secondary battery, wherein a mixed powder containing 30 parts by weight is used.

2. An alkaline secondary battery characterized by mixing 5 to 30 parts by weight of flaky nickel alloy powder with 100 parts by weight of a powder containing a battery active material, fixing the mixed powder to a current collector, and then pressing and molding. Method of manufacturing electrodes.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The electrode for an alkaline secondary battery according to the present invention is a mixed powder containing 10 to 30 parts by weight of a flaky nickel alloy powder with respect to 100 parts by weight of a powder containing a battery active material. Is used.

The shape of the flaky nickel alloy powder is as follows:
Scaly, flaky, flat, etc. shapes, ie long diameter (particle size)
Is not particularly limited as long as it is long and thin. In the present invention, it is particularly preferable that the average particle diameter is usually about 5 to 20 μm and the average thickness is usually 0.9 μm or less. The flaky nickel alloy powder is arranged with a large orientation because of a unique shape having a large aspect ratio (major axis / thickness). That is, when the flaky nickel alloy powder is molded under pressure, the flaky nickel alloy powder is oriented perpendicularly to the pressing direction and in a layered manner.

The scale-like powder can more easily impart shape anisotropy in the electrode as compared with isotropic spherical powder or the like, so that continuous surface or point contact is possible. That is, continuous contact orientation can be ensured in the flaky nickel alloy powder. As a result, even with the same compounding ratio, the flaky powder has better contact orientation, a network having excellent conductivity is formed, and the discharge capacity and the like can be improved.

When the average particle size is less than 5 μm, the flaky nickel alloy powder may be smaller than the active material such as the hydrogen storage alloy powder and the nickel hydroxide powder. In this case, one particle of the flaky nickel alloy powder cannot contact over a plurality of active material powder particles, and a large number of flaky nickel alloy powder particles are required to make contact over the active material powder particles. As a result, the contact resistance increases due to the increase in the number of contacts, which may lead to an increase in the internal resistance of the electrode. On the other hand, if the average particle size exceeds 20 μm, segregation due to the difference in shape or size from the active material powder during mixing, or a bent product is roundly aggregated, thereby ensuring sufficient continuous contact orientation. become unable.

The kind of the alloy of the flaky nickel alloy powder is not particularly limited as long as the desired conductivity and the like can be secured, and for example, a known nickel alloy can be used.
Among them, it is preferable to use a nickel alloy containing an element that improves the ductility of nickel as the second component. Such components include, for example, Co, Cu, Al, B,
P and the like. These can be used alone or in combination of two or more. Such nickel alloys include, for example, Ni-Co, Ni-Cu, Ni-Al, Ni-
Binary alloys such as B-based alloys and ternary alloys such as Ni-Cu-P-based alloys can be used, and these can be used alone or as a mixed powder of two or more kinds. Among these, Ni-Co type, Ni-
It is desirable to use a Cu type or the like.

The content of the second component in the above nickel alloy may be appropriately changed according to the kind of the second component and the like, and is generally 50% by weight or less, particularly in the range of 2 to 20% by weight. Is preferred.

For example, when the nickel alloy is of a Ni—Co type, the Co component is usually about 2 to 50% by weight,
In particular, the content is preferably 3 to 20% by weight. Also, Ni
In the case of -Cu-based, the Cu content is usually preferably about 2 to 50% by weight, particularly preferably 5 to 20% by weight. In any case, if it is less than 2% by weight, the effect of the addition may be reduced. In the positive electrode, the Co component partially dissolves and precipitates when charged / discharged and changes to conductive β-CoOOH via Co (OH) ₂ , which coats the periphery of the positive electrode active material to form a microscopic conductive material. As a result of forming the conductive network, it contributes to improvement of the discharge capacity of the nickel positive electrode. on the other hand,
In the negative electrode, Co and Cu elute during charge and discharge, precipitate as metal in the electrode, form a microscopic conductive network, and contribute to improving the discharge capacity of the alloy negative electrode. That is, when the content is within the above range, continuous contact orientation becomes particularly good, and a large discharge capacity is obtained, which is advantageous in terms of characteristics and economy. Similarly, Ni-
In the case of an Al-based material, the content of the Al component is usually preferably about 2 to 50% by weight, particularly preferably 5 to 20% by weight.

The amount of the flaky nickel alloy powder to be added can be appropriately determined according to the type of the active material and the nickel alloy to be used, and is usually about 5 to 30 parts by weight based on 100 parts by weight of the powder containing the battery active material. It is good.

For example, when a hydrogen storage alloy is used for the negative electrode, the amount is usually 5 to 30 parts by weight, preferably 5 to 15 parts by weight. If the amount is less than 5 parts by weight, the formation of continuous contact orientation of the flaky nickel alloy powder becomes insufficient, and improvement in the internal resistance of the electrode cannot be expected. Therefore, in such a case, there is little improvement in the discharge capacity and cycle characteristics, and the characteristics may vary. When the addition exceeds 30 parts by weight, not only the remarkable improvement of the contact resistance due to the addition is not observed, but also the smooth absorption and storage of hydrogen gas by the flaky nickel alloy powder surrounding the active material. Since release is hindered, the effect of increasing the maximum discharge capacity and reducing the number of cycles until the maximum discharge capacity is reached cannot be achieved. Moreover, the relative amount of active material in the electrode decreases,
Sufficient battery capacity, density, etc. cannot be secured.

For example, when nickel hydroxide powder is used as the positive electrode, the nickel hydroxide powder itself has no conductivity, so that it is necessary to add more flaky nickel alloy powder. Therefore, also in this case, usually 10
The range of about 30 parts by weight is suitable both in terms of characteristics and economy.

The powder containing the battery active material of the present invention contains, in addition to the battery active material powder, components and the like used in known electrodes for alkaline secondary batteries as long as the effects of the present invention are not impaired. May be. The battery active material is not particularly limited, and may be appropriately selected according to the type of battery to be manufactured and the like. That is, in the present invention, the flaky nickel alloy powder can be used in combination with any battery active material. For example, when producing a Ni-metal hydride battery, nickel hydroxide powder can be used as a positive electrode and hydrogen storage alloy powder can be used as a negative electrode as a battery active material.

When nickel hydroxide is used as the active material of the positive electrode, for example, the average particle size is 10 to 40 μm and the composition formula Ni
Powder containing (OH) ₂ , N containing Zn, Co, etc.
i (OH) ₂ powder or the like can be used. In this case, Zn, C
In a Ni (OH) ₂ powder containing o or the like, Zn,
Co and the like are all included in a solid solution in Ni (OH) ₂ or attached to the surface. Z
The content of n, Co, etc. may be usually about 2 to 10% by weight.

When a hydrogen storage alloy is used as the active material of the negative electrode, the type of alloy is not particularly limited as long as it can store and release hydrogen. For example, LaNi ₅
System alloy, MmNi ₅ (Mm is a mixture in which misch means a metal of the rare earth element) alloy represented by the system AB ₅ type composition formula such as alloys, Ti-Mn-Ni alloy, Ti
-Cr-Ni alloy, Zr-Mn-Ni alloy, Ti-
AB-type alloys such as Fe-Ni-based alloys and Ti-Ni-based alloys,
A Laves phase alloy represented by an AB ₂ type composition formula, such as a Zr (Mn, Ni) ₂ alloy, a Zr (V, Ni) ₂ alloy, a Ti (Mn, Ni) ₂ alloy, a Mg ₂ Ni alloy, Ti ₂ N
alloys represented by the composition formula of A ₂ B, such as i-based alloys, VT
A bcc-type V-based alloy containing Ni, such as an i-Ni-based alloy, may be used. Furthermore, any improved type of these alloys or those which form a metal hydride on contact with hydrogen may be used. Among these hydrogen storage alloys, those containing at least one of rare earth elements, titanium, zirconium, magnesium, cobalt, copper, manganese, iron, aluminum, vanadium and chromium in addition to nickel are preferable.

In these hydrogen storage alloy powders, the average particle size is usually about 5 to 70 μm, preferably 10 to 30 μm.
Adjust to use μm. When it is within the above range, when it is incorporated in a battery, sufficient battery characteristics can be obtained, and the flaky nickel alloy powder can be efficiently dispersed.

In the present invention, a part or all of the flaky nickel alloy powder may be subjected to a heat treatment as required. The heat treatment temperature is usually about 300 to 900 ° C., preferably 400 to 700 ° C. This heat treatment can particularly reduce the strain of the flaky nickel alloy powder. The dynamic hardness of the scale-reduced flaky nickel alloy powder is usually 300 DH or less, preferably 250 DH or less. The time for the heat treatment may be appropriately set according to the heat treatment temperature or the like. The heat treatment atmosphere is preferably an inert gas atmosphere such as an argon gas, a nitrogen gas, and a helium gas.

As other components of the electrode powder, for example,
If necessary, resin components such as CMC resin and PTFE resin,
Alternatively, known conductive assistants, antioxidants, rust preventives, and the like can be added. The compounding amount may be appropriately set according to the type of the flaky nickel alloy powder and the like.

Next, these components are mixed. The mixing method may be in accordance with a known method, and mixing can be performed using a mixer generally used in the field of powder metallurgy, for example, a raikai machine, a ball mill, a vibration mill, an attritor, or the like. If the brittle and hard hydrogen storage alloy powder and other softer components are mixed using a raikai machine or the like, the hydrogen storage alloy powder can be further finely pulverized.
In particular, in order to efficiently form the conductive network, it is preferable to use a mechanofusion type mixer capable of applying a shear stress to the mixed powder. As a result, the overlapping or agglomerated powder can be efficiently dispersed one by one, so that the number of stacked active material powders or the like can be reduced. The operating conditions of the mechanofusion type mixer are not particularly limited, but are usually 300 to 900 rpm.
The mixing time may be about 120 to 5 minutes at about pm.

In the present invention, when a resin component is further added in addition to the active material and the flaky nickel alloy powder, a mixer generally used in the field of paint can be used. Examples of such a mixer include a double arm kneader, a wet ball mill, a wet attritor, and the like. During the mixing operation, it is necessary to efficiently disperse the active material powder, the flaky nickel alloy powder, the resin component, and the like, which are particularly overlapped or agglomerated, into particles one by one. Can be dispersed. In particular, when a PTFE resin is used, it becomes gum-like when pressure and shear stress are applied, and since the active material and the flaky nickel alloy powder can be firmly held, it is relatively easy to obtain a thin sheet-like electrode. it can. Therefore, when a PTFE resin is compounded, a two-roll mill (for example, a commercially available product manufactured by Inoue Seisakusho Co., Ltd. can be used) that can knead a high-viscosity type mixture is particularly preferable. The two-roll mill applies strong pressure and shear stress to particles and fluids when raw material passes through the gap between two roll surfaces rotating at different peripheral speeds in opposite directions to each other so that dispersion and mixing can be performed efficiently. it can. The number of rotations in the two-roll mill is not particularly limited, but is usually about 1 to 100 rpm, and mixing may be performed about 100 to 10 times in terms of the number of times of passing through the gap between the two roll surfaces.

When it is necessary to prevent oxidation of the electrode powder, the mixing is preferably performed in a non-oxidizing atmosphere such as argon gas or nitrogen gas. However, when an antioxidant, a rust preventive or the like is used, they can be mixed in the air (in the atmosphere).

Next, the obtained mixed powder is fixed to a current collector while being compressed by a roller or the like, and then pressure-formed together with the current collector to form an integrated sheet-shaped electrode. In this process, the flaky nickel alloy powder and the active material powder are firmly joined to the current collector by pressing. In addition, as a current collector,
Known materials can be used, for example, nickel having a two-dimensional structure,
Expanded metal such as copper, perforated steel sheet plated with nickel, nickel wire mesh, or the like can be used.
Further, at the time of the roller compression, if necessary, after filling the required amount of a part of the mixed powder while compressing the roller into a mold having a shape corresponding to a predetermined electrode shape, and then mounting the current collector, Further, the remaining mixed powder can be filled while being compressed by a roller.

Subsequently, the mixed powder filled in the mold is pressed into a sheet. The pressure in the pressure molding may be appropriately changed according to the composition of the electrode powder and the like. For example,
When a negative electrode made of a hydrogen storage alloy powder is produced, it may be usually about 1000 to 5000 kgf / cm ² . In general, flaky powder has little pressure dependency due to molding, and therefore, the effect of pressurization exceeding 5000 kgf / cm ² is relatively small. On the other hand, when producing a positive electrode made of nickel hydroxide, since the binding property of the nickel hydroxide powder itself is poor,
Usually, it may be set to about 2000 to 8000 kgf / cm ² . However, when a binder such as PTFE resin is added, the resin is fiberized by shearing stress due to roller compression, so that a flexible thin electrode sheet can be obtained even at a relatively low pressure. Therefore, in such a case, the pressure may be set to 200 to 1000 kgf / cm ² . By the pressure molding, the flaky nickel alloy powder is continuously in contact and oriented, so that the current can be efficiently collected from the active material. As a result, an electrode with reduced internal resistance can be obtained.

[0037]

The present inventor aims at improving the internal resistance of the electrode in order to further improve the discharge capacity and the like.
Improve the extensibility of nickel in the process of variously examining methods to easily produce electrodes by pressing powder mixed with nickel powder or other metal powder as conductive powder or alloy powder mainly composed of nickel When a flaky nickel alloy powder composed of nickel and a metal from which ions dissolve when charged and discharged when incorporated into a battery or a battery is used in the battery active material, there is no segregation of the powder and the powder is activated when pressed. It has been found that the contact resistance is improved by firmly bonding with the substance, and that a more microscopic conductive network is formed by the dissolved ions. As a result, the internal resistance of the battery can be improved, the discharge capacity increases, and the number of cycles to reach the maximum discharge capacity is small,
In addition, they have found that they have effects such as easy processing, and have completed the present invention.

[0038]

According to the present invention, the flaky nickel alloy powder is added to the battery active material, and the resulting mixed powder is molded under pressure. Therefore, the electrodes can be produced relatively easily without segregation of the powder. . In a battery incorporating this electrode, the discharge capacity of the battery is significantly improved, and the number of cycles reaching the maximum discharge capacity can be reduced.

[0039]

Hereinafter, the features of the present invention will be described in more detail based on examples and comparative examples.

Examples 1 to 12 (1) Preparation of mixed powder for positive electrode and preparation of positive electrode Nickel hydroxide powder (average particle size: 10 μm)
The scale-like Ni-5% by weight Co alloy powder (average particle diameter 10 μm, thickness 0.5 μm) was changed from 10% by weight to 30% by weight as shown in Table 1 to 400 g with a mechanofusion device at 400 rpm. Mixing was performed for 10 minutes to obtain mixed powders.

Next, the mold was first filled with 1.0 g of each mixed powder while being roller-compressed, and then a nickel expanded metal as a current collector was placed thereon. Finally, 1.0 g of the remaining mixed powder was roller-compressed. While filling.

Next, at a pressing force of 5000 kgf / cm ² ,
A sheet having a size of 40 mm (thickness 0.9 mm) was prepared. A nickel lead plate was bonded to the obtained sheet, and the sheet was wrapped with a hydrophilic non-woven polypropylene fabric as a separator.
This sheet was used as a positive electrode (Examples 1 and 2). Also, P
A positive electrode was produced in the same manner as in Example 2 except that 3% by weight of TFE resin was added and the pressure was set to 1000 kgf / cm ² (Example 3).

For comparison, the same procedure as in Example 2 was carried out except that flaky Ni powder (average particle size: 10 μm, thickness: 0.5 μm) was used instead of the flaky Ni-5 wt% Co alloy powder. To produce a positive electrode (Comparative Example 1).

(2) Preparation of Mixed Powder for Negative Electrode and Preparation of Negative Electrode Hydrogen storage alloy powder (LaNi
_3.4 Co _1.2 Al _0.4 ) 100 g of scaly Ni-5% by weight
The Co alloy powder (average particle size: 12 μm, thickness: 0.8 μm) was changed from 5% by weight to 15% by weight as shown in Tables 2 to 4 and mixed by a mechanofusion device at 500 rpm for 10 minutes.

Next, first, 1.0 g of the mixed powder was filled in a mold while being roller-compressed, and then a copper-plated nickel expanded metal as a current collector was placed thereon. Was filled with roller compression.

Then, at a pressure of 3000 kgf / cm ² ,
A sheet having a size of × 40 mm (thickness: 0.6 mm) was prepared. A nickel lead plate was bonded to the obtained sheet, and the sheet was wrapped with a hydrophilic non-woven polypropylene fabric as a separator.
This sheet was used as a negative electrode (Examples 4 to 6 and Examples 8 to
11). In addition, PTFE resin was added at 3% by weight,
A negative electrode was produced in the same manner as in Example 6, except that the pressure was changed to 000 kgf / cm ² (Example 7). Further, a negative electrode was produced in the same manner as in Example 6 using a flaky Ni-5 wt% Co alloy powder heat-treated in argon at 600 ° C. for 30 minutes (Example 12).

For comparison, the same procedure as in Example 6 was carried out except that flaky Ni powder (average particle size: 10 μm, thickness: 0.8 μm) was used instead of the flaky Ni-5 wt% Co alloy powder. To produce a negative electrode (Comparative Example 2). Similarly, instead of the flaky Ni-5% by weight Co alloy powder, granular Ni
A negative electrode was produced in the same manner as in Example 8 except that powder (average particle size: 10 μm) was used (Comparative Example 3).

Test Example 1 (1) Assembly of Open Battery A battery was assembled using the electrodes produced in the above Examples and Comparative Examples.

The positive electrode and the negative electrode wrapped by the separator are sandwiched between the electrodes using a ready-made counter electrode having a sufficiently large capacity with respect to each electrode, and an open-type battery using a 6 M potassium hydroxide solution as an electrolyte is assembled. Was. This open type battery
It was set in a thermostat at 0 ° C.

(2) Battery charge / discharge cycle test When testing the positive electrode, a charge current of 29 mA / g was used for 10 minutes.
After charging for 0.5 hours and resting for 0.5 hour, the discharge current is 58 mA
/ G until the voltage drops to 0.8 V, and when testing the negative electrode, charge for 4 hours at a charging current of 100 mA / g, pause for 0.5 hour, and then discharge for 100 mA / g.
An experiment was repeated in which charging and discharging were repeated in a cycle of discharging until the voltage dropped to 0.8 V, and the maximum discharge capacity and the number of cycles until reaching the maximum discharge capacity were measured. The results are shown in Tables 1 to 4.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

[Table 4]

From Table 1, it can be seen that, for the positive electrode, the case where flaky Ni-5% by weight Co alloy powder was added to nickel hydroxide (Example 2) was the case where the flaky Ni powder was added (Comparative Example 1). It can be seen that the number of cycles to reach the maximum discharge capacity is smaller and the maximum discharge capacity is larger than that of.

As can be seen from Tables 2 and 3, for the negative electrode, the case where the scaly Ni-5 wt% Co alloy powder was added to the hydrogen storage alloy powder (Example 6) was the case where the scaly Ni powder was added. It can be seen that the number of cycles to reach the maximum discharge capacity is smaller and the maximum discharge capacity is larger than in (Comparative Example 2).

Further, as is apparent from Table 3, the various flaky nickel alloy powders added to the hydrogen storage alloy powder had a maximum particle size as compared with the granular one (Comparative Example 3). The number of cycles to reach the discharge capacity is small and the maximum discharge capacity is large.

From the results shown in Tables 2 and 4, it can be seen that when the heat-treated flaky nickel alloy powder is used (Example 12), the maximum discharge capacity is larger than when no heat treatment is performed (Example 6). .

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshiro Niimi 1-1-303 Ichiriyama, Otsu City, Shiga Prefecture (72) Inventor Tetsuo Sakai 1-81-31 Midorigaoka, Ikeda-shi, Osaka Industrial Technology Institute Osaka Institute of Technology

Claims (8)

[Claims] The present invention relates to an electrode powder, wherein a scale-like nickel alloy powder of 5 to 30 parts per 100 parts by weight of a powder containing a battery active material is used.
An electrode for an alkaline secondary battery, wherein a mixed powder containing parts by weight is used. 2. A flaky nickel alloy powder having an average particle size of 5 to 5.
The electrode for an alkaline secondary battery according to claim 1, wherein the electrode has a thickness of 20 µm and an average thickness of 0.9 µm or less. 3. A flaky nickel alloy powder comprising Co, Cu,
2. The electrode for an alkaline secondary battery according to claim 1, wherein the electrode is a nickel alloy powder containing at least one of Al, B and P in a range of 50% by weight or less. 4. The electrode for an alkaline secondary battery according to claim 1, wherein part or all of the flaky nickel alloy powder is heat-treated at 300 to 900 ° C. 5. The electrode for an alkaline secondary battery according to claim 1, wherein the battery active material is nickel hydroxide containing 2 to 10% by weight of at least one of cobalt and zinc. 6. The battery active material is a hydrogen storage alloy containing nickel, and the hydrogen storage alloy is a rare earth element, titanium, zirconium, magnesium, cobalt,
The electrode for an alkaline secondary battery according to any one of claims 1 to 4, comprising at least one of copper, manganese, iron, aluminum, vanadium, and chromium. 7. A method according to claim 1, wherein 5 to 30 parts by weight of the flaky nickel alloy powder is mixed with 100 parts by weight of the powder containing the battery active material, and this mixed powder is fixed to a current collector and then molded under pressure. Of producing an electrode for an alkaline secondary battery. 8. An electrode according to claim 1, wherein at least nickel hydroxide is used as a battery active material as a positive electrode, and at least a hydrogen absorbing alloy is used as a battery active material as a negative electrode. Nickel-metal hydride battery.