JPH0620717A - Manufacture of sealed nickel-cadmium storage battery - Google Patents

Abstract

PURPOSE:To simplify manufacturing processes, and provide a long-life sealed Ni-Cd storage battery by applying water treatment to a negative electrode obtained of CdO to be a negative electrode, and combining it with a positive electrode mainly comprising Ni(OH)6 to which Co is added. CONSTITUTION:A negative electrode obtained of CdO is treated in hot water of a specified temperature to be used as a negative electrode. Using Ni(OH)6 to which Co is added for a positive electrode, a battery is composed. Otherwise, Cd(OH)2 is added to CdO to form a negative electrode, and it is combined with a positive electrode mainly comprising Ni(OH)6 including Co. At this time, addition quantity of Cd(OH)2 is set to be within a specified weight%, and paste is applied to a core material to form the Cd electrode. Co is used as carbonyl cobalt, and the Cd is press moulded. In this constitution, formation of the Cd negative electrode solely can be omitted, and a manufacturing processes can be simplified. An average voltage is high, and a battery life is long when charge and discharge are repeated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sealed nickel-cadmium storage battery.

[0002]

2. Description of the Related Art Alkaline storage batteries used as various power sources have been widely used for various portable devices and large-sized industries for various reasons because they can be expected to have high reliability and can be made compact and lightweight.

In this alkaline storage battery, zinc, iron, hydrogen, etc. are targeted for the negative electrode, but cadmium is currently the mainstream in practical use. On the other hand, as the positive electrode, an air electrode, a silver oxide electrode, and the like are partially taken up, but in most cases, a nickel electrode. The characteristics have been improved from the pocket type to the sintered type, and it has become possible to further seal and expand the applications.

This sealing is generally based on the so-called Neumann method. To achieve this, the negative electrode usually has a higher capacity than the nickel electrode, and in addition to the same capacity as the nickel electrode, an uncharged active material for guaranteeing charging is also used. And an active material in a charged state for discharge guarantee are additionally provided. If the negative electrode is manufactured in a non-formed state, it is uncharged so that it can be used for guaranteeing charging, and it is problematic to form an active material in a charged state for discharging guarantee, and various proposals for different types of negative electrodes have been made.

As a method of forming a negative electrode active material in a charged state for guaranteeing discharge, most of the cadmium electrode is prepared by using oxide as a starting material of active material and adding a part of metal powder. In other words, the oxide corresponds to the non-activated material and is the same as the metal formed. However, the problem is that metal cadmium is expensive, and if the surface is oxidized, it is difficult to guarantee the discharge as it is. Therefore, a method in which a cadmium electrode obtained from cadmium oxide is partially charged in advance is often used. In this method, washing with water is required for charging operation and alkali removal.

[0006] Therefore, as one solution, metallic cobalt is used as the cobalt used in the nickel electrode, and the metallic cobalt is oxidized at the initial stage of charging, the nickel electrode is not charged during that period, and the negative electrode is charged. A method that utilizes a phenomenon that does not contribute to discharge has been proposed. This method is excellent because it requires no special processing or materials.

[0007]

However, the method of partial chemical formation among the above-mentioned prior arts has a complicated manufacturing process, and the method of using cobalt has a low average voltage, and further, a battery when charging and discharging are repeated. There was a problem that the life was short.

In order to solve the above-mentioned problems of the prior art, the present invention provides a sealed nickel-cadmium storage battery which can be simplified in manufacturing process, has a high average voltage, and has a long battery life when repeatedly charged and discharged. The purpose is to provide the law.

[0009]

In order to achieve the above object, the first aspect of the sealed nickel-cadmium storage battery of the present invention is provided.
The second production method is a method of producing a sealed nickel-cadmium storage battery composed of at least a cadmium negative electrode and a nickel positive electrode, wherein the negative electrode obtained from cadmium oxide is used as the negative electrode after water treatment, It is characterized in that a positive electrode whose main component is nickel hydroxide to which cobalt is added is used as a positive electrode, and the negative electrode and the positive electrode are combined to form a battery.

In the above structure, water is 50 to 100 ° C.
It is preferable that it is warm water. Next, the second manufacturing method of the sealed nickel-cadmium storage battery of the present invention is to combine a negative electrode obtained by adding cadmium hydroxide to cadmium oxide and a positive electrode containing nickel hydroxide containing cobalt as a main component. It is characterized in that a battery is constructed and formed.

In the above construction, the amount of cadmium hydroxide added is preferably in the range of 10 to 30% by weight. Further, in the above structure, a cadmium electrode obtained by applying a paste to a core material is preferable.

Further, in the above structure, it is preferable that the cobalt is carbonyl cobalt. Further, in the above configuration, it is preferable to include a step of pressurizing the cadmium electrode.

[0013]

According to the structure of the first manufacturing method of the present invention described above, since the formation of the cadmium negative electrode alone can be omitted,
The manufacturing process can be simplified. In addition, the average voltage is high, and moreover, the battery life can be extended when charging and discharging are repeated.

In the above construction, the temperature of the water during the water treatment of the negative electrode is not limited, but it is 50 to 1 in order to shorten the time.
Hot water at 00 ° C is good. Next, according to the configuration of the second production method of the present invention, since the purpose of the treatment with water is to change part of the cadmium oxide to cadmium hydroxide, it is necessary to add cadmium hydroxide to the cadmium oxide in advance. Is an effective means. In this case, the amount of cadmium hydroxide added is set to about 10 to 30% by weight, and if too much is added, the bulk density of cadmium hydroxide is small, and the packing density becomes small.
Charging efficiency during chemical conversion is also reduced. Further, since the volume of cadmium hydroxide increases due to expansion, the cadmium electrode may be pressurized before assembly in consideration of insertion into a battery case.

The cobalt powder to be added to the nickel electrode is not limited, but carbonyl cobalt is preferable because fine powder is obtained and the purity is relatively high. As a compound of cobalt other than metal, cobalt oxide powder is preferable because it does not have harmful anions, and cobalt hydroxide may be used.

[0016]

EXAMPLES The present invention will be specifically described with reference to the following examples. In the present invention, since it is possible to form cadmium for discharge assurance by treatment with water, by partially forming cadmium hydroxide than cadmium oxide alone, the acceptability of charging is improved, and cobalt is formed at the initial charging stage of the nickel electrode. It is considered that the nickel electrode is oxidized at a potential lower than that of the nickel electrode, and during that period, the nickel electrode is not charged and the negative electrode is charged.

Even when the same cadmium hydroxide is present, the water treatment shows the same discharge characteristics as the case where the cadmium electrode is preliminarily partially charged rather than the case where cadmium hydroxide is added. Therefore, cadmium hydroxide is oxidized. It is also presumed that it is better to form on the surface of the cadmium particles.

Example 1 Commercially available cadmium oxide powder was mixed with 5 parts of polyvinyl alcohol.
A (wt)% ethylene glycol solution is made into a paste such that the resin is 2 parts with respect to 100 parts of cadmium oxide. This paste was applied to an iron-made nickel-plated punching metal plate having a thickness of 0.17 mm, a hole diameter of 1.8 mm and an opening degree of 53%, and smoothed through a slit of 0.6 mm. Then, it was dried at 170 ° C. for 5 hours. The obtained electrode was passed through a roller press to a thickness of 0.5.
It was adjusted to 5 mm. The paste-type cadmium electrode thus obtained was used for SubC type with a width of 33 mm and a length of 2 mm.
It was cut to 30 mm and the lead plate was attached by spot welding. This was immersed in warm water at 50 ° C. for 2 hours.

On the other hand, 87 parts of a commercially available nickel hydroxide powder and 7 parts of cobalt powder were mixed and then a 2 (wt)% aqueous solution of carboxymethyl cellulose was used to obtain a paste. This paste was filled and applied on a foamed nickel substrate having a thickness of 1.5 mm, a pore diameter of 200 μm and a porosity of 95%, and dried at 120 ° C. for 1 hour. The resulting electrode is pressed to a thickness of 0.80
It was adjusted to mm. The foamed nickel electrode obtained in this way is used for Sub C type with a width of 33 mm and a length of 160 mm.
Then, the lead plate was attached by spot welding.
The actual discharge capacity of this nickel electrode is 2.8A at 0.2C.
h.

A sealed nickel-cadmium storage battery was constructed using a polyamide nonwoven fabric separator. Specific gravity 1.2
An electrolytic solution in which 25 g / liter of lithium hydroxide was dissolved was injected into the caustic potash aqueous solution of No. 5. The battery is a SubC type. This battery is designated as A.

For comparison, a battery obtained by the same process as the battery A except that the water treatment of the cadmium electrode was not performed was added as B. Further, the cadmium electrode was previously charged in a 30 wt% caustic potash aqueous solution at 1.5 A for 20 minutes, washed with water, and dried to secure a discharge guarantee capacity in advance. Batteries were added as C.

As the first formation, each battery was set at an ambient temperature of 2
Initial charging was performed at 5 ° C. and 0.3 A. The flat parts around 0.9 V were all about 1 hour, and the potential started to rise after that. Charging was carried out for 13 hours. Then discharge is 0.6A
I did it in. As a result, A and C showed 2.79 Ah, but B had 2.45 Ah. The average voltage was 1.25 V for A and C, but 1.19 V for B.

Thereafter, formation of 150% charge at 0.4 A and discharge to 0.8 V at -1 A was repeated twice to complete formation. After the formation was completed, the discharge capacity and the average voltage were examined. First,
When 1 C (2.8 A) discharge of each battery was performed, A and C showed 2.75 Ah, but B was 2.26 Ah. The average voltage was 1.20V for A and C, but B
Was 1.08V. Finally, in order to check the life, when 125A was charged at 0.7A and discharged up to 0.8V at 1A, A and C were 95% or more of the initial capacity in 600 cycles, but B reached 62%. Fell.

Example 2 After adding 15% by weight of cadmium hydroxide to a commercially available cadmium oxide powder, the same procedure as in Example 1 was repeated except that a 5% (by weight) solution of polyvinyl alcohol in ethylene glycol was used as the resin for cadmium oxide and cadmium hydroxide. 2. Total amount
Make the paste into two parts. This paste has a thickness of 0.17 mm, a hole diameter of 1.8 mm, and an opening degree of 53%.
It was applied to a punching metal plate made of iron and plated with nickel and smoothed through a slit of 0.6 mm. Then, it was dried at 170 ° C. for 5 hours. The obtained electrode was adjusted to have a thickness of 0.55 mm through a roller press. The paste type cadmium electrode thus obtained was cut into a width C of 33 mm and a length of 230 mm for Sub C type, and a lead plate was attached by spot welding.

A battery was constructed in the same manner as in Example 1, and the formation and characteristic evaluation were performed in the same manner as in Example 1. As a result, almost A
It showed the same performance as. As described above, according to the embodiment of the present invention, either a cadmium electrode obtained by treating a cadmium electrode obtained from cadmium oxide with warm water at 50 to 100 ° C. or by adding cadmium hydroxide to cadmium oxide is used. By constructing a battery by combining it with a nickel electrode mainly containing nickel hydroxide to which cobalt is added, the process can be simplified and there is no deterioration in performance.

[0026]

As described above, according to the production method of the present invention, the formation of the cadmium negative electrode alone can be omitted.
The manufacturing process can be simplified. Further, the average voltage does not decrease, and moreover, the battery life can be extended when charging and discharging are repeated.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoichiro Tsuji 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A method for producing a sealed nickel-cadmium storage battery comprising at least a cadmium negative electrode and a nickel positive electrode, wherein the negative electrode obtained from cadmium oxide is treated with water as the negative electrode, and the positive electrode is used. A method for producing a sealed nickel-cadmium storage battery, characterized in that a positive electrode containing nickel hydroxide to which cobalt is added as a main component is used, and the negative electrode and the positive electrode are combined to form a battery. 2. The method for producing a sealed nickel-cadmium storage battery according to claim 1, wherein the water is hot water at 50 to 100 ° C. 3. A sealed nickel-containing battery comprising a negative electrode obtained by adding cadmium hydroxide to cadmium oxide and a positive electrode containing cobalt hydroxide containing nickel hydroxide as a main component to form a battery. Cadmium battery manufacturing method. 4. The method for producing a sealed nickel-cadmium storage battery according to claim 3, wherein the amount of cadmium hydroxide added is in the range of 10 to 30% by weight. 5. The closed nickel-type according to claim 1, which is a cadmium electrode obtained by applying a paste to a core material.
Cadmium battery manufacturing method. 6. The method for producing a sealed nickel-cadmium storage battery according to claim 1, wherein the cobalt is carbonyl cobalt. 7. The method for producing a sealed nickel-cadmium storage battery according to claim 1, which comprises a step of pressurizing a cadmium electrode.