JP2925578B2 - Method for manufacturing electrode plate for storage battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrode plate for a storage battery, and more particularly to a method for manufacturing a nickel positive electrode for an alkaline storage battery.

2. Description of the Related Art As a method for filling an active material of a nickel positive electrode for an alkaline storage battery, a porous body such as a nickel sintered substrate is immersed in an impregnating liquid such as nickel nitrate to impregnate the porous body with a nickel salt, A chemical impregnation method which repeats an operation of producing an alkali hydroxide by producing nickel hydroxide has been widely adopted. In this chemical impregnation method, in order to improve electrode performance, a predetermined amount of a different metal salt such as a cobalt salt and / or a cadmium salt is added to the nickel salt in advance, and the solid solution is co-folded in an alkali to form a solid solution. A method for forming the battery has been proposed [Reference: Secondary Battery, 4th Collection (1962) Yamashita P28, Ikeda P39, JP-B-42-21115, JP-B-59-10538, JP-B-60-12742. JP, JP-A-62-86661,
See JP-A-63-211563, etc.].

By the way, when the above-mentioned different metal salt is added, the effect of improving the battery performance differs depending on the amount of addition. For example, when the foreign metal hydroxide is a cobalt salt, a small amount of the added metal can provide a high capacity battery, and a large amount thereof can provide a battery excellent in high temperature characteristics. Therefore, it is necessary to adjust the optimal addition amount of the different metal salt according to the intended use of the battery. However, since the use of nickel electrodes is widespread, the impregnating liquid having a very wide variety of compositions needs to be provided in advance in order to add the optimum amount for each use.
As a result, there is a problem that the manufacturing process becomes complicated.

In order to solve the above-mentioned inconvenience, there has been proposed a method in which, after filling with nickel hydroxide, immersing in a single solution of a different metal salt to be added and performing an alkali treatment operation as many times as necessary (Japanese Patent Laid-Open No. 51-121742) Gazette, JP-B-57-5018, JP-A-62-37874, JP-A-57-205968, etc.).

Problems to be Solved by the Invention However, in the above-mentioned method, since a nickel hydroxide filling operation and an alkali treatment of a foreign metal salt are performed separately, a solid solution of nickel hydroxide and a foreign metal salt is not formed. As a result, the foreign metal salt exists alone,
There was a problem that the intended battery performance could not be improved.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a method of manufacturing an electrode plate for a storage battery, which can solve the above-described disadvantages.

Means for Solving the Problems In order to achieve the above object, the present invention provides a first step of impregnating a porous substrate with a first metal salt solution, and without drying the first metal salt solution. A second step of immersing the porous substrate in a second metal salt solution having a composition different from that of the first metal salt solution; and drying the porous substrate to form the first and second metals. The method is characterized by comprising a third step of forming a mixed crystal of a salt and a fourth step of immersing the porous substrate in an alkaline solution to convert the mixed crystal into an active material.

A porous base material is impregnated with a metal salt solution serving as a main active material as a first metal salt solution, and then as a second metal salt solution having a composition different from that of the first metal salt solution. By impregnating with a solution of a different metal salt different from the metal salt to be formed and drying it, a mixed crystal of the different metal salt and the metal salt serving as the main active material is formed, and this is activated in an alkaline solution. When materialized, a solid solution of the different metal hydroxide and the metal hydroxide serving as the main active material is formed. Therefore, depending on the type of the different metal salt in the second metal salt solution, the reactivity of the active material can be improved, the expansion of the active material can be suppressed, and the battery performance can be improved. Specifically, when the present invention is applied to a method for producing a nickel positive electrode for an alkaline storage battery, the charging performance at a high temperature is improved if the foreign metal salt is a cobalt salt, and the cycle life is improved if the foreign metal salt is a cadmium salt. Is improved.

Further, the amount of the metal hydroxide formed from the metal salt in the second metal salt solution in the active material can be adjusted by the time or the number of times of immersion in the second metal salt solution in the second step. By simply providing the first metal salt solution and the second metal salt solution, that is, by simply preparing two baths of the impregnating liquid, the first metal salt solution is formed from the metal salt in the second metal salt solution. The amount of metal hydroxide added to the active material can be adjusted. Therefore, it is possible to obtain active materials having various compositions according to applications with simple equipment.

Embodiment An embodiment of the present invention will be described below with reference to FIG. 1 and FIG.

[Example I]

FIG. 1 is a process diagram showing the manufacturing process of the present invention. First, a nickel sintered substrate having a porosity of about 80% is immersed in a nickel nitrate solution to impregnate the nickel sintered substrate with nickel nitrate having a specific gravity of about 1.7. (S1). Next, the nickel sintered substrate is immersed in a cobalt nitrate solution containing about 30% of nickel nitrate for 5 seconds (S2), and part of the nickel nitrate is replaced with cobalt nitrate having a specific gravity of about 1.5. The reason why nickel nitrate is added in advance is to prevent the composition of the solution from being significantly changed due to the introduction of nickel nitrate impregnated with S1. Next, the nickel sintered substrate is dried (S3),
A mixed crystal of nickel nitrate and cobalt nitrate is formed. Thereafter, the nickel sintered substrate is immersed in a sodium hydroxide solution to perform an alkali treatment (S4), thereby converting the mixed crystal into an active material. Thereafter, the nickel sintered substrate is washed with water (S5) and dried (S6). Such an active material filling operation was repeated five times to produce a nickel electrode. Then, the electrode plate was subjected to ordinary chemical conversion, and a nickel-cadmium battery was produced by combining the electrode plate with a cadmium negative electrode having a sufficient capacity.

The battery fabricated in this manner is hereinafter referred to as (A ₁ ) battery.

(Examples II, III, IV)

10 pieces of nickel sintered substrate each in cobalt nitrate solution
A battery was fabricated in the same manner as in Example I except that the battery was immersed for 30 seconds, 30 seconds, and 60 seconds.

The batteries fabricated in this manner are referred to below as (A ₂ )
The batteries are referred to as batteries, (A ₃ ) batteries, and (A ₄ ) batteries.

(Comparative example)

A battery was fabricated in the same manner as in Example I except that the nickel sintered substrate was not immersed in the cobalt nitrate solution.

The battery fabricated in this manner is hereinafter referred to as (X) battery.

[Experiment]

After charging the (A ₁ ) battery of the present invention to the (A ₄ ) battery and the (X) battery of the comparative example at a charging current rate of 0.1 C for 16 hours, the battery was discharged to 1.0 V at a discharging current of 1 C, and the discharging time was reduced. FIG. 2 shows the measurement results. The charge / discharge temperature is 20
The measurement was performed under two conditions of ° C and 45 ° C.

As shown in FIG. 2, various characteristics by dipping time t ₁ is found to be obtained. Specifically, the immersion time t ₁
Is 0 <t ₁ ≦ 10 seconds (for example, (A ₁ ) battery and (A ₂ ) battery), a battery having a higher capacity than the (X) battery of the comparative example can be obtained at any charging and discharging temperature. , 30 <t ₁
For batteries with ≤60 seconds (eg, (A ₄ ) batteries), the charge / discharge temperature is 45
A battery excellent in the case of ° C (ie, excellent in high-temperature characteristics) can be obtained. In addition, the immersion time t ₁ is between 10 <
In the case of a battery with t ₁ ≦ 30 (eg, (A ₃ ) battery), a battery having a good balance between high-temperature characteristics and discharge capacity can be obtained.

In the above embodiment, a nickel electrode has been described as an example, but the present invention can be applied to other electrodes (for example, cadmium electrode). However, the effect of the additive is maximized in the case of the nickel electrode.

Further, in the above embodiment, the cobalt salt is used as the heterometal salt, but the present invention is not limited to this. For example, a cadmium salt or a mixed salt of cobalt and cadmium can be used.

Effect of the Invention As described above, according to the present invention, only the first metal salt solution and the second metal salt solution having a composition different from that of the first metal salt solution are provided (that is, the impregnating solution is used). Only two tanks are prepared), it is possible to form a solid-solution active material having a variety of compositions according to the application, so that the battery performance can be improved with simple equipment. It works.

[Brief description of the drawings]

FIG. 1 is a process chart in the case of producing a nickel positive electrode for an alkaline storage battery by the method of the present invention, and FIG. 2 is a graph of (A ₁ ) to (A ₄ ) batteries produced by the method of the present invention and comparative examples. It is a graph which shows the relationship between the immersion time and discharge time when the (X) battery produced by the manufacturing method is discharged at 20 degreeC and 45 degreeC.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Noritoshi Ikeda 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) H01M 4 / 26-4/32 H01M 10/24-10/30

Claims (1)

(57) [Claims] A first step of impregnating a porous substrate with a first metal salt solution; and a step of drying the first metal salt solution without drying the first metal salt solution. Second composition different from
A second step of immersing the porous substrate in a metal salt solution, and a third step of drying the porous substrate to form a mixed crystal of the first and second metal salts. A fourth step of immersing the mixed crystal to make the mixed crystal an active material.