JPH11135111A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the formation charge efficiency of a positive electrode plate and prolong service life performance at low cost by providing a raw material of a positive electrode active substance with an average particle size of powder, consisting essentially of a monoxide salt and an average particle size of trilead tetraoxide (red lead) powder being a specific range. SOLUTION: Powder of monoxide salt of 1 to 10 microns in means particle size obtained by classification and powder of trilead tetraoxide of 4 microns or more in the mean particle size are employed, and these are mixed with diluted sulfuric acid to make a paste-shaped active substance. By defining an mean particle size within this range, bonding force between active substance particles can be reinforced. The mean particle size is 50% particle size in particle volume reference. This paste shaped active substance is charged in a lead alloy based lattice body, and a positive electrode is obtained. By adding trilead tetraoxide powder, formation charge efficiency can be improved, and formation can be made with less power consumption and in short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead storage battery, and more particularly to a positive electrode active material, which aims to extend the life of the battery.

[0002]

2. Description of the Related Art A sealed lead-acid battery is widely used as a power source for an uninterruptible power supply because of its features of low cost and high reliability. The lead storage batteries used in these devices are strongly required to be reduced in cost, and cost reduction is being promoted by simplifying the manufacturing method. As one means for simplifying the manufacturing method, there is a method generally called battery case formation, that is, a method in which a battery is assembled and then charged to perform formation. In addition, in the case formation method, since the electrolyte used during formation becomes the electrolyte of the completed battery, it is necessary to use sulfuric acid having a higher concentration than the formation method using a conventional tank tank.

However, there is a problem that the use of a high-concentration electrolytic solution lowers the formation charge efficiency of the positive electrode plate. Therefore, as a means for increasing the formation charge efficiency, a method of adding lead tetroxide (Pb ₃ O ₄ ) to the raw material of the positive electrode active material is disclosed in JP-A-62-93857 and JP-A-64-8938.
No. 9263 discloses this. However, when a commercially available method of adding lead trioxide to lead monoxide is used, the bonding between particles is weak, so that the active material is likely to fall off, and as a result, the life of the battery is shortened. There is a problem.

As a means for adding lead trioxide to the positive electrode active material and prolonging the life of the battery, an attempt to coexist lead trioxide and lead monoxide in the same particle has been made in Japanese Patent Application Laid-Open No. 06-7682.
No. 2 discloses this. However, in this method, it is difficult to control the lead tetroxide ratio (lead tandem ratio) of each particle, so that the performance of a battery using the lead tends to vary and the production cost increases. There is.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to manufacture a lead-acid battery having a high positive electrode plate formation charge efficiency, low cost, and excellent life performance. That is.

[0006]

When lead trioxide is added to lead monoxide, there is a problem that the bonding force between particles formed when the paste is aged and dried is weakened. The present inventors have found that the bonding force between active material particles strongly depends on the average particle diameter of lead monoxide and lead tetroxide. The present invention
A mixture of a powder mainly composed of lead monoxide having an average particle diameter of 1 to 10 μm and a powder mainly composed of lead tetroxide having an average particle diameter of 4 μm or more is used as a raw material of a positive electrode active material. It is a feature.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a powder of lead monoxide and powder of lead tetroxide, each having a predetermined average particle size obtained by classification, are kneaded with dilute sulfuric acid to obtain a paste-like active material. Produced. This paste-like active material was filled in a lead alloy lattice to form a positive electrode. The addition of the lead tetroxide powder is necessary to increase the formation charge efficiency as described later. The average particle size of the classified lead monoxide powder and lead tetroxide powder was measured using a LA-500 type laser diffraction particle size distribution analyzer manufactured by HORIBA. In the present invention, a 50% particle diameter based on the particle volume is defined as an average particle diameter. In addition, the negative electrode was produced by a conventional method using a conventional raw material, as described later. One embodiment of the present invention will be described below.

[0008]

【Example】

(Examples 1 to 5) 70 to 80 wt. %, The average particle diameter is 0.5, 1,
Five kinds of powders of 5, 10, and 15 μm were obtained. On the other hand, 9
By classifying the powder having an oxidation degree of 9.9% lead trioxide, three kinds of powders having average particle diameters of 5, 10 and 15 μm were obtained. These powders were subjected to the following experiments in combinations shown in Tables 1 and 2. 70 to 80 wt. % Lead powder containing 100% by weight, lead tetroxide 30 parts by weight, concentration 35
wt. % Of sulfuric acid was kneaded to prepare a paste-like active material for a positive electrode.

On the other hand, the lead monoxide used for the negative electrode was produced by a conventional method using an unclassified ordinary product. That is, 70 to 80 wt. % Lead powder containing 100 parts by weight, lignin 0.2 parts by weight, barium sulfate 1 part by weight,
35 wt. % Of sulfuric acid was kneaded to prepare a paste-like active material for a negative electrode.

Approximately 35 g of these prepared pastes are w4
A grid of 0 mm x l 70 mm x t 3 mm made of a lead alloy was filled and left at 80 ° C for 24 hours under a nitrogen atmosphere to produce an unformed electrode plate. The two positive plates and the three negative plates were combined via a glass fiber separator and assembled into an ABS battery case. % Dilute sulfuric acid electrolyte was injected. Thereafter, the battery is charged with an amount of electricity 2.5 times the theoretical capacity of the positive electrode active material to form a battery case, and has a nominal capacity of 7A.
h (however, a capacity of 20 hours) was prepared. In addition, the charging time at the time of battery case formation is 40 hours. The formation charge efficiency was calculated by measuring the amount of PbO ₂ in the positive electrode active material.

The manufactured battery was subjected to a life test under the following conditions in accordance with JIS C8702. That is, charging at 25 ± 2 ° C. and 2.275 V / cell as the ambient temperature,
Discharge to a final voltage of 1.7 V / cell at a current of 0.25 CA every two months to confirm the capacity. Then, the above-mentioned 0.
The time when the 25 CA discharge capacity was reduced to 50% or less of the initial capacity was defined as the life of the battery. In addition, the battery which did not reach the end of the life was continuously tested under the conditions described above.

Comparative Example 1 As a comparative example, a battery using a positive electrode not using lead trioxide was prepared. That is, 70 to 80 wt. % Of lead powder containing 100% by weight (average particle diameter 5 μm), and a concentration of 35 wt. % Sulfuric acid (20 parts by weight) to obtain a paste active material for a positive electrode. Fill it into a grid made of lead alloy, and under a nitrogen atmosphere,
It was left at 80 ° C. for 24 hours to produce an unformed lead storage battery electrode plate. Thereafter, a negative electrode and a battery were prepared and tested under the conditions shown in (Examples 1 to 5).

Comparative Example 2 As a comparative example, a commercially available lead tetroxide having an average particle size of 3 μm manufactured by Mitsui Kinzoku Co., Ltd. was used. 70 to 80 wt. Powder containing 100%
Parts by weight (average particle diameter 5 μm) and the above-mentioned lead tetroxide 30
Parts by weight, concentration 35 wt. % Sulfuric acid (20 parts by weight) was kneaded to prepare a paste active material for a positive electrode. After this,
A negative electrode and a battery were prepared and tested under the conditions shown in Examples 1 to 5.

(Comparative Example 3) Lead monoxide was used in an amount of 70 to 80 wt.
% Lead powder containing 100% by weight (average particle diameter 0.5 μm) and lead tetroxide having an average particle diameter of 5 μm shown in Examples 1 to 5 were used. Then, 70 to 80 wt. % Of lead powder containing 30% by weight of lead trioxide having an average particle diameter of 5 μm, and a concentration of 35 wt. % Sulfuric acid (20 parts by weight) was kneaded to prepare a paste active material for a positive electrode. Thereafter, a negative electrode and a battery were prepared and tested under the conditions shown in (Examples 1 to 5).

Comparative Example 4 Lead monoxide was used in an amount of 70 to 80 wt.
% Of lead powder (average particle diameter 15 μm) and lead tetroxide having an average particle diameter of 5 μm shown in Examples 1 to 5 were used. Then, 70 to 80 wt. % Lead powder containing 100% by weight of lead trioxide 3 having an average particle size of 5 μm.
0 parts by weight, concentration 35 wt. % Sulfuric acid (20 parts by weight) was kneaded to prepare a paste active material for a positive electrode. After this,
A negative electrode and a battery were prepared and tested under the conditions shown in Examples 1 to 5.

Table 1 shows the formation charge efficiency when the battery thus prepared was formed into a battery case, and Table 2 shows the result of measuring the life of the battery. From Table 1, it can be seen that the formation charge efficiency is improved by adding lead trioxide to the positive electrode active material irrespective of the average particle size, and the formation can be performed in a short time with small power consumption.

[0017]

From Table 2, it can be seen that the average particle size of the powder containing lead monoxide as a main component is in the range of 1 to 10 μm, and the average particle size of the powder of lead tetroxide is in the range of 4 μm or more (Example 1).
In Nos. To 5), the life of the battery is long, and a life of 3 years or more equivalent to that of Comparative Example 1 to which lead trioxide is not added can be obtained, and the effect is recognized. Note that the upper limit of lead tetroxide is not particularly limited, but the upper limit of currently available ones is one.
It is about 5 μm.

[0019]

[0020]

As described above, the raw material lead powder for a lead storage battery according to the present invention comprises a lead active material having an average particle diameter of 1 to 10 μm and a lead trioxide having an average particle diameter of 4 μm or more. By using as a raw material which is a main component of the present invention, it is excellent in that the formation charge efficiency can be increased and the life of the battery can be prolonged.

Claims (1)

[Claims] 1. A lead-acid battery comprising a powder mainly composed of lead monoxide and a powder of lead trioxide (lead red) as a raw material of an active material for a positive electrode. A lead-acid battery having an average particle diameter in a range of 1 to 10 μm and an average particle diameter of a lead tetroxide powder in a range of 4 μm or more.