JPH06283172A - Positive electrode plate for lead-acid battery - Google Patents

Abstract

PURPOSE:To provide a positive electrode plate for lead-acid battery having high capacity and excellent durability by using a material lead powder for which lead powder of different grain sizes containing different amounts of metal lead are mixed together at a specific ratio. CONSTITUTION:Lead powder having a peak of grain size distribution in the range of 0.5mum-3mum and containing less than 5% of metal lead, and lead powder having a peak of grain size distribution in the range of 1mum-20mum and containing 5-20% of metal lead, are mixed together to provide material lead powder. Concerning the ratio of mixture, the lead powder of 0.5mum-3mum is mixed at the ratio of 10-60%. A positive electrode active material manufactured by the material lead powder is provided with an active material having a fine structure by the 0.5mum-3mum of lead powder, and with an active material having a large structure by the lead powder of 1mum-20mum. The active material utilization factor is improved by the structure of the fine active material, while the durability is improved by the active material having the large structure.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an anode plate for a lead battery.

[0002]

2. Description of the Related Art Hitherto, as a means for improving the utilization rate of a positive electrode active material for a lead battery, a lamella that has a hollow carbon balloon added to the active material or graphite having large anisotropy has been added to the active material. A method of adding spherical carbon fine particles having a structure is known. The addition of hollow carbon balloons is described in JP-A-62-160659. The method of adding graphite having large anisotropy is described in, for example, JP-A-56-109460. The addition of spherical carbon fine particles is described in JP-A-2-297861.

Conventionally, as a means for improving the durability of a lead battery positive electrode plate, polymer fibers coated with or embedded with metallic lead powder and lead oxide powder are added. Methods such as adding fluororesin fibers are known. A method of adding a metal lead powder or a lead oxide powder coated or buried therein is described in JP-A-2-106874. The method of adding the fluororesin fiber is described in JP-A-3-201363.

[0004]

However, the conventional method of adding hollow carbon balloons or graphite having large anisotropy for the purpose of improving the utilization rate of the positive electrode active material improves the utilization rate of the active material. However, the utilization rate is improved because the addition of carbon causes an excessive amount of water to be incorporated into the paste to form many pores of about 1 μm in the anode active material, which are effective for improving the utilization rate. However, the strength of such an anode active material is very weak. In order to improve this drawback, fluorocarbon resin fibers and polymer fibers are added to those with carbon added, but although some effects are recognized, it does not reach the active material strength of the anode plate without carbon added. There was a problem.

The object of the present invention is to have a particle size distribution peak in the range of 0.5 μm to 3 μm, lead powder containing less than 5% metallic lead and a particle size distribution peak in the range of 1 μm to 20 μm, and An object of the present invention is to provide an anode plate for a lead battery in which both the utilization rate and the durability of the anode active material are improved by using, as a raw material, a mixture of lead powder containing an amount of metallic lead of -20%.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention has a particle size distribution peak in the range of 0.5 μm to 3 μm and a lead powder containing less than 5% metallic lead and 1 μm.
5 ~ 20% with peak of particle size distribution in the range of ~ 20μm
It was decided to mix the lead powder containing the above metallic lead and to use it as the raw material lead powder for the anode plate for the lead battery.

[0007]

Function: Lead powder having a particle size distribution peak in the range of 0.5 μm to 3 μm and containing less than 5% metallic lead and 1 μm to 2 μm.
When an anode plate for a lead battery is manufactured by using a raw material lead powder mixed with a lead powder containing 5 to 20% of metallic lead having a particle size distribution peak in the range of 0 μm, the particle size distribution of 0.5 μm to 3 μm can be obtained. An extremely fine active material structure is formed by the lead powder having a peak and containing less than 5% of metallic lead, and the active material utilization rate is improved. Further, an active material having a large and firm structure is formed by lead powder containing a peak of particle size distribution in the range of 1 μm to 20 μm and containing 5 to 20% of metallic lead. The durability is improved.

[0008]

EXAMPLE An example of the present invention will be described. (Example 1) Lead powder having a particle size distribution peak in the range of 0.5 μm to 3 μm and containing less than 5% metallic lead and 1
5-2 with peak of particle size distribution in the range of μm to 20 μm
It was decided to investigate the optimum mixing ratio of lead powder containing 0% metallic lead. A lead powder having a particle size distribution peak in the range of 0.5 μm to 3 μm and containing less than 5% of metallic lead is A lead powder, and a particle size distribution peak in the range of 1 μm to 20 μm is 5 to 20%. Lead powder containing metallic lead is referred to as B lead powder. First, A lead powder is mixed with B lead powder in a ratio of 0 to 100%, and the mixed lead powder is used to prepare a positive electrode plate for a lead battery, and a utilization rate at the time of discharging for 5 hours (hereinafter referred to as 5HR). Based on the discharge duration after 200 cycles of JIS and life test, the mixing ratio of the active material utilization rate and the excellent durability is examined. The lead battery anode plate used in these studies was manufactured according to the following procedure. A Lead powder is 0 to 100% B
To the mixed lead powder of 10 specifications mixed with lead powder, 2d, 2 mm polyester fiber was added 0.07 wt% to the lead powder,
After kneading while adding water, kneading was performed while adding dilute sulfuric acid having a specific gravity of 1.26 (20 ° C.). The ten specifications of this kneaded paste were all adjusted to have the same water content and the same hardness. After filling the grid body (w108 × h115 × 1.45) made of the lead-antimony alloy with the paste,
After aging in an atmosphere of 50 ° C. and 95% RH and drying at 120 ° C., it was used as an anode plate for examining the utilization rate and durability of the active material. Next, using the anode plate, a test method of a 5HR discharge test as a method for evaluating the utilization rate of the active material and a JIS life test as a durability evaluation test will be shown. The 5HR discharge test was carried out by injecting diluted sulfuric acid with a specific gravity of 1.28 (20 ° C) into a cell consisting of one fully formed anode plate and two cathode plates and discharging at 5HR current (1.4A) to obtain the cell voltage. When the voltage reaches 1.75 V, the discharge electricity quantity is obtained, and the active material utilization rate is calculated from this and the separately obtained amount of the active material. In the JIS life test, using the above cells, discharging was performed at a discharge current of 5 A for 1 hour, and immediately charging was performed at a charge current of 1.25 A for 5 hours. The discharge duration when the cell voltage reaches 1.70V is determined. This is a test in which the number of cycles when the discharge duration is less than 42 minutes is the life of the cell. FIG. 1 shows the test results. Conventionally, the utilization rate of the active material in the 5HR discharge test of the lead battery anode plate made only of B lead powder was about 50%, and the utilization rate of the lead battery anode plate made only of A lead powder was about 60%. is there. The cause of such a difference in the utilization rate due to the difference in the lead powder is that the active material structure formed differs depending on the particle size of the lead powder. The lead A powder with fine particles has a high utilization factor because the active material to be formed has a fine structure and there are many portions that react with dilute sulfuric acid which is the electrolytic solution. However, the active material formed of B lead powder having a large particle size has a large structure, and therefore has a small portion that reacts with dilute sulfuric acid and thus has a low utilization rate.

The results of the JIS life test are as follows.
The discharge duration at the time of 00 cycles is 50 min for the active material made only of the B lead powder, and less than 42 min for the life judgment of the active material made only of the A lead powder. The difference in the durability of the active material is also greatly influenced by the difference in the structure of the active material. Since the active material structure made of only the A lead powder is fine, there are many parts that react with dilute sulfuric acid, so the utilization rate is high, but as the JIS life test is repeated,
The active material was consumed in the reaction at an early stage, and after 200 cycles, the active material could no longer be discharged. On the other hand, the active material made of only the B lead powder has a large structure of the active material, and thus the utilization factor is low, but even if the JIS life test is repeated, the consumption of the active material is large from the surface of the active material having a large structure. Since it proceeds, it is still in a state where it can be sufficiently discharged even after 200 cycles. From the above, the optimum mixing ratio of A lead powder and B lead powder for improving both the utilization rate and durability of the active material of the lead battery anode plate as compared with the conventional one is shown in FIG. It has been found that the B lead powder may be mixed in a proportion of 10 to 60%.

A lead plate was prepared in the same manner as in the above-described method for preparing an anode plate for a lead battery using lead powder in which A lead powder was mixed at a ratio of 30% and B lead powder at a ratio of 70%. The test was conducted. The result is shown in FIG. As a comparison, a life test was also performed on a lead battery anode plate made only from the A lead powder and a lead battery anode plate made only from the B lead powder. The structure of the life test cell is the same as that of the above cell, and the JIS life test method is also the same. Fig. 2 shows the relationship between the number of cycles and the discharge duration. A positive electrode plate for a lead battery made only of lead powder A has a high discharge duration at the beginning of the life test, but has a life of 200 cycles. . An anode plate for a lead battery made only of B lead powder has a life of up to 200 cycles but has a low initial discharge duration. However, the positive electrode positive electrode plate prepared using the mixed lead powder has a higher initial discharge duration than the others, and the discharge duration is higher than the current level even after 200 cycles. From this, it became clear that by mixing the A lead powder and the B lead powder, both the utilization rate of the active material and the durability can be improved as compared with the conventional one.

Next, how to obtain the lead A powder and the lead B powder was examined. First, FIG. 3 shows a particle size distribution of lead powder produced by the pole mill method. It can be seen that the lead powder produced by the ball mill method is a lead powder containing a large amount of lead powder having a particle diameter of 0.5 μm to 3 μm. Therefore, it was decided to obtain lead A powder by classifying lead powder having a particle size of 3 μm or more. Next, FIG. 4 shows the particle size distribution of the lead powder produced by the Burton pot method. The particle size distribution of the lead powder produced by the Burton pot method is in the range of 1 μm to 20 μm and shows a substantially uniform particle size distribution.
It can be used as lead powder. Further, when the amount of metallic lead of the lead A powder obtained by classifying lead powder having a particle size of 3 μm or more and produced by a ball mill method was measured, it was found to be less than 5%. Similarly, it was found that the amount of metallic lead in the B lead powder was 5 to 20%. The reason why the amount of metallic lead in the lead powder is different is that the size of the lead powder is different due to the difference in the manufacturing method of the lead powder. This is because the B lead powder having a small amount of particles and large particles does not easily oxidize and a large amount of metallic lead is present.

[0012]

[Table 1]

[0013]

As described above, the lead battery positive electrode plate according to the present invention is prepared by mixing A lead powder with B lead powder at a ratio of 10 to 60%, and therefore, compared with the conventional lead battery positive electrode plate. , A
The lead powder forms an active material having a fine structure effective for improving the utilization rate, and it is not necessary to add an additive for making the structure of the active material fine. In addition, the B lead powder makes the structure of the active material large and solid, and even if there are many fine parts in the active material, the large and solid parts become the skeleton of the active material and improve the durability of the active material. There is no need to add additives to improve.

Further, the lead powder produced by the ball mill method used in the present process has a particle size distribution peak in the range of 0.5 μm to 3 μm by removing lead powder of 3 μm or more, and the amount of metallic lead is Lead powder of less than 5% can be easily obtained. Also, the lead powder produced by the Burton pot method is 1
Since there is a particle size distribution peak in the range of μm to 20 μm and the amount of metallic lead is 5 to 20%, it is not necessary to perform classification. Therefore, it is not necessary to newly consider a lead powder manufacturing apparatus for manufacturing lead powder such as A lead powder and B lead powder. It is excellent in that an anode plate for a lead battery, which has improved utilization rate and durability of such an active material, can be produced by an existing process.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a mixing ratio of A lead powder and B lead powder, a 5HR utilization rate of a lead battery anode plate using the mixed lead powder as a raw material, and a discharge duration time after 200 cycles of JIS life test. Is.

FIG. 2 shows JIS life test results of a lead battery anode plate prepared by mixing 30% A lead powder and 70% B lead powder and a lead battery anode plate prepared only by A lead powder and B lead powder. It is a figure.

FIG. 3 is a diagram showing a particle size distribution of lead powder produced by a ball mill method.

FIG. 4 is a diagram showing a particle size distribution of lead powder produced by the Burton pot method.

Claims (3)

[Claims] 1. A lead paste prepared by kneading lead powder with water and dilute sulfuric acid.
Alternatively, in a lead battery positive electrode plate coated on a lead alloy grid, a lead powder having a particle size distribution peak in the range of 0.5 μm to 3 μm and containing less than 5% metallic lead and 1 μm to 20 μm.
An anode plate for a lead battery, characterized in that a lead powder obtained by mixing lead powder having a particle size distribution peak in the range of m and containing 5 to 20% of metallic lead is used as a raw material. 2. A particle size distribution peak in the range of 0.5 μm to 3 μm, and the proportion of lead powder containing less than 5% metallic lead is 10 to 60%. Anode plate for lead batteries. 3. A ball mill-type lead powder manufacturing apparatus for producing
It has a peak in the range of 5 μm to 3 μm, has a peak in the range of 1 μm to 20 μm produced by a lead powder containing less than 5% metallic lead and a Burton pot type lead powder manufacturing apparatus, and has 5-2.
The positive electrode plate for a lead battery according to claim 1, wherein lead powder containing 0% metallic lead is mixed.