JP2003132880A - Method for manufacturing lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the active material utilization factor of a positive electrode plate for a lead-acid battery by raising the generation factor of tetrabasic lead sulfate in the positive electrode plate, while it is known to maintain a high temperature and a high humidity for a long time in a maturing process for generating tetrabasic lead sulfate in the positive electrode plate to raise the active material utilization factor. SOLUTION: The manufacturing method of the lead-acid battery comprises a step of applying a paste-like active material on a current collector. The paste like active material is made through steps including a water kneading step of a lead powder mainly of lead oxide in water, a sulfuric acid kneading step of kneading while sulfuric acid or diluted sulfuric acid is added next to the water kneading step, and a finishing kneading step carried out next to the sulfuric acid kneading step. The temperature of the paste-like active material in the the sulfuric acid kneading step is made to be in the range of 60 to 90 deg.C. The temperature of the paste-like active material is made to be not higher than 50 deg.C by the kneading end of the finishing kneading step.

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 lead storage battery, and more particularly to a kneading process for kneading lead powders such as lead oxide to prepare a paste-like active material.

[0002]

2. Description of the Related Art Conventionally, a lead storage battery has a lead powder containing lead oxide as a main component and a part of metallic lead, synthetic resin fibers, carbon,
Add a predetermined amount of additives such as barium sulfate and lignin, knead with water and dilute sulfuric acid to prepare a paste-like active material, and further fill the current collector of lead or lead alloy with the paste, and perform the aging and drying steps. After that, the electrode plate was produced.

The unactivated material after the aging / drying step is a mixture of tribasic lead sulfate, lead sulfate and lead oxide, and in the subsequent step, these unactivated materials are converted into lead dioxide in the positive electrode and negative electrode in the negative electrode. Then, it was oxidized or reduced to lead and obtained as the active material of the lead storage battery.

In lead-acid batteries, especially control valve type lead-acid batteries, it has been common to use an unactivated material containing tribasic lead sulfate as the main component. On the other hand, tetrabasic lead sulfate is known as another component of the non-activated material, and when lead dioxide obtained from tetrabasic lead sulfate is used for the positive electrode, a high utilization rate of the active material during discharge can be obtained. There is an advantage called.
Conventionally, in order to obtain this tetrabasic lead sulfate, it is necessary to age it in a high temperature atmosphere of about 80 ° C. However, the degree of production of tetrabasic lead sulfate is low, and the active material utilization rate is remarkably increased. Had not reached.

As the lead powder used at this time, the ratio of tetrabasic lead sulfate can be made higher under the same conditions by using the Burton method than the ball mill method.

However, when comparing tetrabasic lead sulfate obtained from the Burton method lead powder and tribasic lead sulfate from the viewpoint of utilization rate of the active material, tetrabasic lead sulfate becomes tribasic lead sulfate. Although they are superior in comparison, they are inferior to the tetrabasic / tribasic lead sulfate obtained from the lead powder of the ball mill method, so that when the lead powder of the Burton method is used, Even though the production rate was higher than that in the case of using the ball mill method lead powder, the tribasic lead sulfate produced by the ball mill method lead powder was superior in the utilization rate of the active material. Further, it has been difficult to increase the production rate of tetrabasic lead sulfate from the ball mill method lead powder.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a high-utility lead-acid battery electrode plate and a high-capacity lead-acid battery by more easily producing the tetrabasic lead sulfate as described above. . In particular, it is an object of the present invention to provide a lead storage battery having a higher capacity by increasing the production rate of tetrabasic lead sulfate from a ball-milled lead powder, which has been conventionally considered difficult.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is a kneading step of kneading lead powder mainly composed of lead oxide with water, and this kneading step. Is a method of manufacturing a lead-acid battery in which a paste-like active material produced through a sulfuric acid kneading step of kneading while adding sulfuric acid or dilute sulfuric acid and a finishing kneading step performed after the sulfuric acid kneading step is applied to a current collector. Then, the temperature of the paste-like active material during kneading in the sulfuric acid kneading step is set to 60 ° C. to 90 ° C., and the temperature of the paste-like active material is set to at least 50 ° C. or less by the end of kneading in the finishing kneading step. It is characterized by.

Further, the invention according to claim 2 of the present invention is, in the method for producing a lead storage battery according to claim 1, characterized in that as the mass of lead powder mainly composed of lead oxide to be kneaded increases,
It is characterized by increasing the addition rate of sulfuric acid or dilute sulfuric acid in the sulfuric acid kneading step.

The invention according to claim 3 of the present invention is the method of manufacturing a lead storage battery according to claim 2, wherein the addition rate of sulfuric acid or dilute sulfuric acid is V (kg / min), and the lead oxide is the main component. When the weight of the lead powder to be set is W (kg), the addition rate of sulfuric acid or dilute sulfuric acid is set as V = k × W (provided that k is a constant of 0.015 to 0.030). It is what

Further, the invention according to claim 4 of the present invention is obtained by a ball mill method as a lead powder mainly containing lead oxide in the method for producing a lead storage battery according to any one of claims 1 to 3. It is characterized by using lead powder.

According to a fifth aspect of the present invention, in the method for producing a lead storage battery according to any one of the first to fourth aspects, the lead powder mainly containing lead oxide contains lead tin. It is characterized by.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 1, a predetermined amount (Wkg) of lead powder obtained by the ball mill method is weighed and put into a kneader in step 1. When an additive such as polyester synthetic resin fiber is used, the additive is added to the lead powder in step 2 before adding water, sulfuric acid or dilute sulfuric acid, and both are mixed (dry kneading) in step 3. . Following this dry kneading in step 3, a predetermined amount of water is added in step 4,
Further, in step 5, kneading with water is performed.

Thereafter, sulfuric acid is kneaded in step 6 while adding a predetermined amount of sulfuric acid or dilute sulfuric acid at a predetermined addition rate V (kg / min).

In the present invention, the addition rate V of sulfuric acid or dilute sulfuric acid is changed according to the weight W of the lead powder. More specifically, the addition rate of sulfuric acid or dilute sulfuric acid is increased as the weight W of the lead powder increases. Actually, the addition rate V (kg / min) of sulfuric acid or diluted sulfuric acid is calculated and set from the lead powder amount W (kg) by the following formula (1).

V (kg / min) = k (constant) × W (kg) Formula (1) Here, the constant k is preferably set to 0.015 to 0.030. When sulfuric acid or diluted sulfuric acid is added at the addition rate of sulfuric acid or diluted sulfuric acid calculated from such k value and lead powder amount W, the temperature of the paste is about 60.
It will be in the range of 90 ° C to 90 ° C. In the paste kneading according to the conventional technique, the paste temperature is lower than 60 ° C. by cooling the kneading machine with water or the like in order to suppress the dissipation of water due to the temperature rise of the paste. In the present invention, the addition rate of sulfuric acid or diluted sulfuric acid added in the paste kneading is made faster than the conventional example, and the sulfuric acid or the sulfuric acid or It is characterized by setting the addition rate of dilute sulfuric acid.
That is, the exothermic reaction of addition of sulfuric acid or dilute sulfuric acid is utilized to accelerate the production of tetrabasic lead sulfate without cooling the paste during kneading.

After adding a predetermined amount of sulfuric acid or dilute sulfuric acid, finish kneading is subsequently carried out in step 7. In this finishing kneading step, in order to prevent the loss of water in the paste after the addition of sulfuric acid or dilute sulfuric acid, the temperature of the paste should be increased to 50 ° C. immediately after the addition of sulfuric acid or dilute sulfuric acid.
Cool to: Further, when the temperature of the paste exceeds 50 ° C., the water content remarkably decreases, and the physical properties of the paste change at the time of filling the paste, which is not preferable.

Even when the lead powder of the ball mill method is used instead of the lead powder of the Burton method, that is, even when the crystal form of lead oxide (PbO) that constitutes the lead powder is tetragonal, it is four times during the paste kneading. It is possible to obtain basic lead sulfate. Further, according to these methods, it becomes possible to select an appropriate addition rate of sulfuric acid or dilute sulfuric acid regardless of the size of the batch size (kneading amount) at the time of kneading, and even if the lead powder amount changes. By generating an appropriate amount of heat generation, the paste temperature during kneading can be maintained within an appropriate temperature range.

The sulfuric acid used in the sulfuric acid kneading step in the present invention does not specify its concentration but means a so-called sulfuric acid solution containing a sulfuric acid component. Of course, a sulfuric acid solution may be used, or a dilute sulfuric acid solution. May be

The concentration of dilute sulfuric acid added to the paste kneading is preferably 40% by weight or more from the viewpoint of causing a sufficient exothermic reaction and obtaining the effect of the present invention more remarkably. However, if the concentration of the dilute sulfuric acid becomes too high, problems occur in the corrosiveness of the dilute sulfuric acid with respect to equipment and handling during adjustment of the concentration. Therefore, the dilute sulfuric acid concentration is preferably 70% by weight or less. Therefore, the concentration of dilute sulfuric acid in the present invention is 40% by weight to 70%.
A weight% range is suitable. In addition, lead powder (Pb
Addition of 10 to 40% by weight of ₃ O ₄ ) accelerates the effect of the formation of tetrabasic lead sulfate. Furthermore, if the kneading machine is cooled by water cooling or air cooling during kneading, the formation of tetrabasic lead sulfate is not observed even if the addition rate of dilute sulfuric acid is increased, and the kneading machine is cooled during dilute sulfuric acid dropping. Doing so is not preferable for the production of tetrabasic lead sulfate.

According to the above construction, it is possible to promote the reaction between lead powder mainly composed of lead oxide and sulfuric acid or dilute sulfuric acid, so that tetrabasic lead sulfate can be produced extremely efficiently. Become. As a result, even in the aging step, the unformed positive electrode plate is likely to contain a large amount of highly utilized tetrabasic lead sulfate, and if such an electrode plate is applied to the positive electrode plate in particular, the utilization factor of the active material battery is improved. As a result, it is possible to increase the capacity and weight of the lead storage battery.

[0023]

EXAMPLES Examples for showing the effects of the present invention will be described below.

The lead oxide (PbO) content is 70% by mass,
1000 kg, 500 kg and 1 of lead powder obtained by the ball mill method containing 30 mass% of metallic lead (Pb), respectively.
Along with weighing 00 kg, 500 kg of lead powder by the Burton method having a lead oxide (PbO) content of 85 mass% and a metallic lead (Pb) content of 15 mass% is weighed and charged into a kneader. After that, water in an amount corresponding to 12 mass% of the mass of the lead powder is put into the kneading machine and kneading is performed for 5 minutes. Then, sulfuric acid was kneaded while adding an amount of dilute sulfuric acid (concentration: 55% by mass) corresponding to 13% by mass of the lead powder at various addition rates. The addition rate V was set by changing the constant k as shown in Table 1 in the above formula (1). Further, the paste temperature was measured immediately before the completion of the sulfuric acid kneading.

[0025]

[Table 1]

After the addition of dilute sulfuric acid was completed, the paste container was water-cooled and subjected to final kneading for 5 minutes to obtain an active material paste for the positive electrode. In the water cooling, the amount of cooling water and the water temperature were set so that the paste temperature was in the range of 45 ° C to 50 ° C at the time when finishing kneading for 5 minutes was completed.

Thereafter, these active material pastes were mixed with Pb-
After filling a grid made of 0.08 mass% Ca-2.0 mass% Sn alloy and allowing it to age for 24 hours in an atmosphere having a temperature of 85 ° C and a relative humidity of 95RH%, the temperature was further increased to 50 ° C.
It was left to stand in an atmosphere for 12 hours and dried to obtain an unformed electrode plate for a positive electrode.

The active materials were sampled from these unformed electrode plates and subjected to X-ray diffraction to find the peak intensity (P _4BS ) of the (311) plane of tetrabasic lead sulfate (4BS) and the tribasic lead sulfate (3BS). The ratio (P _4BS / P _3BS ) to the peak intensity (P _3BS ) of the (300) plane of () was measured. The results are shown in Table 2. Table 2 also shows the results of measuring the paste temperature at the end of dilute sulfuric acid kneading in paste kneading.

[0029]

[Table 2]

From the results shown in Table 2, it is clear that tetrabasic lead sulfate is produced in the active material and the addition rate of dilute sulfuric acid at that time has an influence. Further, regardless of changes in the lead powder mass W, the constant k is set to 0.015 to 0.030, and the dropping rate V of dilute sulfuric acid is calculated as the product of this constant k and the lead powder mass W to obtain the peak of the unactivated material. Strength ratio (P _{4B S}
/ _P3BS ) is increased, and the production ratio of tetrabasic lead sulfate in the unactivated material can be increased. Further, the paste temperature at the end of the dropwise addition of dilute sulfuric acid is 60 ° C to 9 ° C.
It can be seen that the temperature range is 0 ° C., and that this temperature range is extremely preferable in increasing the production ratio of tetrabasic lead sulfate produced during the kneading with dilute sulfuric acid.

In the method of the present invention, the paste temperature during the kneading with dilute sulfuric acid can be controlled by controlling the addition rate of dilute sulfuric acid. Further, as for the type of lead powder, it is found that the lead powder produced by the ball mill method can produce tetrabasic lead sulfate at a higher ratio than the lead powder produced by the Burton method.

Although the concentration of dilute sulfuric acid was set to 55% by mass in this example and the comparative example, when the concentration of dilute sulfuric acid exceeds 70% by mass, heat generation during paste kneading becomes excessive, and during kneading. It is not preferable as a paste because lead sulfate is partially formed therein, and it is not suitable for use as an active material even after aging reaction.

Next, in Table 1, No. 5 to No. 8 and No. 13-No. The unformed electrode plates using the paste of 16 (the filling amount of the paste per sheet is 28 g) are combined as the positive electrode plate, and the negative electrode plate according to the conventional method is combined through the separator made of the glass mat, and the Voltage 1
A control valve type lead-acid battery having a rated capacity of 6.5 AH for 20 hours at 2 V was constructed.

Discharge duration was measured when these control valve type lead-acid batteries were subjected to 19.5 A (3 CA) constant current discharge (discharge end voltage 9.6 V) in an atmosphere of 25 ° C. The results are shown in Table 3.

[0035]

[Table 3]

From the results shown in Table 3, according to the constitution of the present invention, the battery using the electrode plate having a high production ratio of tetrabasic lead sulfate in the unformed active material is excellent in high rate discharge performance. Thus, the utilization rate of the active material at that time was high.

Further, it is understood that the high rate discharge performance can be further improved by using the lead powder by the ball mill method than by the lead powder by the Burton method.

[0038]

As described above, according to the constitution of the present invention, in the paste kneading process, the reaction between the lead powder and sulfuric acid or dilute sulfuric acid can be rapidly advanced,
Since tetrabasic lead sulfate can be obtained during the kneading process, the utilization factor of the active material can be improved, the capacity of the lead storage battery can be increased, and the weight of the lead storage battery can be reduced, which is extremely useful industrially.

[Brief description of drawings]

FIG. 1 is a flowchart showing a kneading process of a paste-like active material used in the method for manufacturing a lead storage battery of the present invention.

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Claims (5)

[Claims] 1. A water kneading step of kneading lead powder mainly composed of lead oxide with water, a sulfuric acid kneading step of kneading while adding sulfuric acid or dilute sulfuric acid after the water kneading step, and a sulfuric acid kneading step. A method of manufacturing a lead storage battery, wherein a paste-like active material produced through a finishing kneading step is applied to a current collector, wherein the temperature of the paste-like active material during kneading in the sulfuric acid kneading step is 60 ° C to 90 ° C. At the same time, the temperature of the paste-like active material is kept at least 50 ° C. or lower by the time the kneading in the finishing kneading step is completed, the method for producing a lead storage battery. 2. The method for producing a lead storage battery according to claim 1, wherein the rate of adding the sulfuric acid or the dilute sulfuric acid is increased as the mass of the lead powder mainly containing lead oxide is increased. 3. The addition rate of the sulfuric acid or dilute sulfuric acid is V
(Kg / min), where W (kg) is the weight of the lead powder mainly composed of lead oxide, the addition rate of sulfuric acid or dilute sulfuric acid is V = k × W (where k = 0.015 to 0. The constant is set to 030), The manufacturing method of a lead storage battery according to claim 2, wherein. 4. The method for manufacturing a lead storage battery according to claim 1, wherein the lead powder mainly containing lead oxide is obtained by a ball mill method. 5. The method for producing a lead storage battery according to claim 1, wherein the lead powder mainly containing lead oxide contains lead tin.