JPH03134960A - Manufacture of negative electrode plate for lead-acid battery - Google Patents

Abstract

PURPOSE:To enhance the service rate of active substance without sacrificing the lifetime by mixing a certain specified amount of yellow litharge with lead powder, whereto water and sulfuric acid are added to turn into paste, applying it to a grating, and storing in an atmosphere of a certain temp. and humidity as maturing process. CONSTITUTION:To lead powder a yellow litharge (Pb0) is added in an amount 3.5-13.5 wt.% of the total powder amount, whereto water and sulfuric acid are added, followed by kneading to yield a paste. The amount of sulfuric acid added when the paste is kneaded shall be 0.1-0.5 mol% to one mol Pb0 contained in the lead powder. After applying the paste to a grating, it is stored in an atmosphere of over 80 deg.C and over 85% RH as maturing process. Thus a neg. electrode plate is achieved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a method for manufacturing lead-acid batteries, and includes 2.
- In particular, this aims to improve the utilization rate of active materials in paste-type negative electrode plates.

Conventional technology The negative electrode plate of a lead-acid battery is usually made by adding water and sulfuric acid to lead powder, then adding organic additives and fine carbon powder, etc., and kneading it into a paste, which is then made into a paste using cast grids, expanded metal, etc. It is manufactured by coating it on a lattice body and then aging and drying it. Most of the lead powder used at this time is produced by a ball mill type or Burton pot type lead powder machine, so its composition is red litharge [hereinafter referred to as pb○ (
RF, D)], and contains a small amount of metallic lead. In addition, the active material composition of the unformed board is tribasic lead sulfate as the main component, Pb0(R
It is generally made of metal lead (ED) or metal lead.

Problems to be Solved by the Invention The negative electrode plate utilization rate of the lead-acid battery manufactured in this manner is extremely low at about 50% of the theoretical value at a 5-hour rate discharge at room temperature. In addition, the lower the temperature and the higher the current discharge, the lower the utilization rate of 3.＼-7 becomes.
There was a problem in that the utilization rate decreased to about 10% of the theoretical value when it became discharged.

Means to Solve the Problems The present invention aims to improve the active material utilization rate of such a negative electrode plate, and in particular to improve the rapid discharge characteristics.As a specific means, water and sulfuric acid are added to lead powder. Knead to make a paste,
In a production method in which this is applied to a cast grid or expanded metal grid and aged and dried, yellow litharge (hereinafter referred to as PI)O (YELLOW) is preferably added to the lead powder in a range of 3.5 to 3.5% of the total amount of powder. 13.5% by weight is mixed, and this is aged by storing and drying in an atmosphere with a temperature of 80"Q or higher and a humidity of 85% or higher during aging and drying, and tetrabasic sulfuric acid is added to the active material of the unformed board. It is characterized by generating salt.More preferably, the amount of sulfuric acid added during paste kneading is in the range of 0.1 m 01 to 0.5 mol with respect to Pb01 m01 contained in the lead powder. It is characterized by adding.

Effect: By the method described above, the utilization rate of the active material of the negative electrode plate can be significantly improved.

In other words, conventionally, lead powder mainly composed of Pb0 (RED) produced using a lead powder machine such as Pall Milk Eve was used, and the active material composition of the unformed board after kneading, aging and drying was generally 3. Aging and drying was performed in which the main component was basic lead sulfate. Since this tribasic lead sulfate generally has a very small crystal particle size of about 1 μm on average, the size of the pores formed between the active material particles is correspondingly small with an average pore size of 1 μm or less.

After the unformed plate was chemically formed, the bores of the live material remained in their original shape before chemical formation, and the average pore diameter was also extremely small. For this reason, the movement and supply of the electrolyte by diffusion etc. cannot be performed smoothly, and although the life characteristics are good, the active material utilization rate is low, making it difficult to obtain a capacity.

On the other hand, in the present invention, PB is contained in lead powder.

(YELLOW) in the range of 3.5 to 13.5% by weight.
/＼-1 Mix to form a paste, age and dry it in an atmosphere with a temperature of 80°C or higher and a humidity of 85% or higher to form tetrabasic lead sulfate as the main component in the active material of the unformed plate. As a result, the bore of the active material is made larger, and the diffusion and penetration of the electrolytic solution is made smoother, thereby significantly improving the active material utilization rate.

That is, the crystal particle size of tetrabasic lead sulfate is much larger than that of tribasic lead sulfate, reaching several tens of microns in size. For this reason, the average pore diameter of the bore of the active material becomes large, and as a result, the bore of the electrode plate after chemical formation is also large, allowing smooth diffusion and movement of the electrolyte and its supply into the paste. . Therefore, the active material utilization rate is significantly improved compared to that of an unformed plate active material containing tribasic lead sulfate as a main component.

Examples Examples of the present invention will be described below. At the stage of adding water and sulfuric acid to lead powder and kneading it into a paste, pbo (yELLoW) is added from 0% by weight to 15% by weight in lead powder.
Various lead oxides were prepared by mixing them in increments of 0.5% by weight. Next, as a typical example of the amount of sulfuric acid added to these lead oxides, 0.3 mOl of sulfuric acid was added to Pb01m01 and kneaded to create a paste. These pastes were aged under A-82 types of aging and drying conditions shown in Table 1 to obtain negative electrode plates.

As a result of measuring the active material of the obtained negative electrode plate by X-ray diffraction, it was found that under aging and drying conditions A and B, pb.

The amount of (YKLLOW) mixed with the powder is 3.5% by weight.
The main component of the undropped product was tribasic lead sulfate, and the main component of the other products was tetrabasic lead sulfate.

Furthermore, a battery having a voltage of 12 V and a 5-hour rate capacity of 25 Ah was prepared using the obtained negative electrode plates, and chemical conversion was performed inside the battery case. Thereafter, the battery was allowed to stand at -15°C for 20 hours, and discharged at a current of 150A, and the discharge duration until the terminal voltage of the battery decreased to 6V was determined.

The results are shown in the first piece. As is clear from the figure, those aged by humans under conventional aging and drying conditions are PbO
Even if the amount of Pt+0 (YKLLOW) mixed increases, the discharge duration does not increase at all, whereas in the case of aging drying condition B of the present invention, the discharge duration increases as the amount of Pt+0 (YKLLOW) mixed increases. The time becomes longer, and when the amount of the mixture exceeds 3.5% by weight of the total amount of powder, the discharge duration increases rapidly, and it can be seen that there is a remarkable effect.

Figure 2 shows that using a battery treated under aging and drying condition B, discharge is performed at a 5-hour rate current until the terminal voltage of the battery drops to 10.5V, and charging is performed to 130% of its discharge capacity. In a cycle test, the discharge capacity was 5
The results of determining the cycle in which the time rate capacity decreases to 50% are shown. As the figure clearly shows, Pb0 (YELLOW)
It can be seen that when the mixing amount exceeds 13.5% by weight, the cycle rate decreases rapidly. This is due to the formation of too much tetrabasic lead sulfate, which causes the pore size of the living matter bore to become too large.
This seems to be due to the weakening of the bonding force between the active materials.

Effect of the invention As described above, according to the present invention, conventional pb.

(RED) is used as the main component, and a negative electrode plate with tribasic lead sulfate as the main component of the active material composition of the unformed plate has good life characteristics, but the problem is that the active material utilization rate is low. , pb in lead powder.

(YELLOW) and by making tetrabasic lead sulfate the main component of the active material composition of the unformed plate, the utilization rate of the active material is improved without changing the life characteristics at all.

[Brief explanation of the drawing]

Figure 1 shows PB due to differences in aging and drying conditions. FIG. 2 is a diagram showing the relationship between the mixing amount of Pb0 (YICLLOW) and the initial capacity, and FIG. 2 is a diagram showing the relationship between the mixing amount of Pb0 (YKLLOW) and the life cycle.

Claims (2)

[Claims] (1) A method for producing a negative electrode plate for a lead-acid battery, in which lead powder is mixed with water and sulfuric acid to form a paste, the paste is applied to a grid, and then aged and dried. Resurge [PbO (YELLOW)] from 3.5 to 3.5 of the total amount of powder
A method for producing a negative electrode plate for a lead-acid battery, characterized in that the paste is mixed in a range of 13.5% by weight, and the paste is aged by storing it in an atmosphere with a temperature of 80° C. or higher and a humidity of 85% or higher. (2) The lead-acid battery according to claim 1, wherein the amount of sulfuric acid added during paste kneading is in the range of 0.1 to 0.5 mol per 1 mol of PbO contained in the lead powder. Manufacturing method of negative electrode plate.