JPH1154114A - Plate for lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate by which localization of an additive can be prevented and a utilization factor of an active material can by uniformly kept and whose local softening can be restrained by filling paste obtained by kneading the active material by sticking a carbon additive to surfaces of respective particles of lead powder of a main raw material of the active material, in a base board. SOLUTION: A plate is manufactured as follows. First of all, a carbon additive 2 is added by a quantity corresponding to about 0.2% to its lead powder in the lead powder as a main raw material of an active material. It is mixed by a ball mill, and the additive 2 is stuck to surfaces of particles 1 of lead powder, and an active material 3 is obtained. Next, a prescribed quantity of water and a dilute sulfuric acid having specific gravity of about 1.265 are added in the active material 3, and are kneaded for about 18 minutes, and paste is manufactured. This paste is applied to and filled in a lattice base board by, for example, manual painting, and this is adjusted in a thickness by a roller, and is dried, and is formed as an active material filling part, and is formed as a positive electrode by performing formation processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-acid battery electrode plate housed in a lead-acid battery battery case.

[0002]

2. Description of the Related Art An electrode plate for a lead-acid battery is prepared by adding an additive to lead powder as an active material, mixing the lead powder and the additive and kneading the paste to produce a paste. The paste is dried and then subjected to a chemical conversion treatment.

[0003] Additives increase the conductivity between active materials,
It is added to the lead powder of the active material for the purpose of increasing the pores that favor the discharge reaction in the electrode plate, and carbon-based conductive materials such as graphite, acetylene black, and Ketjen black are often used. Have been.

[0004]

However, the carbon-based additive has a very low bulk density relative to lead powder, which is an active material of a lead-acid battery, and therefore, this carbon-based additive is contained in a high-density lead powder. Even if the above additive is added and kneaded, the lead powder and the additive are not uniformly mixed, and the additive locally gathers and is localized.

[0005] In the area of the active material filled portion in the electrode plate, a part of the active material disappears during formation or charge / discharge, and pores are generated.
Here, when the additive is not uniformly distributed but localized in the entire region of the active material filling portion, the generation of pores in the portion where the additive is localized in large amounts is accelerated, and The specific surface area is locally increased, and as a result, the utilization rate of the active material in the localized portion is larger than that in the other portion where the amount of the additive is small, and in the portion where the utilization ratio is large. Deterioration of the active material proceeds early, and the crystal becomes finer and softer, which causes a reduction in battery life.

The present invention has been made in view of such a point, and an object of the present invention is to prevent localization of an additive, maintain the utilization rate of an active material uniformly, and maintain the locality of the active material. An object of the present invention is to provide a lead storage battery electrode plate capable of suppressing softening.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a carbon-based additive is added to the surface of each particle of lead powder which is a main material of an active material. An active material material is adhered to the paste, the active material material is kneaded to form a paste, and the paste is filled in a substrate. A carbon-based additive is attached to the surface of each particle of a certain lead powder to form an active material, and a lead powder having no additive attached to the particles is added to the active material.
It is characterized in that a paste is obtained by kneading these active material and lead powder, and the paste is filled in a substrate.

[0008]

Embodiments of the present invention will be described below. In the present invention, as shown in FIG. 1, a carbon-based additive 2 is attached to the surface of each particle 1 of lead powder as a main raw material of an active material to form an active material 3, and this active material 3 is used. Kneading to make a paste, this paste is
As shown in FIG. 5, the substrate 4 is filled into an active material filled portion 5 to constitute, for example, a positive electrode for a lead storage battery. In addition, 6 shown in FIG. 2 is an ear formed integrally with the substrate 4, and 7 is a foot.

The process for manufacturing this electrode plate is as follows. First, in a lead powder as a main raw material of an active material, for example, Ketjen black (manufactured by Lion Corporation) as a carbon-based additive is added to the lead powder. And add the amount equivalent to 0.2% by weight. Then, the lead powder and Ketjen Black are mixed by a ball mill, and Ketjen Black is adhered to the surfaces of the particles of the lead powder to obtain an active material.

Next, a predetermined amount of water and dilute sulfuric acid having a specific gravity of 1.265 are added to the active material thus obtained, and the active material is kneaded for 18 minutes to prepare a paste. Is applied to a grid substrate having a size of 63.8 × 45 × 2.7 mm in an amount of 25.4 g, for example, by hand coating, and then filled with a roller, which is then dried and dried to form an active material-filled portion. After the treatment, a positive electrode is obtained.

When a paste is prepared using an active material in which an additive is previously adhered to the surface of each lead powder particle, the additive is uniformly distributed in the paste and its localization is prevented. Therefore, the additive is evenly distributed in the active material filled portion formed by filling the paste into the lattice substrate, and the localization is prevented.

[0012] To confirm this, an electrode plate as a comparative product was manufactured by the following conventional process. First, ketjen black as a carbon-based additive is added to lead powder in an amount equivalent to 0.2% by weight of the lead powder,
Further, a predetermined amount of water and dilute sulfuric acid having a specific gravity of 1.265 are added to the lead powder and kneaded for 18 minutes to prepare a paste. The paste is manually applied to a grid substrate having a size of 63.8 × 45 × 2.7 mm in an amount of 25.4 g. This was applied and filled by application, and the thickness was adjusted with a roller. The paste was dried to form an active material filled portion, and then subjected to a chemical conversion treatment to obtain an electrode plate.

In the electrode plate of the present invention and the electrode plate of the comparative product, the upper part on the side where the ears are arranged, the middle part between the ears and the feet, and the lower part on the side where the feet are arranged Convenience 3
The active material was sampled from each of the four locations, and the content of Ketjen Black (additive) in the active material was measured.

According to this measurement, in the comparative product, the Ketjen black content in the upper, middle, and lower portions of the electrode plate is 0.18%, 0.14%, 0.15%, and the difference of a maximum of 0.04% is partially obtained. In contrast, in the product of the present invention, the content of Ketjen Black at the top, center, and bottom of the electrode plate is
There is only a maximum difference of 0.01% between 0.18%, 0.17%, and 0.17%, which indicates that the additive is uniformly distributed in the entire region of the active material filling portion.

As described above, according to the electrode plate of the present invention, the additive is uniformly distributed over the entire region of the active material filled portion in the electrode plate of the additive, and the localization of the additive is prevented. Pores are evenly generated in the entire region of the active material filling portion, so that the utilization rate of the active material is uniform, local softening is suppressed, and the battery life is improved.

In order to confirm this, the active material filled portion obtained in the present invention and the conventional process was formed and dried to form a positive electrode plate. One positive electrode plate and two ordinary negative electrode plates were used. And a retainer mat is arranged between the positive and negative electrode plates to form an electrode plate group. The retainer mat is impregnated with a dilute sulfuric acid electrolyte to obtain a lead-acid battery having a capacity of 3 hours and a capacity of 1500 mAh according to the present invention. A lead-acid battery having a capacity of 1500 mAh was prepared. And 1500% which is 80% capacity of 1500mAh
mAh, and then charge the battery with 110% of electricity. The discharge voltage is 1.65V.
It was determined that it had reached its end of life by cutting it.

As a result, the cycle life of the conventional lead-acid battery was 232 cycles, whereas that of the lead-acid battery of the present invention was 279 cycles, which is an improvement of about 28%. Discharge: 2 hours and 24 minutes at 500 mA (DOD 80%) Life with a cut of 1.65 V Charging: 2 steps constant current 1st step 1 hour 50 minutes at 0.4 CA (600 mA) 2nd step 1 hour 46 at 0.08 CA (120 mA) In each of the above embodiments, an additive is attached to the surface of the lead powder particles to form an active material, and only the active material is kneaded to produce a paste. However, in the active material material in which the additive is adhered to the surface of the lead powder particles, the lead powder in which the additive is not adhered to the surface of the particles is added, and the mixture is kneaded to form a paste. May be filled in a lattice substrate to form an active material-filled portion, and an electrode plate may be formed in such a process.

Also in this case, the additives are uniformly distributed to prevent their localization, and it is possible to keep the utilization rate of the active material uniform and to suppress the local softening. Further, as a means for attaching the additive to the surface of the lead powder particles, a method by vapor deposition or a method by spraying can be adopted.

[0019]

As described above, according to the present invention, the additive can be uniformly distributed over the entire area of the active material filling portion to prevent the localization of the additive, and therefore, the utilization rate of the active material can be kept uniform. The battery life can be improved by suppressing the local softening.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of an active material according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state where a substrate is filled with the active material and dried.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lead powder particle 2 ... Additive 3 ... Active material material 4 ... Substrate 5 ... Active material filling part 6 ... Ear part 7 ... Foot part

Claims (2)

[Claims] An active material is prepared by adhering a carbon-based additive to the surface of each particle of lead powder, which is a main raw material of the active material, and the active material is kneaded to form a paste. An electrode plate for a lead storage battery, characterized by being filled. 2. A carbon-based additive is attached to the surface of each particle of lead powder, which is a main raw material of the active material, to form an active material, and no additive is attached to the particles in the active material. An electrode plate for a lead storage battery, characterized in that a lead powder is added, the active material and the lead powder are kneaded to form a paste, and the paste is filled in a substrate.