JP2000149981A - Lead-acid battery, and additive therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a capacity from being deteriorated in accompaniment with charge and discharge of a lead-acid battery, and to reduce internal resistance to increase the capacity of the battery. SOLUTION: A polymer compound containing any one selected from the group comprising polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, polyacrylic acid and esters thereof, which have 30-3000 of polymerization degree respectively, or the polymer compound and colloidal barium sulfate is/are contained in an electrolyte and/or an electrode active material molding. (A) represents a discharge capacity in a charge-discharge cycle test for this battery, and (B) is a discharge capacity in the same test for a conventional battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a lead storage battery having a large electric capacity and a small decrease in the electric capacity due to repeated charging and discharging, and an additive for the lead storage battery.

[0002]

2. Description of the Related Art Lead-acid batteries are subject to repeated charging and discharging,
Since the crystals of lead sulfate grow and become inactive, the amount of the electrode active material decreases and the capacity of the battery decreases. As a countermeasure, there is a method of overcharging with a small current for a long time to convert lead sulfate to metallic lead again. However, this method has a poor effect because only a small part of the crystal-grown lead sulfate becomes metallic lead. . In addition, there is a method of adding various additives to the electrolytic solution, for example, fine particles of carbon, etc., but fine particles of carbon are easily oxidized at the positive electrode, disappear in a relatively short time, and the effect is lost with this There was a drawback.
Conventionally, the effect of lignin added as a binder of the electrode active material molded body of a lead storage battery to improve the battery characteristics has been slightly recognized, but the effect is slight, and the organic acid generated by electrolytic oxidation at the positive electrode has been recognized. However, there were side effects such as corrosion of the conductor, and the usefulness was poor.

[0003]

SUMMARY OF THE INVENTION The present invention has found an additive for a lead-acid battery which has a much longer life and is less expensive than these conventional methods. A first object of the present invention is to extend the charge / discharge cycle life of a lead storage battery. A second object of the present invention is to increase the capacity of a lead storage battery. A third object of the present invention is to reduce the internal resistance of a lead storage battery. A fourth object of the present invention is to improve the rapid charging performance of a lead storage battery.

[0004]

Means for Solving the Problems According to the present invention, a polymerization degree of 3 is contained in an electrolyte of a lead storage battery and / or in an electrode active material molded product.
A polymer compound containing any one of the group consisting of polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, polyacrylic acid, or an ester thereof of 0 to 3000, or any one of the polymer compound and colloidal barium sulfate particles And a polymer compound containing any one of the group consisting of polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, and esters thereof having a polymerization degree of 30 or more and 3000 or less; It is a lead storage battery additive containing either a molecular compound and colloidal barium sulfate particles.

[0005]

The present inventors have found that lead-acid batteries can be used in electrolytes and / or
Alternatively, a linear organic polymer compound having a hydroxyl group in the molecule, such as polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, or an ester thereof, having a specific range of polymerization degree is added to the positive electrode active material molded body. As a result, as shown in FIG. 1, they have found that the charge / discharge cycle life can be remarkably extended as compared with the conventional case of no addition. The mechanism by which polyvinyl alcohol, etc. with a specific degree of polymerization in a specific range contributes to prolonging the charge / discharge cycle life of a lead-acid battery and increasing the battery capacity is unknown, but the hydroxyl group of polyvinyl alcohol, etc. and a lead ion form a complex, and this complex It is presumed that fine metallic lead is deposited on the negative electrode as a result of the electrolytic reduction of. Organic polymer compounds having hydroxyl groups, such as polyvinyl alcohol, have a tendency for protons to coordinate to hydroxyl groups in dilute sulfuric acid electrolyte, become positively charged, and adsorb to the negative electrode of the battery. It is thought that growth is suppressed.
In addition, since the positively charged electrode is electrically repelled by the positive electrode, it is less likely to disappear due to electrolytic oxidation at the positive electrode. The addition of colloidal barium sulfate has the effect of suppressing the growth of these crystals by providing crystal nuclei of lead sulfate and metallic lead. The addition of stannous ions prevents the reduction of hydrogen overvoltage due to the dissolution of antimony used as an alloy component of the positive electrode grid in the electrolyte and the deposition on the negative electrode. This has the effect of completely decomposing the lead sulfate of the negative electrode without generation.

The present invention has an extremely high effect, which is unprecedented in the prior art. The effect of the present invention is to extend the charge / discharge cycle life of a lead-acid battery by several times. Could not be expected at all with the improvement of.

The high molecular compounds such as polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid and esters thereof used in the present invention preferably have a degree of polymerization of 30 or more and 3000 or less, particularly 50 or more and 500 or less. Are more effective. When used in combination with barium sulfate, the effective range of the degree of polymerization is even wider. When these polyvinyl alcohols are added to the electrolytic solution, they are usually added in such an amount as to give a concentration of about 0.1%, but a sufficient effect is observed in a wide range of 0.01 to 10%. Also, when it is contained in the electrode active material, 0.001 to 1% based on the electrode active material.
Is desirably added and mixed.

The colloidal barium sulfate used in the present invention has an average particle size of 1 μm or less, preferably 0.1 μm or less.
It is preferable that the thickness be 1 micrometer or less and 0.005 micrometers or more. When mixed with the active material of the electrode, the addition amount is sufficient to be 1000 ppm or less.
The effect is also recognized at pm. In addition, when added as an additive to a finished battery, the content of the electrolyte solution is 500 ppm to 1 ppm.
About 0 ppm is preferable. The colloidal particles of barium sulfate used in the present invention can be made by adding an excess of sodium sulfate or sulfuric acid to an aqueous solution of a barium salt, for example, a 0.5 to 1 molar aqueous solution of barium acetate or barium chloride. In order to prevent aggregation, these particles are desirably added to the electrolyte in a state of being dispersed in water, or added in a state of being dispersed in water at the time of kneading the electrode paste. Further, when dispersed in an aqueous solution of a polymer compound such as polyvinyl alcohol, it can be more stably dispersed. Stannous ions can be added as an aqueous solution of stannous sulfate or the like, and the concentration in the electrolyte is 0.001 mol to 0.2 mol,
Preferably it is 0.01 mol to 0.1 mol.

[0009]

【Example】

Example 1 50 ml of electrolyte of a lead-acid battery with a capacity of 4 AH
Was added and dissolved in 100 mg of polyvinyl alcohol having a polymerization degree of 300. The discharge condition was 4 hours at a current of 1 A at a current of 2 A until the terminal voltage reached 1 V. The charge and discharge were repeated, and the time for each discharge was measured. . For comparison, the same charge / discharge was repeated for the same battery without the addition. As a result, as shown in FIG. 1, the battery (A) of the present invention to which polyvinyl alcohol was added was the conventional product (B) without addition.
In comparison with the above, a remarkable improvement in the charge / discharge cycle life was observed. The internal resistance of the battery (A) of the present invention at the time of 100 charge / discharge cycles was almost the same as that of the unused battery, and was one third of that of the conventional battery (B).

[0010]

Example 2 To 100 g of lead oxide, 10 ml of polyvinyl alcohol having a concentration of 2% and a polymerization degree of 2,000 was added and kneaded well. The mixture was used as a positive electrode of a lead storage battery, electrolyzed with 1A for 24 hours, and subjected to a forming treatment. Using this battery, discharging was performed at a current of 2 A at a terminal voltage of 1 V and charging was performed at a current of 1 A for 4 hours, charge and discharge were repeated, and the amount of electricity for each discharge was measured. For comparison, the same charge / discharge was repeated for a similar battery in which polyvinyl alcohol was not added to the positive electrode active material. As a result, in the battery of the present invention to which polyvinyl alcohol was added, the number of charge / discharge cycles in which the discharge capacity deteriorated to half of the maximum value was 200 cycles or more, and the other conditions were the same without adding polyvinyl alcohol. Compared to the battery has about 60 cycles,
The improvement of the charge / discharge cycle life of 3 times or more was recognized.

[0011]

Example 3 50 ml of electrolyte of a lead-acid battery with a capacity of 4 AH
An aqueous solution containing 50 mg of polyethylene glycol having a degree of polymerization of 50 and 5 mg of barium sulfate having a particle diameter of 0.3 μm was added and mixed. The discharge conditions were 2 A at a terminal voltage of 1 V, and the charge conditions were 1 A at 4 A for 4 hours. The charge and discharge were repeated, and the time for each discharge was measured. For comparison, the same charge / discharge was repeated for the same battery without the addition. As a result, the battery of the present invention to which polyethylene glycol and barium sulfate were added had a charge / discharge cycle number of 300 cycles or more in which the discharge capacity deteriorated to half of the maximum value as compared with the conventional battery without the addition,
A remarkable improvement in the charge / discharge cycle life of 5 times or more was recognized as compared to about 60 cycles of the battery without addition of polyethylene glycol and under the same other conditions.

[0012]

Example 4 50 ml of electrolyte of a lead-acid battery with a capacity of 4 AH
An aqueous solution containing 50 mg of polyvinyl alcohol having a polymerization degree of 3500 and 2 mg of stannous sulfate was added and mixed. The discharging conditions were 2 A at a terminal voltage of 1 V, the charging conditions were 4 A at a current of 1 A, and charging and discharging were repeated. The time for each discharge was measured. For comparison, the same charge / discharge was repeated for the same battery without the addition. As a result, in the battery of the present invention, the number of charge / discharge cycles at which the discharge capacity deteriorates to half of the maximum value is 30 compared to the non-added conventional product.
Compared to a battery with no addition and other conditions of about 60 cycles with no addition and under the same other conditions, a remarkable improvement of the charge / discharge cycle life of 5 times or more was recognized.

[0013]

As is apparent from the above description, the lead storage battery of the present invention has a small decrease in battery capacity due to repeated charging and discharging, has a long life, and significantly increases the life of the lead storage battery by adding a small amount. The raw material is produced in large quantities for use in adhesives and the like, so that it can be manufactured at extremely low cost.For example, electric vehicles, uninterruptible power supplies, and batteries suitable for power storage of commercial power supplies, etc. A battery can be provided.

[Brief description of the drawings]

FIG. 1 is a graph comparing the progress of a discharge capacity in a charge / discharge cycle test of a battery of the present invention with a conventional product.

[Explanation of symbols]

A, Discharge capacity of the battery of the present invention in a charge / discharge cycle test B, Discharge capacity of a conventional battery in a charge / discharge cycle test

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Claims (6)

[Claims] 1. A polymer compound containing any one selected from the group consisting of polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid and esters thereof having a polymerization degree of 30 or more and 3000 or less, or the polymer compound and a colloid A lead-acid battery comprising any one of barium sulfate particles in an electrolyte and / or a molded article of an electrode active material. 2. The lead-acid battery according to claim 1, wherein the degree of polymerization of the polymer compound is 50 or more and 500 or less. 3. The lead-acid battery according to claim 1, further comprising 0.001 to 0.2 mol of stannous ions in the electrolyte. 4. A polymer compound containing any one selected from the group consisting of polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, polyacrylic acid, and esters thereof having a polymerization degree of 30 or more and 3000 or less, or the polymer compound and a colloid An additive for a lead-acid battery, comprising any one of barium sulfate particles. 5. The additive for a lead storage battery according to claim 4, wherein the degree of polymerization of the polymer compound is 50 or more and 500 or less. 6. The additive according to claim 4, further comprising 0.001 to 0.2 mol of stannous ions in the electrolyte.