JP2001313064A - Lead storage battery and its additive agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a degradation of a capacity accompanying a charge/ discharge electricity of a lead storage battery, to reduce an internal resistance, and to increase capacity of a battery. SOLUTION: The lead storage battery includes polyacrylic acid or its ester, and polyvinyl alcohol in an electrolyte and/or a negative electrode active- material molding body. Moreover, an additive agent for the lead storage battery contains at least 1 kind in a group consisting of stannous sulfate, stannic sulfate, and colloid-like lead sulfate, and at least 1 kind in a groups consisting of polyacrylic acid, polyacrylic acid ester, and polyvinyl alcohol soluble lignin.

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 electric capacity due to repeated charge and discharge, and an additive thereof.

[0002]

2. Description of the Related Art Lead-acid batteries are subject to repeated charging and discharging,
As a result of the recrystallization of the active material due to the electrochemical reaction of the negative electrode active material, these particles grow and the electrical conduction is cut off or the surface area of the active material is reduced, and the capacity of the battery is reduced. And the internal resistance increases. Conventionally, measures have been taken to secure conduction by compressing both electrodes from outside the container for the purpose of securing conduction between these electrode active materials and the current collector,
The effect was small and inadequate. In addition, there is a method of adding various additives, for example, fine particles of carbon or polyvinyl alcohol (PVA), to the electrolytic solution. However, there are problems such as precipitation in the electrolytic solution and decay during storage. There was a disadvantage that the effect was lost.

[0003]

SUMMARY OF THE INVENTION The present invention has found a more stable and inexpensive additive for a lead-acid battery 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 deteriorated lead storage battery and restore it to a capacity close to that before deterioration. A third object of the present invention is to reduce the internal resistance of a lead-acid battery and enable a large current discharge. 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 The present invention relates to a lead-acid battery containing polyacrylic acid or an ester thereof in an electrolytic solution and / or a molded negative electrode active material, and polyacrylic acid or an ester thereof and polyvinyl alcohol. To
A lead-acid battery contained in the electrolytic solution and / or the molded negative electrode active material, and a lead-acid battery additive containing polyacrylic acid or an ester thereof, and polyacrylic acid or an ester thereof and polyvinyl alcohol; And / or at least one of the group consisting of stannous sulfate, stannic sulfate, and colloidal lead sulfate, and polyacrylic acid, polyacrylate, and polyvinyl alcohol. And at least one member of the group consisting of soluble lignin.

[0005]

The present inventors disclosed in Japanese Patent Application Laid-Open Nos. Hei 10-228922 and Hei 10-241677 that fine carbon particles were contained in an electrolyte of a lead storage battery and / or in an active material molded product, and a water-soluble and acid-resistant It has been discovered that the addition of an organic polymer compound, for example, polyvinyl alcohol, can significantly prolong the charge / discharge cycle life as compared with the conventional case of no addition. As a result of our subsequent research,
It has been found that this effect is mainly attributable to the regeneration of crystalline lead sulfate into active lead by the effect of increasing the hydrogen overvoltage of the negative electrode. Further, polyacrylic acid, its esters and copolymers have been found as substances having a large effect of increasing the hydrogen overvoltage of the negative electrode, and these compounds and mixtures of these compounds with polyvinyl alcohol and / or soluble lignin have been used in lead-acid batteries. The present invention has been found to be extremely effective in regenerating the negative electrode active material and to have excellent performance as an activator for a lead storage battery. In addition, at this time, when at least one of stannous sulfate, stannic sulfate, and colloidal lead sulfate coexist, it is possible to obtain a battery having a larger capacity, a lower internal resistance, and withstanding a large current charge and discharge. That is what I found.

That is, conventionally, in a lead battery, when charge and discharge are repeatedly performed, lead sulfate crystals gradually grow on the surface of the negative electrode, and the grown lead sulfate crystals have a potential at the hydrogen generation potential of the negative electrode during normal charging. It was not sufficiently decomposed and remained as it was, causing so-called sulfation, causing the capacity to gradually decrease. However, when polyacrylic acid and its ester, copolymer, or soluble lignin are present in the electrolytic solution, or when polyvinyl alcohol coexists with these, these organic polymers are adsorbed on the surface of the negative electrode, and a hydrogen overvoltage occurs. 200 to 3
As a result of raising the voltage by as much as 00 mV, the potential of the negative electrode becomes a potential sufficient to decompose the grown lead sulfate crystal, so that the charging current is not wasted in the generation of hydrogen and the regeneration of the negative electrode is efficiently performed even in a short-time charging. That's what I found.
In addition, the mechanism by which stannous sulfate, stannic sulfate, colloidal lead sulfate and the like act as nuclei of metallic lead crystals generated as an active material of the anode during charging, and Sb adhered to the anode It is considered that the generation point of hydrogen caused by impurities such as Fe and Fe is covered with tin or fine metallic lead to prevent generation of hydrogen, thereby improving the charging efficiency of the negative electrode.

The advantage of using polyacrylic acid and its ester and copolymer in the present invention as compared with the case of adding polyvinyl alcohol is that the stability of the additive when stored for a long period of time is high. Being better. That is, an aqueous solution of polyvinyl alcohol alone produces turbidity in several months, whereas no abnormality is observed even after one year when polyacrylic acid, its ester, or copolymer is added. Furthermore, it is recognized that when polyvinyl alcohol and / or soluble lignin are added to polyacrylic acid and its ester or copolymer, a greater effect can be obtained on the regenerating effect of the battery as compared with the case of using polyacrylic acid or polyvinyl alcohol alone. Was. As the copolymer of polyacrylic acid used in the present invention, acrylic acid-sulfonic acid copolymer, acrylic acid-
There are acrylic ester copolymers and acrylic acid-maleic acid copolymers.

The amount of the additive used in the present invention is 0.001% of polyacrylic acid in 10N sulfuric acid which is an electrolyte of a lead battery.
It is preferable to add 0.001% to 1% of polyvinyl alcohol and / or soluble lignin, and the addition method is to add an aqueous solution in advance or add a powder to the electrolyte. It can also be dissolved. Since stannous sulfate, stannic sulfate, and colloidal lead sulfate act as crystal nuclei, they are effective even in a very small amount, and are usually 0.0001 mol to 0.1 mol in the electrolytic solution.
It is preferably present in an amount of about 01 mol. In particular, stannous sulfate or stannic sulfate has a large effect of reducing the internal resistance. A lead plate is used as an electrode plate, and an electrolytic solution of 5 mol of dilute sulfuric acid is used. 01 mol)
In addition, when charge and discharge are repeated for 30 cycles, fine metal lead crystals are formed on the surface of the negative electrode, and the internal resistance is significantly reduced.

[0009]

【Example】

Example 1 A lead plate was used as an electrode, 10 N sulfuric acid was used as an electrolyte, and no addition was made of polyvinyl alcohol 0.03
%, Acrylic acid-acrylate copolymer 0.0
When 3% and 0.03% of an acrylic acid-maleic acid copolymer were added, scanning was performed at a rate of 10 mV / sec from the equilibrium potential in a negative direction, and the potential with respect to the Hg-HgSO4 electrode was recorded. The result is shown in FIG. As is clear from the results, in the case of the additive-free A, a current accompanying the electrolysis of water already flows from -1.3 V, and the reduction of lead sulfate is hindered. , C, and D, a small current flows even at -1.5 V, the hydrogen overvoltage is large, the generation of hydrogen is prevented, and the reduction of lead sulfate proceeds efficiently. In particular, system C to which an acrylic acid-based additive is added,
In D, the effect is remarkable.

[0010]

Example 2 (E) No Addition to Electrolyte of Lead Acid Battery
(F) 0.03% of polyvinyl alcohol, (G) 0.03% of acrylic acid-sulfonic acid copolymer, (H) 0.01% of polyvinyl alcohol, 0.2% of acrylic acid-maleic acid copolymer, 0% of stannous sulfate .01 mol were added, and a charge end voltage of 2.75 V and a discharge end voltage of 1.75 mol were added.
A charge / discharge cycle test was performed at 0 V, charge 0.25 C, and discharge 0.5 C. As a result, as shown in FIG.
The sulfonic acid copolymer-added (G) and the polyvinyl alcohol, acrylic acid-maleic acid copolymer, and stannous sulfate-added (H) are the non-added (E) and the conventional product (F) containing only PVA. As compared with the above, a remarkable improvement in the charge / discharge cycle life was observed.

[0011]

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. Thus, a battery suitable as a battery for an electric vehicle, an uninterruptible power supply, or the like can be provided.

[Brief description of the drawings]

FIG. 1 is a graph comparing the hydrogen overvoltage of a battery additive of the present invention with a conventional product.

FIG. 2 is a graph comparing the charge / discharge cycle life of the battery of the present invention with a conventional product.

[Explanation of symbols]

A: Potential-current characteristic in electrolyte solution containing no additive B: Potential-current characteristic in electrolyte solution containing only PVA C: Potential-current characteristic in electrolyte solution containing additive acrylic acid polymer of the present invention D : Potential-current characteristics in electrolyte containing additive acrylic acid-maleic acid copolymer of the present invention E: Change in capacity of conventional battery due to charge and discharge. F: Change in capacity due to charge and discharge of another conventional battery. G: Change in capacity due to charging and discharging of the battery of the present invention. H: Change in capacity due to charge and discharge of another battery of the present invention.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shoya Ozawa 39 F-term (reference) 5H028 AA01 AA06 EE04 EE06 FF02 FF09 5H050 AA02 AA07 AA08 BA09 CA06 CB15 DA03 DA09 EA01 EA23 EA28

Claims (5)

[Claims] 1. Polyacrylic acid or an ester thereof,
A lead-acid battery characterized in that it is contained in an electrolytic solution and / or a molded negative electrode active material. 2. A lead-acid battery comprising polyacrylic acid or an ester thereof and polyvinyl alcohol in an electrolytic solution and / or a molded negative electrode active material. 3. An additive for a lead storage battery, comprising polyacrylic acid or an ester thereof. 4. Polyacrylic acid or an ester thereof,
An additive for a lead storage battery, comprising: polyvinyl alcohol and / or soluble lignin. 5. At least one of the group consisting of stannous sulfate, stannic sulfate, colloidal lead sulfate and at least one of the group consisting of polyacrylic acid, polyacrylate, polyvinyl alcohol and soluble lignin. An additive for a lead-acid battery, comprising: