JPH08293308A - Lead plate for lead acid battery and manufacturing method thereof - Google Patents

Abstract

PURPOSE: To prevent the corrosion of a current collector and manufacture a long-lived electrode plate for lead-acid battery by successively forming a lead dioxide layer and a conductive polymer coating layer on the surface of the current collector, and filling an active material onto the surface. CONSTITUTION: A lead dioxide layer 2 is formed on the surface of a lead or lead alloy current collector 1 by electrolytic oxidation. The resulting current collector 1 is electrolessly dipped in a solution containing a conductive polymeric monomer (for example, pyrrole or the like) or its low polymer to form a conductive polymer coating layer 3 on the surface of the current collector. A prescribed paste obtained by kneading lead powder, water and sulfuric acid as main components is applied to the surface of the conductive polymer coating layer 3, and a prescribed active material paste is then filled thereon. Thus, a fine and uniform protecting film of the conductive polymer can be formed on the surface of the current collector 1, and the corrosion of the current collector 1 can be prevented to provide a long-lived electrode plate for lead-acid battery.

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, and more particularly to a current collector thereof.

[0002]

2. Description of the Related Art The lead plate of a lead-acid battery generally contains lead powder, which is a mixture of metallic lead and lead oxide, as a main component, and an active material paste prepared by kneading this with water and, if necessary, sulfuric acid. It is made by filling the current collector of No. 3 with this, and this unformed plate is formed into a battery.

In this battery, there is a problem of corrosion of the current collector on the positive electrode side and liquid reduction and self-discharge accompanied by generation of hydrogen on the negative electrode side, and a current collector excellent in corrosion resistance is being searched for.

In response to this problem, in recent years, a technique has been developed in which a conductive polymer film is formed on the surface of an alloy by electrolytic polymerization to compensate for the weak points of the current collector.

For example, in Japanese Patent Application No. 4-228150, it is possible to electrochemically polarize lead or a lead alloy current collector in an aqueous solution containing a monomer such as polypyrrole, polyaniline, or polyphenylene, or a solution using an organic solvent. Has been shown to form a conductive polymer film on the surface.

There is also known a technique of applying polyaniline or polypyrrole to the whole electrode plate by an electrochemical means.

Since the film formed by these electrolytic synthesis methods is hardly affected by the property of the surface of the current collector to be coated, it has an advantage that a strong conductive film suitable for current application can be formed.

[0008]

However, in the method of forming a conductive coating film by the above-mentioned electrolytic polymerization method, the gas generation accompanying the energization and the polymerization of the polymer film proceed in parallel, so that the surface of the coating film becomes porous due to bubbles. A large number of parts were generated, and a solid three-dimensional compound sometimes grew.

Therefore, it cannot be said that it is an appropriate method from the viewpoint of protecting the surface.

The present invention is intended to solve such a problem, and provides a manufacturing method capable of forming a film uniformly without forming gas when forming a conductive polymer film on the surface of a current collector. It is provided.

[0011]

The present invention comprises a step of forming lead dioxide on the surface of a current collector by electrolytic oxidation and a step of electroless dipping in a solution containing a monomer of a conductive polymer or its low polymer. Disclosed is a method for producing an electrode plate for a lead storage battery, which has a conductive polymer layer formed on it and is used as a current collector.

[0012]

In the method of the present invention, when lead dioxide comes into contact with the monomer or low polymer of the conductive polymer in the solution, the conductive polymer film is formed on the surface of lead dioxide without applying a polarization potential by external energization. This is based on the principle of forming in the vicinity.

Furthermore, since electricity is not supplied from the outside,
It is possible to form a thin and strong protective coating along the lead dioxide layer formed on the surface of the current collector without generating gas during the polymerization reaction.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a lead-acid battery according to the present invention in which lead dioxide is formed on the surface and electrolessly dipped in a solution containing a monomer of a conductive polymer to form a conductive polymer film on the surface of the lead dioxide layer. It was done.

Here, 1 is a current collector made of lead or lead alloy, 2 is a lead dioxide layer formed by electrolysis on the surface of the current collector, and 3 is a periphery of the lead dioxide layer. It is a conductive polymer layer formed on.

This surface oxidation is performed by polarization to the positive electrode side in a solution containing dilute sulfuric acid, an acid such as phosphoric acid, a neutral salt of an alkali metal or an alkaline earth metal, a hydroxide or the like as a supporting salt. You can These surfaces are not necessarily washed after the surface oxidation, but may be washed with water and dried to prepare for electroless immersion.

The electroless dipping solution is a solution having a composition basically used for electrolytic polymerization, such as an aqueous solution containing aniline, pyrrole, phenylene or the like as a monomer of a conductive polymer, or an organic solvent system such as propylene carbonate, tetrahydrofuran or alcohol. Can be applied. These can be used by mixing a plurality of materials. The material may be a low polymer of monomers.

As these solutions, a solution in which a monomer is dispersed in pure water containing no electrolyte can be used, but the presence of a supporting salt containing a sulfate ion such as sulfuric acid or sodium sulfate is more preferable in order to enhance the conductivity. .

This polymer forms a composite conductive polymer even in the presence of a plurality of types of monomers.

These can be applied to both positive and negative electrodes once the conductive film is formed. When electroless immersion is performed, the surface of the current collector is uniformly covered with polymer, so even if electrolytic polymerization is performed on it, there is no local solid growth, and additional electrolytic polymerization is added if necessary. May be. The electroless immersion time is appropriately selected depending on conditions such as temperature and concentration.

Next, in order to clarify the effect of the present invention, an electrode plate to which the present invention was applied was prepared and an evaluation test by overcharge was conducted.

Calcium 0.07% and tin 1.3%
Either a lead alloy lattice containing Si or a lead alloy lattice containing 3% antimony is used as a current collector, and electroless dipping is performed on the collector to form a conductive polymer coating layer, After that, a predetermined paste prepared by kneading lead powder, water, and sulfuric acid as main components was applied to obtain an unformed electrode plate.

A predetermined active material paste was filled in this to manufacture the electrode plate of the present invention. The electroless immersion conditions of the current collector are shown below.

[Invention 1] A lead dioxide layer was formed on the surface of the current collector by oxidizing the current collector made of a calcium alloy in dilute sulfuric acid having a specific gravity of 1.28 at 50 mA / cm ² for 1 hour. This was immersed for 2 minutes at room temperature in a 0.01 mol dilute sulfuric acid solution containing 2% pyrrole as an electroless immersion solution. Then, it was washed with water and dried to fill the paste, which was used as the electrode plate of the present invention.

[Invention 2] The same electrode plate as in Example 1 was prepared except that 1% pyrrole and 1% aniline were added to the electroless immersion solution.

[Invention 3] The same electrode plate as in Example 1 except that after electroless immersion, a lead plate was used as a counter electrode in the same immersion liquid and electrolytic polymerization was added at 50 mA / cm ² for 1 hour. .

[Invention 4] 3 seconds at 130 ° C. after electroless immersion
Same as Example 1 except that the heat treatment was performed for 0 minutes.

[Invention 5] Using an antimony alloy current collector, an electrode plate was produced under the conditions of Invention 1.

[Conventional Example 1] 0.01 containing 2% of pyrrole
The same as in Invention 1 except that the battery was charged at 50 mA / cm ² for 1 hour in a dilute molar sulfuric acid solution.

[Conventional Example 2] The same as Conventional Example 1 except that an antimony alloy current collector was used.

Using these as the positive electrode and a conventional negative electrode plate as the counter electrode, a battery equivalent to 36B20 was constructed. Overcharged under conditions of electrolyte specific gravity 1.30, voltage 2.45V / cell, 70 ° C, sampled every week, and capacity test at room temperature for 5 hours. The body was observed for corrosion.

FIG. 2 shows changes in the 5-hour rate capacity of the present inventions 1 to 4 and the conventional example 1. As the result shows, in the present invention, the electrode plate capacity was stable for a long period of time as compared with the conventional example. Further, when the corrosion state of the lattice was compared after 10 weeks, in the conventional electrode plate, the corrosion proceeded intensively in the portion considered to correspond to the pinhole, and peeling was also observed in the vicinity thereof. On the other hand, no corrosion of the current collector was observed in any of the electrode plates of the present invention.

FIG. 3 shows changes in the overcharge current value of a battery in which the conditions of present invention 5 and conventional example 2 are applied to a current collector made of a lead alloy containing antimony.

As a result, in Conventional Example 2, an increase in electrolysis of water caused by the deposition of antimony dissolved from the positive electrode on the negative electrode was observed with the passage of time. On the other hand, in the present invention 5, the overcharge current was stable at a low value and exhibited excellent liquid reduction characteristics.

This difference is considered to be due to the difference in the denseness of the electroconductive polymer coating by electrolytic polymerization with gas generation and electroless immersion of the present invention without gas generation.

[0037]

As described above, according to the present invention, after a lead dioxide layer is formed on the surface of a current collector, the current collector is electrolessly dipped in a solution containing a monomer of a conductive polymer or a low polymer. Since a dense and uniform protective film of a conductive polymer is formed on the surface of the current collector, it is possible to prevent corrosion of the current collector and provide a long-life lead-acid battery electrode plate.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a cross-sectional view of a current collector surface of the present invention.

FIG. 2 is a diagram showing a result of an overcharge evaluation test.

FIG. 3 is a diagram showing changes in electrolysis current during overcharge.

[Explanation of symbols]

 1 Current collector 2 Lead dioxide layer 3 Conductive polymer layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Kondo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A step of forming a lead dioxide layer on the surface of a current collector by electrolytic oxidation, and the current collection by electrolessly immersing the current collector in a solution containing a monomer of a conductive polymer or a low polymer thereof. A method for producing a lead storage battery electrode plate, comprising the steps of forming a conductive polymer coating layer on the body surface and filling the surface of the conductive polymer coating layer with an active material. 2. A lead or lead alloy current collector, a lead dioxide layer formed on the surface of the current collector, a conductive polymer layer formed on the lead dioxide surface, and the conductive polymer. An electrode plate for a lead storage battery, comprising an active material layer formed on the surface of the layer.