JP2001307761A - Sealed lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed lead acid battery having improved trickling life characteristic for inhibiting the decreasing amount of water to be held by a sealed lead acid battery negative plate in an electrolyte. SOLUTION: In the sealed lead acid battery, the content of lignin sodium sulfonate as a lignin compound is 0.15-0.70 wt.% in terms of a negative active material and the content of barium sulfate is 2.1-5.0 wt.% in terms of the negative active material. A modified polyphenylene ether resin is used as a resin material for an electric bath.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead-acid battery used as an emergency backup power source for communication equipment, UPS and the like.

[0002]

2. Description of the Related Art Conventionally, lignin compounds such as ligninsulfonate, barium sulfate and the like have been widely used as additives used for a negative electrode plate of a sealed lead-acid battery in order to prevent shrinkage of the active material and increase the specific surface area of the active material. Had been.

As a resin material used for the battery case, an acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as an ABS resin) is widely used for a sealed lead-acid battery for reasons such as productivity and price.

In recent years, however, there has been a demand from the market for a sealed lead-acid battery used for an emergency backup power supply or the like to be used for a long time, that is, to prolong the trickle life. With the use of the battery for a long period of time, in the conventional sealed lead-acid battery, the moisture in the electrolytic solution permeates the battery case resin material and escapes outside the battery, and the capacity of the battery decreases. As a result, the battery life could not be maintained for the period required by the market.
In addition, the decrease in the amount of water due to the dissipation of water does not proceed evenly to the battery components impregnated with the electrolyte such as the positive electrode plate, the negative electrode plate, and the separator. It has been found that the amount of the electrolyte that the plate impregnates and keeps is reduced, and the life is frequently increased.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a reduction in the amount of water in an electrolytic solution due to the dispersion of water from a battery case material generated when a sealed lead-acid battery of the conventional configuration as described above is used, and a negative electrode active material. An object of the present invention is to provide a sealed lead-acid battery that can suppress a decrease in the amount of electrolyte therein and can be used in a trickle for a long period of time.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an electrode group having a positive electrode, a negative electrode and a mat separator in a battery case made of resin, and impregnating the electrode group with an electrolytic solution. In a sealed lead-acid battery having a held configuration, 2.1 mass% to 5.0 mass% of barium sulfate is added to the negative electrode active material, and a polyphenylene ether resin is used as a resin material of the resin container. It was done. In addition to the above structure, preferably, sodium ligninsulfonate is added to the negative electrode active material in an amount of 0.15% by mass to 0.7% by mass.

According to the present invention, the period until the amount of the electrolytic solution held by the negative electrode active material is reduced can be lengthened by the above configuration, and the life of the battery case can be extended when a trickle is used. .

[0008]

Embodiments of the present invention will be described below.

First, a lattice body is manufactured using a lead-calcium-tin alloy. The configuration of the lattice is not particularly limited, but a conventional cast lattice or an expanded lattice can be used.

[0010] The above-mentioned lattice is filled with an active material paste. The active material paste is generally prepared by adding sulfuric acid-resistant synthetic resin fibers and various additives to a mixed powder of lead and lead oxide mainly composed of lead monoxide (hereinafter referred to as lead powder), and then adding water. And diluted sulfuric acid. As the paste for the positive electrode active material, a paste obtained by adding lead oxide to lead oxide can be used in consideration of the formation efficiency and the initial capacity characteristics of the storage battery. After filling the positive electrode active material, aging and drying are performed to form an unformed positive electrode plate.

As for the negative electrode plate, similarly to the positive electrode plate, an active material paste in which lead powder is kneaded with water and dilute sulfuric acid is used. The amount of barium sulfate added to the lead powder is based on the weight of the negative electrode active material after formation. 2.1 mass% to 5.0 mass%. With the amount of barium sulfate as described above, it is possible to suppress a decrease in the amount of electrolyte impregnated in the negative electrode active material. Further, by adding 0.15% by mass to 0.7% by mass of sodium ligninsulfonate to the negative electrode active material, the effect of suppressing a decrease in the amount of electrolyte impregnated in the negative electrode active material can be made more remarkable. it can.

The mechanism is that barium sulfate becomes a nucleus of lead sulfate during the discharge reaction to promote a uniform discharge reaction, and the lignin compound suppresses the crystal growth of the nucleus to form a giant lead sulfate crystal. It is presumed that while suppressing the generation of water and maintaining the affinity between lead sulfate and water, a decrease in the amount of water retained in the negative electrode active material is suppressed. After that, the grid body filled with the negative electrode active material is 40 to 8
Aged and dried at a temperature of about 5 ° C. to produce an unformed negative electrode plate.

The unformed positive and negative electrode plates are combined with a mat separator to form an electrode plate group. As the mat separator, a normal nonwoven fabric made of glass fiber can be used. Here, when there are a plurality of polar plates having the same polarity, the lugs of the same polarity are assembled and welded to form a terminal extraction portion, and then inserted into a resin container.

The electrode plate group of the sealed lead-acid battery is a negative electrode plate located at the end of the electrode plate group in consideration of the oxygen gas absorption reaction at the negative electrode plate, and such an electrode group is housed in a battery case. if you did this,
The configuration is such that the negative electrode plate directly contacts the battery case material. In such a case, in particular, water is transferred from the negative electrode plate to the battery case, and the probability that the electrolytic solution content of the negative electrode plate is reduced becomes very high.

In the present invention, a polyphenylene ether resin (hereinafter, referred to as a PPE resin) is used as a resin material for the battery case.

It is preferable to use a modified polyphenylene ether resin (hereinafter referred to as a modified PPE resin) obtained by blending with a polystyrene resin or graft-polymerizing with styrene in consideration of moldability and the like.

Since the PPE resin has a low water permeability, it can suppress the permeation of water in the battery case. Further, since the water absorption is low, the PPE resin is impregnated in the negative plate even in a configuration where the negative plate and the battery case are in contact with each other. It is possible to prevent the water in the electrolyte solution from being transferred to the battery case and being lost.

Thereafter, a lid is joined to the battery case, and the terminal portion is sealed. Then, a chemical solution obtained by adding an additive such as sodium sulfate to dilute sulfuric acid is poured into the battery. To form the sealed lead-acid battery of the present invention.

[0019]

EXAMPLE The trickle life characteristics of the sealed lead-acid batteries according to the examples of the present invention and the comparative example were evaluated, and the effect of the present invention was clarified. The contents are described below.

With the structure shown in Table 1, sealed lead-acid batteries of the present invention and comparative examples were produced. All nominal voltage 12V, 2
The zero hour rate rated capacity is 7 Ah.

[0021]

[Table 1]

In the negative electrode active materials shown in Table 1, the contents of sodium ligninsulfonate and barium sulfate, and the following evaluations were made for batteries A to Q using an ABS resin or a modified PPE resin as a battery case resin material. The method was used to evaluate the torcle life characteristics. The end plate of the electrode group of the test battery was a negative electrode plate, and was configured to directly contact the inner wall of the battery case.

The test conditions are as follows.

<Trickle Life Test> (1) Battery A to Battery M at 25 ° C.
, The battery is discharged to a final voltage of 9.6 V by 21A discharge, and the initial capacity is calculated.

(2) 1 at 60 ° C. ± 2 ° C.
Perform 3.8V constant voltage charging for 3 weeks.

(3) The capacity is confirmed under the condition of (1).

(4) The charge / discharge cycle of (2) and (3) is performed, and the cycle is repeated until the discharge capacity becomes equal to or less than 1/2 of the initial capacity. The charging period at this time is defined as a trickle life.

FIG. 1 shows the test results.

Analysis of the battery that had reached the end of its life revealed that the electrolyte in the negative electrode active material was depleted, leading to a reduction in capacity. As is clear from the results of FIG. 1, the batteries K, L, N, O, Q, and R according to the configuration of the present invention can all have a longer electrolyte retention period in the negative electrode active material when using a trickle. It was confirmed that the battery exhibited good trickle life characteristics as compared with Comparative Examples Batteries A to M and P.

The effect of the present invention can be obtained by adding a layered compound such as talc or mica as a modified PPE resin or a filler such as glass fiber.

[0031]

From the above results, according to the structure of the present invention, the trickle life characteristic can be improved in the sealed lead-acid battery, and the industrial effect is extremely effective.

[Brief description of the drawings]

FIG. 1 is a diagram showing a trickle life characteristic of a sealed lead storage battery according to an example of the present invention and a comparative example.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takehiro Sasaki 1006 Kazuma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. HA01

Claims (2)

[Claims] 1. A sealed lead-acid battery in which an electrode group having a positive electrode, a negative electrode, and a mat separator is housed in a resin container, and the electrode group is impregnated and held in an electrolytic solution. A sealed lead-acid battery, wherein barium sulfate is added in an amount of from 5.0% by mass to 5.0% by mass, and a polyphenylene ether resin or a modified polyphenylene ether resin is used as a resin material of the resin battery case. 2. An amount of 0.15% by mass to 0.7% in the negative electrode active material.
The sealed lead-acid battery according to claim 1, wherein sodium ligninsulfonate by mass% is added.