JPS61256566A - Enclosed clad lead storage battery - Google Patents

Abstract

PURPOSE:To improve the discharge capacity thus to improve the service life by employing a tube of thin composition thereby providing an electrical resistance suitable for the case where fluid electrolyte is limited. CONSTITUTION:A tube 2 of thin composition is employed to prevent separation of electrolyte at the tube section thus to improve the discharge performance of an enclosed clad lead storage battery employing a lead alloy core metal 1 which will never lower the hydrogen overvoltage considerably. In other word, a tube having the electrical resistance in dilute sulfric acid having the specific gravity of 12.00 under the temperature of 25 deg.C is employed. Consequently, the discharge capacity is improved resulting in improvement of service life under remarkable charge/discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to an improvement in a clad sealed lead acid battery with limited fluid electrolyte.

Prior art and its problems Sealed lead-acid batteries with limited electrolyte are usually limited to paste type batteries. This is because in clad batteries, the electrolyte is separated in the tube, impairing the discharge performance of the positive electrode plate. However, in paste-type dense lead-acid batteries, because the grid is made of an alloy such as a lead-calcium alloy that does not significantly reduce hydrogen overvoltage, the grid may corrode or elongate during deep charging and discharging.
Furthermore, there was a problem in that the active material softened and fell off, resulting in poor life performance.

Means for Solving the Problems The present invention provides a clad sealed lead-acid battery using a lead alloy core that does not significantly reduce hydrogen overvoltage by making the structure of the tube sparse to prevent separation of the electrolyte in the tube portion. It has improved discharge performance, and has a specific gravity of 1,
Electrical resistance in 200 dilute sulfuric acid is 0,002Ω・d
A tube of m2 or less is used.

Function: In conventional liquid batteries, the structure of the tube needs to be made dense to prevent the positive electrode active material from softening and falling off. The electrical resistance of this material is usually 0.0030.1 m2 or more. Even in a tube with such a dense structure, in a normal battery that uses an excess liquid electrolyte, the electrolyte is not separated in the tube, and sufficient discharge performance can be obtained without any problem. However, when the fluid electrolyte is restricted, the electrolyte is separated in the tube, impairing discharge performance.

In the present invention, since the structure of the tube is made sparse, separation of the electrolyte in the tube portion is prevented, and discharge performance is not impaired. In addition, when the fluid electrolyte is restricted, the dissolution and precipitation of lead ions during charging and discharging is restricted, and the active material does not soften or fall off, and even if the structure of the tube is made sparse, it does not have a negative effect on the lifespan. There is no possibility that it will cause any adverse effects.

Embodiment An embodiment of the lead-acid battery according to the present invention is shown in FIG. In the figure, 1 is a lead alloy core metal, which is made of an alloy such as lead-calcium-tin that does not significantly reduce the hydrogen overvoltage.

Reference numeral 2 denotes a tube, which is made into a nonwoven fabric by braiding or binding fibers made of acid-resistant and oxidation-resistant materials such as alkali-containing glass, polyester, polyacrylonitrile, and hydrophilic polyethylene. This tube has an electrical resistance of 0.0 in dilute sulfuric acid with a specific gravity of 1.200 at 25°C.
02Ω・dm2 or less. 3 is a positive electrode active material, 4 is an upper lead alloy joint, and 5 is a lower joint, which is made of plastic. 6
is a negative electrode plate, which, like the positive electrode plate, is preferably made of a lead alloy that does not significantly reduce hydrogen overvoltage. 7 is a porous separator;
Mats and porous bodies made of fibers made of acid-resistant and hydrophilic materials, such as alkali-containing glass, polyester, polyacrylonitrile, and hydrophilic polyethylene, are preferred and have excellent liquid retention properties. 8 is a battery case, 9 is an exhaust section having a valve function, 10 is a positive/loss terminal, and 11 is a negative terminal.

The electrolyte is impregnated and held in the positive and negative electrode active materials, tubes, and separators, and the fluidity of the electrolyte is limited.

Since the clad lead-acid battery according to the present invention has the above-described configuration, oxygen gas generated from the positive electrode plate easily reaches the negative electrode plate and reacts therewith. In other words, sealing can be achieved through an oxygen cycle.

Further, the positive electrode active material mainly comes into contact only with the electrolytic solution impregnated in the tube, and a charging/discharging reaction proceeds.

In a typical liquid battery, the large opening formed by the weave of the tube is also filled with electrolyte and participates in the charging and discharging reactions. The charge/discharge reaction is the dissolution of lead ions.

The process progresses by precipitation, so when cycles of deep discharge are repeated, the active material particles change their shape and the bonds between the particles are broken, softening them. However, in the battery according to the present invention, the positive electrode active material comes into contact with the electrolyte only at the portion where it contacts the porous tube, so dissolution and precipitation of lead ions are suppressed, and there are few changes in shape or breakage of bonds between particles.

Next, we fabricated prototype batteries with various tube contents for clad-type sealed lead-acid batteries with limited fluidity electrolyte, and examined their discharge performance. The 5HR discharge capacity was determined for the initial period, after overcharging at 101-IR lightning current of 100H, and after 500 cycles of charging and discharging at a depth of discharge of 60%, and is shown in Table 1. The capacity is expressed as a ratio of 100 to that of a battery using a normal tube.

Initially, there is not much difference in discharge capacity even if the electrical resistance of the tube is significantly different, but after overcharging, especially after a charge/discharge cycle, there is a significant difference in capacity, and the electrical resistance becomes 0,003Ω.
・Performance deteriorates significantly at dm2 or higher. This is because the decomposition and loss of the electrolyte that occurs during overcharging and charge/discharge cycles mainly results in a decrease in the amount of electrolyte that is impregnated into the tube. This is because the ion conductivity was hindered by the separation in some parts.

Table 1 Effects of the Invention The present invention improves the discharge capacity of clad-type sealed lead-acid batteries by making the structure of the tube sparse and making the electrical resistance suitable for the case where the fluid electrolyte is limited. This enables a sealed battery with excellent discharge life performance.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing a clad type dense rJI lead-acid battery according to the present invention. DESCRIPTION OF SYMBOLS 1... Core metal, 2... Tube, 3... Positive electrode active material, 6... Negative electrode plate, 7... Separator, 9... Exhaust part-X 1 Figure

Claims (1)

[Claims] 1. A tube whose electrical resistance in dilute sulfuric acid with a specific gravity of 1.200 at 25°C is 0.002Ω・dm^2 or less,
A clad-type sealed lead-acid battery that uses a lead alloy core that does not significantly reduce hydrogen overvoltage, an exhaust section that has a valve function, and a porous separator that has good liquid retention, and that limits the amount of fluid electrolyte.