JPH10255756A - Lead storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent any contact between an electrolyte and metallic lead so as to suppress a dissolution reaction of a negative electrode of a lead storage battery by covering lugs of the negative electrode connected to a negative electrode strap and/or the strap with an insoluble and acid resistant resin. SOLUTION: A grid made of a lead-antimony alloy is used for a grid of a positive electrode of a battery, while an expand grid made of a lead- calcium-tin alloy is used for a grid of a negative electrode 3. Five positive electrodes are contained in a bag-like separator 5 made of a porous synthetic resin, and laminated alternately with six negative electrodes 3, thereby constituting one cell. The lugs of the positive electrode plates and negative electrodes 3 are welded to each other via metallic lead in a rack manner, thus constituting a strap part. The lugs 2 of the negative electrode and/or a negative electrode strap 1 are covered with an insoluble and acid resistant resin, i.e., a polyethylene resin, polypropylene, a fluororesin or a rosin resin, to be isolated from an electrolyte. Consequently, it is possible to prevent any dissolution reaction so as to enhance reliability of a lead storage battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead storage battery.

[0002]

2. Description of the Related Art A lead-acid battery is generally used after being charged and discharged for a long period of time. One of the modes of deterioration is deterioration of the negative electrode portion. Most of the deterioration of the negative electrode part is the sulfation in which the active material becomes inactive lead sulfate,
In many cases, the battery discharge characteristics gradually decrease, leading to the end of life.
However, the conditions under which the sulfation process is slow,
In other words, if the dilute sulfuric acid is consumed and the electrolytic solution is in an alkaline region and used for a long period of time, the metal lead portion constituting the negative electrode, that is, the negative electrode strap portion and the lattice portion will dissolve and appear thin and thin. I knew I was going to do it. When used in such a state, there is a possibility that a thinned portion may be blown out by a discharge with a large current. A site which is most affected by such a phenomenon and in which fusing or accompanying spark may occur is the negative electrode strap portion near the electrolyte surface and its periphery. In particular, the lattice lug connected to the negative electrode strap is a region where the lug is relatively thin and is susceptible to the above-mentioned dissolution reaction.

As a countermeasure against such a phenomenon, Japanese Patent Laid-Open No.
As disclosed in JP-A-49352, a method of arranging a sulfuric acid-absorbing substance on a lead portion exposed in a gas phase in a battery case, that is, a shelf portion has been adopted, but contact between the electrolyte and the shelf is inevitable. As a result, the influence of the dissolution reaction was unavoidable.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to suppress the dissolution reaction of such a negative electrode portion and to ensure the reliability and safety of a lead storage battery. .

[0005]

In order to solve the above-mentioned problems, in the present invention, the lattice lug connected to the negative electrode strap portion, and in some cases, the negative electrode strap portion are covered with a water-insoluble and acid-resistant resin. By doing so, since the electrolytic solution and the metallic lead do not come into contact for a long period of time, the dissolution reaction can be suppressed.

[0006]

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

FIG. 1 is a partially cutaway perspective view of an automotive lead storage battery 55D23 manufactured by a conventional method. A cast lattice made of a lead-antimony alloy is used for the grid body of the positive electrode plate of this battery, and an expanded grid made of a lead-calcium-tin alloy is used for the negative electrode plate 3. The five positive plates are housed in a bag-shaped separator 5 made of a microporous synthetic resin, and are alternately stacked with the six negative plates 3 to constitute a group of electrodes for one cell.

The ears of the positive electrode plate and the negative electrode plate are welded in a ledge shape with metallic lead to form a strap portion.

In the present invention, the ear 2 of the negative electrode plate 3 as shown in FIG. 1A or the ear 2 and the negative electrode strap 1 as shown in FIG. And coated with an acid-resistant resin. The coated resin portion 8 is shown by hatching in FIG.

With the configuration of the negative electrode portion of the lead-acid battery according to the present invention, the ear connected to the negative electrode strap portion or the negative electrode ear portion even under the conditions in which the dissolution reaction occurs as described above. And the negative electrode strap part is covered with acid resistant resin for a long time, so that part is insulated from the electrolyte,
The dissolution reaction is suppressed.

[0011]

【Example】

[0012]

[Table 1]

Hereinafter, as shown in Table 1, 55D23 type batteries B to H whose predetermined portions were coated with various resins were produced as prototypes. For comparison, a conventional battery A without resin coating was used.

After forming the negative electrode straps in the batteries B and C, hot melt mainly composed of polyethylene resin was applied to the portions shown in Table 1 to cover the portions.

Similarly, for the batteries D and E, after forming the negative electrode straps, hot melt mainly composed of a polypropylene resin was applied to the portions shown in Table 1 to cover the portions.

For the batteries E and F, after forming the negative electrode strap, a fluororesin dispersion was applied to each of the portions shown in Table 1 to cover them.

For the battery H, a resin mainly composed of denatured rosin, which is usually used for soldering flux, was dissolved in isopropyl alcohol and applied to the negative electrode grid body ears before forming the strap. When forming the strap, the resin applied to the portion to be welded to the strap was not volatilized in the same manner as normal soldering, and the rosin resin coating was formed only on the ears connected to the strap.

The following test was carried out using the battery thus manufactured, and the performance change of the battery due to the thinning phenomenon due to the dissolution of the negative electrode metal part, particularly the strap part, was examined. The test conditions were performed according to the following procedure.

The battery is charged to 50%. Next, at an environmental temperature of 0 ° C., after discharging for 1 hour at a current of 10 A, charging for 5 hours at a constant voltage of 13.5 V and a maximum current of 25 A is defined as one cycle.
Repeat 5 times.

Thereafter, a 200 A discharge is performed, the voltage is measured for the fifth second at that time, and if the voltage at this time is 6 V or more, the same operation is repeated.

The results are shown in the graph of FIG. Conventional product A
Had a shorter number of cycles than the other batteries. When investigating the cause, the ear part connected to the negative electrode strap was cut at the base and it was impossible to discharge, and the metal part such as the strap part, the ear part or the negative electrode lattice body was markedly Skinnyness was observed.

In the other prototype batteries (B to H), the number of cycles was thinner for the metal portion of the uncoated portion, but before the metal portion was degraded due to the sulfation of the negative electrode or the like, the metal portion became thinner. No such situation as partial disconnection occurred.

[0023]

As described above, the present invention can suppress the deterioration due to the dissolution of the negative electrode strap metal portion which may occur when the battery is used with a tendency to discharge and is used without being sufficiently charged. It enhances reliability and has great industrial value.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a configuration near a strap portion of a lead storage battery according to the present invention.

FIG. 2 is a diagram showing charge and discharge cycle characteristics of a conventional product and a lead storage battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative-electrode strap part 2 Negative-electrode ear part 3 Negative electrode plate 4 Positive-electrode strap part 5 Separator 6 Battery case 7 Cover 8 Resin coating part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masashi Izawa 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A lead-acid battery in which a lattice lug connected to a negative electrode strap is coated with a water-insoluble and acid-resistant resin. 2. A lead-acid battery, wherein the negative electrode strap portion and a lattice lug connected to the negative electrode strap portion are coated with a water-insoluble and acid-resistant resin. 3. The lead-acid battery according to claim 1, wherein the water-insoluble and acid-resistant resin is any one of a polyethylene resin, a polypropylene resin, a fluorine resin and a rosin resin.