JP3211087B2 - Lead storage battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates to a grid alloy and a separator for a lead storage battery.

[0002]

2. Description of the Related Art A lead alloy containing antimony has good castability in production and increases the strength of a lattice, and is excellent in charge recovery properties after overdischarged and left for a long time in terms of characteristics. On the other hand, there has been a problem that self-discharge increases and electrolyte solution decreases during use of the battery. This is because antimony used for the positive electrode elutes into the electrolytic solution and precipitates on the surface of the negative electrode, thereby forming a local battery of lead and antimony at that portion to promote self-discharge. On the other hand, the lead-calcium-based alloy lattice body has a tendency to increase the number of maintenance-free batteries using the lattice body since the decrease of the electrolyte during use of the battery is reduced and the water replenishment work becomes unnecessary.

[0003]

[Problems to be solved by the invention]

However, when a lead-calcium alloy lattice is used for the positive electrode, abnormal overdischarge occurs, or when left unattended for a long period of time, a high-resistance passive film is formed at the interface between the positive electrode lattice and the active material. Therefore, the charge receiving performance is deteriorated, and it may not be possible to charge the battery in practical use depending on use conditions.

Accordingly, the positive electrode plate is made of a so-called low antimony lead alloy having an antimony content of 4% by weight or less, which is lower than the conventional one. Has been planned.

On the other hand, the negative electrode has no problem due to charge recovery after overdischarge,
By expanding the lead-calcium alloy or using a lattice formed into a punched plate, the use of antimony is reduced from the negative electrode, self-discharge is reduced, and the hydrogen overvoltage is increased to increase the electrolysis of the electrolyte during charging. Hybrid type batteries, which are unlikely to occur, have come to be used according to their respective applications. This type of battery used a papermaking type in which a glass mat was attached as a separator, and after forming each electrode plate, it was combined and formed into an electrode plate group.However, in order to reduce the fiber diameter used for papermaking, There is a limit, adjust the pore size as a separator,
In order to complicate the shape of the holes, silicon dioxide was mixed, but this was insufficient to suppress the migration of antimony from the positive electrode to the negative electrode.

[0006]

[Means for Solving the Problems]

The present invention provides a positive electrode plate using a lead-antimony-based alloy lattice having an antimony content of not more than% by weight, a negative plate using a lead-calcium-based alloy lattice, and a thermoplastic synthetic resin. An object of the present invention is to provide a lead-acid battery in which self-discharge is reduced by forming an electrode group with separators having a hole diameter of 3 μm or less and having a hole diameter concentrated around 1 μm.

[0007]

[Action]

A positive electrode plate of a lead-antimony-based alloy lattice having an antimony content of 4% by weight or less, a negative electrode plate using a lead-calcium-based alloy lattice, and a thermoplastic synthetic resin, and a maximum pore diameter of 3 μm or less by solvent extraction. In addition, by using a separator whose pore size is concentrated and distributed in the vicinity of 1 μm, elution of antimony is reduced, antimony eluted in the electrolytic solution is captured by the separator, and migration to the negative electrode is suppressed, and self-discharge is prevented. Is reduced.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be described.

For the positive electrode plate, a lattice body prepared by using a lead-antimony alloy composed of 4% by weight of antimony, 0.2% by weight of arsenic, and the balance being lead is prepared. On the other hand, 0.02% of the active material weight
The polyester fiber was cut into a length of about 2 mm so that the amount of the polyester fiber became about 2 mm, and added during the kneading of dilute sulfuric acid and the active material to prepare a paste. After filling this paste into the grid,
After aging and drying, an unformed positive electrode plate having a height of 120 mm, a width of 108 mm and a thickness of 1.8 mm was prepared.

The negative electrode plate is composed of a lead-calcium alloy containing 0.08 calcium.
A slab having a weight percentage of 0.6% by weight, tin and the balance being lead is cold-rolled with a roll to produce a 0.8 mm-thick thin plate, which is expanded into a mesh to form a lattice. Next, barium sulfate having a particle size of 3 μm or less is added to the lead oxide together with the lignin-based organic matter so that the amount of barium present in the active material becomes 1% by weight, and the paste obtained by kneading with dilute sulfuric acid is obtained. Filling the grid, laminating a sheet mainly composed of pulp on one or both sides, aging and drying, height 12
An unformed negative electrode plate having a thickness of 0 mm, a width of 108 mm and a thickness of 1.5 mm was prepared.

The separator is made of a material mainly composed of polyethylene as a thermoplastic resin, and a sheet in which pores are formed by extracting a mixture in the solvent with a solvent, a sheet mainly composed of pulp, the surface of which is protected with a phenol resin, and silicon dioxide. Mixed together to form a papermaking type reinforcing fiber sheet with a height of 12
The sheet was cut into 4 mm, 115 mm in width and 0.6 mm in thickness, and a glass mat of the same size and 1.2 mm in thickness was attached thereto and used.
FIG. 1 shows the results of comparing the pore size distributions of the polyethylene sheet and the reinforcing fiber sheet. While the conventional papermaking type reinforcing fiber sheet has a maximum pore diameter of 20 μm and the pore diameter is distributed over a wide range up to 1 μm or less, the sheet mainly composed of polyethylene almost concentrates at about 1 μm with a maximum pore diameter of about 3 μm. , Indicates that the pore diameter is uniformly small throughout.

[0012] These electrode plates and each separator are combined to form an electrode plate group, and an electrolyte solution in which 5 g of sodium sulfate is dissolved is injected, and then the battery is formed to form a positive electrode active material amount per cell. Was adjusted so as to obtain a battery of 500 g and a negative electrode active material of 400 g. The specific gravity of the electrolyte was 1.26, and each of 12 lead-acid batteries of 55D23 type stipulated in the JIS standard was created.
A self-discharge comparative test was performed. The results are shown in the following table.

[0013]

[Table 1]

At a constant current of 8 A, these batteries are first kept at 20 ° C.
The capacity was measured when discharged to 1.7 V / cell, and the capacity was measured by leaving the battery in an atmosphere at 40 ° C. for 3 months and discharging at a constant current of 8 A to 1.7 V / cell. From this result, the sheet mainly composed of polyethylene retained 63.5% capacity compared to the initial stage, but the conventional papermaking type reinforcing fiber sheet
It turned out that the self-discharge amount was large at 49.8%.

This is because the maximum pore diameter in the separator is about 3 μm and 1 μm.
The fact that the shape of the hole penetrating through the separator is concentrated at the same time as being concentrated in a small portion in the vicinity, because the migration of antimony ions from the positive grid to the negative plate is suppressed. . However, if the hole diameter is too small, the absolute volume of the hole diameter decreases and the electrical resistance increases, resulting in a decrease in voltage characteristics when discharged with a large current, as in the case of a battery for an automobile. Be disadvantaged.

Here, polyethylene is selected as the material of the synthetic resin that forms the main component of the separator. However, the same applies to the case where polypropylene, a copolymer thereof, a vinyl halide, or a vinylidene polymer, which has a small pore size by solvent extraction, is used. The result can be obtained.

Further, in the embodiment, the flat separator is used. However, by storing the positive electrode plate in a bag shape, the migration of antimony from the side can be prevented, and a good result can be obtained.

[0018]

【The invention's effect】

As described above, the present invention comprises a positive electrode plate of a lead-antimony alloy lattice having an antimony content of 4% by weight or less, a negative electrode plate using a lead-calcium alloy lattice, and a separator made of a thermoplastic synthetic resin. By using the electrode group, a lead-acid battery having excellent self-discharge characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing a pore size distribution of a separator in the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 10/06 H01M 2/16 H01M 4/68

Claims (1)

(57) [Claims] 1. A positive electrode plate using a lead-antimony alloy lattice having an antimony content of 4% by weight or less, a negative electrode plate using a lead-calcium alloy lattice, and a solvent comprising at least a thermoplastic synthetic resin. The maximum pore size is 3
A lead-acid battery using an electrode group formed of separators having a pore size distribution of not more than 1 μm and concentrated around 1 μm.