JPH0256860A - lead acid battery - Google Patents

Abstract

PURPOSE:To improve the life characteristic without reducing the liquid reduction characteristic by containing antimony in a battery system of a positive electrode active material, an electrolyte, a separator and others. CONSTITUTION:Antimony is contained in a battery system of a positive electrode active material, an electrolyte, a separator and others in a battery using an alloy not containing antimony for a lattice. Since antimony is contained in the battery system, antimony is deposited on the surface of a negative electrode active material by the repetition of a charge and a discharge, and the hydrogen generation potential of a negative electrode is reduced. When the addition of antimony is much, the hydrogen generation potential is made too noble and causes an overcharge and a thermal runaway. When the addition is few on the contrary, the effect is almost nil. About 2-100mug/cm<2> is appropriate for the quantity of antimony to be deposited. The life characteristic can be improved without sharply reducing the liquid reducing characteristic of a battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a lead-acid battery using an antimony-free alloy for the positive electrode grid and the negative electrode grid.

BACKGROUND OF THE INVENTION In recent years, lead-acid batteries have been put into practical use in which antimony-free alloys are used in the positive and negative electrode grids for the purpose of significantly improving self-discharge characteristics and liquid reduction characteristics. A typical example is a battery using a lead-lucium tin alloy.

Problems to be Solved by the Invention When a lead-acid battery using an alloy that does not contain antimony for the positive electrode grid and negative electrode grid is charged and used using a constant voltage charging method, performance decreases due to insufficient charging of the positive electrode active material. Easy to do. In other words, this type of battery has a high hydrogen overvoltage;
When charging of the negative electrode active material is completed, the potential shifts to a base hydrogen generation potential. At this time, since charging of the positive electrode active material is not completed, the potential is not maintained at which the charging of the positive electrode active material can be completely completed, and a portion of the active material remains in the state of lead sulfate.

Moreover, by repeating charging and discharging, the highly porous negative electrode active material shrinks and loses its porosity. As a result, the apparent hydrogen overvoltage becomes larger than initially, the potential of the positive electrode active material becomes a base potential, and the amount of lead sulfate increases. In this way, the remaining lead sulfate gradually becomes coarser,
This may lead to sulfation of the positive electrode active material.

On the other hand, when an alloy containing antimony is used for either the positive electrode lattice or the negative electrode lattice, the above phenomenon is extremely unlikely to occur. This is because antimony precipitates as a negative electrode active material through repeated charging and discharging, lowering the hydrogen overvoltage.

Conversely, in this type of battery, the hydrogen generation potential of the negative electrode tends to shift to a higher potential as the battery is used, which is why the overcharge current increases and thermal explosion occurs.

Therefore, in the case of the lead-antimony alloy currently used for boat fishing, the antimony content is 2 to 3%, but 0.
．． By setting the content to about 1 to 0.5%, it is possible to keep the hydrogen generation potential of the negative electrode almost constant. However, this method has problems with the castability of the lattice, the strength of the lattice, etc., and mass production is nearly impossible.

An object of the present invention is to provide a lead-acid battery using an alloy that does not contain antimony in the lattice, in which the above-mentioned problems can be solved by the presence of antimony in the battery system. be.

Means for Solving the Three Problems In order to achieve the above objects, the present invention provides a lead-acid battery that uses an antimony-free alloy for the positive electrode grid and the negative electrode grid, and provides a positive electrode active material, an electrolytic solution, a separator, and a battery system including a battery. A lead-acid battery was created with the presence of antimony.

Function In the present invention, since antimony is present in the battery system, antimony is deposited on the surface of the negative electrode active material by repeated charging and discharging.
Lowers the hydrogen generation potential of the negative electrode. If the amount of antimony added is large, the hydrogen generation potential becomes too noble, leading to overcharging and thermal explosion.

Conversely, if the amount added is small, there is almost no effect.

The amount of precipitated antimony is 2 to 100μg/
An appropriate amount is about 100 ml.

The state of antimony at the time of addition may be any of metal, salt, and solution.

Example As an example using the technology of the present invention, 48Ah15II l
'? A battery with 0.02 wt% of antimony added to the electrolyte (A) and a battery without any antimony in the battery system using conventional technology (B) were manufactured, and these two batteries were subjected to SAE life tests. Comparison was made by

FIG. 1 is a comparison diagram of life characteristics. Incidentally, the amount of liquid loss during the life test is shown in Fig. 2.

As is clear from FIG. 1, battery (A) has a lifespan approximately 40% longer than battery (B). Further, as shown in FIG. 2, the liquid reduction characteristics are slightly worse than those of (B), but they are sufficiently satisfactory as maintenance-free batteries.

In addition, since the amount of antimony precipitated is about 2 to 100 μg/c, a) When 0.005 to 0.1 wt.% of antimony is included in the positive electrode active material.

b) When adding 0.005 to O, 1 wt% of antimony to the electrolyte, and using a separator containing clo, 02 to 0.4 wt% of antimony, the same effect can be obtained by setting I was able to do that.

After fully charging the battery at the end of its life using the constant current charging method, we measured the charging potential of the negative electrode and found that the battery (Δ) had shifted to a potential that was only 0.02V less base than the initial stage. (B) had shifted to a base potential of 0.09V.

As described above, the technology of the present invention enables approximately 40% reduction compared to the conventional method.
It has become possible to extend the life of the

Effects of the Invention As described above, the present invention improves the battery life characteristics without significantly deteriorating the liquid reduction characteristics of the battery by allowing antimony to exist in the battery system when an alloy that does not contain antimony is used in the bipolar lattice. Now I can do it.

[Brief explanation of the drawing]

FIG. 1 is a comparison diagram of life characteristics, and FIG. 2 is a diagram of liquid loss during a life test.

Claims (1)

[Claims] (1) In a lead-acid battery that uses an antimony-free alloy for the positive electrode grid and negative electrode grid, the positive electrode active material, the electrolyte,
A lead-acid battery characterized by the presence of antimony in the battery system of the separator.