JPH02299154A - Lead-acid battery - Google Patents

Abstract

PURPOSE:To improve the charging effect in the high-temperature atmosphere and extend the life of the charge/discharge cycle while maintaining the maintenance-free property by providing an alloy layer with the specific composition on the surface of a lattice body made of a Pb-Ca alloy with the specific composition. CONSTITUTION:A metal layer containing at least two or more kinds of elements among a group of Bi, As, Cu, Ag and Fe at the total quantity 0.2wt.% or below in a Pb-Sb-Sn alloy containing Sb 0.8-50wt.% and Sn 1.0-10wt.% is provided on the surface of a lattice body made of a Pb-Ca alloy containing Ca 0.02-0.15wt.%, Sn 0-5.0wt.% and the remainder of Pb. The Sb and Bi in the alloy layer formed on the surface of the lattice body are adsorbed by a positive electrode active material while in use, the coarsening of the active material is suppressed, and a battery is considered to be charged at high efficiency.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to lead-acid batteries, and in particular, aims to improve the charging efficiency of maintenance-free lead-acid batteries for automobiles in high-temperature atmospheres and to improve the charge-discharge cycle life. It is something.

BACKGROUND OF THE INVENTION With the spread of automobiles, particularly passenger cars, there has been a demand for lead-acid batteries for automobiles to be maintenance-free. For this reason, Pb--Ca alloys have been put into practical use as grid alloys for maintenance-free batteries with less self-discharge and less liquid leakage.

Furthermore, with the recent development of car electronics, the number of electrical components installed has increased, and the load on batteries has increased.

Furthermore, as the interior of the engine compartment becomes denser and the number of automobiles increases, traffic congestion increases, and power batteries are often used under high temperature conditions. increases, the environmental temperature becomes higher,
It has come to be used under extremely harsh conditions.

Therefore, in order to increase durability while maintaining maintenance-free properties by using a Pb-Ca-based alloy in the lattice, Pb
-Means have been developed such as using a rolled sheet made of Ca-Sn ternary alloy as a lattice body to improve corrosion resistance, increasing the lattice cross-sectional area, increasing the amount of active material, and adopting a structure in which the lattice is wrapped in active material. It has been.

On the other hand, in order to suppress damage to batteries in high-temperature atmospheres,
Sometimes batteries are placed horizontally to prevent overcharging by lowering the voltage setting of the regulator.

In addition, when the ambient temperature rises, a sensor detects this and automatically lowers the voltage of the regulator. Additionally, some vehicles that get hot have a shield to prevent the batteries from getting too hot.

Problems that the invention aimed to solve In this way, maintenance-free performance, which is a strong demand in the market, was achieved through the development of Pb-Ca alloys, and the electrode plates were improved in order to increase their durability against harsh usage conditions. It's here. Improvements have also been made in vehicle design.

As described above, as market conditions become more severe, the state of battery deterioration is also changing. Therefore, it is necessary to make improvements that suit the usage conditions and respond to market demands.

The present invention aims to increase charging efficiency in a high-temperature atmosphere while maintaining maintenance-free properties, thereby extending the life of the charge/discharge cycle.

That is, with the development of car electronics, the load on electrical equipment has increased, engine compartments have become denser, road conditions have become more congested, and the tendency for engine compartments to become hot has rapidly increased. Therefore, batteries have also been required to have durability against high temperatures. Therefore, the purpose is to improve corrosion resistance, further enhance charge acceptance, and improve high temperature durability to improve life performance.

Means for Solving the Problems The present invention provides calcium (Ca) in the amount of 0.02 to 0.15w.
t%, tin (Sn) in O to 5.0wt%, and the balance is lead (Pb) on the surface of the Pb-Ca-based alloy lattice body.
Antimony (Sb) is 0.8 to 50 wt%, Sn is 1.
Bismuth (Bi) is further added to the Pb-Sb-Sn alloy containing 0 to 10 wt%.

Arsenic (As), copper (Cu), silver (Ag), iron (Fe)
By using a lattice body with an alloy layer containing at least two of the elements of the group consisting of 0.2 wt% or less in total, it is possible to maintain the maintenance-free performance of the Pb-Ca alloy. Improves charge acceptance,
Furthermore, it improves corrosion resistance and high-temperature durability.

and (, 0.05 to 0.12 wt% of Ca and 0.0% of Sn.
Using a Pb-Ca-Sn alloy of 1 to 1 wt% and the balance being Pb as a base material, Pb-5b-Sn is applied to one or both sides of the base material.
and Bi, As, Cu.

It uses an expanded lattice processed from a lead alloy sheet with an alloy layer containing at least two of A g * Fe in a total addition amount of 0.2 wt% or less, and Pb-Sb-Sn and Bi , As.

The thickness of the alloy layer containing at least two of Cu, Ag, and Fe is such that the ratio of the Pb-Ca-Sn alloy to the base material thickness is 1.0% or less.

By using the above lattice, Pb-Ca-
Maintaining the excellent maintenance-free performance of Sn alloys,
The aim is to improve charge acceptance when used in a high-temperature atmosphere, and to improve durability to achieve a longer life.

Methods for forming a thin layer made of a different alloy on the surface layer of the lattice include a method of stacking a base alloy plate and a different alloy foil and cold or hot rolling, or a method of forming a thin layer of a different alloy on the base alloy lattice. There are methods such as electrodeposition.

The lattice of the present invention may be used for both the positive electrode and the negative electrode, but if it is used only for the positive electrode, there will be almost no deterioration in maintenance performance, so if maintenance performance is important, a lattice with a dissimilar alloy layer may be used. It is preferable to use a Pb-Ca-Sn alloy lattice body for the positive electrode and a Pb-Ca-Sn alloy lattice body for the negative electrode.

Function: As described above, the present invention uses Pb-Sb-Sn, Bi, As, and Cu in the surface layer of the Pb-Ca based alloy lattice.

By using a lattice body having an alloy layer containing at least two of Ag and Fe, it is possible to maintain the maintenance performance of the Pb-Ca alloy lattice body, improve charge acceptance, and improve high-temperature durability. It increases power.

Pb-Sb-Sn-(Bi, A
s, Cu, Ag, Fe) Sb in the alloy layer.

Bi and the like are adsorbed to the positive electrode active material during use, suppressing coarsening of the active material and forming a fine crystal structure. It is thought that by maintaining these fine crystals, charging can be performed with high efficiency.

In addition, when charging and discharging cycles are repeated, the negative electrode active material shrinks and its surface area becomes smaller.As a result, it tends to impede the charging efficiency of the subelectrode when charging at a constant voltage. Even in response to such a phenomenon, it is thought that the precipitation of a very small amount of Sb, Bi, etc. on the negative electrode active material has the effect of suppressing the influence on the charging efficiency of the positive electrode.

Furthermore, Sb, Bi, etc. adsorbed on the positive electrode active material increase the bonding strength between the active materials, increase the adhesion between the lattice and the active material, and suppress the softening of the active material due to repeated deep discharges. When used in a high-temperature atmosphere, corrosion of the lattice progresses, the electrode plates grow, and the lattice and active material separate. By increasing the force, the adhesion with the lattice body becomes stronger,
It is thought that the high temperature durability is improved.

As described above, in the present invention, sb, Bi, etc. arranged on the surface of the lattice body are dispersed in the positive electrode active material or the negative electrode active material, and it seems that charging efficiency is improved. By including Sn in the alloy on the surface of the grid, even more efficient charge acceptance was observed. By making Sn exist in the alloy, S
It is thought that it acts to promote the release of Bi, Bi, etc., and is quickly adsorbed into the active material, improving the physical properties of the active material.

On the other hand, the alloy layer on the surface of the lattice is very thin, being 1.0% or less of the thickness of the Pb--Ca alloy base material. The electrochemical properties of the lattice pair are those of a Pb-Ca alloy,
It has a high hydrogen overvoltage. Therefore, the battery of the present invention has less self-discharge (and less loss of electrolyte).
It maintains the excellent maintenance-free performance of the alloys.

Note that when the amount of SE) in the surface layer of the lattice body was less than 0.8 wt%, no significant effect of increasing the charging efficiency of the present invention was observed. On the other hand, if it exceeds 50 wt%, the amount of sb deposited on the negative electrode will increase rapidly, which will increase the rate of electrolyte reduction and reduce maintenance performance, making it unsuitable for fields that require maintenance-free operation. Not yet.

Furthermore, at least Bi, As, Cu, and Ag.

By containing two or more types of Fe in trace amounts of less than 0.2 wt% in total, the charging potential of the negative electrode is kept constant, especially during repeated charging and discharging, and excellent charging efficiency is maintained until the end of the life. It is considered that 0.2wt
If it exceeds %, the maintenance performance decreases, making it unsuitable for applications where maintenance is desired. Preferably 0, 1
wt% or less.

The base metal alloy exhibits excellent maintenance performance by containing 0.02 to 0.15 wt% of Ca. 0.15w
t%, it is not preferable because corrosion resistance decreases.

Further, by adding 5.0 wt% or less of Sn, corrosion resistance is further improved. Especially, 0.05~0.12w
Pb with t% Ca and 0.1-1.0 wt% Sn
By using an expanded lattice made from a cold-rolled alloy sheet, it has excellent maintenance-free performance.

EXAMPLES Next, the structure and effects of the present invention will be explained using examples.

Using a Pb-0,07wt%Ca-0,25wt%Sn alloy, a continuous casting plate with a thickness of 10nva and a width of 80mm was made (
This was used as the base material.

This base material alloy plate has a thickness of 0.1-Pb-5,0wt%5
b-5,0wt%5n-0,02wt%B1-0.01
Alloy foils of wt%Ag-0,001wt%Fe were stacked and cold rolled to produce a rolled sheet having a dissimilar alloy layer on the surface. The rolled sheet was expanded and filled with an active material to form a positive electrode plate.

The above positive electrode plate and Pb-0,07wt%Ca-0,25wt
%Sn alloy base material and a negative electrode plate using a polyethylene porous sheet separator to form an electrode plate group, and a battery (
A) was assembled.

Note that the battery had a 5-hour rate capacity of 48AH.

As a comparative example, Pb-0.07wt%C Otori-0.25w
Using a positive electrode plate and a negative electrode plate using a base material of t%Sn alloy,
The battery (B) was assembled.

A charge/discharge cycle life test was conducted using these batteries (A) and (B). The test was performed by discharging at 25A for 8 minutes and charging at a constant voltage of 14.5V for 12 minutes (maximum current 25A).
The charging and discharging performed was defined as one cycle. In addition, the environmental temperature is 80
℃. and 3 at 300A every 360 cycles.
Discharged for 0 seconds. The life span was defined as the time when the voltage at the mouth became 7.2 V or less for 30 seconds.

Figure 1 shows the results of the charge/discharge cycle life test.

As is clear from the figure, the battery (A) of the present invention has excellent life performance. On the other hand, the conventional battery used for comparison (B)
had a short lifespan. The conventional battery (B), which had reached the end of its service life, was charged at a constant current of IOA for 8 hours, and then discharged at 300A. As a result, the 30-second mouth pressure was 8.2 V, which was lower than 9.1 V for the battery (A) of the present invention in the same cycle, but still had a sufficient usable capacity.

Next, these batteries (A) and (B) were disassembled and the state of deterioration of the electrode plates was examined. The active material of the electrode plate of the battery (A) of the present invention had progressed to softening and was at the end of its service life. However,
The electrode plate of the conventional battery (B) had little deterioration (it was in a usable condition).

From the above test results, the battery (A) of the present invention was repeatedly charged and discharged in a high-temperature atmosphere, corrosion of the lattice progressed, and the active material also deteriorated, reaching the end of its life. The capacity of battery (B) decreased not due to deterioration of the electrode plates, but due to insufficient charging.

Note that the amount of electrolyte solution decreased during charge/discharge cycles was small in the battery (A) of the present invention as well as in the conventional battery (B).

In the previous example, an example was shown in which trace amounts of Bi, Fe, and Ag were added. Of course, similar effects were obtained even when Cu and As other than those shown in the examples were used. However, the details of the mechanism by which these elements work are not yet clear.

Effects of the Invention As described above, the lead-acid battery of the present invention has excellent maintenance performance, significantly improves high-temperature durability, and
It exhibits excellent charging efficiency.

[Brief explanation of the drawing]

A: Battery of the present invention, B: Battery of conventional example.

Claims (3)

[Claims] (1) Calcium (Ca) 0.02-0.15wt%
, contains 0 to 5.0 wt% of tin (Sn), and the balance is lead (P).
b) 0.8 to 50 wt% of antimony (Sb) and 1.0 to 1.0 of Sn on the surface of the Pb-Ca-based alloy lattice body consisting of
In addition to the Pb-Sb-Sn alloy containing 10 wt%, bismuth (Bi), arsenic (As), copper (Cu), silver (Ag),
1. A lead-acid battery characterized by having a lattice body having an alloy layer containing at least two types of elements of the group consisting of iron (Fe) in a total amount of 0.2 wt% or less. (2) Ca 0.05-0.12wt%, Sn 0.1
Contains ~1wt% Pb-Ca-Sn with the remainder being Pb
The alloy is used as a base material, and the above Pb-
The lead-acid battery according to claim 1, characterized in that an expanded lattice made of a lead alloy having an alloy layer containing Sb-Sn, Bi, As, Cu, Ag, and Fe is used. (3) A thin Pb-S layer with a thickness comparison of 1.0% or less of the base material alloy is formed on the surface of the base material of the Pb-Ca-Sn alloy.
The lead-acid battery according to claim 1, characterized in that a lattice body having an alloy layer containing b-Sn and at least two of the group consisting of Bi, As, Cu, Ag, and Fe is used.