JPH10199562A - Sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide longer service life by optimizing the amount of silica in a separator. SOLUTION: This sealed lead-acid battery is of retainer type which uses a positive pole grid of Pb-Ca alloy, whereas metallic tin or tin compound is added to a positive pole active substance by 0.5% and over, 5% and under in terms of metallic tin per positive pole active substance weight, and a separator whose main ingredient is fine glass fiber including silica powder of 30% and over, 80% and under is used as an electrolyte holder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a Pb-C
a sealed lead-acid battery using an a-based alloy lattice,
As a specific measure to improve the initial performance and the life performance, and particularly to suppress the adverse effect when the life performance is improved by adding tin or a tin compound to the positive electrode active material, a silica powder is added to the separator and the silica is added. By adjusting the amount to 30% or more and 80% or less, it is intended to achieve a longer life than the conventional one.

[0002]

2. Description of the Related Art A sealed type lead-acid battery is currently most widely used, and there is a retainer type battery in which a fine glass mat separator is in contact with positive and negative plates.

[0003] In this sealed battery, a Pb-Ca based alloy lattice is often used for the positive electrode. In this case, the cycle life is considerably shorter than that of a conventional liquid battery using an Sb alloy lattice for the positive electrode. It has been known. In addition, the sealed lead-acid battery has a low active material utilization rate in order to stabilize the above-mentioned life performance. Therefore, the energy density is considerably lower than that of the liquid battery from the beginning, and it is expected to be applied to EV applications. It is a big problem in planning.

[0004]

Many measures have been taken for a long time to improve the energy density of a sealed lead battery using a Pb-Ca alloy. For example, Japanese Patent Application Laid-Open No. 54-49538 proposes a method for improving initial performance by adding tin sulfate or tin dioxide to a positive electrode active material. However, this method has not yet been put to practical use because, as a result of our research, tin elutes from the positive electrode and precipitates on the negative electrode plate, lowering the charging efficiency of the negative electrode and reducing the life performance. all right.

[0005]

SUMMARY OF THE INVENTION The sealed lead-acid battery of the present invention is a sealed lead-acid battery of the retainer type using a positive electrode grid of a Pb-Ca alloy, wherein a metal tin or tin compound is used as a positive electrode active material. 0.1 in metal tin equivalent per substance weight.
5% or more and 5% or less, and 30% or more and 80%
A separator mainly composed of fine glass fibers containing the following silica powder is used as an electrolyte holder. Further, the specific surface area of the silica powder in the separator is 50 to 500 m ² / g.
It is characterized by being.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealed lead-acid battery according to the present invention
Using a positive electrode lattice of a Pb-Ca alloy, metal tin or a tin compound is added to the positive electrode active material in an amount of 0.5% to 5% in terms of metal tin per weight of the positive electrode active material, and 30% to 8%.
A separator mainly composed of fine glass fibers containing 0% silica powder is used as an electrolyte holder. Further, the specific surface area of the silica powder in the separator is 50 to 500 m ² / g.
Use the one in the range. By doing so, not only the initial energy density but also the life performance can be significantly improved.

As a result of various studies, we have found that tin eluted from the positive electrode active material is easily adsorbed on silica powder in the separator. It is considered that since silica has a large specific surface area, tin eluted in the electrolytic solution is easily adsorbed to the silica powder, and as a result, tin is prevented from depositing on the negative electrode plate.

The following example shows an example of the result.

[0009]

EXAMPLE A tin sulfate powder was added to a positive electrode grid made of a Pb-0.08% Ca-1.0% Sn alloy at the time of paste pulverization in an amount of 0.1% (B) in terms of metal tin per weight of a converted active material. 0.
5% (C), 1% (D), 2% (E), 5% (F), 7
% (G) to produce a 2.2 mm thick positive electrode plate filled with a paste. These 11 positive plates and 1. .
12 paste-type negative electrode plates with a thickness of 7 mm and a specific surface area of 20
15% (b), 30% of 0 m ² / g silica powder
(C), 50% (d), 80% (e), 90% (f) from the fine glass mat separator containing about 60Ah
A (3 hR) -12 V retainer-type sealed battery was manufactured according to a normal manufacturing method.

A battery using a conventional standard electrode plate to which tin sulfate is not added (A), and a battery using a conventional separator (a) to which tin sulfate is added but containing no silica as a separator. Was also produced. These batteries were subjected to predetermined injection and charging according to a conventional method, and subjected to the following tests.

First, 1/3 CA discharge capacity was measured at 30 ° C. The test results are shown in FIG. As can be seen from the figure, when the amount of tin sulfate added is up to 5%, the capacity is greatly improved by adding 0.5% or more of tin sulfate.
In addition, when the amount of silica in the separator is increased, the porosity of the separator is reduced, so that the discharge capacity is slightly reduced.

Next, these batteries were subjected to a life test. Life test at 40 ° C, rated at 80 at 1/3 CA current
%, And then charged under a general condition of charging 110% of the discharge amount at a constant current. The test results are shown in FIG.

[0013] Tin sulfate is added in an amount of 0.5% or more and 5% or less,
The battery in which the amount of silica in the separator was 30% or more and 80% or less had remarkably superior life performance as compared with a conventional battery in which tin sulfate was not added. On the other hand, tin sulfate was added to the positive electrode at 0.1.
The life performance of the battery using the electrode plate to which only 1% was added was not much different from the battery to which no electrode was added. In the case where the amount of silica in the separator was 90% regardless of the amount of tin sulfate added, the capacity was reduced at an early stage. Possibly, in this case, the amount of silica was too large, so that the movement of the electrolyte impregnated into the separator was too slow, which adversely affected the battery performance.

When the amount of tin sulfate in the positive electrode active material was as high as 7%, the capacity was reduced promptly regardless of the amount of silica in the separator. When the amount of tin deposited on the negative electrode plate after disassembly after the life test was examined, a large amount of tin was deposited on the negative electrode plate regardless of the amount of silica in the separator when the amount of tin sulfate was 7%. Even when the amount of tin was 5% or less, a large amount of tin was precipitated when the amount of silica in the separator was less than 30%.

[0015] From the above, tin is added to the positive electrode active material in an amount of 0.1.
5% to 5% added, and 30% to 80% silica powder
It has been found that by using the added separator, not only the energy density of the sealed lead storage battery of the retainer type can be improved, but also a long life can be achieved.

In this embodiment, tin sulfate was used as tin. However, there was almost no difference between tin oxide and tin metal. Although the main component of the separator is fine glass fiber of 0.5 to 5 microns, it has been found from the test results so far that the result of this test does not depend on the fiber diameter of the separator.

In this test, silica powder of 200 m ² / g was used. As a result of the test, 50 m ² / g to 500 m ² / g was used.
The effect was significant when silica having a specific surface area of ² / g was used. When a silica powder having a specific surface area of more than 500 m ² / g was used, there was a tendency that a decrease in the capacity became large probably because the movement of the electrolytic solution was not good.

[0018]

According to the present invention, a sealed lead-acid battery using a Pb-Ca alloy grid as the positive grid has a positive electrode active material of 0.5%.
% To 5% at the same time the addition of tin or tin compounds, silica powder 50m ² / g~500m ² / g 30
% To 80%, not only the initial energy density but also the life performance is remarkably improved, and the industrial value of the retainer-type sealed lead-acid battery is extremely large from the viewpoint of practical use.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing the relationship between the amount of tin added, the amount of silica in a separator, and the initial capacity.

FIG. 2 is a characteristic diagram showing the relationship between the amount of tin added, the amount of silica in a separator, and the life performance.

Claims (2)

[Claims] 1. A closed lead-acid battery using a positive electrode grid of a Pb—Ca alloy, comprising metal tin or a tin compound as a positive electrode active material in an amount of 0.5% or more in terms of metal tin per weight of the positive electrode active material. Add 5% or less and 30%
A sealed sealed lead-acid storage battery characterized in that a separator mainly composed of fine glass fibers containing not less than 80% of silica powder is used as an electrolyte holder. 2. The silica powder in the separator has a specific surface area of 50 to 500 m ² / g.
The sealed lead storage battery of the retainer type described in 1.