JPH08298119A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE: To prevent the deterioration of a positive electrode active material and improve the life performance by using the positive electrode active material added with a selenium compound and/or an electrolyte added with phosphoric acid. CONSTITUTION: A selenium compound 0.001-0.1% is added to a positive electrode paste to obtain a positive electrode plate containing a positive electrode active material. The positive electrode plate, paste type negative electrode plate, and a separator are laminated to obtain a layered product. Granular silica holding an electrolyte added with phosphoric acid 0.25-1.5% is filled around the layered product to obtain a sealed lead-acid battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the improvement of the life performance of a sealed lead-acid battery, and in particular, the addition of a selenium compound to the positive electrode active material and the addition of phosphoric acid to the electrolytic solution can prevent the deterioration of the positive electrode active material. The purpose is to prevent and improve the life performance of the sealed lead-acid battery and to stabilize it.

[0002]

2. Description of the Related Art Sealed lead-acid batteries include a gel type battery in which an electrolytic solution is gelled and fixed by adding colloidal silica to the electrolytic solution, and a fine glass mat separator which is most widely used at present. Positive and negative, a retainer type battery in contact with the negative electrode plate, and development in recent years,
There is a granular silica battery in which granular silica is filled between the electrode plates and around the electrode plate group.

It is known that each of these sealed batteries has a considerably shorter cycle life than that of a conventional liquid battery using an Sb alloy grid for the positive electrode. One of the causes is deterioration (softening) of the positive electrode active material. In batteries with gelled electrolyte, phosphoric acid has been added to the electrolyte for a long time to delay the softening of the positive electrode active material.However, if the amount of phosphoric acid added is large, the initial capacity will rather decrease. To do.
In addition, in a retainer type battery or a granular silica type battery, addition of phosphoric acid not only lowers the initial capacity but also shortens the life performance.Therefore, adding phosphoric acid alone can prevent deterioration of the positive electrode active material and improve the life performance. Was considered difficult.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the softening of the positive electrode active material of a sealed lead acid battery and to improve the life performance of the battery. As a result of various tests, we found that by adding a selenium compound to the positive electrode active material and further adding phosphoric acid to the electrolytic solution, the battery life could be extended. The effect is shown below using a retainer battery.

[0005]

[Example] Selenium sulfate powder was added to the positive electrode paste at 0.001% (C), 0.01% (D), and
A 2.4 mm-thick positive electrode plate added with 0.1% (E) and 1% (F) was produced, and 10 positive electrode plates, 11 negative electrode plates of 1.7 mm thickness and a fine glass mat separator were manufactured. From the above, a retainer type sealed battery of about 63 Ah (3hR) -12V was manufactured according to a normal manufacturing method. A battery using a conventional positive electrode plate (A, B) in which selenium sulfide powder was not added to the positive electrode active material was also manufactured. A predetermined amount of phosphoric acid [0.25%, 0.5%, 0.75%,
1%, 1.25%, 1.5% (per weight of electrolytic solution)] The diluted sulfuric acid added was injected, predetermined charging was performed, and the following tests were performed. A battery (A) containing no selenium and no phosphoric acid added to the positive electrode plate was manufactured and tested at the same time.

These batteries were first measured for 1/3 CA discharge capacity. The results are shown in FIG. 1. In the battery in which phosphoric acid was added to the electrolytic solution, the capacity significantly decreased as the amount of phosphoric acid added increased. However, the capacity of the battery in which selenium sulfide was added to the positive electrode active material in an amount of 0.001% or more at the same time was not so different from the capacity of the battery without the additive (A). That is, it was found that selenium has a function of improving the initial capacity of the battery (utilization rate of the positive electrode active material).

After the initial capacity test, charging / discharging was repeated in a pattern in which the discharge depth was 80% and 110% of the discharge amount was constant current, and the life performance of the battery was examined. The results are shown in Figure 2. As can be seen from the figure, 0.001 of selenium sulfide was added to the positive electrode active material.
% To 0.1%, phosphoric acid 0.25 in the electrolyte
% -1.5% or less additive-free battery (A)
It had a longer life than The battery containing only selenium sulfide had a better life performance than the additive-free battery (A) up to 0.1%. However, the life performance of the battery containing 1% selenium deteriorated.

After the test, these batteries were disassembled,
In the additive-free battery (A), the softening of the positive electrode active material was remarkable. In the battery containing only phosphoric acid, the positive electrode plate was hard and firm, but had low porosity. This seems to be the reason why the performance is difficult. In the battery to which only selenium was added, the positive electrode plate was softened more than ever, but in the battery to which phosphoric acid was added, the positive electrode plate was moderately hard. This is probably the reason why the life performance was good.

From the above results, it was found that phosphoric acid hardens the positive electrode active material and selenium has a softening effect. It is a new discovery that the life performance is improved as compared with the conventional non-added battery by adding the appropriate amounts of two kinds of additives having adverse effects at the same time. Further, even if selenium alone is added, if it is 0.1% or less, it can be said that the life performance is improved as compared with the conventional non-addition.

Although selenium sulfide powder was used as selenium, it goes without saying that the same effect can be obtained with compounds such as metal selenium and selenium oxide.

In this embodiment, the retainer type battery was tested, but the same effect can be obtained by using the gel type or granular silica type battery.

[0012]

As described above, the present invention improves the life performance of a sealed lead acid battery by adding selenium to the positive electrode active material and phosphoric acid to the electrolytic solution. From the standpoint of commercialization of storage batteries, their industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the added amount of phosphoric acid and selenium and the initial capacity.

FIG. 2 is a characteristic diagram showing the relationship between the added amount of phosphoric acid and selenium and life performance.

Claims (2)

[Claims] 1. A gel type in which an electrolytic solution is gelled and fixed by colloidal silica, a so-called retainer type in which the electrolytic solution is held in a separator made of fine glass fibers, or granules in which the electrolytic solution is filled around the electrode plate group. A sealed lead acid battery of the granular silica type retained on silica, characterized in that 0.001% or more and 0.1% or less of a selenium compound is added to the positive electrode active material. 2. Phosphoric acid is used as an electrolyte in an amount of 0.25 per amount of the electrolyte.
% Or more and 1.5% or less is added, Claim 1 characterized by the above-mentioned.
The sealed lead-acid battery according to.