JPH01302656A - Sealed type lead-acid battery - Google Patents

Abstract

PURPOSE:To prevent overflow accident of an electrolyte by using a fibrous separator, whose thickness under pressurization of 50kg/dm<2> in the condition fully moistened with dilute sulfuric acid and swollen is over 80% of the thickness under pressurization of 10kg/dm<2> in dried condition. CONSTITUTION:A battery jar 1 made of polypropylene is used, whose one side is opened, wherefrom a positive electrode plate 2, fibrous separator 3, negative electrode plate 4 are put into the battery jar in the sequence as named, and then a soft plastic material 5 is heat welded to the wall of battery jar followed by sealing. Therein the separator 3 has a thickness under pressurization of 50kg/dm<2> in the condition fully moistened with dilute sulfuric acid and swollen is over 80% of the thickness under pressurization of 10kg/dm<2> in dried condition. This ensures stable discharging performance from immediately after fabrication of the battery till the time it has been left as it is for a long period, and risk of leakage is removed associate with excessive compressive deformation of the separator 3 caused by drop of the battery internal pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention prevents as much as possible changes in the thickness of the battery case due to a decrease in battery internal pressure in a sealed lead-acid battery in which at least one side of the battery case is made of a flexible plastic material. This prevents hot electrolyte accidents.

Prior art and its problems The internal pressure of a sealed lead-acid battery decreases during storage due to the reaction between the oxygen gas inside the battery and the negative electrode plate. Furthermore, a fine fiber separator is generally provided inside the storage battery in order to isolate the positive electrode plate and the negative electrode plate and to hold the electrolyte, but this separator is easily deformed by compressive force. For this reason, in sealed lead-acid batteries whose container walls are made of flexible plastic materials, as the internal pressure of the battery decreases, the material
is deformed inward, causing compressive deformation of the separator holding the electrolyte, and there is a risk that the electrolyte will be liberated from the separator and leak through the exhaust hole.

The use of rigid separators is thought to be an effective way to solve these problems, but in a cage-type sealed lead-acid battery, which has a structure in which all the electrolyte in the battery is contained in the separator and electrode plates, the battery reaction does not occur. (1) The contact between the negative electrode plate and the electrolyte, which is essential for achieving this, is actually achieved through close contact between the electrode plate and the separator, so it is difficult to achieve sufficient contact with a rigid separator.

In addition, one possible solution to this problem is to fabricate the battery in advance using a thick fiber separator and then inject enough electrolyte so that it will not become cloudy even if the battery is left for a long time, but this is extremely difficult. When using thick separators,
Due to the large Nilemen I-group length during assembly, it is difficult to assemble, and immediately after charging the battery, the internal pressure of the battery has not decreased, so the electrolyte is not compressed by the separator. The electrolyte in the separator is significantly smaller than the holding capacity of the element, and the electrolyte in the separator is locally dispersed, resulting in insufficient contact between the electrode plates and the electrolyte, making it impossible to obtain satisfactory discharge performance. .

Means for Solving the Problems The present invention provides a battery in which at least one side of the battery case is made of a flexible plastic material, and the thickness of the battery when pressurized with 10 kg/d in a dry state is Thickness is 80% when 50 K g/dd pressure is applied in a sufficiently moist state.
By using the above-mentioned fibrous separator, stable discharge performance is ensured from immediately after battery manufacture to after long-term storage, and the risk of liquid leakage due to excessive compressive deformation of the separator due to a drop in internal pressure of the battery can be ensured. It's time to remove it.

Example One embodiment of the present invention will be described.

Using a polyglobylene battery case 1 with one side open as shown in Fig. 1, the positive electrode plate 2, separator 3, and negative electrode plate 4 are stacked in the order from the side (open side) inside the case as shown in Fig. 2. After that, the flexible plastic material 5 was thermally welded to the wall of the battery case to seal it. The separator material used is a mixture of V11 fine glass fiber and plastic fiber, and is different from the conventional product and 1. 50Kg/da when fully moistened with dilute sulfuric acid.
The ratio of the thickness when pressurized to the dry thickness when pressurized at 10 kg/dm2 is 74% (A) and 77% (B), and the product of the present invention has a ratio of the above thickness of 82 % (C) and 86% (D) were used to produce batteries.

After injecting a predetermined amount of dilute sulfuric acid into these batteries and charging them,
The 0.2C discharge performance was measured after being left for 4 hours and for 2 months. In addition, for products that had been left for two months, after discharge, the batteries were placed so that the exhaust hole was facing downward, and constant voltage charging was performed at 2.50 V/cell to check for leakage of electrolyte from the exhaust hole. . These results are shown in Table 1. The conventional product had a problem with either the initial volume i or the hot liquid during inverted charging, but the product of the present invention gave good results in both cases.

Table Thickness of router, t2 is 610Kg/d1 in dry state! This is the separator thickness when pressurized.

Note 2. The initial capacity is the capacity after 4 hours of charging, and the capacity after being left is 2.
This is the capacity after being left unused for several months.

Effects of the Invention As described above, the sealed lead-acid M battery according to the present invention always has a stable discharge capacity and can eliminate the risk of electrolyte leakage, and has great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a diagram not showing the structure of a battery case with an opening I7 on one side used in the test, and FIG. 2 is a cross-sectional view of the main part 4JI of the test battery. 1... Telephone number! J 2...Positive electrode plate 3...Separator 4...Negative electrode plate 5...Flexibility that seals the side wall of the battery case by heat welding ``゛2 ．Nuki Z times

Claims (1)

[Claims] In a battery where at least one side of the battery case is made of flexible plastic material, the weight in dry state is 10Kg.
It is characterized by using a fibrous separator whose thickness when pressurized at 50 kg/dm^2 is 80% or more of the thickness when pressurized with dilute sulfuric acid. Sealed lead acid battery.