JPS6180750A - Separator for sealed type lead storage battery - Google Patents

Abstract

PURPOSE:To obtain a separator free of shrinkage and adhering to terminal plates when impregnated with liquid, and spreading an electrolyte uniformly by letting a glass fibre sheet contain an inorganic laminated compound which swells at the time of impregnation. CONSTITUTION:As one of the inorganic laminated compounds which swell when a glass fibre sheet containing such compounds is impregnated with liquid, it is possible to mention mica. Also, if the ratio of inorganic laminated compound to glass fibre sheet is 5wt% minimum, the effect of its adhesion to the terminal plates is improved, but it is preferable to keep the upper limit of the ratio at about 50wt% for avoiding an unnecessary rise in the electric resistance of the separator and from an economical point of view.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in separators used in sealed lead-acid batteries.

[Conventional technology]

Conventionally, sealed lead-acid batteries have a Yin/Yang structure in which active materials are applied to the electrode substrate. When assembling the electrode plates, a separator made of glass fiber sheet is inserted between both TM plates in order to maintain a constant distance between the two electrode plates and to ensure that the electrolyte, such as dilute sulfuric acid, spreads over the electrode plates. It is common to intervene.

(Problem R4 to be solved by the invention) However, the glass fiber sheet used for the separator of the sealed lead-acid battery described above tends to shrink in thickness when it absorbs electrolyte, so the sheet is formed relatively thick. However, even if this is inserted between both electrodes and these are installed in a compressed state inside an electric cell, a gap will be created between the electrode plate and the glass fiber sheet due to the shrinkage of the glass fiber sheet, and the active material will not be applied. It does not adhere uniformly to both electrode plates.

Therefore, the electrolyte does not spread uniformly to both electrode plates, resulting in a decrease in battery capacity and voltage during discharge, or a decrease in the gas absorption state of the cathode plate, resulting in a shortened battery life. However, there has been a desire to develop a separator for sealed lead-acid batteries that does not shrink and allows electrolyte to spread uniformly over the electrode plates.

(Means for Solving the Problems) In view of the current situation, the present invention provides a separator for a sealed ship battery in which the electrolyte is uniformly spread over the electrode plate, and is made by forming glass fiber into a sheet shape. In the separator for a sealed lead-acid battery, the glass fiber sheet contains at least 5% by weight of an inorganic layered compound that exhibits III'Q when impregnated with liquid.

The glass fibers used in the present invention are not particularly different from conventional ones, and are generally those having an average m* diameter of 0.1 to 5 microns.

Examples of the inorganic layered compound contained in the glass fiber sheet that swells when impregnated with liquid include swellable mica. Furthermore, if the content of the inorganic layered compound in the glass fiber sheet is at least 5% by weight, the adhesion effect to the electrode plate will be exhibited.
In order to avoid an unnecessary increase in the electrical resistance value of the separator, it is preferable to set the upper limit of gold to approximately 50% by weight from an economic standpoint.

When swellable mica is used as the swellable inorganic layered compound, it may be in either a powder or sol form, and when it is contained as a powder, it is more preferably a total size of 10 to 50 meshes.

The separator of the present invention may be formed into a sheet by adding at least 5 layers of swellable inorganic layered compound gold between the glass fibers.
k%, and by making paper or molding it into a desired thickness.

Note that a separator may be obtained by mixing glass fibers or synthetic fibers with a larger average fiber diameter than the glass fibers, and adding an inorganic layered compound that swells when impregnated with liquid. Further, separators having different contents of inorganic layered compounds (Examples) The present invention will be explained below with reference to Examples and conventional examples.

As an example, as an alkali glass compound with excellent acid resistance, 50 mesh of powdered swellable mica was added at 5% by weight and 1% by weight.
0 heavy view%, 20 weight Ik%, 30 heavy view%, 40 heavy view%,
A porous sheet-like separator was obtained by containing 60% by weight of SO and 60% by weight, respectively, and forming it to a thickness of 1.0 m using a paper-making method. Obtained separator gold samples 1 to 7
A reminder.

Next, as a conventional example, glass fibers with an average fiber diameter of 1 micron obtained by melt-spinning alkali glass with excellent acid resistance were made into a sheet with a thickness of 1 μm using a papermaking method to form a porous sheet separator. Obtained. The obtained separator was designated as Sample 8.

Thereafter, the electrical resistance value, recovery rate, and liquid content gk were measured for each of Samples 1 to 8 of the Example and the Conventional Example.

The results are shown in Table-1.

Table 1 As is clear from Table 1, the separators of the examples of the present invention (Samples 1 to 7) are superior in recovery rate and liquid content compared to the conventional separator (Sample 8). The shrinkage of the separator is well prevented during IW.
It was confirmed that the penetration of the liquid was f minutes and that the electrical resistance value was not a problem for practical use.

Next, a sealed lead-acid battery was assembled using the separators of Samples 2 and 4.6 of the above-mentioned practical example and the separator of Sample 8 of the conventional example, and battery tests were conducted on the initial capacity, remaining capacity, and number of lifetimes for each. Ta. The results are shown in Table-2.

Table 2 The evaluation of the battery test in the table is based on the seven cell test results of the example.
The characteristic value of the battery with all the built-in batteries was divided by the characteristic value of the battery with the conventional separator built in, and the result was expressed as a percentage (%).

As is clear from Table 2, the battery incorporating the actual separator (sample 2, 4.6) i has a lower initial capacity than the battery incorporating the conventional separator (sample 8) t'.
It has been confirmed that the battery characteristics in terms of remaining capacity and number of lifespans are excellent.

(Effect of the invention) According to the present invention, at least 5% by weight of the inorganic layered compound that swells when impregnated with liquid is contained in the glass fiber sheet.
Since it is contained therein, it has the effect of being able to spread the electrolytic solution uniformly by forming a tight layer on the electrode plate without shrinking when it is impregnated with the liquid.

Claims (1)

[Claims] A separator for a sealed lead-acid battery made of glass fiber formed into a sheet, the separator for a sealed lead-acid battery comprising at least 5% by weight of an inorganic layered compound that swells when impregnated with liquid in the glass fiber sheet.