JPH01169869A - Lead-acid battery - Google Patents

Abstract

PURPOSE:To improve the life and prevent the reduction of the battery capacity by using lattices not containing antimony for paste supporters of positive and negative electrodes, providing a specific nonwoven fabric on the side in contact with the positive electrode between both electrodes, and providing a specific separator on the side in contact with the negative electrode. CONSTITUTION:In a battery using a lattice body not containing antimony for the paste supporter of a positive electrode, a nonwoven fabric 1 mainly made of glass fibers with the average fiber diameter of 5-10mum is arranged on the side in contact with the positive electrode to apply the proper pressure to an electrode plate group, a porous sheet 2 with the maximum hole diameter of 15mum or below is arranged on the side in contact with a negative electrode as a separator. The life is thereby improved, the reduction of the battery capacity is reduced, the battery can be formed into a bag shape, the internal short circuit due to the drop of the active material can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates in particular to a separator for lead-acid batteries used for starting automobile engines, etc.

Prior art PB-Ca- on grid as paste support for lead-acid batteries
Lead-acid batteries that use 3N alloys and lattice bodies that do not contain antimony have recently become widely used due to their low self-discharge and excellent liquid reduction properties. .

Problems to be Solved by the Invention However, batteries using such antimony-free lattices as the positive electrode paste support have poor cycle life characteristics when repeatedly charged and discharged deeply compared to batteries containing antimony. It had the disadvantage of being shorter.

As a means to solve this drawback, it has been proposed to use a nonwoven fabric mainly made of glass fibers with a fiber diameter of 4μ or less as a separator, but in this case, the diffusion of the electrolyte in the separator is inhibited, resulting in a decrease in battery capacity. There was a problem that it caused a decline.

The present invention aims to improve battery life and suppress such a decrease in battery capacity.

Means for Solving the Problems As a means to solve these problems with a lead-acid battery using a lattice that does not contain antimony, the present invention provides the first method.
As shown in the figure, the average fiber diameter is 6 to 10 on the side in contact with the positive electrode.
A non-woven fabric 1 mainly composed of glass fibers of μ is placed, and moderate pressure is applied to the electrode plate group, and the maximum pore diameter of this non-woven fabric reaches about 70 to 100 μ, making it unable to fully function as a separator. A microporous sheet 2 with a maximum pore diameter of 15 μm or less was placed on the side in contact with the negative electrode to serve as a separator.

The material of the microporous sheet 2 here may be pulp, synthetic resin fiber, etc., as long as it is normally used in lead-acid batteries; plastic film is most suitable.

By providing a lip 3 if necessary, the thickness of the nonwoven fabric or the actual thickness of the sheet can be reduced.

In this case, it is effective for liquid retention to provide the lip 3 between the nonwoven fabric and the sheet. Moreover, when these are integrated into a bag shape, the lip 3 can be provided facing the negative electrode side as shown in FIG. 2 so that it can be easily folded.

Function Conventionally, a glass nonwoven fabric (mat) that comes into contact with the anode active material and prevents it from falling off is considered to have an average fiber diameter of about 15 to 19 μm, and has been used for many years. However, although this is effective when an antimony alloy is used in the lattice, it is no longer effective when antimony is not included because the particle size of the fallen active material becomes small. In the present invention, as a result of studies using glass nonwoven fabrics (mats) with several fiber diameters,
Glass mats with an average fiber diameter of 6 to 10μ have an excellent longevity.
Moreover, it was discovered that the decrease in battery capacity was also small.

By integrating a microporous sheet with such a glass mat and using it together, it can be made into a bag shape, and internal short circuits due to falling off of the active material can be prevented.

Example The effects of the present invention will be described below with reference to Examples.

Example 1 Extended lattice made of Pb-3n-Ca alloy was used for the positive and negative electrodes, 6 positive electrodes and 6 negative electrodes were used for each cell, the materials of sheet 2 and glass mat 1 were selected as shown in Table 1, and the cell was heated for 6 hours. The rate of discharge time and the number of lifetimes according to JIS were measured.

From Table 1, it can be seen that a glass fiber diameter of 10 μm or less has a significant effect on the lifespan. However, below 5μ, the battery capacity shows a significant decrease. Therefore, the fiber diameter is 6 to 10
It can be seen that the range of μ is effective.

Example 2 A similar test was conducted by providing a lip on the sheet 2 and changing the thickness of the glass mat 1. We also investigated the effects of attaching the glass mat 1 to the lip 3 side of the sheet 2 and to the flat surface on the opposite side of the lip 3. The results are shown in Table 2.

Table 2 From the results, it can be seen that when a glass mantle is pasted on the lip side, it does not depend much on the thickness of the glass mat and has an effect on the lifespan. It can also be seen that when a glass mat is pasted on the flat surface opposite to the lip, it has a large effect on the discharge duration.

In this test, the side portions of the sheet 2 were ultrasonically welded to a glass mat to form a bag. If ultrasonic welding is not possible,
The active material protruded from the sides and caused a short circuit, resulting in a short life.

Effects of the Invention As described above, the present invention can both increase the life span and maintain capacity of a lead-acid battery using a lead alloy that does not contain antimony in the lattice.
Its industrial value is great.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views of embodiments of the present invention. 1... Glass fiber nonwoven fabric, 2... Sheet, 3... Rib. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
(Fig.

Claims (4)

[Claims] (1) A lattice that does not contain antimony is used as the paste support for the positive and negative electrodes, and between the two electrodes, a nonwoven fabric mainly made of glass fiber with an average fiber diameter of 5 to 10 μ is placed on the side in contact with the positive electrode.
A lead-acid battery characterized in that a separator made of a microporous sheet with a maximum pore diameter of 15 μm or less is disposed on the side in contact with the negative electrode. (2) The lead-acid battery according to claim 1, wherein the microporous sheet in contact with the negative electrode is made of a microporous plastic film. (3) The lead-acid battery according to claim 2, wherein ribs are provided on the contact surface of the microporous sheet with the nonwoven fabric mainly made of glass fiber. (4) The lead-acid battery according to claim 3, wherein the separator is bag-shaped.