JPH02177253A - Closed type lead accumulator - Google Patents

Abstract

PURPOSE:To increase the amount kept of an electrolyte by 50 defining a separator that its matrix is an alkali silicate inclusive glass fiber of specified standard fiber size and including a specified amount of alkali and that it includes a specified amount of porous glass fiber, porous glass powder and/or porous silicic acid powder. CONSTITUTION:For a separator, matrix is an alkali silicate inclusive glass fiber of specified standard fiber size and including a specified amount of porous glass fiber, porous glass powder and/or porous silicic acid powder are included. The standard fiber size is not more than 2mum, the amount of alkali is 8 to 20weight%, and the amount of the porous glass fiber, porous glass powder and/or porous silicic powder is defined as 3 to 70% of the weight of the separator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sealed lead-acid battery, and particularly to a sealed lead-acid battery that is hard to cause stratification of an electrolyte and has a long life.

[Prior Art] A sealed lead-acid battery has a structure in which a separator and an electrode plate are stacked in a sealed container, and the electrolyte in the battery flows into the separator and the holes in the positive and negative electrodes. It is kept in such a way that it never happens.

This sealed lead-acid battery has characteristics such as excellent leakage resistance, no need for water replenishment, and low self-discharge.

By the way, as described in Japanese Patent Publication No. 63-27826, in a large-capacity sealed lead-acid battery with a high plate height, even though the liquid is uniform during injection, repeated charging and discharging causes The concentration of the electrolytic solution held within the pores of the separator and electrode plate differs in the vertical direction. That is, a stratification phenomenon occurs in which the concentration of the electrolyte becomes higher in the lower part of the separator. This stratification phenomenon tends to occur mainly in the separator area, so in order to prevent this, it is necessary to increase the liquid retention capacity of the separator, to ensure that there is no difference in liquid retention capacity between the upper and lower parts of the separator, or to prevent it from occurring in the electrolyte. It is required to increase the viscosity by adding fine silicic acid powder.

Conventionally, separators mainly made of glass fiber have been used. Various improvements have been attempted to improve the liquid retention properties (liquid retention characteristics) of this separator.

For example, JP-A-62-133669, JP-A No. 62-138
No. 751 describes a separator coated with or mixed with powder of SiO2, TiO2, or rare earth element oxide. JP-A-63-152853 describes the use of silica or expanded pearlite as powder.

Also, JP-A-63-143742, JP-A No. 63-1463
No. 48 describes a separator made of hollow tubular glass fiber.

Furthermore, Japanese Patent Publication No. 83-27826 discloses a method of adding a small amount of silicon dioxide fine powder to an electrolytic solution to increase its viscosity and prevent stratification.

[Problems to be Solved by the Invention] In the products in which powder is applied or mixed as in JP-A-82-133689 and JP-A-82-136751, the distance between the pores between glass fibers is Although it has the effect of increasing the liquid absorption power due to capillary phenomenon, the volume occupied by the glass fibers and powder itself increases, so the space volume in which the liquid should be held becomes smaller, and the amount of liquid retained becomes smaller. There is a risk.

If the glass fiber is formed into a hollow tubular shape as in JP-A-63-143742 and JP-A-63-146348, the volume occupied by the glass fiber itself becomes smaller.

However, the manufacturing cost of hollow tubular glass la fibers is significantly higher than that of ordinary glass fibers, and the price of the separator also exceeds the practical range.

[Means for solving the L1 problem] The sealed lead-acid battery of the present invention has an electrode plate and a separator arranged in a stacked manner within a battery container, and has a structure in which the electrode plate and the separator are arranged in a stacked manner to the extent that they do not flow freely into the pores of the separator and the electrode plate. This invention relates to a sealed lead-acid battery in which an amount of electrolyte is retained.

The separator is mainly composed of alkali-containing silicate glass fibers (hereinafter sometimes simply referred to as alkali-containing glass fibers) having an average fiber diameter of 2 μm or less and an alkali content of 8 to 20% by weight.

This separator contains porous glass fiber, porous glass powder and/or porous silicic acid powder in an amount of 3 to 70% by weight.

[Function] In the sealed lead acid battery of the present invention, the alkali-containing glass fibers are bonded together by a water glass-like substance produced from the alkali-containing glass fibers.

Porous glass fibers, porous glass powder and/or porous silicic acid powder are entangled with this alkali-containing glass fiber,
Alternatively, at least a portion thereof is bonded to the alkali-containing glass fiber by the water glass-like substance.

In this way, porous glass fiber, porous glass powder and/or
Alternatively, since it contains porous silicic acid powder, the volume for holding electrolytic energy is expanded only in the pores of the porous glass fiber and/or powder. Therefore, even if the number of glass fibers and the number of powder particles per unit volume of the separator are increased, the same volume for holding the electrolyte as before can be secured. If the number of fibers or powder particles is increased, the spacing within the separator will be narrowed, and the liquid retention force due to capillary action will be strengthened.

For this reason, the sealed lead-acid battery of the present invention can increase the amount of electrolyte retained, and can equalize the liquid retention in the vertical direction of the separator.

As mentioned above, in the separator of the sealed lead acid battery of the present invention, porous glass fiber, glass powder and/or
Alternatively, porous silicic acid powder is used, but these ia
The pores in the fiber or powder must be continuous pores (also called open pores) that communicate with the outside. Since the pores are continuous as described above, it is possible to hold the electrolytic solution within the pores in a form that can contribute to the electromotive reaction. Since these continuous pores are significantly finer than the gaps between fibers or between fibers and powder, liquid retention due to capillary action is strong, and this also equalizes the liquid retention in the vertical direction of the separator. It becomes like this.

When the separator of the sealed lead-acid battery of the present invention contains porous glass powder and/or porous silicic acid powder, this porous glass powder is different from a crushed product of bubble-containing glass such as expanded perlite. It is. That is, the pores in a glass containing bubbles such as expanded pearlite have a large diameter, for example, on the order of mrn.

Therefore, in this type of crushed glass containing bubbles,
They are particles with almost no pores, and even if they are mixed into a separator, they cannot improve liquid retention like the porous glass powder of the present invention.

It is possible to use sulfuric acid in the battery to remove acid-soluble components and make them porous, but in this case, acid-soluble components leak into the electrolyte, resulting in a decrease in battery performance. Therefore, it must be treated in advance so that it has good acid resistance when it is set in the battery.

The present invention will be explained in more detail below.

The separator used in the sealed lead-acid battery of the present invention has an average diameter of 2 μm or less and is mainly composed of alkali-containing silicate glass fibers having an alkali content of 8 to 20% by weight.

If the diameter of these alkali-containing silicate glass fibers is excessively large, the maximum pore diameter of the separator will increase, which may reduce the liquid retention capacity due to capillary phenomenon.
It is preferable that the average diameter is 2μ or less, particularly 0.9μ or less. On the other hand, if the glass fiber diameter is too small, the cost of the separator will increase, so it should be 0.4μ or more, especially 0.4μ or more.
It is preferable that the thickness is 6μ or more.

In the separator used in the sealed lead-acid battery of the present invention, the average diameter of the alkali-containing silicate glass fiber is 2 μm.
or less, and particularly preferably 0.6 to 0.9 μm.

When alkali-containing silicate glass fibers are used, a water glass-like substance is generated on the surface of the alkali-containing silicate glass fibers during the papermaking process of the manufacturing process, and the stickiness of this water-glass substance causes the fibers to stick to each other or the fibers and the powder. In the present invention, among alkali-containing silicate glass fibers, those having good acid resistance are preferably used because they are used in storage batteries. The degree of acid resistance is preferably such that the weight loss is 2% or less when measured according to JISC-2202 in the state of glass fibers with an average fiber diameter of 1 μm or less, and the composition of such glass 1ala is 60-75% 5102 and 8-20% R20 (Na
20, alkali metal oxides such as K2O) (5t02+R20 is 75 to 90%), and in addition, for example, Cab%MgO, B203, AfL20s
, ZnO, Fe2es, and the like. An example of a preferable alkali-containing silicate glass is shown in Table 1 below.

Table 1 In the present invention, as the alkali-containing silicate glass fiber,
It may also contain medium-fine glass fibers with an average diameter of more than 2 μm and less than 10 μm, and large-diameter glass fibers with an average diameter of 10 to 30 μm.
20% by weight of alkali-containing silicate glass fibers (μm or less)
Hereinafter, it is preferable that the blending ratio of large-diameter fibers is 15% by weight or less. By blending such medium-fine glass fibers and large-diameter glass fibers, it is possible to reduce the cost of glass W4 fibers. If the ratio is too large, the maximum pore diameter of the separator will become excessively large and the liquid retention properties will deteriorate, so it is preferable that the amounts of these components are as described above.

The porous glass fiber and powder added to this alkali-containing silicate glass fiber are 5i0295-1001% by weight, apparent specific gravity 1.4-1.8, and porosity 20-20.
45% by volume is preferred.

The porous glass fibers have an average length of 0.1 to 40 mm, especially 0.5 to 15 mm, and an average diameter of 0.5 to 2
Preferably, the thickness is 0 μm.

The porous glass powder has an average particle size of 40 μm or less,
Particularly preferred is one having a weight of 0.5 to 5.0 gm.

Furthermore, porous silicic acid powder containing silicon dioxide as a main component can also be used for the same purpose. Materials of this type include, for example, silica porous microballoons and silica beads obtained using a liquid phase interfacial reaction. Regarding the former, the particle diameter is 0.1 to 20 μm and the specific surface area is 200 to 90 μm.
0ITIt/g and about 0.4 to 1.5c per 1g
It is a material that can contain liquid c and is an extremely effective material for increasing the absorption amount and absorption power of electrolyte solution, and is suitable for use in the separator of the present invention.

The separator used in the sealed lead acid battery of the present invention includes:
3-70%, preferably 10-50% of the separator weight
Especially preferably, those containing 20 to 40% of porous glass fibers, porous glass powder and/or porous silicic acid powder (that is, one or both of the fibers and the powder) are used.

In the present invention, porous glass fibers and porous glass powder can be produced by contacting glass fibers or powder containing acid-soluble components with a liquid containing an acid to elute the acid-soluble components.

In this case, E glass composition is suitable as the glass composition.

Examples of the composition range and specific gravity of E-glass that can be used are as follows. (Weight% composition) SiO250-65 CaO10-25 A1203 10-20 B203 5-20 Mg0 8 or less Na20 and 20 Total amount 0.1-2 Specific gravity
2.4-2.6 In addition, as another glass containing an acid-soluble component, a glass having a phase separation region composition of soda borosilicate glass shown in FIG. 2 is also suitable, and in this case, the glass fiber or powder is heat-treated. and acid-insoluble SiO
It is preferable to separate the phase into a phase enriched in 8203-Na20 and an acid-soluble 8203-Na20 phase, and then elute the acid-soluble phase. Furthermore, CaO3-25%, 82 oz 8-3
0%, 5L0245~70%, Alt 2035~1
Vine also uses 5% glass (unit weight %).

The separator used in the sealed lead-acid battery of the present invention is made by intertwining the alkali-containing silicate glass fibers with porous glass fibers, porous glass powder, and/or porous silicic acid powder by wet paper-making, and by using special It is preferable that they be bonded to each other without an adhesive, but they may also contain some amount of organic fiber.

In order to manufacture such a storage battery separator of the present invention, it is advantageous to use, for example, the following method.

That is, FA method (flame method), centrifugal method and other glass shortening methods
! Relatively short glass fibers manufactured by the fiber manufacturing method are prepared, and are defibrated, cut, and dispersed using a pulper.

Alternatively, the glass fibers may be cut into short lengths using an appropriate cutting means while being fed to the paper machine net.

Note that the cut glass fibers are made into paper in the form of a net, and at that time, it is preferable that the pH in the disintegrator and/or the pH in the papermaking tank be about 3 or less, for example about 2.5. By disintegrating and/or wet papermaking in such an acidic region, an adhesive layer of a water glassy substance is formed on the surface of the glass fiber, and then this is heated at a predetermined temperature, e.g.
By heating to 160°C, it becomes possible to bond the glass fibers to each other by the water glassy substance on their surfaces. That is, when the glass fibers constituting the separator have an alkali-containing silicate glass composition. In this process, the alkali component and silica component in the glass fiber react with water for dispersion in an acidic range of pH 2.5, forming a water glass layer on the surface of the glass fiber, and this water glass layer acts as an adhesive. The glass fibers are then firmly bonded to each other.

In such a case, even if the length of the glass iam is short and the fibers are relatively less entangled with each other as in the present invention, it is possible to obtain a separator with sufficient adhesion and high strength. This wet-formed glass fiber paper product is generally dried along a drum or dryer to form a product.

Note that a dispersant may be used when dispersing fibers in water during papermaking. In addition, a dialkyl sulfosuccinate is sprayed onto a wet-processed fiber paper product, for example, a fiber paper product on a paper-making net, and then the paper product is dried] JJI! !
On the other hand, Te0. By attaching 5 to 10% by weight of OO, the liquid retention property of the separator can be improved due to the hydrophilicity of the dialkyl sulfo-sacinate. Instead of spraying the dialkyl sulfosuccinate as described above, it may be mixed into the dispersion water in the papermaking tank.

The electrode plate used in the sealed lead-acid battery of the present invention is not particularly limited, and its thickness, shape, etc. are also not particularly limited.

The thickness of the separator is not particularly limited either, but it is preferably greater than the average fiber length of the glass fibers.

〔Example] Examples and comparative examples will be described below.

Example 1 70 parts by weight of alkali-containing glass fibers having the composition A in Table 1 and having an average diameter of 0.8μ and E glass having an average diameter of 0.8μ were immersed in sulfuric acid having a specific gravity of 1.2 for 72 hours to form a porous structure. A separator for a storage battery according to the present invention was manufactured using 30 parts by weight of the chemically treated product.

Table 2 shows the measurement results for various properties of this separator.

The methods for measuring various characteristic values in Examples and Comparative Examples are as follows.

■ Thickness (mm) Measure the sample while pressing it in the thickness direction with a load of 20 kg/dm'. (JIS (knee 2202)■
Fabric weight (g/crn') This is a value obtained by dividing the sample weight by the sample area.

■ Liquid content (g/cc) Set sample 2 on plate 1 as shown in Figure 6. Packing density: 0.1-6 g/crn'), specific gravity: 1.3 from above.
After leaving it for 36 hours, remove sample 2 from plate 21, determine the liquid content in areas No. 1 (top), No. 2 (middle), and No. 3 (bottom), respectively. is divided by the sample volume in the area.

The composition of the E glass used in the examples is as follows. (Weight %) SiO254.9%, AIL20314.3%, CaO22.8%, B20t 5.8%, Na2O and 200.5%, Fe20zO, 4% The ratios of the fiber and powder of this E glass are respectively !
When immersed in sulfuric acid No. 1 and 2 and measured the weight loss over time, the weight gradually decreased until 6 hours passed, but
There is almost no weight loss after 6 hours, and there is almost no change in fiber diameter or particle size even after 72 hours.
A weight loss of about 44% was observed over a period of 72 hours. From these facts, it is considered that porous glass fiber or powder having a porosity of about 40% is mixed in the separator manufactured in this example.

Furthermore, since the acid-soluble content is eliminated, the glass after treatment has good acid resistance.

Example 2 A separator was manufactured in the same manner as in Example 1 except that E-glass 8a fibers having an average diameter of 9 μm were used, and the six results of measuring the properties are shown in Table 2.

Example 3 A separator was manufactured in the same manner as in Example 1 except that E-glass powder having an average particle size of 13 μm was used instead of E-glass fiber, and its characteristics were measured.

The results are shown in Table 2.

Example 4 E-glass powder having an average particle size of 5 μm was immersed in sulfuric acid having a specific gravity of 1.2 for 72 hours to make it porous. 30 parts by weight of this porous E-glass powder and 70 parts by weight of the same alkali-containing glass fibers used in Example 1 were wet-formed and heat-treated in the same manner as in Example 1 to produce a separator. The measurement results of the properties are shown in Table 2. The E glass composition is as shown in Example 1.

Example 5 A soluble phase was eluted using a glass powder having the distribution area composition of sodium borosilicate glass shown in FIG. 30 parts by weight of porous glass powder and composition A in Table 1 with an average diameter of 0.
A separator for a storage battery according to the present invention was manufactured using 70 parts by weight of 8μ alkali-containing glass fiber.

The measurement results are shown in Table 2.

Example 6 30 parts by weight of porous silicate microballoon powder with an average particle size of about 3 μm (distributed from 0.1 to 11.0 μm) and the same alkali-containing glass fiber film O3i as used in Example 1
A separator was produced by wet paper forming and heating drying in the same manner as in Example 1. The measurement results of its properties are shown in Table 2. The porous silicate microballoon powder used had a density of 0.23, a specific surface area of 808 ni'/g, a pore volume of 1.53 cc/g, and a hollow 20-2 on the wall
It has micropores of 00A, and the inside and outside of the hollow part are communicated through these micropores.

Comparative Example 1 Only the alkali-containing glass fibers used in Example 1 were subjected to wet paper forming and heat treatment in the same manner as in Example 1 to produce a separator. The measurement results of its characteristics are shown in Table 2.

/ Table 2 / As is clear from Table 2, in the separators according to Examples 1 to 6, the average liquid content was 10% lower than that of Comparative Example 1.
It has increased by ~20%. Also, N with respect to the average liquid content
The deviation of the liquid content of each part of 011 to 3 is 8 in Comparative Example 1.
While it ranges from 9 to 108%, in Examples 1 to 3 it falls within the range of 95 to 103%, and it is clear that the liquid retention characteristics in the vertical direction of the separator are equalized.

[Effects of the Invention] As described above, in the sealed lead-acid battery of the present invention, the separator has a high liquid retention property, and the liquid retention property is equalized in the vertical direction of the separator, thereby preventing the stratification phenomenon. Ru.

Therefore, not only small-capacity sealed lead-acid batteries but also large-capacity sealed lead-acid batteries with high plate heights can have stable and excellent battery performance and have a long life. In this sealed lead-acid battery, the material cost of the separator is low.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a method for measuring liquid content. Second
The figure is a glass composition diagram. 1... Plate, 2... Trying on.

Claims (1)

[Claims] A sealed lead-acid battery in which an electrode plate and a separator are stacked in a battery container, and an electrolyte is retained in the pores of the separator and the electrode plate, wherein the separator has an average fiber diameter of Porous glass fiber, porous glass powder, and/or porous silicic acid that is 2 μm or less and is mainly composed of alkali-containing silicate glass fiber with an alkali content of 8 to 20% by weight, and 3 to 70% of the weight of the separator. A sealed lead acid battery characterized by containing powder.