JPH0760674B2 - Storage battery separator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a storage battery separator, and more particularly to a storage battery separator mainly composed of glass fiber.

[Prior Art] As a storage battery separator containing glass fiber,
Various types have already been proposed and put into practical use, but they are roughly classified into the following three types. That is, those mainly containing short glass fibers, those obtained by mixing and molding short glass fibers and synthetic fibers, and those holding powder in short glass fibers.

Of these, those mainly composed of short glass fibers,
A separator for a storage battery with an average diameter of 0.5 to 1.0 μm and an average length of 7 to 50 mm and containing alkali silicate glass fibers having a density of 0.10 to 0.13 g / cm ³ (Japanese Patent Application No. 58-225846), and the average of the glass fibers above the separator. The diameter of the separator is 0.3 to 0.6 μm, and the average diameter of the lower part is 0.7 to 1.0 μm. The average diameter of the glass fibers above the separator is smaller than the average diameter of the glass fibers below the separator (Japanese Patent Application No. 58-207106). )
Have been proposed by the applicant. In addition, large-diameter glass fiber with an average diameter of 13 to 30 μm and an average length of 3 to 100 mm 2
A storage battery separator (Japanese Patent Application No. 58-10059) comprising 0 to 80% by weight and thin glass fibers having an average diameter of 3 μm or less has also been proposed.

As consisting of short glass fiber and synthetic fiber of
Alkali-containing silicate glass fiber 60 with an average diameter of 0.5 to 1.0 μm
.About.90% by weight, 8 to 35% by weight of alkali silicate glass fiber having an average diameter of 10 to 20 .mu.m, 2 to 7% by weight of acrylic fiber and / or polyester fiber of 1.0 to 1.5 denier, and 0.
5-1.0 denier hot water soluble polyvinyl alcohol fiber
The present applicant has proposed a separator for a storage battery (Japanese Patent Application No. 59-81290) in which 0.04 to 0.6% by weight is wet mixed.

In addition, as the one in which the powder is held in the glass short fiber, an alkali-containing silicate glass fiber having an average diameter of 0.5 to 1.0 μm and an alkali-containing silicate glass powder having an average diameter of 20 μm or less is added to the separator weight of 1 to 3. 40% by weight mixed battery separator (Japanese Patent Application No. 59-70682), average diameter 0.5-1.0μ
m alkali silicate glass fiber with a specific surface area of 100 m ² /
There has been proposed a storage battery separator (Japanese Patent Application No. 59-70683) in which 1 to 40% by weight of the separator is mixed with silica powder of g or more.

As the glass fiber constituting the separator for the storage battery, the liquid absorbing property of the obtained separator, a small diameter fiber for sufficiently enhancing the liquid retaining property, and a raw material cost because it is cheaper than a small diameter fiber It is preferable to use it in combination with a large diameter fiber in order to reduce the cost and to increase the tensile strength of the obtained separator.

Further, in the conventionally proposed storage battery separator, even if the fiber diameter of the glass fiber is relatively large or small, the average length of the fiber is relatively long. It was

For example, in Japanese Patent Application No. 58-225846, the average diameter is
The average length is 7 to 50 mm at 0.5 to 1.0 μm.
In 290, it is said that fine fibers having an average diameter of 0.5 to 1.0 μm have an average length of 7 to 50 mm, and thick fibers having an average diameter of 10 to 20 μm have an average length of 5 to 80 mm. Japanese Patent Application Sho 58
-10059 has 3 to 1 if the average diameter is 13 to 30 μm.
It is said that an average length of 4 to 30 mm is preferable if the diameter is 00 mm and the average diameter is 3 μm or less. In addition, Japanese Patent Application No. 59-7068
2 and 59-70683 describe that the average diameter is 0.5 to 1.0 μm and the average length is 7 to 50 mm, and when the average diameter is 1 μm or more, the average length is preferably 5 to 80 mm. There is.

In the conventional storage battery separator, the average length of the glass fibers is set to such a length for the following reason. That is, with respect to the large diameter fiber, the cutting cost becomes high to shorten it, and it becomes difficult to fabricate the large diameter fiber. Further, regarding the small-diameter fiber, if the length is short, the fibers are not sufficiently entangled with each other, and the mechanical strength of the obtained separator decreases.

[Problems to be Solved by the Invention] However, when the length of the glass fibers constituting the separator is long, the dispersibility of the glass fibers during the papermaking is deteriorated, and the surface condition of the obtained separator is deteriorated. Therefore, the oxidation resistance time of the storage battery incorporating this separator is reduced.

The entanglement of the glass fibers is too strong, the swelling of the separator is hindered when absorbing the electrolytic solution, and the expansion of the separator is reduced, so that the liquid retention amount under pressure is reduced.

Therefore, a separator having good characteristics cannot be obtained.

[Means for Solving Problems] The present invention solves the problems of the above-mentioned conventional techniques, has good strength, excellent electrolyte retention under pressure, good surface condition, and oxidation resistance time. It is an object of the present invention to provide an improved storage battery separator.

The storage battery separator of the present invention is composed of 100% by weight of alkali-containing silicate glass fibers, the alkali-containing silicate glass fibers are entangled by wet papermaking, and are bonded to each other without a special adhesive. A separator for use, wherein the alkali-containing silicate glass fiber has an average diameter of 2 μm or less and an average length of less than 4 mm.
To 100% by weight, an average diameter of more than 2 μm and less than 10 μm, and an alkali silicate glass fiber having an average length of 4 mm or less 0 to 20% by weight, and an average diameter of 10 to 30 μm and an alkali silicate glass having an average length of 3 mm or less. It is characterized by comprising 0 to 50% by weight of fibers.

The present invention will be described in more detail below.

The alkali silicate glass fiber constituting the storage battery separator of the present invention is a fine fiber having a diameter of 2 μm or less and a length of 4 m.
50 to 100% by weight of less than m, 0 to 20% by weight of medium-fine fibers with a diameter of more than 2 μm and less than 10 μm and a length of 4 mm or less, and of large diameter fibers with a diameter of 10 to 30 μm and a length of 3 mm or less 0
-50% by weight.

In the above small diameter, medium-thin, and large-diameter glass fibers, if the average length of the fibers is too long, the improvement of the surface state of the separator of the present invention and the effect of improving the electrolyte holding power cannot be sufficiently obtained, On the contrary, when the average length of the fibers is too short, the tensile strength of the obtained separator is lowered, and the collection rate of the glass fibers is lowered in the paper making step during the production of the separator, resulting in poor yield.

Therefore, the length of the glass fiber having a diameter of 2 μm or less is preferably 0.2 mm or more and less than 4 mm, particularly 0.2 to 3.7 mm. Further, the length of the medium-fine glass fiber having a diameter of more than 2 μm and less than 10 μm is preferably 0.2 to 0.4 mm, and the length of the large diameter glass fiber having a diameter of 10 to 30 μm is 0.5 to 3 mm.
mm is preferred.

If the proportion of the large-diameter glass fibers exceeds 50% by weight, the large-diameter fibers are difficult to bond.

Next, a suitable range of the composition of the glass fiber in the present invention will be described.

As the glass fibers constituting the separator of the present invention, alkali-containing silicate glass fibers are used in order to bond the fibers together without using an adhesive. When the alkali-containing silicate glass fiber is used, a water glass-like substance is generated on the surface of the glass fiber in the paper making process of the manufacturing process, and the fibers are adhered to each other due to the stickiness of the water glass-like substance. In the present invention, among alkali-containing silicate glass fibers, those having good acid resistance are preferably used since they are used for storage batteries. The degree of acid resistance is preferably 2% or less in weight loss when measured according to JIS C-2202 in the state of glass fibers having an average fiber diameter of 1 mμ or less. In addition, the composition of such glass fibers mainly contains 60 to 75% by weight of SiO ₂ and 8 to 20% of R ₂ O (alkali metal oxides such as Na ₂ O and K ₂ O) ( However, SiO ₂ + R ₂ O is 75 to 90
%) And others such as CaO, MgO, B ₂ O ₃ , Al ₂ O ₃ , ZnO, Fe
Examples include those containing one kind or two or more kinds such as ₂ O ₃ . An example of a preferable alkali silicate glass is shown in Table 1 below.

In the storage battery separator of the present invention, thin, medium, and thick alkali-containing silicate glass fibers having such a composition are intertwined by wet papermaking and are bonded to each other without a special adhesive. , Substantially consisting of glass fibers.

In order to manufacture such a storage battery separator of the present invention, glass fibers previously cut to a predetermined length may be mixed and manufactured in a desired proportion, for example, by the following method. Is advantageous.

That is, glass fibers with a relatively long length, such as FA method (flame method), centrifugal method, and other short glass fiber manufacturing methods, which have a relatively long length, are prepared, and these are made into a predetermined length. Disconnect. Then, mix fibers of each of these diameters at an appropriate ratio,
This is disintegrated and dispersed with a pulper.

Alternatively, instead of cutting in advance as described above, the prepared glass fibers may be blended, and the glass fibers may be cut into short pieces by an appropriate cutting means while the glass fibers are being supplied to the paper machine net.

Even in the case of ordinary papermaking, even fine fibers with a length of 10 to 60 mm, which are only about 4 to 30 mm, or medium fine fibers, and large diameter fibers with a length of 6 to 30 mm (average 25 mm), are cut beforehand as in the former. Or by cutting in the middle like the latter, thin fibers are less than 4 mm, medium and thin fibers are 4 mm or less, and large fibers are 3 mm.
Below.

The cut glass fibers are paper-made on a net. At that time, the pH in the disintegrator and / or the pH in the paper-making tank is preferably less than about 3, for example, about 2.5.
By defibration and / or wet papermaking in such an acidic region, an adhesive layer of water glass is formed on the surface of the glass fiber, and then the glass fiber is heated to a predetermined temperature, for example, 80 to 160 ° C. The water glass on the surface makes it possible to adhere to each other.

That is, since the glass fiber constituting the separator of the present invention has an alkali-containing silicate glass composition, the alkali component and the silica component in the glass fiber react with water for dispersion in an acidic region of about pH 2.5. A water glass layer is formed on the glass fiber surface, and this water glass layer acts as an adhesive to firmly bond the glass fibers to each other.

For this reason, even if the length of the glass fiber is short and the entanglement of the fibers is relatively small as in the present invention, it is possible to sufficiently bond and obtain a high-strength separator.
The wet-processed glass fiber papermaking product is generally dried along a drum or a dryer to obtain a product.

A dispersant may be used for dispersing the fibers in water during papermaking. Further, a wet-processed fiber paper product, for example, a fiber paper product on a paper making net is sprayed with dialkyl sulfosuccinate, and 0.005 to 10% by weight of the dialkyl sulfosuccinate is adhered to the glass fiber to obtain dialkyl sulfosuccinate. The hydrophilicity of the separator can improve the liquid retention of the separator. Instead of spraying the dialkyl sulfosuccinate as described above, it may be mixed in the dispersion water in the paper making tank.

The thickness of the separator of the present invention itself varies depending on the storage battery used, but is generally preferably 0.3 to 3 mm.

[Operation] The separator of the present invention has excellent dispersibility because the glass fiber constituting the separator has a short fiber length, and the resulting separator has a smooth surface and an excellent surface condition. If the surface of the separator is smooth, it can sufficiently adhere to the electrode plate, so that the oxidation resistance time of the battery can be improved.

Further, since the fiber length is short, the entanglement of the fibers becomes appropriate, the liquid holding amount at the time of absorbing the liquid increases, and the swelling property of the separator is not hindered by the mutual tension of the fibers. Therefore, the amount of liquid retained under pressure is increased, and the battery performance can be improved.

Thus, even with glass fibers having such a short fiber length, by setting the pH in the papermaking process to an acidic range of about 2.5, the surface water vitrification effect, without using organic fibers, binders, etc., It is possible to obtain an extremely high strength paper product.

Incidentally, in the present invention, the organic fibers conventionally required for producing the separator, the binder and the like are not required at all, and the separator of the present invention does not contain the organic fibers, the resin binder and other special adhesives. As a result, the following effects are achieved.

That is, when organic fibers and the like are present, the adhesive force generated by melting these when heated inhibits the expansive force of the binder when absorbing liquid, and thus the liquid retention under pressure of the separator decreases. Becomes For example, if you experience the liquid retention properties of a normal 100% glass fiber separator and a glass fiber separator containing 5.0% by weight of organic fiber (all sample sizes are 100 mm × 100 mm × 1.03 mm thickness ( Volume 10.30c
m ³ ), weight 1.42 g), water content without load and water content with load of 20 kg (load in the thickness direction), the measurement results shown in Table 2 are obtained.

As is clear from Table 2, a 100% glass fiber separator is extremely excellent in liquid retention.

Further, while organic fibers and other adhesives may weaken the acid resistance of the separator, the separator made of glass fiber as in the present invention has extremely excellent acid resistance.

[Examples] Examples and comparative examples will be described below.

Example 1 A glass fiber having an average diameter of 0.8 μm, the composition of which is A in Table 1, was dispersed by a pulper, and then cut and disintegrated by using a high-speed disintegrator, and this was wet papermaking with a liquid of pH 2.5. Then 140
A mat-shaped storage battery separator was manufactured by heating to ° C.

Table 3 shows the results of measurement of tensile strength, liquid absorption rate, liquid retention property, and oxidation resistance time of this separator together with the fiber length.

Example 2 A separator was manufactured in the same manner as in Example 1 except that 70% by weight of the glass fiber having the average diameter of 0.8 μm and 30% by weight of the glass fiber having the average diameter of 10 μm were used.

Table 3 shows the measurement results of various characteristics of this separator.

Example 3 A separator was produced in the same manner as in Example 1 except that precut glass fibers having an average diameter of 0.8 μm and an average length of 2 mm were produced at pH 3.0 without using a high-speed disintegrator. .

Table 3 shows the measurement results of various characteristics of this separator.

Comparative Example 1 A separator was produced in the same manner as in Example 3 except that glass fibers having an average diameter of 0.8 μm and an average length of 9 mm were used.

Table 3 shows the measurement results of various characteristics of this separator.

Comparative Example 2 70% by weight of glass fibers having an average diameter of 0.8 μm and an average length of 10 mm, and glass fibers 30 having an average diameter of 19 μm and an average length of 10 mm 30.
A separator was produced in the same manner as in Example 3 except that the weight% was used.

Table 3 shows the measurement results of various characteristics of this separator.

Comparative Example 3 75% by weight of glass fibers having an average diameter of 0.8 μm and an average length of 10 mm, 20% by weight of glass fibers having an average diameter of 19 μm and an average length of 10 mm, and organic fibers (material acrylic resin, diameter 1.0 denier, length 5 mm) A separator was produced in the same manner as in Example 3 except that 5% by weight was used.

Table 3 shows the measurement results of various characteristics of this separator.

Comparative Examples 4 to 7 With respect to the separators manufactured according to the examples of Japanese Patent Application No. 59-81290 (Japanese Patent Application Laid-Open No. 60-225352) and the methods of Comparative Examples 1 to 3, various characteristics were respectively examined, and the results are shown in Table 3. It was shown to.

From Table 3, the following is clear.

That is, the separator made of the short fibers of the present invention has high strength, excellent liquid absorbency and liquid retention, and particularly excellent liquid retention under pressure. Moreover, the oxidation resistance time is greatly improved. Especially when manufactured at pH 2.5 during disaggregation,
Remarkably excellent effect is exhibited.

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 ² . (JISC-2202) Unit weight (g / cm ³ ) A value obtained by dividing the sample weight by the sample area.

Density (g / cm ³ ) Sample (weight W) Area (S) of 10 cm × 10 cm (S) When the load of 20 kg is applied to the thickness of the sample, the formula: W / (S ×
It is represented by the value given by T) (g / cm ³ ).

Tensile strength (g / 15mm width) It is indicated by the value (g) of external force when pulling both ends of a sample with a width of 15mm and cutting it.

Absorption rate (mm / min) Determined by making the sample vertical and immersing the lower part in a dilute sulfuric acid solution with a specific gravity of 1.03, and measuring the liquid level that rises with time.

Liquid retention (g / cc) Obtain water content (g) in a sample with 10 cm x 10 cm x 1 cm thickness when water is included and no weight is applied or a weight of 20 kg is applied in the thickness direction. This is shown by the value divided by the volume (cc) of the sample.

Oxidation resistance (hr) Sample (size 70 x 70 mm) in a test device as shown in Fig. 1.
Set 1 and load (lead block (70 × 70mm) 5kg) 2
After mounting, about 1000 ml of dilute sulfuric acid (specific gravity 1.300 / 20 ° C.) is injected as an electrolytic solution 4 into an acid resistant container (about 132 × 185 × 102 mm) 3 (this liquid level 4a is maintained during the test. ). Then, the temperature of the electrolytic solution is maintained at 45 ± 2 ° C., and the terminal voltage is measured at regular intervals while applying a constant current (direct current) of 2.5 A. (Note that in FIG. 1, 5 and 6 are glass plates (70 ×
70 × 5mm), 7 and 8 are contact plates (insulating plates) (50 × 50 × 3mm),
9 is an anode plate (pure lead plate) (50 × 50 × 3 mm), 10 is a cathode plate (pure lead plate) (50 × 50 × 3 mm), and 11 is an acid resistant resin stand. ) The oxidation resistance time (hr) is displayed as the time when the terminal voltage becomes 2.6 V or less or the voltage decrease rate becomes 0.2 V / hour or more.

[Effects of the Invention] As described in detail above, the storage battery separator of the present invention has 50 to 100% by weight of alkali-containing silicate glass fibers having a diameter of 2 µm or less and a length of less than 4 mm, a diameter of more than 2 µm and less than 10 µm, and a length of 4
0 to 20% by weight of alkali silicate glass fiber having a diameter of 10 mm or less, and 0 to 50% by weight of alkali silicate glass fiber having a diameter of 10 to 30 μm and a length of 3 mm or less, 100% by weight of alkali silicate glass fiber The alkali-containing silicate glass fibers are entangled by wet papermaking and are adhered to each other without a special adhesive, and the surface is smooth and the separator has a good surface condition. In addition, the oxidation resistance time of the battery can be improved.

The liquid absorbing property and the liquid retaining property are good, and particularly the liquid retaining property under pressure is excellent, so that the battery performance can be significantly improved.

 High strength can be obtained.

And so on.

Therefore, according to the separator of the present invention, a high-performance storage battery can be manufactured, and its industrial utility is extremely high.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an apparatus used for measuring an oxidation resistance time in Examples and Comparative Examples. 1 ... Sample, 2 ... Load, 3 ... Container, 4 ... Electrolyte, 9 ... Anode plate, 10 ... Cathode plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroki Kitawaki 4-chome, Doshomachi, Higashi-ku, Osaka City, Osaka Prefecture Nihon Sheet Glass Co., Ltd. 56) References JP-A-60-225352 (JP, A)

Claims (3)

[Claims] A storage battery separator comprising 100% by weight of alkali-containing silicate glass fibers, wherein the alkali-containing silicate glass fibers are entangled by wet papermaking and bonded to each other without a special adhesive. The alkali-containing silicate glass fiber is 50 to 100% by weight of the alkali-containing silicate glass fiber having a diameter of 2 μm or less and a length of less than 4 mm, and the alkali-containing silicate glass having a diameter of more than 2 μm and less than 10 μm and a length of 4 mm or less. Fiber 0-20% by weight and diameter 10-
Alkali-containing silicate glass fiber with a length of 30 μm and a length of 3 mm or less 0
A separator for a storage battery, which is characterized by containing 50% by weight. 2. Alkali-containing silicate glass fiber having a diameter of 2 μm or less, a length of 0.2 mm or more and less than 4 mm, 50 to 100% by weight, and a diameter of 2 μm.
m to less than 10 μm, length 0.2 to 4 mm, alkali silicate glass fiber 0 to 20% by weight, and diameter 10 to 30 μm, length
The storage battery separator according to claim 1, which comprises 0 to 50% by weight of 0.5 to 3 mm of alkali silicate glass fiber. 3. The length of the alkali-containing silicate glass fiber having an average diameter of 2 μm or less is 3.7 mm or less.
Item 2. The storage battery separator according to Item 2 or Item 2.