JP3060694B2 - Sheet separator and sealed lead-acid battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like separator and a sealed lead-acid battery, and more particularly to a long-life and inexpensive sheet-like separator and a sealed lead-acid battery that are less likely to cause stratification of an electrolyte.

[0002]

2. Description of the Related Art A sealed lead-acid battery has a structure in which a separator and an electrode plate are stacked in a sealed container, and an electrolyte in the battery flows into the separator and holes of the positive and negative electrodes. It is kept so that there is no. This sealed type lead-acid battery has the features that it has excellent liquid leakage resistance, does not require rehydration, and has little self-discharge.

As described in JP-B-63-27826, a large-capacity sealed lead-acid battery having a high electrode plate height is charged and discharged despite being uniform at the time of pouring. When the process is repeated, the concentration of the electrolyte held in the pores of the separator and the electrode plate becomes different in the vertical direction. That is, a stratification phenomenon occurs in which the concentration of the electrolytic solution becomes higher toward the lower part of the separator. Since this stratification phenomenon is likely to occur mainly in the separator portion, in order to prevent this, it is necessary to increase the liquid retaining power of the separator and to make sure that there is no difference in liquid retaining properties even above and below the separator, or that the electrolytic solution It is required to increase the viscosity by adding fine silica powder.

Heretofore, as the separator, those mainly composed of glass fiber have been mainly used. In order to prevent the occurrence of the stratification phenomenon, various improvements have been attempted with respect to improving the liquid retaining property (liquid retaining property) of the separator used.

For example, Japanese Patent Application Laid-Open Nos. 62-133669 and 62-136751 describe a separator coated or mixed with a powder such as SiO ₂ , TiO ₂ or a rare earth element oxide. JP-A-63-152853,
Nos. 62-221954 and 61-269852 describe the use of silica or expanded pearlite as a powder. JP-A-63-143742 and JP-A-63-146348 disclose a separator made of a hollow tubular glass fiber.

[0006] A conventional improvement technique represented by the above-mentioned publication is as follows.
It is roughly divided into the following. Reduce the average fiber diameter of the glass fibers. Use organic fiber together. Use silica powder together.

[0007] However, reducing the average fiber diameter of the glass fibers increases the cost. Further, the glass fiber separator can obtain good liquid absorption by the force of the capillary phenomenon, but still has a problem that the repulsion force at the time of liquid injection is reduced.

When organic fibers are used in combination, there is a possibility that impurities may elute into the liquid.

When silica powder is used in combination, the density of the separator increases, the porosity decreases, the amount of liquid retained decreases, and the battery capacity decreases. When silica powder is used in combination, it is easy to add the silica powder to the electrolytic solution, but the process becomes complicated, and the resulting battery becomes expensive.On the other hand, silica is used in the separator. At present, mixing is not practical because of the following reasons. That is, papermaking cannot be performed as a separator only with silica powder, and therefore, silica powder is added to a material mainly composed of glass fiber and mixed.
If the proportion of the silica powder is small, the effect of preventing the stratification phenomenon is low, and if the proportion of the silica powder is large, papermaking becomes difficult.

As described above, there has not been provided a separator for a sealed lead-acid battery which is excellent in the effect of preventing the stratification phenomenon and is easy to manufacture. Therefore, the conventional sealed lead-acid battery is stratified and has a short life.

To solve the above-mentioned conventional problems and to provide a long-life and inexpensive sealed lead-acid battery in which stratification of the electrolyte is unlikely to occur, the present applicant has proposed that the flow rate of the electrolyte is 100 mm. Per hour / hour or less using a sealed lead-acid battery, and a patent application was previously filed (Japanese Patent Application Laid-Open No. 2-2).
No. 26654). In addition, as a sealed lead-acid battery that is unlikely to cause stratification of the electrolyte, has a long life, and is inexpensive,
The inventors found a device using a separator having a flow rate of the electrolyte of not more than 100 mm / hour, and filed a patent application (Japanese Patent Application No. 1-45454; hereinafter, referred to as "first application"). This prior application separator is practically substantially composed of only glass fibers having an average fiber diameter of 0.65 μm or less, or
Alkali-containing glass fibers 95 to 3 having an average fiber diameter of 2 μm or less
0% by weight, and specific surface area 100m produced by wet method
^{It is} substantially composed of 5 to 70% by weight of silica powder of ² / g or more.

[0012]

Problems to be Solved by the Invention
According to No. 4, a low-cost sealed lead-acid battery that does not easily stratify, has a long service life, and is inexpensive is provided, but further has the following problems.

That is, when the electrode group is set in the battery case and the electrolytic solution is injected, the pressure in the bath becomes smaller than the set pressure in the dry state. In this case, the softening rate of the anode active material is increased, and the active material is easily dropped. It is difficult for the separator and the electrode plate to adhere to each other, a gap is formed, and the battery capacity is reduced. As a result, although the flow rate of the electrolyte solution is small, as described above, since the injection repulsion force is small, the battery performance is not sufficiently improved. Not done. Such a problem arises. Further, in the separator according to the prior application, which is substantially composed of only ultrafine glass fibers having an average fiber diameter of 0.65 μm or less, the cost increases. On the other hand, as described above, in order to prevent the stratification phenomenon, the hardness of the separator containing the silica powder is too high, which is not preferable.

In addition, there is no conventional separator capable of absorbing a variation in the thickness of the electrode plate and ensuring a constant pressure. If the pressure is too low, the discharge characteristics (particularly, high-rate discharge) are inferior or excessive. At present, it is difficult to insert the battery case into the battery case under strained pressure, and even when the battery case swells or cannot be inserted.

As described above, including the above-mentioned prior application, in the related art, a separator for a sealed type lead-acid battery which is excellent in the effect of preventing stratification, can be easily manufactured, and can maintain a constant pressure, and the like. By using a separator,
There has not been provided a sealed lead-acid battery that has improved battery performance, has a longer life, and is inexpensive.

The present invention solves the above-mentioned conventional problems, it is difficult for the electrolyte solution to be stratified, and has a high effect of preventing softening of the active material.
It is an object of the present invention to provide a sheet-type separator capable of providing a long-life and inexpensive sealed lead-acid battery and a sealed lead-acid battery using the same.

Another object of the present invention is to provide a sheet-like separator in which stratification of an electrolytic solution is unlikely to occur and which can maintain a constant pressure, and a sealed lead-acid battery using the same.

[0018]

According to the first aspect of the present invention, the flow rate of the electrolyte solution is 100 mm / hr.
In the following sheet-like separator, in the injection repellency curve when dilute sulfuric acid is injected as shown in FIG. 1, when the repulsion value is: S point = Pkg / dm ² B point ≧ 0.55 Pkg / dm ² C point ≧ 0.40 Pkg / dm ² .

According to a second aspect of the present invention, in the separator of the first aspect, the flow rate of the electrolyte is 80 mm.
/ Hr or less.

According to a third aspect of the present invention, there is provided the sheet-like separator according to the first or second aspect, wherein the separator is substantially composed of only glass fibers.

The sheet-like separator according to claim 4 is the separator according to claim 3, wherein the average fiber diameter is 0.4 to 0.7 μm.
40-60% by weight of small-diameter glass fibers having an average fiber diameter of 0.
20% by weight or less of medium and small diameter glass fibers exceeding 7 μm and less than 1.1 μm, 60 to 40% by weight of medium and large diameter glass fibers having an average fiber diameter of 1.1 to 5.0 μm, and 5.0 μm of average fiber diameter
, And is substantially constituted by 15% by weight or less of large-diameter glass fibers having a diameter of more than 30 μm.

A sheet-like separator according to a fifth aspect is the separator according to the fourth aspect, wherein the average fiber diameter is 0.50 to 0.6.
44-56% by weight of small-diameter glass fibers having a diameter of 5 μm, 10% by weight or less of medium- and small-diameter glass fibers having an average fiber diameter of more than 0.65 μm and less than 2.0 μm, and medium- and large-diameter glasses having an average fiber diameter of 2.0-4.5 μm. 3. 44-56% by weight of fiber and average fiber diameter
10% by weight of large-diameter glass fiber exceeding 5 μm and not more than 30 μm
It is characterized by being substantially constituted as follows.

According to a sixth aspect of the present invention, there is provided the sheet separator according to the first to third aspects, wherein a part or all of the glass fibers are subjected to a water-repellent treatment.

According to a seventh aspect of the present invention, in the sheet separator according to the sixth aspect, the water-repellent treatment is performed by a silane coupling agent.

The sheet-like separator according to claim 8 is the separator according to claim 7, wherein the water-repellent treated glass fiber has an average adhesion rate of the silane coupling agent to the glass fiber of 0.01 to 4.0% by weight. It is characterized by.

In a ninth aspect of the present invention, the ratio of the water-repellent glass fibers is 5 to 100% by weight based on the glass fibers constituting the separator. And

A sheet-like separator according to a tenth aspect is the separator according to the sixth to ninth aspects, wherein the average fiber diameter of the glass fibers is 2 μm or less.

[0028] The sheet-like separator according to claim 11 is the separator according to claims 6 to 9, wherein the glass fiber comprises a thin glass fiber having an average fiber diameter of 2 μm or less and an average fiber diameter of 2 μm.
m, and a part or all of the small-diameter glass fiber and / or the large-diameter glass fiber is water-repellent.

The sheet-like separator according to claim 12 is the separator according to claims 6 to 10, wherein the average fiber diameter is 0.4 to
40 to 60% by weight of small diameter glass fiber of 0.7 μm, 20% by weight or less of medium and small diameter glass fiber exceeding 0.7 μm and less than 1.1 μm, medium thickness of 1.1 to 5.0 μm It is characterized by being substantially composed of 60 to 40% by weight of glass fiber having a diameter of 15% by weight or less and large diameter glass fiber having an average fiber diameter of more than 5.0 μm and 30 μm or less.

The sheet-like separator according to claim 13 is the separator according to claim 12, wherein the average fiber diameter is 0.50 to 0.50.
44-56% by weight of small-diameter glass fibers of 0.65 μm, 10% by weight or less of medium- and small-diameter glass fibers having an average fiber diameter of more than 0.65 μm and less than 2.0 μm, and an average fiber diameter of 2.0-4.5 μm
44 to 56% by weight of medium and large diameter glass fibers, and large diameter glass fibers 10 having an average fiber diameter of more than 4.5 μm and 30 μm or less.
It is characterized by being substantially constituted by weight% or less.

According to a fourteenth aspect of the present invention, in the sheet separator according to the first or the second aspect, the sheet separator is substantially composed of organic fibers and glass fibers.

The sheet-like separator according to claim 15 is the separator according to claim 14, wherein the organic fibers have an average fiber diameter of 2
It is a polypropylene fiber having a mean fiber length of 2 to 25 mm with a size of ２０20 μm.

The sheet-like separator according to claim 16 is the separator according to claim 14 or 15, wherein the organic fibers 7 to 3 are used.
It is characterized by being substantially composed of 5% by weight and 93 to 65% by weight of glass fiber.

A sheet-like separator according to a seventeenth aspect is the separator according to the fourteenth to sixteenth aspects, wherein the average fiber diameter of the glass fibers is 2 μm or less.

The sheet-like separator according to claim 18 is the separator according to claims 14 to 16, wherein the glass fibers are glass fibers having an average fiber diameter of 2 μm or less and glass fibers having an average fiber diameter of 2 μm or less.
And more than one glass fiber.

A sheet-like separator according to a nineteenth aspect is the separator according to the fourteenth to sixteenth aspects, wherein the glass fibers are thin glass fibers having an average fiber diameter of 0.4 to 0.7 μm.
0 to 60% by weight, average fiber diameter exceeding 0.7 μm and 1.1 μm
20% by weight or less of medium- and small-diameter glass fibers having a mean diameter of less than 20 m, 60 to 40% by weight of medium and large-diameter glass fibers having an average fiber diameter of 1.1 to 5.0 μm, and a large diameter of not less than 30 μm and having an average fiber diameter of more than 5.0 μm. It is characterized by being composed of 15% by weight or less of glass fiber.

A sheet-like separator according to a twentieth aspect is the separator according to the nineteenth aspect, wherein the glass fibers are thin glass fibers having an average fiber diameter of 0.50 to 0.65 μm.
% By weight, medium fiber glass fiber having an average fiber diameter of more than 0.65 μm and less than 2.0 μm 10% by weight or less, average fiber diameter
It is characterized by being composed of 44 to 56% by weight of medium and large diameter glass fibers of 4.5 to 4.5 μm and 10% by weight or less of large diameter glass fibers having an average fiber diameter of more than 4.5 μm and 30 μm or less.

According to a twenty-first aspect of the present invention, there is provided the sheet-like separator according to the first aspect, wherein the separator is mainly composed of glass fiber, and is mixed with 0.5 to 5.0% by weight of polyethylene powder.

A sheet-like separator according to a twenty-second aspect is the separator according to the twenty-first aspect, wherein the glass fibers are 25 to 60% by weight of small-diameter glass fibers having an average fiber diameter of 0.4 to 0.7 μm and an average fiber diameter of 0.7 μm. 0 to 20% by weight of medium and small-diameter glass fibers exceeding 1.1 μm and an average fiber diameter of 1.1 to 5.
It is characterized by being comprised of 75 to 40% by weight of medium and large diameter glass fibers of 0 μm and 0 to 15% by weight of large diameter glass fibers having an average fiber diameter of more than 5.0 μm and 30 μm or less.

The sheet-like separator according to claim 23 is the separator according to claim 22, wherein the glass fibers are thin glass fibers having an average fiber diameter of 0.50 to 0.65 μm.
0% to 10% by weight of medium and small diameter glass fibers having an average fiber diameter of more than 0.65 μm and less than 2.0 μm.
It is characterized by being composed of 71 to 36% by weight of medium and large-diameter glass fibers of 4.5 to 4.5 μm and 0 to 10% by weight of large-diameter glass fibers having an average fiber diameter of more than 4.5 μm and 30 μm or less.

According to a twenty-fourth aspect of the present invention, there is provided a sealed lead-acid battery according to the first aspect.
24. A sheet separator according to any one of the above items 23 to 23.

Hereinafter, the present invention will be described in detail. First, the principle of the liquid repellency curve shown in FIG. 1 will be described. FIG.
In the graph, the horizontal axis represents the liquid saturation and the vertical axis represents the repulsion.

When the electrolyte is gradually (every 2 minutes) charged under a constant load of the fine glass fiber mat, a locus as shown in FIG. 1 is taken. The positions of the points A, B, and C of the curve move up and down by changing the diameter of the glass fiber constituting the glass fiber mat.

The locus from point S to point B goes down due to contraction of the separator. Locus from point B to point A due to expansion of the fine glass fiber mat. At the point A, the liquid saturation becomes almost 100%. Locus from point A to point C Due to re-shrinkage of the separator. The principle is the same as that of the locus from point S to point B (however, the positions of points B and C always satisfy point B> point C). Displacement between point B and point C Measurement of repulsion is short (2 minute interval)
Since the repelling force is measured before the electrolyte solution after injection is uniformly diffused into the fine glass fiber mat,
A phenomenon such as point B> point C occurs.

The sheet-like separator of the present invention is a separator having a flow rate of the electrolytic solution of 100 mm / hr or less.
When the flow rate of the electrolytic solution exceeds 100 mm / hr, the so-called stratification phenomenon in which the electrolytic solution concentration changes in the vertical direction of the separator when charge and discharge are repeated becomes remarkable because the ability to retain the electrolytic solution is small. The flow rate of the electrolytic solution is preferably as small as possible from the viewpoint of preventing the stratification phenomenon,
If it is too small, a great deal of time is required for injection. Therefore, in the separator used in the sealed lead-acid battery of the present invention, the flow rate of the electrolytic solution is 80 mm / hr or less, preferably 5 to 80 mm / hr, more preferably 20 to 70 mm / hr.
mm / hr.

In the present invention, the liquid repellency of the sheet-like separator and the flow rate of the electrolyte can be determined by the methods described in Examples below.

The sheet-like separator of the present invention may employ the following embodiments. (1) Glass fiber only. (2) Glass fiber only, part of which is water-repellent. (3) Those composed of organic fibers and glass fibers. (4) Glass fiber and polyethylene powder.

In the case of the above (1), when the diameter of the glass fiber is small, the liquid flowing speed is low, but the liquid repelling force is small. Conversely, when the glass fiber diameter is large, the liquid repelling force is large, but the liquid flowing speed increases. Therefore, a combination of glass fiber diameters is required in order to satisfy the liquid flow rate and liquid repellency as specified in the present invention, and it is preferable to use the following fiber composition I, more preferably fiber composition II.

Fiber blend I Fine glass fiber having an average fiber diameter of 0.4 to 0.7 μm: 40
Medium fiber glass fiber having an average fiber diameter of more than 0.7 μm and less than 1.1 μm: 20 wt% or less Medium glass fiber having an average fiber diameter of 1.1 to 5.0 μm: 6
0 to 40% by weight Large-diameter glass fiber having an average fiber diameter of more than 5.0 μm and 30 μm or less: 15% by weight or less Fiber blend II Small-diameter glass fiber having an average fiber diameter of 0.50 to 0.65 μm:
44 to 56% by weight Medium and small diameter glass fibers having an average fiber diameter of more than 0.65 μm and less than 2.0 μm: 10% by weight or less Medium and large diameter glass fibers having an average fiber diameter of 2.0 to 4.5 μm: 4
4 to 56% by weight Large-diameter glass fiber having an average fiber diameter of more than 4.5 μm and 30 μm or less: 10% by weight or less In the case of the above (2), the water-repellent treatment is preferably performed by a silane coupling agent, The treated glass fiber has an average adhesion rate of the silane coupling agent to the glass fiber of 0.01 to 4.0% by weight, particularly 0.05 to 2.
It is preferably 0% by weight, and the ratio of the water-repellent glass fibers is preferably 5 to 100% by weight based on the glass fibers constituting the separator. The silane coupling agent firmly adheres to the glass fiber surface and makes the surface water-repellent. For this reason, it is possible to increase the liquid repelling force and reduce the liquid flowing speed. If the degree of the water-repellent treatment is out of the above range, such effects may not be sufficiently achieved. Since silane has a remarkably high adhesive force to the glass fiber surface, it hardly elutes into the electrolytic solution, which is extremely advantageous.

In the embodiment (2), the glass fiber composition is as follows: (A) The average fiber diameter of the glass fiber is 2 μm or less. (B) The glass fibers are composed of small-diameter glass fibers having an average fiber diameter of 2 μm or less and large-diameter glass fibers having an average fiber diameter of more than 2 μm. (C) The glass fiber is composed of the above-mentioned fiber blend I, preferably the fiber blend II. In the cases (B) and (C), the fiber diameter of the glass fiber to be subjected to the water-repellent treatment is not particularly limited, and at least one of the small diameter and the large diameter glass fibers, the small diameter, and the medium diameter At least one of small, medium and large glass fibers
Seeds can be water repellent.

In this case, a small amount of another substance harmless to the battery may be mixed as a reinforcing material (Japanese Patent Application Laid-Open No. 64-523 / 1988).
No. 75).

In the embodiment (3), the organic fibers have an average fiber diameter of 2 to 20 μm and an average fiber length of 2 to 2 μm.
5 mm polypropylene fibers are preferred, and organic fibers 7 to
It is preferable that it is substantially constituted by 35% by weight and 93 to 65% by weight of glass fiber.

That is, polypropylene fibers have high water repellency and are effective in the present invention. If the average fiber diameter of the polypropylene fiber is less than 2 μm, it is expensive, and if it exceeds 20 μm, the effect is small. If the average fiber length is less than 2 mm, the cutting cost is high and the practicality is low. If the average fiber length is more than 25 mm, the dispersibility is poor. In addition, the mixing ratio of organic fibers is 7% by weight.
If it is less than 35% by weight, the effect is small.

Also in the mode (3), the glass fiber constitutions (A) to (C) can be adopted as the glass fiber constitution.

In the above embodiment (4), the polyethylene powder preferably has an average particle size of 2 to 10 μm. If the average particle size of the polyethylene powder is less than 2 μm, the cost becomes high, and if it exceeds 10 μm, the effect of reducing the liquid flowing speed decreases, and any case is not preferable.

When the ratio of such polyethylene powder is 0.1.
If the amount is less than 5% by weight, a sufficient effect of mixing the polyethylene powder cannot be obtained. If the amount is more than 5.0% by weight, the amount of the polyethylene powder is too large, and the electrolyte does not easily permeate into the separator. Therefore, the ratio of the polyethylene powder in the separator is set to 0.5 to 5.0% by weight.

Since the polyethylene powder is hydrophobic, by mixing it, the flow rate of the electrolyte in the separator can be effectively reduced. For this reason, the stratification phenomenon of the separator is prevented.

Further, the polyethylene powder has an effect of weakening the adhesion between the glass fibers, so that the separator becomes soft and flexible. For this reason, it is possible to secure a constant tension.

Moreover, by using polyethylene powder, it is possible to secure required characteristics without using fine glass fibers. Therefore, it is possible to provide a separator at a low cost by using a relatively large diameter glass fiber.

For this reason, the blending ratio of the glass fibers can increase the blending ratio of the glass fibers having a relatively large diameter compared to the above-mentioned fiber blends I and II. For example, the following fiber blend III, preferably fiber blend IV , Average fiber diameter 1.1 to 5.0 μm
The ratio of the glass fiber of medium and large diameters can be increased.

Fiber composition III Fine glass fiber having an average fiber diameter of 0.4 to 0.7 μm: 25
-60% by weight Medium and small diameter glass fibers having an average fiber diameter of more than 0.7 μm and less than 1.1 μm: 0 to 20% by weight Medium and large diameter glass fibers having an average fiber diameter of 1.1 to 5.0 μm: 7
5 to 40% by weight Large-diameter glass fiber having an average fiber diameter of more than 5.0 μm and 30 μm or less: 0 to 15% by weight fiber-containing IV Small-diameter glass fiber having an average fiber diameter of 0.50 to 0.65 μm:
24 to 56% by weight Medium and small diameter glass fibers having an average fiber diameter of more than 0.65 μm and less than 2.0 μm: 0 to 10% by weight Medium and large diameter glass fibers having an average fiber diameter of 2.0 to 4.5 μm: 7
1 to 36% by weight Large-diameter glass fiber having an average fiber diameter of more than 4.5 μm and 30 μm or less: 0 to 10% by weight According to the separator according to the aspect of (4), in the measurement method in Examples described below, Characteristics can be secured.

Electrolyte flow rate: 100 mm / hour or less Apparent density / tight pressure: 1.3 × 10 ⁻⁴ or more 20 kg / dm ² Density under pressure: 0.165 g / cm ³ or less Tensile strength: 200 g / 15 mm width Liquid retention: 0.6 g / cc or more Liquid absorption: 50 mm / 5 minutes or more Since the glass fibers used in the present invention are used for storage batteries even among alkali-silicate glass fibers, Those having good acid resistance are preferably used. The degree of acid resistance is desirably that the weight loss is 2% or less when measured according to JIS C-2202 in the state of glass fibers having an average fiber diameter of 1 μm or less. In addition, the composition of such glass fibers may be 60 to 75% SiO 2 by weight.
₂ and 8 to 20% of R ₂ O (alkali metal oxide such as Na ₂ O, K ₂ O) mainly (provided that SiO ₂
+ R ₂ O 75 to 90%), Other example CaO, M
One containing one or more of gO, B ₂ O ₃ , Al ₂ O ₃ , ZnO, Fe ₂ O _{3 and the} like can be mentioned. An example of a preferred alkali-containing silicate glass is shown in Table 1 below.

[0063]

[Table 1]

For producing the separator of the present invention, for example, the following method is advantageous. That is, a glass fiber having a relatively short length produced by a FA method (flame method), a centrifugal method, or another method for producing short glass fiber is prepared, and defibrated, cut, and dispersed by a pulper. Alternatively, the glass fiber may be cut into short pieces by an appropriate cutting means during the supply of the glass fiber to the papermaking machine net.

The cut glass fiber and polyethylene powder (in the above-mentioned embodiment (4)) are made on a net. This wet-formed glass fiber paper is generally dried along a drum or a dryer to obtain a product.

In the papermaking, a dispersant may be used when the fibers are dispersed in water. Further, a dialkyl sulfosuccinate is sprayed on a wet paper-formed fiber paper, for example, a fiber paper on a paper-making net, and adhered to the glass fiber in an amount of 0.005 to 10% by weight to obtain a dialkyl sulfo. The liquid retaining property of the separator can be improved by the hydrophilicity of the succinate. Instead of spraying the dialkyl sulfosuccinate as described above, the dialkyl sulfosuccinate may be mixed into the dispersion water in the papermaking tank.

The thickness of the separator of the present invention is not particularly limited, but is preferably not less than the average fiber length of the glass fibers.

The sealed lead-acid battery of the present invention can be easily manufactured by using such a separator of the present invention according to a conventional method.

[0069]

EXAMPLES Examples and comparative examples will be described below.
The methods for measuring the flow rate of the electrolytic solution, the repelling force of the electrolyte solution, the battery life cycle, the tensile strength, the liquid absorbing property, the liquid retaining property, the thickness and the basis weight in Examples and Comparative Examples are as follows.

Flow Rate of Electrolyte Solution A sample is cut into a size of 50 mm × 250 mm. Two acrylic plates (width 70 to 8) placed opposite each other with spacers at both ends so that the weight of the sample is about 6.75 g (packing density 0.16 to 0.21 g / cm ³ )
(0 mm x length 500 mm). Immerse the sample in water. The wet sample is set on the measuring jig. A sulfuric acid solution having a specific gravity of 1.3 is gently injected from above the acrylic plate with a pipette. The injection of the sulfuric acid solution is set to 100 mm from the top of the sample, and the height is kept constant by adding a liquid as needed. The sulfuric acid solution is previously colored with red ink or methyl orange. 5 minutes, 10 minutes, 30 minutes, after finishing pouring the electrolyte,
The falling distance after 60 minutes is measured with a steel measure. Time is measured accurately with a stopwatch. The measurement is performed three times for each sample.

Injection repulsion force Measured as follows using a repulsion force tester shown in FIG. (1) 30 samples (100 mm x 100 mm)
Cut one sheet). (2) The weight of one set of samples 1 is measured. (3) Perform preliminary experiments first.

Preliminary experiment procedure: The sample 1 was set on a repulsion tester, the handle 2 was turned, the sample 1 was compressed, the compression force was detected by the load cell 3, read by the pressure gauge 4, and set to 40 kg / m ² pressure. I do. After setting, gradually add water 5 from the top of the sample 1 and check how many cc of water comes out from the side of the sample. The amount of liquid when water comes out from the side is defined as (W).

(4) After completion of the preliminary experiment, the sample is set on a repulsion tester and set to a pressure of 40 kg / m ² again. (After setting, adjust the pressure to 40 kg again every minute,
(5kg) After setting, measure the thickness of the sample at 4 points with a caliper. (6) Charge 10 g of water at a time, and measure the change in pressure after 2 minutes. (7) The same measurement as in (6) is performed by halving the input amount of water to 5 g from around 20 g of the amount of water (preliminary experimental value). (8) Next, extra water (water that cannot be absorbed by the sample) is sucked with a dropper and a syringe, and the amount of the sucked water is measured and recorded. (9) Finally, suck up the water in the sample with a syringe. (10) The operation of (9) is to be performed finely until the pressure no longer changes. (11) The measurement shall be performed twice or more. (12) The results are shown as points S, B, and C in the graph of FIG.

Battery Life Cycle A sealed lead-acid battery was assembled using various separators. The assembled sealed lead-acid battery has a width of 40 mm and a height of 7
0 mm × 3.3 mm thick positive electrode plate and a negative electrode plate having the same size and a thickness of 2.0 mm are laminated by applying a pressure of 20 kg / dm ² through a predetermined separator, 43 cc of H ₂ SO ₄ having a specific gravity of 1.30 was injected per cell, and the capacity per cell was 5 Ah / 20 HR. The battery assembled in this manner was subjected to an alternate charge / discharge life test with one cycle of "discharge at 1.4 A for 3 hours and charge at 1.02 A for 5 hours". When the capacity of the battery is 4.2 Ah (= 1.
4A × 3h) or less was defined as the life.

Tensile strength A sample having a width of 15 mm is pulled at both ends, and is indicated by an external force value (g) when the sample is cut.

The liquid-absorbent sample is vertically set, and its lower part is immersed in a dilute sulfuric acid solution having a specific gravity of 1.03, and the liquid level rising for 5 minutes is measured.

Liquid holding property The weight and thickness of the sample are measured in advance. This was immersed in a water-filled band for 30 seconds, and then pulled up on a tilting stand, and 45 °
After holding the sample for 5 minutes, the weight of the sample is measured, and the liquid retention is determined by the following equation. Liquid retention (g / cc) = (W ₂ −W ₁ ) / l × W × t W ₁ : Weight of sample before immersion (g) W ₂ : Weight of sample after immersion (g) l: Length 25 cm W : Width (cm) 5 cm t: Actual thickness of sample (cm) Apparent density / tightness 60 kg / dm ² Apparent density D _{60 when} pressurized and 10 kg / d
Value obtained by dividing the difference between the apparent density D ₁₀ of ₂ under pressure in _{^{50kg / dm 2 (D 60 -D}} 10) / 50 That is represented by (apparent density /緊圧).

This is a value obtained by dividing the basis weight of the sample by the area of the sample.

The thickness is measured with the sample pressed in the thickness direction with a load of 20 kg / dm ² . (JISC-2202) Examples 1 and 2, Comparative Examples 1 to 5 Sheet-like separators having the values shown in Table 2 and a liquid repelling force were prepared, and the battery life cycle was examined. The results are shown in Table 2. Indicated.

[0080]

[Table 2]

Examples 3 to 5 and Comparative Examples 6 to 11 Various physical properties and characteristics of the glass fiber-containing separator shown in Table 3 were examined, and the results are shown in Table 3.

[0082]

[Table 3]

Example 6 For the glass fiber blending system having the average fiber diameter shown in FIG. 3 below, the liquid flowing speed and the liquid repellency (point B) were examined. The results are shown in FIG. In FIG. 3, the solid line shows the results of a glass fiber blending system having an average fiber diameter of 0.6 μm and 2.0 μm, and the broken line shows the results of a glass fiber blending system having an average fiber diameter of 0.6 μm and 4.0 μm. It is apparent from FIG. 3 that the blending range of α is suitable.

As shown in Table 3, when a small amount of glass fiber having a diameter of more than 30 μm and exceeding 30 μm is mixed in a small amount as in Example 5, the cost can be reduced. If the mixture is too much mixed, as in Comparative Example 11, the liquid flow rate and the repellency of the injected liquid deteriorate, so that the mixing ratio is not more than 15% by weight, preferably 10% by weight.
It must be:

Examples 7 to 23 and Comparative Examples 12 to 14 Various characteristics were examined for separators having the following glass fibers blended as shown in Tables 4 to 6, and the results are shown in Tables 4 to 6.

[0086]

[Table 4]

[0087]

[Table 5]

[0088]

[Table 6]

Examples 24 and 25 and Comparative Examples 15 to 20 Various characteristics of the fiber-containing separators shown in Table 7 were examined, and the results are shown in Table 7. The organic fibers used are as follows.

Polypropylene fiber = Average fiber diameter 8 μm Average fiber length 5 mm Polyethylene fiber = Average fiber diameter 8 μm Average fiber length 2 mm Polyester fiber = Average fiber diameter 7 μm Average fiber length 5 mm

[0091]

[Table 7]

Examples 26 to 29 and Comparative Examples 21 to 26 Various properties of the fiber-containing separator shown in Table 8 were examined, and the results are shown in Table 8.

[0093]

[Table 8]

Examples 30 to 37 and Comparative Examples 27 to 34 Separators for storage batteries were manufactured using the materials shown in Tables 9 and 10, and the results of measuring various characteristics are shown in Tables 9 and 10. In addition, the results of comprehensive evaluation from the measurement results of each characteristic are shown in Tables 9 and 10 as x = impossible and o = good.

[0095]

[Table 9]

[0096]

[Table 10]

The following is clear from Tables 9 and 10. That is, the separator according to the aspect (4) of the present invention has excellent stratification prevention effect, and thus has excellent life performance, particularly excellent alternating charge / discharge life performance. In addition, the liquid retentivity is remarkably high, and the apparent density / toning pressure is 1.3 × 10 ⁻⁴ or more, so that it can be easily incorporated into a sealed lead-acid battery case. The larger the apparent density / stress is, the higher the elasticity is, the easier it is to compress when placed in a battery case, and the superior the pressing force after being placed, indicating that it is suitable as a separator. As described above, since the separator is soft and highly resilient, even if the number of the electrode plates is large, the tension is absorbed, and the separator is easily put in the case of the sealed lead-acid battery, and the tension varies. Nothing.

[0098]

As described in detail above, the sheet-like separator of the present invention has a remarkably high liquid-retaining property for the electrolytic solution, the liquid-retaining property in the vertical direction of the separator is equalized, and the stratification phenomenon and the activity are improved. Since the material is prevented from softening, it has an extremely long life performance.

Therefore, not only a small-capacity sealed lead-acid battery but also a large-capacity sealed lead-acid battery having a high electrode plate has a long life with stable and excellent battery performance. It is clear that this extended life exhibits a long life performance not only in the alternating charging and discharging as tested, but also in the application of floating charging.

In the case of the sheet separator according to any one of the fourth to twentieth aspects, it is possible to provide a sheet separator having a particularly low flow rate of the electrolyte and a high repulsion force.

In particular, the sheet-like separator of claims 21 to 23 is easy to incorporate into a battery case because it is soft and rich in elasticity. Also, the tension is constant. Moreover, this separator can be composed mainly of glass fibers having a relatively large diameter, so that it is possible to reduce the cost of the separator and to provide an inexpensive sealed lead-acid battery excellent in manufacturing workability.

According to the sealed lead-acid battery of the twenty-fourth aspect, a sealed lead-acid battery having a long service life, low cost, and excellent battery performance is provided.

[Brief description of the drawings]

FIG. 1 is a graph showing an injection repulsion curve.

FIG. 2 is a diagram illustrating a measuring device for liquid repellency;

FIG. 3 is a graph showing the results of Example 5.

[Explanation of symbols]

 1 sample 2 handle 3 load cell 4 pressure gauge 5 water

Continuing from the front page (72) Inventor Shoji Sugiyama 3-5-11 Doshomachi, Chuo-ku, Osaka-shi, Osaka Inside Nippon Sheet Glass Co., Ltd. (72) Inventor Yasuhide Nakayama 6-6 Josaicho, Takatsuki-shi, Osaka Yuasa Battery Co., Ltd. Inside the company (72) Katsumi Kitagawa 6-6 Josai-cho, Takatsuki-shi, Osaka Yuasa Battery Co., Ltd. (72) Inventor Kenjiro Kishimoto 6-6 Josai-cho, Takatsuki-shi, Osaka Yuasa Battery Co., Ltd. (56) Reference Reference JP-A-2-226654 (JP, A) JP-A 1-248459 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/14-2/18

Claims (24)

(57) [Claims] 1. A sheet-like separator in which the flow rate of an electrolytic solution is 100 mm / hr or less, and in a liquid repelling force curve when dilute sulfuric acid is injected as shown in FIG. sheet separator, characterized in that when a point B ≧ 0.55Pkg / dm ² C point ≧ 0.40Pkg / dm ² to pkg / dm ^2. 2. The sheet-like separator according to claim 1, wherein the flow rate of the electrolyte is 80 mm / hr or less. 3. The sheet-like separator according to claim 1, which is substantially composed of only glass fibers. 4. A small glass fiber having an average fiber diameter of 0.4 to 0.7 μm, 40 to 60% by weight, a medium diameter glass fiber having an average fiber diameter of more than 0.7 μm and less than 1.1 μm, and not more than 20% by weight.
Medium-diameter glass fiber 60 having an average fiber diameter of 1.1 to 5.0 μm
-40% by weight and an average fiber diameter of more than 5.0 μm and 30
The sheet-like separator according to claim 3, which is substantially constituted by 15% by weight or less of a large-diameter glass fiber having a diameter of not more than μm. 5. A small-diameter glass fiber having an average fiber diameter of 0.50 to 0.65 μm, 44 to 56% by weight, and an average fiber diameter of 0.65 μm.
10% by weight of medium- and small-diameter glass fibers exceeding 2.0 m and less than 2.0 μm
Hereinafter, it is substantially composed of 44 to 56% by weight of medium and large diameter glass fibers having an average fiber diameter of 2.0 to 4.5 μm and 10% by weight or less of large diameter glass fibers having an average fiber diameter of more than 4.5 μm and 30 μm or less. The sheet-like separator according to claim 4, which is formed. 6. The sheet-like separator according to claim 1, wherein at least a part of the glass fiber has been subjected to a water-repellent treatment. 7. The sheet separator according to claim 6, wherein the water-repellent treatment is performed using a silane coupling agent. 8. The water-repellent treated glass fiber has an average adhesion rate of the silane coupling agent to the glass fiber of 0.01 to 0.01.
The sheet-like separator according to claim 7, which is 4.0% by weight. 9. The ratio of the glass fiber subjected to the water-repellent treatment is 5 to 100% by weight with respect to the glass fiber constituting the separator.
The sheet-like separator according to claim 7 or 8, wherein 10. The sheet-like separator according to claim 6, wherein the average fiber diameter of the glass fibers is 2 μm or less. 11. The glass fiber is composed of a small-diameter glass fiber having an average fiber diameter of 2 μm or less and a large-diameter glass fiber exceeding an average fiber diameter of 2 μm, and a part of the small-diameter glass fiber and / or the large-diameter glass fiber or 7. All the parts are water-repellent.
10. The sheet separator according to any one of claims 9 to 9. 12. A small-diameter glass fiber having an average fiber diameter of 0.4 to 0.7 μm, 40 to 60% by weight, a medium-diameter glass fiber having an average fiber diameter of more than 0.7 μm and less than 1.1 μm, and an average of 20% by weight or less. It is substantially composed of medium to large diameter glass fibers having a fiber diameter of 1.1 to 5.0 μm, 60 to 40% by weight, and large diameter glass fibers having an average fiber diameter of more than 5.0 μm and 30 μm or less, 15% by weight or less. The sheet separator according to any one of claims 6 to 10. 13. A small-diameter glass fiber having an average fiber diameter of 0.50 to 0.65 μm, 44 to 56% by weight, and an average fiber diameter of 0.65.
More than 10 μ% by weight of medium- and small-diameter glass fibers exceeding 2.0 μm and less than 2.0 μm, 44-56% by weight of medium- and large-diameter glass fibers having an average fiber diameter of 2.0 to 4.5 μm, and exceeding 4.5 μm in average fiber diameter The sheet-like separator according to claim 12, which is substantially constituted by 10% by weight or less of a large-diameter glass fiber of 30 µm or less. 14. The sheet-like separator according to claim 1, which is substantially composed of an organic fiber and a glass fiber. 15. The organic fiber has an average fiber diameter of 2 to 20 μm.
The sheet-like separator according to claim 14, wherein the sheet-like separator is a polypropylene fiber having an average fiber length of 2 to 25 mm. 16. The sheet-like separator according to claim 14, which is substantially composed of 7 to 35% by weight of organic fibers and 93 to 65% by weight of glass fibers. 17. The sheet-like separator according to claim 14, wherein the average fiber diameter of the glass fibers is 2 μm or less. 18. The sheet-like separator according to claim 14, wherein the glass fibers are composed of glass fibers having an average fiber diameter of 2 μm or less and glass fibers having an average fiber diameter of more than 2 μm. 19. The glass fiber has an average fiber diameter of 0.4 to
40 to 60% by weight of small diameter glass fiber of 0.7 μm, 20% by weight or less of medium and small diameter glass fiber exceeding 0.7 μm and less than 1.1 μm, medium thickness of 1.1 to 5.0 μm The sheet-like separator according to any one of claims 14 to 16, comprising a glass fiber having a diameter of 60 to 40% by weight and a large-diameter glass fiber having an average fiber diameter of more than 5.0 µm and 30 µm or less being 15% by weight or less. . 20. The glass fiber has an average fiber diameter of 0.50 to 0.50.
44-56% by weight of small-diameter glass fibers of 0.65 μm, 10% by weight or less of medium- and small-diameter glass fibers having an average fiber diameter of more than 0.65 μm and less than 2.0 μm, and an average fiber diameter of 2.0-4.5 μm
44 to 56% by weight of medium and large diameter glass fibers, and large diameter glass fibers 10 having an average fiber diameter of more than 4.5 μm and 30 μm or less.
20. The sheet-like separator according to claim 19, wherein the sheet-like separator is constituted by less than or equal to% by weight. 21. The sheet-like separator according to claim 1, wherein the sheet-like separator is mainly composed of glass fibers, and is mixed with 0.5 to 5.0% by weight of polyethylene powder. 22. The glass fiber has an average fiber diameter of 0.4 to
25 to 60% by weight of small-diameter glass fiber having a diameter of 0.7 μm, 0 to 20% by weight of medium- and small-diameter glass fibers having an average fiber diameter of more than 0.7 μm and less than 1.1 μm, and an average fiber diameter of 1.1 to 5.0 μm. 75 to 40% by weight of large-diameter glass fiber, and 0 to 1 large-diameter glass fiber having an average fiber diameter of more than 5.0 μm and 30 μm or less.
The sheet-like separator according to claim 21, which is composed of 5% by weight. 23. The glass fiber has an average fiber diameter of 0.50 to 0.50.
24-56% by weight of 0.65 μm thin glass fiber, 0-10% by weight of medium and thin glass fiber having an average fiber diameter of more than 0.65 μm and less than 2.0 μm, average fiber diameter of 2.0-4.5 μm
71 to 36% by weight of medium and large diameter glass fibers, and large diameter glass fibers 0 having an average fiber diameter of more than 4.5 μm and 30 μm or less.
23. The sheet separator according to claim 22, comprising 10% by weight. 24. A sealed lead-acid battery using the sheet-like separator according to any one of claims 1 to 23.