JP2005108538A - Separator for sealed lead-acid battery, and sealed lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator for a sealed lead-acid battery for high voltage capable of preventing a stratification phenomenon without increasing the density of the separator, and of preventing a lead permeation short circuit, and having a certain tight contact property secured; and to provide a sealed lead-acid battery. <P>SOLUTION: This separator for a sealed lead-acid battery has a structure wherein chain connection structure powder-like silica particles are interlaid, in a dispersed state, in a sheet of a mat structure manufactured by using a minute glass fiber as a main constituent to form a three-dimensional network of the silica particles throughout the sheet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention particularly relates to a high-voltage sealed lead-acid battery separator and a sealed lead-acid battery.

In a sealed lead-acid battery having a structure in which oxygen gas generated from the positive electrode is absorbed by the negative electrode during charging, the positive electrode plate and the negative electrode plate are laminated via a separator that also serves as an electrolyte holding body impregnated with a sulfuric acid electrolyte. Therefore, compared with an open-type lead-acid battery having a flowing electrolytic solution, the amount of the electrolytic solution is limited to eliminate the fluidity, and oxygen gas can easily pass through the separator. However, in a battery having such a structure, sulfate ions are consumed by the active material during discharge and the specific gravity of the electrolyte decreases, and when discharged, the specific gravity of the electrolyte increases and the specific gravity of the electrolyte increases. It is known that the concentration gradient of the sulfuric acid electrolyte solution, that is, the stratification phenomenon occurs at the upper and lower parts of the separator.
Conventionally, in a sealed lead-acid battery for high voltage, there has been a problem that the electrode plate height becomes high in order to satisfy the demand for higher capacity, and thus the stratification phenomenon becomes remarkable. In order to prevent this stratification phenomenon, (1) increase the electrolyte retention of the separator, (2) make no difference in electrolyte retention above and below the separator, (3) from the top to the bottom of the separator It is effective to make it difficult for the electrolyte solution to move to (4), and to improve the adhesion between the separator and the electrode plate.

For this reason, as a sealed lead-acid battery separator with improved electrolyte retention, a wet-mixed glass fiber having an average fiber diameter of 0.5 to 5.0 μm and silica powder (for example, Patent Document 1 or 2), Also known is a wet blend of acid-resistant glass fibers having an average fiber diameter of 2 μm or less, silica powder having a specific surface area of 100 m ² / g, and beaten cellulose or fibrillated cellulose (Patent Document 3).
These separators for sealed lead-acid batteries have high electrolyte affinity and electrolysis that powder silica with complex pore structure possesses by dispersing and holding powder silica in the gaps of the glass fiber mat-like sheet. In addition to utilizing the liquid retainability, the pore diameter of the entire separator is reduced to improve the electrolyte retainability.
However, in order to efficiently produce a separator having a structure in which powdered silica is dispersed and held in the void portion of such a glass fiber mat-like sheet by a wet papermaking method, a flocculant is added during wet papermaking, Powdered silica must be adsorbed and held on the glass fiber surface. However, since the added flocculant also has an action of adsorbing the powdered silica, the powdered silica particles that have formed secondary particles at the time of the raw material are further agglomerated during wet papermaking to form larger silica agglomerates. A collection is formed.
That is, as shown in FIG. 2, spherical silica primary particles (see FIG. 2 (a)) are aggregated in a lump to form silica secondary particles 4 ′ (see FIG. 2 (b)) in the raw material state. Although it is powdery silica particles, the silica secondary particles 4 ′ are further aggregated by the action of an aggregating agent during wet paper making to form a larger lump silica aggregate 4 (see FIG. 2 (c)). The silica aggregate 4 is in a state of being dispersed and held in the void portions of the entire glass fiber mat-like sheet so as to be adsorbed and held on the surface of the glass fiber 1 (see FIG. 2 (d)).

  Also, as a sealed lead-acid battery separator with improved adhesion between the separator and the electrode plate, that is, tightness, a combination of a thin glass fiber and a large glass fiber (Patent Document 4) is known. . In this sealed lead-acid battery separator, by combining glass fibers with a small diameter or large diameter as appropriate, the electrolyte flow rate of the separator is reduced to significantly increase the electrolyte retention, and the electrolyte retention in the vertical direction of the separator is even. In addition, the liquid repulsive force is increased to increase the tightness.

Japanese Patent Laid-Open No. 60-221554 JP-A 61-269852 JP-A-4-22061 JP-A-5-67463

However, in the case of the sealed lead-acid battery separators of Patent Documents 1 to 3, in order to prevent the stratification phenomenon, the powdered silica is configured to be dispersed and held so as to improve the electrolyte retention of the separator. However, as described above, since the powdery silica secondary particles 4 ′ in the raw material form a larger silica aggregate 4 and are dispersed and held in the void portions of the glass fiber mat-like sheet, A relatively large space 5 is easily formed between the aggregates 4 and 4 (see FIG. 2D). Accordingly, since the electrolyte easily moves downward through the space 5, the stratification phenomenon in which the high specific gravity sulfuric acid electrolyte moves downward due to repeated charge and discharge as described above is likely to occur. It cannot be prevented. As a countermeasure, a method of increasing the content of powdered silica and reducing the space 5 can be considered. However, in this case, the separator has a high density and the space ratio is reduced, and the electrical resistance of the separator is reduced. In addition to the increase, there is a disadvantage that the electrolytic solution holding capacity decreases and the battery capacity decreases.
Moreover, since the separator for sealed lead-acid batteries of Patent Document 4 does not contain powdered silica and is substantially composed only of glass fibers, the pore diameter of the separator cannot be reduced and the pore structure cannot be complicated. There is a problem that lead penetration short circuit (dendritic short circuit) caused by lead powder entering the separator and growing in a dendritic shape and penetrating through the separator cannot be prevented.
Therefore, in view of such a conventional problem, the present invention can prevent a stratification phenomenon without increasing the density of the separator, prevent a lead penetration short circuit, and ensure a certain tightness. An object of the present invention is to provide a sealed lead-acid battery separator and a sealed lead-acid battery for high voltage.

In order to achieve the above object, the separator for a sealed lead-acid battery according to the present invention has a chain connected structure powder form in a sheet of a mat structure formed mainly from fine glass fibers as described in claim 1. Silica particles are interposed in a dispersed state, and a three-dimensional network network of the silica particles is formed on the entire sheet.
Moreover, the separator for sealed lead-acid batteries according to claim 2 is characterized in that, in the separator for sealed lead-acid batteries according to claim 1, 1 to 50% by mass of the chain linked structure powdered silica particles is contained. And
The sealed lead-acid battery separator according to claim 3 is the sealed lead-acid battery separator according to claim 1 or 2, wherein the density of the separator is 0.30 g / cm ³ or less.
Moreover, the separator for sealed lead-acid batteries according to claim 4 is the separator for sealed lead-acid batteries according to any one of claims 1 to 3, wherein the separator is mainly composed of the fine glass fiber and the chain connection structure. It is formed by wet-mixing powdered silica particles.
Moreover, the sealed lead-acid battery according to the present invention uses the separator according to any one of claims 1 to 4 as described in claim 5.

The separator for a sealed lead-acid battery according to the present invention has chain-like linked structured powdery silica particles interposed in a dispersed state in a mat-structured sheet made mainly from fine glass fibers, and the silica is dispersed throughout the sheet. Since a three-dimensional network network of particles is formed, it is possible to form voids that are relatively uniform in size and refined over the entire separator. This makes it difficult for the electrolyte solution to move downward through the gap, thus preventing the stratification phenomenon and reducing the overall pore diameter of the separator and complicating the pore structure. Can be prevented. In addition, it is not necessary to increase the content of powdered silica to prevent stratification and lead permeation short circuiting as in the case of using conventional spherical powdered silica. Densification does not reduce the space ratio, and it does not increase the electrical resistance of the separator or decrease the electrolyte holding capacity to decrease the battery capacity. Further, since a relatively uniform fine void is formed in the entire separator, good electrolyte solution retention is given to the entire separator, and electrolyte solution retention in the vertical direction of the separator can be equalized. In addition, since the silica particles form a three-dimensional network network throughout the separator, the separator can be provided with a certain level of tension (cushioning), and the battery assembly of the sealed lead-acid battery can be improved. The adhesion between the electrode plate and the electrode plate can be improved. Furthermore, even if the silica particles form an aggregate, the conventional silica particles do not become a massive silica aggregate in which the silica particles are in close contact with each other. Therefore, the dewaterability during wet papermaking is improved and productivity can be improved.
For this reason, by using the separator for sealed lead-acid batteries of the present invention, high output and high capacity can be achieved, and a sealed lead-acid battery for high voltage can be obtained.

The separator for a sealed lead-acid battery according to the present invention has chain-like linked structured powdery silica particles interposed in a dispersed state in a mat-structured sheet made mainly from fine glass fibers, and the silica is dispersed throughout the sheet. A three-dimensional network of particles is formed.
This is schematically shown in FIG. 1, focusing on powdered silica. As shown in FIG. 1, spherical silica primary particles (see FIG. 1 (A)) are connected in a linear, beaded, branched, or annular shape to form silica secondary particles 2 ′ (see FIG. 1 (B)). ) Are chain-linked structured powdery silica particles in the raw material state, but due to the action of the flocculant during wet papermaking, the silica secondary particles 2 'are agglomerated to form a long chain. A silica aggregate 2 (see FIG. 1 (C)) that is grown while maintaining a connected structure is formed, and the silica aggregate 2 is adsorbed and held on the surface of the glass fiber 1 (FIG. 1 (D )), And is dispersed and held in the voids of the entire glass fiber mat-like sheet.
In other words, when the silica particles form a silica aggregate, they grow while maintaining a chain-like connection structure to form an aggregate, so that the silica particles are distributed over the entire sheet of the glass fiber mat structure. The separator is formed in such a state that the silica particles are formed, and unlike the separator using the conventional spherical powdery silica, the silica particles do not form a lump in close contact with each other. A large space is not formed in between, and spaces 3 and 3 that are relatively uniform in size and miniaturized are formed in the entire separator.
Therefore, since it becomes difficult for the electrolyte to move downward through the space 3, the stratification phenomenon can be prevented, and the pore diameter of the separator can be reduced as a whole and the hole structure can be complicated. Prevention can be achieved. In addition, it is not necessary to increase the content of powdered silica to prevent stratification and lead permeation short circuiting as in the case of using conventional spherical powdered silica. Densification does not reduce the space ratio, and it does not increase the electrical resistance of the separator or decrease the electrolyte holding capacity to decrease the battery capacity. Further, since a relatively uniform fine void is formed in the entire separator, good electrolyte solution retention is given to the entire separator, and electrolyte solution retention in the vertical direction of the separator is equalized. In addition, since the silica particles form a three-dimensional network network throughout the separator, the separator can be provided with a certain level of tension (cushioning), and the battery assembly of the sealed lead-acid battery can be improved. The adhesion between the electrode plate and the electrode plate can be improved. Furthermore, even if the silica particles form an aggregate, the conventional silica particles do not become a massive silica aggregate in which the silica particles are in close contact with each other. Therefore, the dewaterability during wet papermaking is improved and productivity can be improved.

  The separator is preferably obtained by wet-mixing chain connected structure powdered silica particles mainly composed of fine glass fibers. By doing so, chain-like linked structured powdery silica particles are interposed in a uniformly dispersed state in a mat-structured sheet made mainly of fine glass fibers, and the silica particles are uniformly distributed throughout the sheet. 3D mesh network can be formed.

As described above, the chain-linked structure powdery silica particles have a structure in which spherical powdery silica primary particles are connected in a linear, beaded, branched, or annular shape to form powdered silica. Secondary particles are formed.
The content of the chain connected structure powdery silica particles in the separator is preferably 1 to 50% by mass. This is not preferable when the content of the silica particles is less than 1% by mass, because it is difficult to uniformly disperse the silica particles in the separator. When the content exceeds 50% by mass, the density of the separator is improved. This is because it is not preferable because the space ratio is lowered and the electric resistance is increased and the electrolytic solution holding capacity is decreased.

The density of the separator is preferably 0.30 g / cm ³ or less. This is because if the density exceeds 0.30 g / cm ³ , as described above, the separator porosity decreases, and the electrical resistance is increased or the electrolyte holding capacity is decreased.

  As the fine glass fiber, glass fiber having an average fiber diameter of 2.0 μm or less is preferably used. By using such a thin glass fiber, the average pore diameter of the gap portion of the mat-like sheet formed by making the glass fiber can be made 10 μm or less, and by mixing a relatively small amount of powdered silica, It becomes possible to seal the gap (miniaturize the hole diameter).

The separator for a sealed lead-acid battery of the present invention is formed by mixing chain-like linked structured powdery silica particles into a mat-like sheet made mainly from fine glass fibers. In addition to fine glass fibers, organic fibers may be mixed. When the organic fiber is mixed, the strength of the separator can be increased, and the battery assembly workability can be improved.
As the organic fiber, one or more kinds can be selected from polyolefin monofilament, polyester monofilament, heat-fusible polyester fiber, beating acrylic fiber, and fibrillated cellulose.
The content of the organic fiber is preferably 5 to 30% by mass in the total fiber material constituting the separator. This is not preferable when the organic fiber content is less than 5% by mass because the effect of improving the strength of the separator cannot be obtained. When the content exceeds 30% by mass, the content of fine glass fiber is relatively small. This is because the electrolyte solution wettability of the separator is lowered, which is not preferable.
Therefore, when all the fiber materials which comprise a separator consist of the said fine glass fiber and the said organic fiber, the said fine glass fiber shall be 70-95 mass%, and the said organic fiber shall be 30-5 mass%. preferable.

Next, examples of the present invention will be described in detail together with comparative examples.
(Example 1)
80% by mass of glass fiber having an average fiber diameter of 1.0 μm as fine glass fiber, and 10% by mass of core-sheath type heat-fusible polyester fiber having an average fiber diameter of 1.5 denier (Unitika Melty 4080) as organic fiber 5% by mass of monofilament-like polyester fiber (Kuraray ester EP133) having an average fiber diameter of 1.3 denier, and J.C. M.M. 5% by mass of “Huberpol 135” manufactured by Huber is dispersed and mixed in water, an appropriate amount of a cationic polymer flocculant is added, and wet papermaking is performed by a normal wet papermaking method to form a papermaking sheet, followed by drying. Thus, a sealed lead-acid battery separator having a thickness of 0.80 mm and a density of 0.16 g / cm ³ was obtained.

(Example 2)
In the material blending of Example 1, the same procedure as in Example 1 was conducted except that the blending amount of the fine glass fibers was changed to 60% by mass and the blending amount of the chain connected structure powdery silica particles was changed to 25% by mass. A separator for a sealed lead-acid battery having a thickness of 0.78 mm and a density of 0.21 g / cm ³ was obtained.

(Example 3)
In the material formulation of Example 1, the same procedure as in Example 1 was conducted, except that the compounding amount of the fine glass fiber was changed to 40% by mass and the compounding amount of the chain connected structure powdery silica particles was changed to 45% by mass. A separator for a sealed lead-acid battery having a thickness of 0.82 mm and a density of 0.27 g / cm ³ was obtained.

(Comparative Example 1)
80% by mass of glass fiber having an average fiber diameter of 1.0 μm as fine glass fiber, and 10% by mass of core-sheath type heat-fusible polyester fiber having an average fiber diameter of 1.5 denier (Unitika Melty 4080) as organic fiber Disperse and mix 5% by mass of monofilament polyester fiber (Kuraray Ester EP133) with an average fiber diameter of 1.3 denier and 5% by mass of conventional spherical powdered silica particles (Nip Seal NSP) in water. A cationic lead-acid battery having a thickness of 0.79 mm and a density of 0.18 g / cm ^3. A separator was obtained.

(Comparative Example 2)
In the material formulation of Comparative Example 1, the same procedure as in Comparative Example 1 was conducted except that the blending amount of fine glass fibers was changed to 60% by mass and the blending amount of conventional spherical powdery silica particles was changed to 25% by mass, respectively. A separator for a sealed lead-acid battery having a thickness of 0.83 mm and a density of 0.22 g / cm ³ was obtained.

(Comparative Example 3)
In the material formulation of Comparative Example 1, the same procedure as in Comparative Example 1 was conducted, except that the compounding amount of fine glass fibers was changed to 40% by mass and the compounding amount of conventional spherical powdery silica particles was changed to 45% by mass, respectively. A separator for a sealed lead-acid battery having a thickness of 0.77 mm and a density of 0.29 g / cm ³ was obtained.

(Comparative Example 4)
80% by mass of glass fiber having an average fiber diameter of 1.0 μm as fine glass fiber, and 10% by mass of core-sheath type heat-fusible polyester fiber having an average fiber diameter of 1.5 denier (Unitika Melty 4080) as organic fiber Disperse and mix 5% by mass of monofilament polyester fiber (Kuraray Ester EP133) with an average fiber diameter of 1.3 denier and 5% by mass of conventional spherical powdered silica particles (Nip Seal NSP) in water. The cationic polymer flocculant was added to form a paper sheet by wet papermaking by a normal wet papermaking method, and the sheet was compressed with a press in a wet paper state and dried to a thickness of 0. A separator for a sealed lead-acid battery having a size of 81 mm and a density of 0.40 g / cm ³ was obtained.

(Comparative Example 5)
In the material formulation of Comparative Example 4, the same procedure as in Comparative Example 4 was conducted, except that the compounding amount of fine glass fibers was changed to 60% by mass and the compounding amount of conventional spherical powdery silica particles was changed to 25% by mass, respectively. A separator for a sealed lead-acid battery having a thickness of 0.78 mm and a density of 0.43 g / cm ³ was obtained.

(Comparative Example 6)
In the material formulation of Comparative Example 4, the same procedure as in Comparative Example 4 was conducted, except that the compounding amount of fine glass fibers was changed to 40% by mass and the compounding amount of conventional spherical powdery silica particles was changed to 45% by mass, respectively. A separator for a sealed lead-acid battery having a thickness of 0.82 mm and a density of 0.45 g / cm ³ was obtained.

About each separator of the said Examples 1-3 and Comparative Examples 1-6, the liquid dropping speed, the injection | pouring repulsion force, the liquid absorption amount, and the electrical resistance were measured with the following method. The results are shown in Table 1.
[Liquid descent speed]
(1) A separator is cut into a size of 50 mm × 250 mm to prepare a sample, and spacers are provided 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 ). And set between two acrylic plates (width 70 to 80 mm × length 500 mm) placed facing each other.
(2) After the sample set between the acrylic plates is immersed in water, excess water is removed by a dehydrator (dry suction).
(3) A wet sample is set on a measuring jig, and a sulfuric acid solution having a specific gravity of 1.3 is gently poured from above the acrylic plate with a pipette. In addition, the injection of the sulfuric acid solution is set to 100 mm from the upper side to the lower side of the sample, and the liquid is added at any time to keep the height constant. The sulfuric acid solution is previously colored with red ink or methyl orange.
(4) After the pouring of the sulfuric acid solution, the descending distance of the sulfuric acid solution after 5 minutes, 10 minutes, 30 minutes and 60 minutes is measured.
(5) This measurement is performed three times for each sample.
In addition, if a liquid dropping speed is 100 mm / hr or less, it will show that electrolyte solution retention property is favorable.
[Liquid repulsion force]
The measurement is performed as follows using the measuring instrument 10 shown in FIG.
(1) 30 sheets of a separator are cut into 100 mm × 100 mm, a set of 10 sheets is used as a sample, and the weight of the sample is measured.
(2) First, the following preliminary experiment is performed.
The sample 11 is set on the measuring instrument 10, the handle 12 is turned to gradually compress the sample 11, and this compressive force is detected by the load cell 13 and read by the pressure gauge 14, and set to a pressure of 39.2 kPa. Next, water is gradually injected from above the sample 11, and the amount (W) of the liquid injected when the water comes out from the side is measured.
(3) After completion of the preliminary experiment, the sample 11 is set in the measuring device 10 and set again at a pressure of 39.2 kPa. After setting, the pressure is adjusted to 39.2 kPa every minute so that a pressure of 39.2 kPa is applied even after 5 minutes.
(4) The thickness of the sample 11 after setting is measured at four points with a caliper.
(5) 10 g of water is poured into the sample 11 and the pressure after 2 minutes is measured.
(6) From the vicinity where the liquid injection amount becomes (W-20) g, the liquid injection is switched to 5 g at a time, and the same measurement as in (5) is performed.
(7) When the pressure no longer changes, the measurement is terminated.
(8) Perform this measurement twice or more.
(9) The measurement result is plotted on the horizontal axis and the pressure is plotted on the vertical axis, and the pressure P (kPa) at which the pressure is the lowest is read.
(10) The liquid injection repulsive force is calculated by the following formula.
Injection repulsive force (kPa) = P / 39.2
In the case of a separator made of a mat-like sheet mainly composed of fine glass fibers, it gradually contracts as the amount of liquid injected is increased, and then expands to a liquid saturated state, but the separator contracts most. The liquid repelling force in the state was measured.
In addition, if the injection repulsion force is 0.54 kPa or more, it indicates that the tightness is good.
[Liquid absorption]
The amount of liquid absorption was calculated by the following formula.
Liquid absorption (g / g) = {(wet separator weight) − (dry separator weight)} / (dry separator weight)
[Electric resistance]
It measured according to the method of SBA S0402.

Table 1 shows the following. In addition, when comparing single separators between each group of Examples 1-3, Comparative Examples 1-3, and Comparative Examples 4-6, fundamentally, fine glass fiber: organic fiber: powdered silica The separators having the same blending ratio were compared with each other. That is, for example, when comparing Example 1, it compared with Comparative Example 1 and Comparative Example 4.
(1) In the separators of Comparative Examples 1 to 3 manufactured using the conventional spherical silica by the same manufacturing method as in Examples 1 to 3, the liquid descent rate is 116 to 152 mm / hr, and the electrolytic solution retention is good. The standard of 100 mm / hr or less is not satisfied. Further, the injection repulsion force tends to be unable to satisfy the criteria of 0.44, 0.52, 0.61 kPa and 0.54 kPa or more, which is considered to have good tightness. However, for the density of the 0.18~0.29g / cm ^3, is satisfied, which is a good criterion 0.30 g / cm ³ the following conditions, liquid absorption amount, good for the characteristics of the electrical resistance there were.
(2) In the separators of Comparative Examples 4 to 6, which are density-enhancing types of the separators of Comparative Examples 1 to 3 using conventional spherical silica, the liquid drop rate is 48 to 68 mm / hr, and the separators of Comparative Examples 1 to 3 54-59% compared to the above, sufficiently satisfying the standard of 100 mm / hr or less, which is considered to have good electrolyte solution retention. Also, the injection repulsion force is 0.62 to 0.77 kPa, which is 26 to 42% improved compared to the separators of Comparative Examples 1 to 3, and the criterion of 0.54 kPa or more, which is considered to have good tightness. I am fully satisfied. However, for the density of the 0.40~0.45g / cm ^3, not be satisfied are good criteria 0.30 g / cm ³ the following conditions, as compared to the separator of Comparative Examples 1 to 3, The liquid absorption was 34 to 46%, the electrical resistance was 67 to 117% worse, and the product unit price was 55 to 122% higher.
(3) On the other hand, in the separators of Examples 1 to 3 manufactured by the same manufacturing method as Comparative Examples 1 to 3 using chain-linked structure silica, the liquid drop speed is 51 to 79 mm / hr, which is a comparison. Compared to the separators of Examples 1 to 3, it is improved by 48 to 56% and sufficiently satisfies the standard of 100 mm / hr or less, which indicates that the electrolytic solution retainability is good. Also, the injection repulsion force is 0.55 to 0.69 kPa, which is an improvement of 13 to 20% as compared with the separators of Comparative Examples 1 to 3, and a criterion of 0.54 kPa or more, which is considered to have good tension properties. I am satisfied. Further, a 0.16~0.27g / cm ³ also density, which satisfies the good criterion a is 0.30 g / cm ³ the following conditions, liquid absorption amount, the electrical resistance both good and Comparative Example 1 Even if it compared with the separator of -3, it was a result which is not inferior at all.
(4) From the above, the separators of Comparative Examples 4 to 6 are significantly improved and good in both the liquid drop speed and the liquid repelling force compared to the separators of Comparative Examples 1 to 3, but the density is high. There are problems with poor liquid absorption and electrical resistance and high unit price of products. On the other hand, the separators of Examples 1 to 3 have substantially the same liquid absorption rate, electrical resistance, and product unit price as the separators of Comparative Examples 1 to 3, while greatly reducing the liquid drop speed and the injection repulsion force. There are significant advantages.

Explanatory drawing which shows the silica aggregate in the separator for sealed lead acid batteries of this invention Explanatory drawing which shows the silica aggregate in the separator for conventional sealed lead-acid batteries Explanatory drawing showing a measuring instrument for liquid repulsion force

Explanation of symbols

1 Fiber 2 'Chain-linked structured powdery silica particles of the present invention (silica secondary particles)
2 Silica aggregate of the present invention 3 Space 4 'Conventional spherical powdery silica particles (silica secondary particles)
4 Conventional Silica Aggregate 5 Space 10 Injection Liquid Repulsion Measuring Instrument 11 Sample 12 Handle 13 Load Cell 14 Pressure Gauge

Claims (5)

  In a mat-structured sheet made mainly from fine glass fibers, chain-linked structured powdery silica particles are interspersed to form a three-dimensional network of silica particles throughout the sheet. A sealed lead-acid battery separator.   2. The sealed lead-acid battery separator according to claim 1, wherein the chain-linked structured powdery silica particles are contained in an amount of 1 to 50 mass%. ^3. The sealed lead-acid battery separator according to claim 1, wherein the separator has a density of 0.30 g / cm ³ or less.   The sealed lead-acid battery according to any one of claims 1 to 3, wherein the separator is obtained by wet-mixing the chain-like connected structured powdery silica particles mainly composed of the fine glass fibers. Separator for use. A sealed lead-acid battery using the separator according to any one of claims 1 to 4.

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