JP2002110124A - Separator for sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the occurrence of a fracture in a bending part and preclude deterioration due to weathering phenomenon found in an ultrafine glass fiber by increasing durability and preventing deterioration of a separator for a sealed lead-acid battery. SOLUTION: The separator for a sealed lead-acid battery contains, as a main body, glass composition including, by mass%, SiO2 of 63.0-66.0, Al2O3 of 4.0-5.1, B2O3 of 5.5-7.5, Na2O+K2O of 14.6-18.2, MgO of 2.7-3.7, CaO of 3.7-5.3, BaO of 0-0.3, and 0-0.2 others, which constitutes an ultrafine glass fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a separator for a sealed lead-acid battery.

[0002]

2. Description of the Related Art The composition of glass fiber conventionally used for a separator for a sealed lead-acid battery is represented by the following components in terms of% by mass. SiO ₂ 67.0 Al ₂ O ₃ 2.0 B ₂ O ₃ 7.0 Na ₂ O + K ₂ O 15.0 MgO 3.0 CaO 5.0 BaO 0.1 Others 0.9 Is as follows. (1) Since the electrolyte solution of the sealed lead-acid battery is sulfuric acid, an acid-resistant alkali-containing glass is suitable. Therefore, the alkali component (Na ₂ O + K ₂ O) is set to 15.0% by mass. (2) The amount of the SiO ₂ component constituting the skeleton of the glass is preferably large in consideration of acid resistance. However, since the liquidus temperature of the glass is increased and workability is poor, 67.0% by mass is set. (3) Since the average fiber diameter is as thin as 0.7 μm and the specific surface area is large, a so-called weathering phenomenon occurs in which alkali components are eluted by moisture or carbon dioxide gas in the air and glass fibers are destroyed. B ₂ O ₃ for the prevention of the 7.
0 mass%. (4) To improve durability such as water resistance and acid resistance, use SiO
_Although complexation occurs on the _two surfaces to act as a protective film, the spinning temperature is high and fiberization is difficult, so Al ₂ O ₃ is 2.0% by mass. (5) It is mixed and heated with SiO ₂ to lower the melting point of the glass and reduce the effect of melting, thereby improving workability.
MgO + CaO + Ba as it deteriorates water resistance and acid resistance
The total amount of O is set to 8.1% by mass.

[0003]

However, the conventional separator for a sealed lead-acid battery having a glass composition, when used after storage for about two months under conditions of high temperature and high humidity, such as in summer, causes weathering (deterioration) of glass fibers. Then, when the separator is incorporated into the battery, the separator may be broken at the bent portion to make it impossible to produce the battery, or the cross section of the roll may adhere. Furthermore, in the case of a sealed battery used by enclosing an electrode plate, there is a problem that a short circuit occurs due to cracking. Therefore, there is a problem that it is necessary to seal the battery in a cool and dark place and store it with a desiccant when stocked. In addition, since the deteriorated glass fiber is easily broken,
There is a problem that the sealed battery assembled by applying a predetermined pressure cannot maintain the pressure during long-term use, the adhesion between the electrode plate and the separator is reduced, the battery capacity is lost, and the life of the battery is shortened. Therefore, an object of the present invention is to solve the above problems.

[0004]

Means for Solving the Problems] sealed lead acid battery separator of the present invention, in order to achieve the above object, as described in claim 1, the following components SiO ₂ 63.0 to 66 and in wt% _{.0 Al 2 O 3 4.0~ 5.1 B} 2 O 3 5.5~ 7.5 Na 2 O + K 2 O 14.6~18.2 MgO 2.7~ 3.7 CaO 3.7~ 5 .3 BaO 0-0.3 Others It is characterized by being mainly composed of ultra-fine glass fibers having a glass composition of 0-0.2.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The order of glass composition and chemical durability are as follows: (1) Water resistance: ZrO ₂ > Al ₂ O ₃ > TiO ₂ >ZnO>
MgO>CaO> BaO (2) Acid resistance: ZrO ₂ > Al ₂ O ₃ >ZnO>MgO>
It is known that CaO> TiO ₂ > BaO (Glass Engineering, Kyoritsu Shuppan Co., Ltd., p. 287, by Naruse). ZrO ₂ and Al ₂ O ₃ is water, although most excellent against acid resistance, ZrO ₂ is so expensive industrially employed is difficult as a separator material for lead-acid batteries, primarily increasing the Al ₂ O ₃ component To make improvements.

The composition of the glass fiber used in the sealed lead-acid battery separator of the present invention is as follows, expressed by mass%. _{SiO 2 63.0~66.0 Al 2 O 3 4.0~} 5.1 B 2 O 3 5.5~ 7.5 Na 2 O + K 2 O 14.6~18.2 MgO 2.7~ 3. 7 CaO 3.7 to 5.3 BaO 0 to 0.3 Other 0 to 0.2

[0007] SiO ₂ forms a glass skeleton together with B ₂ O ₃ and Al ₂ O ₃ . If it is less than 63% by mass, the chemical durability of the glass is undesirably reduced. If it exceeds 66% by mass, the solubility of the glass decreases, and the working temperature and the liquidus temperature of the glass undesirably increase.

[0008] Al ₂ O ₃ improves the chemical durability which is one of the causes of the deterioration of the glass fiber, especially the decrease in water resistance.
If the content of Al ₂ O ₃ is less than 4.1% by mass, the water resistance is undesirably reduced. If it exceeds 5.1% by mass, the effect of improving the water resistance is not changed, and furthermore, the working temperature and the liquidus temperature of the glass are undesirably increased.

B ₂ O ₃ prevents the weathering phenomenon which is one of the causes of deterioration of glass fibers. The weathering phenomenon means that the average fiber diameter of the glass used for the separator of the present invention is 0.7 μm.
Because of the small thickness and large specific surface area, alkali components are eluted by moisture or carbon dioxide in the air, and glass fibers are destroyed. If B ₂ O ₃ is less than 5.5% by mass, the viscosity of the glass increases, and the working temperature and the liquidus temperature increase, which is not preferable. If the content exceeds 7.5% by mass, the effect of improving the working temperature and the liquidus temperature of the glass is small, and it is not preferable because it is expensive.

[0010] CaO and MgO are glass fluxes. At the same time, they are used to properly maintain the viscosity curve of the glass, and also to maintain chemical durability. Mg
O reduces the liquidus temperature in the range of 2.7 to 3.7% by mass, so it is used in this range. If the content of CaO is less than 3.7% by mass, the chemical durability is undesirably reduced.
If it exceeds 5.3% by mass, the liquidus temperature increases, which is not preferable.

Na ₂ O and K ₂ O are glass fluxes.
At the same time, since the electrolyte solution of the sealed lead-acid battery is sulfuric acid, an acid-resistant alkali-containing glass is preferably used. N
Since the raw material of + K ₂ O is more expensive than a ₂ O, Na ₂ O
Is mainly used. The sum of Na ₂ O + K ₂ O is 14.6
If the content is less than mass%, the solubility of the glass decreases, and the liquidus temperature also increases, which is not preferable. If the total of Na ₂ O + K ₂ O exceeds 18.2% by mass, the chemical durability is lowered, which is not preferable. K ₂ O does not need to be specially prepared as a raw material, but is mixed with a raw material for preparing components other than K ₂ O, such as silica sand and feldspar, so the upper limit is 1.5% by mass.

The glass fiber used in the present invention is prepared in such a manner as to have the above-mentioned composition, melted in a melting furnace, and spun by a centrifugal method or a flame method to obtain an average fiber diameter of 0.5 to 1.
0 μm.

[0013] The separator for a sealed lead-acid battery of the present invention comprises:
100% by mass of the ultrafine glass fiber or 5% by mass
The following are organic binders such as fibrillar acrylic fibers having an average fiber diameter of 10 to 20 μm and a fiber length of 3 to 5 mm, synthetic fibers such as polyester resin and acrylic resin having an average fiber diameter of 10 to 20 μm and a fiber length of 3 to 5 mm, and a specific surface area of 80. ~ 30
0 m ² / g inorganic powder such as silica, average fiber diameter 5 to 20
It can be configured by replacing with a glass long fiber having a fiber length of 5 to 30 mm.

The above-mentioned constituent material is formed by acid or neutrality by a usual paper making technique to obtain a separator for a sealed lead-acid battery having a thickness of 0.5 to 3.0 mm and a basis weight of 70 to 500 g / m ² . Further, if necessary, after papermaking, the separator may be permeated to the surface or inside thereof to be subjected to resin treatment.

[0015]

EXAMPLES Examples, comparative examples and conventional examples of the separator for a sealed lead-acid battery according to the present invention will be described. Embodiment 1 of the present invention
Is 99% by mass of glass fibers having an average fiber diameter of 0.7 μm.
And a fibril-like acrylic fiber having a composition of 1% by mass as a binder of a glass fiber having a thickness of 2.0 by a papermaking method.
A sealed type lead-acid battery separator having a thickness of 320 g / m ^{2 and} a thickness of 320 mm was prepared. Hereinafter, Example 2 and the conventional example were prepared in the same manner as in Example 1 except that the composition of Al ₂ O ₃ was changed mainly in the glass composition. Each example obtained,
With respect to the separator of the comparative example, the evaluation of the glass fiber and the evaluation of the separator were performed. The following table shows the composition of each separator, the glass composition, and the evaluation results.

[0016]

[Table 1]

Among the evaluations of the glass fiber, the deterioration test of the glass fiber is as follows. (1) Conditions for forced deterioration A sample of about 10 g is sampled and placed on a glass mat. The sample is placed in a thermo-hygrostat set at 50 ° C. and 95 RH% and left to stand for 3 days. After 3 days, the sample is taken out and dried in a dryer at 130 ° C.

(2) Measurement of “Deteriorating Rails maintenance rate” About 2 g of a dried sample is collected, 0.8 liter of water is added, and the mixture is defibrated for 100 seconds. After disaggregation, transfer to a measuring cylinder and add water to make 1 liter. Shopper type beating degree tester (based on JISP8121)
After the sample water is charged into the container, the conical valve is lifted upward at a constant speed to flow down. After the drainage from the side pipe has stopped, the drainage amount (X) is accurately read. The shopper freeness (SR) is obtained from the following equation. SR (degrees) = (1000−X) / 10 (1) SR is corrected from the temperature correction table. Find the Rails (fineness) from the SR / Rails conversion table. The “deteriorating rails maintenance rate” is expressed as a change in the rails after the forced deterioration with respect to the glass fiber rails before the forced deterioration. Deteriorating Rails maintenance rate (%) = (Rails after forced deterioration / Rails before forced deterioration) x 100 ... (2)

(3) Measurement of "deterioration toughness retention rate" 3.33 g of a dried sample is sampled three times, disintegrated with a mixer for 2 minutes, and then formed with a square tappy. The sheet thus formed was dried at 105 ° C. and had a width of 25 mm ×
A test piece having a length of 180 mm is collected, and its tensile strength and elongation are measured. Toughness is calculated by the following equation. Toughness (MPa%) = Tensile strength (MPa) × Elongation (%) Expression (3) The “deteriorating toughness maintenance ratio” is expressed by a change in toughness of glass fiber before forced deterioration and toughness after forced deterioration. . Deterioration toughness maintenance rate (%) = (Toughness after forced degradation / Toughness before forced degradation) × 100 (4)

(4) Measurement of “acid resistance” About 2 g of a sample is collected, dried in a drier (105 ° C.), cooled in a desiccator, and precisely weighed (W). The sample is placed in 200 ml of dilute sulfuric acid having a specific gravity of 1.200, and kept in a constant temperature water bath at 80 ° C. for 5 hours. After 5 hours, the mixture is filtered through a glass filter and washed with distilled water until neutral. The washed sample is dried in a drier (105 ° C.), cooled in a desiccator, and precisely weighed (W1). The acid resistance is determined by the following equation. Acid resistance (%) = (W−W1) / W × 100 (5)

(5) Measurement of “Water Resistance” About 2 g of a sample is collected, dried in a drier (105 ° C.), cooled in a desiccator, and precisely weighed (W). A sample is placed in 200 ml of pure water and kept in a constant temperature water bath at 80 ° C. for 5 hours. After 5 hours, the mixture is filtered through a glass filter and washed with distilled water. The washed sample is dried in a drier (105 ° C.), cooled in a desiccator, and precisely weighed (W1). The water resistance is determined by the following equation. Water resistance (%) = (W−W1) / W × 100 (6)

(6) Measurement of "deteriorating bending crack" The glass separator thus prepared is placed in a thermo-hygrostat set at 50 ° C. and 95 RH%, and left standing for a predetermined number of days. After a lapse of a predetermined number of days, the sample is taken out and dried with a dryer at 130 ° C. The separator is bent, and the state of cracks generated outside the bent portion is visually observed. The following was found from Table 1 above. (1) In the conventional example, since Al ₂ O ₃ is as small as 2% by mass, the “deterioration toughness maintenance rate” and the “deterioration rails maintenance rate” of the glass fiber evaluation are deteriorated due to deterioration due to the durability of the glass fiber. And the "acid resistance" and "water resistance" were large, and in the "evaluation of cracking at the time of degrading bending" of the separation evaluation, cracking occurred due to bending. (2) On the other hand, in Example 1, Al ₂ O ₃ contained 5% by mass.
Therefore, the prevention of deterioration due to the durability of the glass fiber is improved, and the “deterioration toughness maintenance rate” and “deterioration rails maintenance rate” of the glass fiber evaluation are high, and “acid resistance” and “water resistance” are high. Is smaller than that of the conventional example, and there is no crack due to the bending in the “deteriorating bending cracking” in the evaluation of Sepa. (3) In the second embodiment, the effect of preventing deterioration is observed as compared with the conventional example, but the effect of preventing deterioration is slightly reduced as compared with the first embodiment. This is because Al ₂ O ₃ is less than 20%. (4) In Comparative Example 2, Al ₂ O ₃ is 40% less than that in Example 1, so that the effect of preventing deterioration is low. (5) Comparative Example 1 has 20% more Al ₂ O ₃ than Example 1, but the effect of preventing deterioration is not particularly different from that of Example 1, but
The working temperature and the liquidus temperature of the glass increase, and the spinnability of the fiber becomes difficult, which is not preferable.

[0023]

The sealed lead-acid battery separator of the present invention has _twice the amount of Al ₂ O ₃ as compared with the prior art, so that the durability such as water resistance can be improved, and the deterioration can be prevented. Can be eliminated. Further, sealed lead-acid battery separator of the present invention, since B ₂ O ₃ is equal to that of the conventional, can prevent deterioration due to weathering phenomena seen with ultrafine glass fibers.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Kawachi 630, Tarui-cho, Fuwa-gun, Gifu Japan Inside the Inorganic Co., Ltd.Tarui Plant (72) Inventor Takuo Mitani 630, Tarui-cho, Fuwa-gun, Gifu Pref. F-term in the factory (reference) 5H021 AA06 BB08 CC01 EE20 EE27 EE28 HH01

Claims (1)

[Claims] 1. The following components expressed in mass%: SiO ₂ 63.0 to 66.0 Al ₂ O ₃ 4.0 to 5.1 B ₂ O ₃ 5.5 to 7.5 Na ₂ O + K ₂ O 14 0.6 to 18.2 MgO 2.7 to 3.7 CaO 3.7 to 5.3 BaO 0 to 0.3 Others Mainly composed of ultrafine glass fibers having a glass composition of 0 to 0.2. For sealed lead-acid batteries.