JPH04334866A - Glass mat for storage battery - Google Patents

Abstract

PURPOSE:To provide a cell glass mat which is never broken at the bent-up surface during a cell assembly process. CONSTITUTION:A glass mat is composed of glass fibers containing alkali which have an average diameter of 16 to 21mum and an average length of 30 to 100mm. An acrylic resin border having a glass transition point of 0 to -40 deg.C is bonded to a glass fiber mat manufactured by wet weaving method at the weight percentage of 8 to 15% of the said glass fiber mat. Resultant glass fiber mats are easy to slide, properly flexible, very strong, and highly resistant to cracking, so they are easy to handle thus allowing easy work during a cell assembly process. In addition, these glass fiber mats have a small electric resistance and little scattering in thickness, allowing high performance cells to be manufactured. They are also cheap to produce.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a glass mat for storage batteries, and more particularly, the present invention relates to a glass mat for storage batteries, and more specifically, in liquid batteries such as lead-acid batteries, the storage battery is placed between a separator and an anode plate for the purpose of preventing the anode active material from falling off. related to glass mats.

0002

[Prior Art] Conventionally, in liquid batteries such as lead-acid batteries, a technique has been adopted in which a glass mat is placed between a separator and an anode plate in order to prevent the anode active material from falling off. This has greatly contributed to the improvement. Conventionally, as this glass mat, a mat made by a dry method in which glass fibers having an average diameter of 19 μm are bonded together with an acrylic resin has been used. That is, spun glass fibers are sprayed with acrylic resin and wound around a drum that reciprocates in the axial direction to form rovings that intersect the winding angles of the glass fibers, and the mat-like material cut from this roving is rolled out. A felt-like mat made by widening the intersection angle of glass fibers is used.

[0003] Glass mats made by such a dry method are
Since the glass fibers are not cut into short pieces, they slide easily and are easy to work with the stacker after being combined with the separator and cut into small pieces.In addition, the average fiber diameter is as thick as 19μm, so electrical resistance is low and battery performance is maintained at high levels. It has advantages such as being able to

However, the above-mentioned conventional glass mats have a drawback in that the thickness varies widely, and because the thickness is non-uniform, the spacing between the electrode plates tends to become uneven when assembling the battery. That is, when manufacturing glass mat by dry method,
Since the felt obtained by rolling cotton has non-uniform thickness, a glass mat with a uniform thickness cannot be obtained.

[0005] Conventionally, therefore, a plurality of sheets of felt have been stacked one on top of the other in an attempt to make the thickness uniform, but a sufficient effect has not been obtained.

[0006] As a solution to such problems,
The present inventors found that 50 to 95% by weight of alkali-containing glass fibers with an average diameter of 13 to 15 μm and 17 to 21 μm in average diameter.
Consisting of 5 to 50% by weight of alkali-containing glass fiber,
An acrylic resin binder with a glass transition point of 30 to 80°C is added to a glass fiber mat manufactured by a wet papermaking method.
We discovered a glass mat for storage batteries in which 15 to 25% by weight of the glass fiber mat is attached, and filed a patent application earlier (Japanese Patent Application No. 1-174950, hereinafter referred to as the "earlier application"). Glass mats for storage batteries have good sliding properties, combine with separators, and have excellent stacker workability after cutting small plates, and have low electrical resistance. Glass mats are provided.

[0007]

[Problem to be solved by the invention] The glass mat for storage batteries of the above-mentioned prior application is laminated with a separator and cut into small pieces, which are punched out using a stacker in the battery assembly process, and stacked with electrode plates to form a group of electrode plates. A hard and rigid glass mat for storage batteries.

On the other hand, in recent years, battery assembly methods have diversified, and for example, a battery assembly method has been implemented in which a separator and a glass mat are bonded together in a band shape, and this is interposed in a meandering manner between a plurality of electrode plates. It started to be done. However, when such a battery assembly method is employed, the glass mat for storage batteries of the prior application mentioned above is hard and has too much rigidity, so there is a problem that it breaks at the meandering bending position.

The present invention maintains the features of the above-mentioned prior application, solves the problems caused by its rigidity, and provides a sufficiently flexible glass mat for storage batteries that does not break even when bent during the battery assembly process. The purpose is to provide

0010

[Means for Solving the Problems] The glass mat for storage batteries of the present invention has an average diameter of 16 to 21 μm and an average length of 30 to 1 μm.
An acrylic resin binder with a glass transition point of 0 to -40°C is added to a glass fiber mat made of 00 mm alkali-containing glass fibers by a wet papermaking method, by an amount of 8 to 15% by weight based on the weight of the glass fiber mat. It is characterized by being made by attaching %.

The present invention will be explained in detail below. The glass mat for a storage battery of the present invention is a glass fiber mat manufactured by a wet papermaking method, and its constituent glass fibers are alkali-containing glass fibers with an average diameter of 16 to 21 μm and an average length of 30 to 100 mm.

[0012] By the way, the following problems can be considered in the glass mat for storage batteries produced by the wet paper-making method. That is, when the average diameter of the constituent glass fibers is large, for example, when the glass mat is composed of 100% by weight of glass fibers with an average diameter of 19 μm, the resulting glass mat becomes less slippery and good handling workability cannot be obtained. . That is, in order to make a glass mat using the wet papermaking method, it is necessary to use glass fibers cut into lengths of 6 to 30 mm, but when making glass fibers of such length, the diameter of the glass fibers is large. Because of the rough glass fiber end surface, the resulting glass mat becomes less slippery. Therefore, from the viewpoint of preventing a decrease in the slipperiness of the glass mat due to such glass fiber end faces, the diameter of the constituent glass fibers is preferably as small as possible. For example, in a glass mat composed of 100% by weight of glass fibers with an average diameter of 14 μm, It has good sliding properties.

However, when considering the electrical resistance of the glass mat, if the average diameter of the constituent glass fibers is small,
For example, if the mat is composed of 100% by weight of glass fibers having an average diameter of 14 μm, the mat will become too clogged and have a high electrical resistance, which is not preferable.

Therefore, in order to provide a glass mat with good slippage and low electrical resistance, the glass mat for storage batteries of the prior application has a glass fiber structure with an average diameter of 13 to 15 μm.
50 to 95% by weight of alkali-containing glass fibers having an average diameter of 17 to 21 μm and 5 to 50% by weight of alkali-containing glass fibers having an average diameter of 17 to 21 μm.

However, as a result of research, the present inventors found that by using an appropriate dispersant, the average length can be increased from 30 to 1.
00mm glass fiber can be dispersed well,
It has been found that it is no longer necessary to use glass fibers cut into 6-30 mm pieces. And the average length is 30-100
By using relatively long glass fiber of mm,
The glass fiber end faces that make the mat slippery as described above are reduced, and the mat slips better, so there is no need to use glass fibers with a small diameter of 14 μm on average. It is also possible to configure. For this reason, in the present invention, the average fiber diameter is 16 to 21 μm and the average length is 30 to 10 μm.
Use 0 mm glass fiber.

[0016] In the present invention, the glass fiber mat made of the above-mentioned glass fiber composition by the wet papermaking method has a glass transition point (T
g) An acrylic resin binder having a temperature of 0 to -40°C is deposited in an amount of 8 to 15% by weight based on the weight of the glass fiber mat.

[0017] If the Tg of the acrylic resin binder used is lower than -40°C, the slipperiness of the glass mat obtained will be poor, and the binder will spread, resulting in a large resistance value of the glass mat obtained. becomes. On the contrary, Tg
When the temperature exceeds 0°C, the resulting glass mat becomes hard and brittle and easily breaks.

[0018] As an acrylic resin binder suitable for the present invention, an acrylic ester copolymer containing methyl methacrylate and acrylic acid as main components and blended so as to have a Tg of 0 to -40°C can be mentioned.

If the amount of the acrylic resin binder attached is less than 8% by weight based on the weight of the glass fiber mat, the tensile strength of the glass mat will be weak and it will be difficult to obtain the necessary strength during processing. If it exceeds this, it becomes easy to break and the electrical resistance becomes high, both of which are unfavorable.

In the present invention, among alkali-containing glass fibers, those having good acid resistance are preferably used since they are used in storage batteries. This degree of acid resistance is based on the JISC-1 standard for glass fibers with an average fiber diameter of 1 μm or less.
Desirably, the weight loss when measured according to 2202 is 2% or less. In addition, the composition of such glass fibers is 60 to 75% SiO2 and 8 to 20% by weight.
% R2O (alkali metal oxides such as Na2O, K2O) (however, SiO2 +R2
O is 75-90%), other examples include CaO, MgO
, B2 O3 , Al2 O3 , ZnO, Fe2 O
Examples include those containing one or more of the following. An example of a preferable alkali-containing silicate glass is shown in Table 1 below.
Shown below.

[0021]

[Table 1]

For producing the glass mat for storage batteries of the present invention, it is advantageous to use, for example, the following method. That is, it is manufactured by a long fiber manufacturing method in which molten glass is continuously drawn out from a nozzle and wound around a drum.
A continuous long fiber is prepared and cut into a predetermined length using a cutter. Alternatively, the glass fibers may be cut into a predetermined length by an appropriate cutting means while being fed to the paper machine net.

[0023] The cut glass fibers having a predetermined length and a predetermined fiber diameter are made into a paper net, and at that time, a sticky material is used to adjust the viscosity of the water in the disintegrator and/or the papermaking tank. The viscosity of the water is preferably about 3 to 15 centipoise. Glass fibers are dispersed by performing wet papermaking at such a viscosity.

In the present invention, a predetermined amount of an acrylic resin binder is applied to such a glass fiber paper sheet by spraying, impregnation, curtain coating, or the like to form a storage battery glass mat. The storage battery glass mat of the present invention produced by such a wet papermaking method is a glass mat with extremely excellent thickness uniformity, with variations in thickness within a range of ±10% of the reference value.

[0025]

[Function] According to the wet papermaking method, a stable continuous sheet can be obtained, so that the storage battery glass mat of the present invention has a uniform thickness with little variation in thickness. Further, the average length of the glass fibers used in the present invention is 30 to
Since the thickness is 100 mm, a glass mat for a storage battery is provided which has good sliding properties, excellent bonding properties with a separator, and excellent workability. Moreover, the average diameter of the glass fibers is 16 to 21
Since the glass mat is relatively thick (μm), a glass mat with low electrical resistance can be provided at low cost. Furthermore, since the binder has a Tg of 0 to -40°C, it is flexible and has excellent cracking resistance when bent, and the binder adhesion rate is 8 to 1.
Since it is 5% by weight, electrical resistance can be kept low.

[0026]

[Examples] The present invention will be explained in more detail with reference to Examples below. Example 1 With the glass fiber composition shown in Table 2, an acrylic resin binder with a Tg shown in Table 2 was attached by a wet method in the amount (ratio to the weight of the glass fiber) shown in Table 2, and each
A glass mat with a thickness of 0.6 mm was manufactured. The slipperiness, cracking resistance, tensile strength, and electrical resistance of each glass mat were examined using the methods described below, and the results are shown in Table 2 along with the results of judgment as glass mats for storage batteries.

Slip property (g) Two samples of 100 mm x 100 mm are used, one of the samples is placed on a measuring table, and a 5 kg presser weight is placed on the edge of the sample with a width of 10 mm. Place the other sample on top (2
The overlapping area of the two samples is 90 mm x 100 mm), and a baking plate (100 mm x 100 mm) is placed on top of which a load is applied. Pull the sample sandwiched between them through the push-pull gauge, and read the load on the push-pull gauge when the sample begins to move.

Resistance to cracking: Items that cracked when bent were rated x, and items that did not crack were rated ○. Tensile strength (kg/15mm width) Find the value (g) of external force when pulling both ends of a 15mm wide sample and it cuts it, divide it by the thickness (mm), and calculate the value of the 15mm wide sample.
m, expressed as a value per 1 mm of thickness.

[0029] Electrical resistance (Ω・dm2/piece) JISC2
Measure according to 313. As a result, all of the mats outside the scope of the present invention (Nos. 1, 3, 6, 7, and 9) lacked the required characteristics as glass mats for storage batteries, but No. ．． Samples Nos. 2, 4, 5, and 8 had good properties.

[0030]

[Table 2]

[0031]

[Effects of the Invention] As detailed above, the glass mat for storage batteries of the present invention has (1) good slipperiness; ■ Appropriate flexibility and high strength. ■ Excellent crack resistance. ■ Compared to ■ and ■, it is easier to handle and work when assembling a storage battery. ■ Low electrical resistance. ■ Small variation in thickness. ■ It is possible to manufacture storage batteries with higher performance than ■ and ■. ■ Costs can be reduced because glass fibers with a relatively large diameter are used. With these excellent features, it is extremely useful industrially as a glass mat for storage batteries.

Claims (1)

[Claims] [Claim 1] Average diameter: 16 to 21 μm, average length: 3
Composed of alkali-containing glass fibers of 0 to 100 mm.
An acrylic resin binder with a glass transition point of 0 to -40°C is added to a glass fiber mat manufactured by a wet papermaking method.
A glass mat for a storage battery, characterized in that the glass fiber is attached in an amount of 8 to 15% by weight based on the weight of the glass fiber mat.