JPS59127367A - Glass mat for storage battery - Google Patents

Abstract

PURPOSE:To obtain a separator for a lead storage battery in which performance reduction is not caused due to gas accumulation and a binder does not migrate into and is not adsorbed on the negative plate by mixing acid-proof oxidation-proof thermoplastic resin fiber used as a binder to make a glass mat for a lead sotrage battery, then fusing the resin fiber by heating before the glass mat is pressed. CONSTITUTION:Thermoplastic resin fiber used as a binder is prepared from polyethylene, polypropylene, acrylonitrile, polyvinyl chloride, a copolymer which is the combination of two or more of these compounds, or mixture consisting of two or more these compounds. When long fibers only are used in making a glass mat, a nozzle part from which fused glass is drawn as fibers is provided with a section through which thermoplastic resin fibers are supplied. In this case, supplied thermoplastic resin fibers and glass fibers are wound around a drum until a given amount of fibers is wound, when the drum is stopped and the supplied fibers are cut. When short fibers of below 5mm. length are used as glass fibers, glass fibers and short thermoplastic resin fibers are mixed while being stirred in a liquid such as water before they are formed into a sheet in such a manner as to make paper. The thus formed sheet is usually heated at a temperature 20-50 deg.C higher than the softening point of the resin until the glass fibers are fused to the resin, when pressing pressure is applied to the sheet to mold it.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to glass mats used in lead-acid batteries (including those used as separators).

Structure of conventional examples and their problems Conventional glass mats and separators mainly made of glass fiber for lead-acid batteries are acid-resistant, and acid-resistant glass fibers are combined with starch-based or gelatin-based binders, or two types of starch-based and acrylic-based binders. A mixed binder or phenolic resin is used as a binder to improve the appearance,
The shape, thickness, etc. were determined.

All of these binders are used in a liquid state and are added as a solid substance, but are sealed to the entire surface of the glass fiber through a process such as impregnation.

The problems with these binders are as follows.

Problems with starch and gelatin binders When an electrolyte is injected, the binder is water-soluble, so it dissolves in the electrolyte and loses its function as a binder. When high-current charging is performed, the glass fibers gradually break apart and protrude from between the electrode plates, making it impossible to maintain proper group pressure. Additionally, glass fibers float inside the container, resulting in a very poor appearance.

Another drawback: In one prefecture where battery cell formation is carried out, the starch and gelatin eluted into the electrolyte are adsorbed to the surface of the negative electrode plate, resulting in lead sulfate stains on the surface, resulting in very poor chemical formation, and during use. It will fall off and a large amount of sediment will accumulate at the bottom of the container (-2), which will cause a big problem in terms of appearance.

b Problems with acrylic binders General problems (1. Starch and acrylic binders) - Problems that occur when the binder is mixed or the starch is adsorbed on the negative electrode plate surface are as described above. If you use an acrylic binder, VC gas will be generated during charging.
In the case of high rate discharge (adsorbed by glass fibers), a gas pocket is completely formed at t, and τ becomes large, causing a decrease in F folding.

In addition, the liquid level often rose due to the formation of gas pockets, which sometimes became a major problem in terms of maintenance.

In some cases, the electrolyte may leak out from the exhaust plug. There is still an apparent rise in the liquid level due to gas accumulation, so even if there is actually a decrease in liquid, the liquid level is still at the specified value 6, so it is measured as an abnormal rise in specific gravity. When adjusting the specific gravity, the amount of sulfuric acid required was reduced, and in some cases it was no longer possible to achieve the specified characteristics.

C. Problems with phenolic binders: When a glass mat is impregnated with binder and heated, the binder leaches out intensively to the surface, and the amount of no-fingure between the inside and outside is different, and the surface grain is Even if it was too small, it could have a negative effect on the diffusion of ions.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and aims to
I! The entire purpose is to improve the performance of glass mats using 2VC or separate lakes mainly made of glass mats.

Structure of the Invention In order to achieve the above-mentioned object, the present invention mixes acid-resistant and oxidation-resistant thermoplastic resin fibers as a binder in a glass mantle for lead-acid batteries, and heat-processes the mixture to completely melt the PL and press it. This makes it possible to bond the glass fibers to each other in a V-shaped manner.

The thermoplastic resin fibers used as binders are polyethylene, Holifropylene, and acrylonitrile.

Polyvinyl chloride and combinations thereof/ζ copolymers,
Alternatively, two or more types may be used in combination.

In the case of a glass mat that uses only long fR fibers, the mixing method is as follows:
Scraping 15 A supply section for plastic resin fibers is provided, and the fibers are wound together with the glass fibers ♀fG on a drum C. When a predetermined amount of winding is reached, the drum is stopped and the supplied fibers are cut. Next E Drum C/This is wound with glass fiber and thermoplastic □F, 4 (31
A mixture of resin fibers # and IL is cut into one plate at right angles to the rotational direction of the drum. Is it heated next?1
The temperature is set 20 to 50°C higher than the softening point of the resin, and when the resin is welded to the glass fibers, press pressure is applied to form the resin. The pressing temperature is room temperature and the stress is 10k7.
/ 100cm ~ 201y7100 cni culm degree is fine. This is cut into a predetermined thick groove and used as a crow cloak.

It uses short fibers of 5 mm or less as glass fibers, and the glass short fibers and thermoplastic resin short fibers are mixed in a liquid such as water with stirring.In this case, the fiber length of the thermoplastic resin is It is important to make the length equivalent to that of glass fiber. If it is longer than the length of the glass fiber, it becomes difficult to disperse it in the liquid.

Next, create a notebook by making this in the same way you would make paper. After drying and heating, it is pressed and bound.

Heating, pressing, etc. are the same as those using all long fibers.

・・If the amount of inder is less than 2% by weight of the whole, H,-<”sufficient effect as an inder cannot be obtained, so 2% by weight
The above is necessary.

The relationship between the amount of binder and the electrical resistance, which is closely related, is shown in Figure 1.

Figure 1 shows experimental measurements taken at a mat thickness of 1 mm and a measurement temperature of 25°C. The glass fibers used are long fibers A and short fibers B.
If the weight limit is exceeded, the electrical resistance will rise rapidly, so
-25 weight equivalents.

As a loose binder, the binding property (i, /< If the binder mixture ratio is less than 2% by weight, it cannot bind sufficiently if the diameter is 1 micron or more, and -! If the fiber diameter is thicker than 2Q microns, the agglomeration of the binder will be noticeable in some parts, and the increase in electrical resistance will be large.

In the case of short fibers, the fiber diameter of 20 microns tends to result in insufficient dispersion.Explanation of Examples The details of the present invention will be explained below using Example JC.

(Example-1, case of long fiber) Glass fiber with a diameter of 20 microns Heat TTf
TfvJ, the number of polyglopylene fibers with a diameter of 20 microns is added such that the weight ratio becomes a factor of 10,
As with the conventional product, f'F was formed using the above-mentioned drum winding method.I used polynolopyrene and left it for 5 minutes at a heating temperature of 160L at 5℃. The mat was molded by pressing at a pressure of 7/cnf at 10 °C.In this way, a glass manotra with a thickness of 1.5 mm was produced.Figure 2 shows this mat 4, and 1 in the figure is a polypropylene fiber 8.2. is glass side 1rf
! , 3 indicates a binding portion between fibers.

Using this glass mat, 1o hour rate total 400Ah
Create a battery and compare the rise in the liquid level and the amount of sediment.
is. After the liquid level is fully charged, use a suction pump to raise the liquid level by 3 degrees below atmospheric pressure.
00mmHl (by reducing the pressure and applying vibration, the
Completely remove all gas and adjust the liquid level to match the reference line. After this, overcharging was performed at 2.3V/cell for 3 months,
All measurements of maximum liquid level rise were L-. The fifth of the sediments is electric carbon b.
After y, the sedimentation tk was measured for 3 months at the end of the test.

For comparison, as conventional products, one using all starch binders and one using acrylic binder are shown in Table 1. The product of the present invention had significantly less sediment and liquid level rise than the conventional product.

(Example-2) Glass fiber total diameter 3 microns, length 5 + 1 mm, polypropylene fM, string, total diameter 5 microns, length 5
±1 mm, stirred and mixed in water at a mixing ratio of 15 times to glass fibers, and created a mat in the same manner as paper making as in the conventional example. Increase the vc temperature to 160 ± 5℃, and increase the temperature to 20℃ under 26℃.
Formed with a press pressure of 7/crl, matte 4'
All created. Figure 3 shows this cloak, 1.2 in Figure 1.
．． 3 indicates the same member as in Example 1.

The maximum pore diameter of the material used as the mat A separator is 3 microns or less. Using this mat 1
A battery with a zero hour zero amount of 50 Ah was prepared, and the amount of precipitate after the first light fli was measured.

The results are shown in Table-2. The product of this invention has a 1 point improvement over conventional products.
Biting (7, it's sinking! 1) I understand that there are few yoshi.

Table 2 (Number of samples n-5) Next, all of the storage batteries marked with E were used according to Examples 1 and 2, and the characteristics upon discharge were compared.

(For long fibers) Battery: 400A h/1oHR (10 pieces each) Binder: Conventional product Adhered to the entire surface of the acrylic fibers.

Inventive product polypropylene fiber It has a weight ratio of 10 to glass fiber. A number of pieces were added and heat treated.

Discharge current 400A Discharge P: +J two voltages 1, 5 Y/cell density 2
The results of the discharge characteristics at 5+2°C are shown in Figure 4.

(For short fa fibers) Batteries csoh'n/1oHR (10 each)...
Inter” - Conventional product, impregnated with acrylic binder.

Uninvented product/Full polypropylene fiber Eh, heat treatment.

Current discharge 50A Voltage 1.60V/cell temperature 25+2°C at discharge length 1 The results of discharge characteristics are shown in Figure 5. Compared to the product of the present invention, there is a voltage drop from the beginning of discharge and a drop in voltage during discharge (during discharge), and when used in series connection of multiple cells, the total chamber pressure becomes lower, which is disadvantageous. According to the present invention, voltage irregularities and drops during discharge are small, so it is very advantageous for applications where the voltage is converted into watts, such as an inverter load.

Advantages of the Invention (1) The present invention does not require the step of impregnating Nino (Ingu) as in conventional products, and improves work efficiency.

(2) Reliable maintenance without performance deterioration due to gas accumulation, rise in liquid level during use, and overflow of liquid associated with 1'Lfc.As there is almost no rise in liquid level, there is an apparent increase in specific gravity. It doesn't happen either.

(3) There is no migration or adsorption of binder to the negative electrode plate, so
'11. Even with tank chemical conversion, there is very little sedimentation, which solves the appearance problem.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between the binder mixing ratio in the glass mantle and the electrical resistance of the mat; Figs. 2 and 3 are diagrams showing the entire glass mat in an example of the present invention; Fig. 4;
FIG. 6 is a diagram showing the IC discharge characteristics of a storage battery using the same glass mat. 1...Thermoplastic resin fiber, 2...Glass fiber,
3... bonding portion between fibers, 4. -4'...Cloak. Name of agent: Patent attorney Toshio Nakao and one other person. '( Figure 1: The color of the pintail is extremely heavy. Figure 2:

Claims (3)

[Claims] (1) A glass mat for storage batteries in which thermoplastic resin fibers are added as a binder to the glass fibers that make up the entire mat, and the glass fibers are fully bonded to each other. (2) The glass mat for a storage battery according to claim 1, wherein the mixing ratio of thermoplastic resin fibers to glass fibers is 2 to 25% by weight. (3) The glass mat for a storage battery according to claim 2, wherein the thermoplastic resin fiber has a diameter of 1 to 20 microns.