JPH01307156A - Separator for storage battery and manufacture thereof - Google Patents

Abstract

PURPOSE:To simplify a manufacturing process and to prevent the generation of peeling off and folding of a separator in assembling an electrode group by forming the separator by bonding a nonwoven fabric, a paste layer containing a filler and a resin, and a glass mat in order. CONSTITUTION:A separator is formed by bonding a nonwoven fabric 2, a paste layer containing a filler and a resin, and a glass mat in order. A paste solution 4 containing a filler and a resin is applied to one side of a nonwoven fabric 2, then a glass mat 9 is brought into contact with the coated surface, and they are dried. The nonwoven fabric 2 fed from a rolled nonwoven fabric 1 is fed from the right to the left in the figure with a nonwoven fabric feeding mechanism, and coated with the paste solution 4 in a paste tank arranged over a roller 7. The glass mat 9 is made to fall down with a glass mat feeding mechanism 5 on the paste coated surface, then they are dried with a drying furnace 12, and cut to form a separator 14. A manufacturing process is simplified and the generation of peeling off and folding of the separator in the assembly of an electrode group is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a separator for storage batteries and a method for manufacturing the same.

(Prior art) M battery separators must have an electrode spacing function between the positive and negative electrodes of a storage battery and a function to prevent electrode reactants from falling off, as well as an excellent electrolyte diffusion function. is necessary. In addition, in order to meet the demands for smaller size and higher performance storage batteries, it has low electrical resistance, and also has a small maximum pore diameter and a small thickness to prevent short circuits caused by dendritic lead that occurs as the electrolyte concentration decreases. A thin separator is desired.

Conventionally, various separators and their manufacturing methods have been developed to meet this requirement, and separators for small, high-performance, long-life storage batteries have been developed using nonwoven fabric, paste layers containing fillers and resins, and glass mats as constituent materials. There is something to do.

The typical structure is one in which a paste layer is sandwiched between two sheets of nonwoven fabric (three-layer structure), and a glass mat is adhered to it (four-layer structure).The thickness of this separator is as follows: The axis is 0.70 to 1.2 m, and relatively many are about 1.0 mm.

The manufacturing method of such a separator (four-layered body) consists of a step of sandwiching a paste liquid between two nonwoven fabrics to form a three-layered body, a step of applying an adhesive to the three-layered body, and a step of applying an adhesive to the three-layered body. This process includes a step of bringing the glass mat into contact with a surface, and a drying/molding step. Note that the nonwoven fabric and the paste layer are bonded together by the adhesive force of the paste liquid itself. In addition, the three-layer structure and the glass mat are bonded using an adhesive, but since the adhesive part causes an increase in electrical resistance, the adhesive cannot be applied to the entire surface, but it is applied locally, for example, in several lines. It is something that will be done.

(Problem to be Solved by the Invention) However, in the above-mentioned separator (four-layer structure), as mentioned above, the three-layer structure and the glass mat are only bonded by locally applied adhesive. Therefore, the polar group (
When assembling the laminate (electrode and separator), the adhesive strength is weak, so the two may be peeled off and assembled, some parts may be peeled off and the three-layer structure may be folded and assembled, or the overall hardness may be weak, resulting in the separator being assembled. Folding and folding (hereinafter referred to as peeling/folding) often occurs. This is an important problem since it causes a deterioration in its function as a separator, and there is a demand for its improvement.

Furthermore, since nonwoven fabrics are relatively expensive, there is a desire to reduce the amount of nonwoven fabrics used.

Furthermore, regarding the method for manufacturing a separator, as described above, 2
This involves the process of sandwiching a paste solution between sheets of nonwoven fabric to form a three-layered structure, and since this sandwiching is extremely difficult and requires a high level of skill, there is a strong desire for improvement. In addition, since the next glass cloak contacting step is carried out after the paste liquid has dried after the above-mentioned settling step, there is a relatively long time lag between the above-mentioned sandwiching step and the next step, which results in a long manufacturing process. It takes time. In addition, the sandwiching process and the glass mat contacting process cannot be combined into a continuous process and cannot be performed continuously on one line. From this point of view, there is an extremely strong desire to simplify the manufacturing method.

The present invention was made in view of these circumstances, and its purpose is to solve the above-mentioned problems of the conventional products, reduce the amount of nonwoven fabric used, and improve the structure of the three-layer structure and glass. An object of the present invention is to provide a separator for a storage battery and a method for manufacturing the separator, which can eliminate the need for an adhesive for adhering to a mat, simplify the manufacturing method of the separator, and prevent the occurrence of peeling and folding when assembled into a pole group. That is.

(Means for Solving the Problems) In order to achieve the above-mentioned problems, the present invention provides a storage battery separator and a method for manufacturing the same having the following configuration.

That is, the separator for a storage battery according to the first aspect is a separator for a storage battery characterized in that a nonwoven fabric, a paste a containing a filler and a resin, and a glass mat are adhered in this order.

Further, the manufacturing method of the second claim is a method for manufacturing a separator for a storage battery, in which a nonwoven fabric, a paste layer containing a filler and a resin, and a glass mat are adhered in this order, wherein one side of the nonwoven fabric is A method for producing a separator for a storage battery is characterized in that a paste solution containing a filler and a resin is applied to the surface of the paste, and then a glass mat is brought into contact with the applied surface, dried, and molded.

(Function) The method for producing a separator for storage batteries according to the present invention is to apply a paste solution containing a filler and a resin to one side of a nonwoven fabric, then bring a glass mat into contact with the applied surface, dry it, and mold it. It is something to do.

Since the paste liquid contains a resin, it can be made to have adhesive strength based on the action of the resin. Moreover, since the paste liquid functions as a separator when it becomes a paste layer, it can be applied to the entire surface. It is also common to apply it to the entire surface.

Therefore, a separator (three-layered body) in which the nonwoven fabric, the paste layer, and the glass mat are bonded to each other on the entire surface is obtained by the adhesive force of this paste liquid.

In this way, the glass mat can be glued on the entire surface,
Compared to the conventional four-layer structure in which glass mats are locally bonded, the separator as a whole has improved hardness and stronger adhesive strength.

Furthermore, since the paste liquid contains a filler and a resin, when it dries and solidifies to form a paste layer, the filler in the paste layer is bound by the resin, so the filler remains stable in the paste. is retained. Therefore, it has low electrical resistance and can function stably as a separator with a small maximum pore diameter.

Furthermore, from a process perspective, the above manufacturing method includes a step of applying a paste liquid to the nonwoven fabric, a step of contacting the glass mat with the applied surface, and a drying/molding step. The smaller the time difference between the application step and the contact step, the better. This is because if the time difference is too large, the paste solution dries, the adhesive action of the paste solution decreases, and the adhesive force becomes weak.

Therefore, the coating step and the contacting step can be performed almost simultaneously and can be performed as a continuous process. Therefore, the method for manufacturing the separator can be simplified. For example, the coating step and the contacting step can be performed in one line as described below.

That is, FIG. 1 schematically shows an example of a manufacturing apparatus and a manufacturing situation for carrying out the method for manufacturing a storage battery separator according to the present invention. As can be seen from this figure, the nonwoven fabric (2) sent out from the rolled nonwoven fabric (1) is passed through rollers (6) and (7) by a nonwoven fabric traveling mechanism (not shown) as shown in the figure. Drive from right to left. During this running, the nonwoven fabric (2) is coated with the paste liquid (4) in the paste liquid tank (3) arranged above the roller (7). At this time, the coating thickness is adjusted by a coater (8) provided at the end of the paste liquid tank (3).

The nonwoven fabric (l111) coated with the paste solution travels to the left in the drawing, but along the way, the glass mat (9) is dropped by the glass mat delivery mechanism (5) and placed on the paste solution application surface. In the figure, (9) shows the glass mat in a falling state.

The nonwoven fabric (II) to which the paste 1 (4) and the glass mat (9) are attached is dried in a drying oven 02), and then cut by a cutting machine 03) to become a storage battery separator 04).

As illustrated above, the coating step and the contacting step can be performed continuously in one line. Furthermore, since these steps and the drying/molding step can be performed in one line, it is also possible to perform all the steps continuously in one line.

As described above, the separator for a storage battery according to the present invention is formed by bonding a nonwoven fabric, a paste layer containing a filler and a resin, and a glass mat in this order. Such a separator is manufactured by the manufacturing method described above.

Therefore, the glass mat can have strong adhesive strength. Easy to manufacture. In addition, it has low electrical resistance and a small maximum pore diameter, and can function stably as a separator.

Furthermore, since one separator includes one nonwoven fabric, the amount of nonwoven fabric used is reduced by half compared to the case of a conventional separator (four layers). Also,
The adhesive required for partial bonding in the case of conventional separators is no longer required.

Note that the three layers of the nonwoven fabric, the paste layer, and the glass mat are not placed in this order (if they are in any other order, the effects described above will not be obtained). In this case, an adhesive application process is required to bond the nonwoven fabric and the glass mat.
The process cannot be simplified, and since the paste layer is not protected by a nonwoven fabric, the paste layer is likely to fall off when the separator is used.

Also, if there are only two layers, the paste layer and the glass mat,
Not only does the paste layer tend to fall off easily, but large pinholes are also likely to exist, and although the pinholes can be solved by increasing the thickness of the paste layer, the thicker the paste layer, the higher the electrical resistance. Problems will arise.

In the storage battery separator and the method for manufacturing the same according to the present invention, the nonwoven fabric is preferably one having acid resistance and oxidation resistance, and nonwoven fabrics such as polyethylene, polypropylene, polyacrylic, or polyester can be used.

Regarding the paste layer or paste liquid, as the filler contained therein, an inorganic powder mainly composed of silicon is suitable,
For example, diatomaceous earth, perlite, zeolite, silicic acid,
Powders such as white carbon and colloidal silica can be used.

As the resin, those having acid resistance and oxidation resistance are suitable, and resins or resin emulsions such as polystyrene, polymethacrylate, polyester, polyacryl styrene, polyvinyl chloride, styrene butadiene rubber, nitrile butadiene rubber are used. can.

Regarding the viscosity of the paste liquid, the higher the viscosity, the better the adhesive force can be obtained, so the higher the viscosity, the better.
It is preferable to increase the viscosity to 0 cps or more. If this viscosity cannot be obtained by adding only the filler and resin and the adhesive strength is insufficient, it is desirable to add a thickener in addition to the above.

As the thickener, sodium polyacrylate, gelatin, polyvinyl alcohol, carboxymethyl cellulose, etc. can be used.

(Example) Examples of the present invention will be described below. It should be noted that all of these Examples were carried out using an apparatus similar to the manufacturing apparatus shown in FIG. 1 described above.

1 x 80 parts of earth perlite powder and 20 parts of white carbon powder
After dispersing in water 100 parts of a filler consisting of 100% styrene-butadiene rubber and 100 parts of an emulsion containing 40% styrene-butadiene rubber, a thickener was added to adjust the viscosity to 400 cps.

This adjustment liquid was made into a paste liquid, and this was applied to one side of a polyester nonwoven fabric (thickness = 70 μm). The coating thickness was 0.2 mm.

Next, a glass mat was placed on the coated surface while the paste solution was not drying, and heated in that state to 170°C. still,
The only pressure applied is the weight of the glass cloak.

After drying and molding, a separator for an H battery was obtained in which three layers, the nonwoven fabric, the paste layer, and the glass mat, were adhered. 37
! ! f was completely glued, making it a solid, plate-like, one-piece product.

The electrical resistance and maximum pore diameter of the separator thus obtained were measured, and a performance evaluation test as a separator was conducted. The maximum pore diameter described below is the average value of the maximum pore diameter measurements.

As a result of the test, the electrical resistance was 0.00058Ω・100cI
1z/sheet, and the maximum pore diameter was 42 μm.

Disaster Prevention I The viscosity of the paste liquid was adjusted to 750 cps. MTJ was prepared in the same manner as in Example 1 except for the viscosity of this paste solution.
The same test as in Example 1 was conducted on the separator for pond use.

As a result, the electrical resistance is 0.00051Ω bow 00cm”7
The maximum pore diameter is 181! It was s.

The viscosity of the main paste solution was adjusted to 1100 cps. A separator for a storage battery was obtained in the same manner as in Example 1 except for the viscosity of this paste liquid, and the same tests as in Example 1 were conducted.

As a result, the electrical resistance is 0.00061Ω・100cm”
There were 7 sheets, and the maximum pore diameter was 11.2 layers.

Implementation M↓ The viscosity of the paste liquid was adjusted to 3300 cps. A separator for a storage battery was obtained in the same manner as in Example 1 except for the viscosity of this paste liquid. Then, the same test as in Example 1 was carried out, and the oxidation resistance time, which is a barometer of service life, was also measured.

As a result, the electrical resistance is 0.00060Ω・100cm”
There were 7 pieces, and the maximum pore diameter was 7.5 μm. Further, the oxidation resistance time was 23011r/sheet.

Kogo ■ 100 parts of a filler consisting of 90 parts of Ekeisou earth and 20 parts of white carbon, and 100 parts of an emulsion containing 30% polymethacrylate were dispersed in water, and a thickener was added to adjust the viscosity to 4000 cps. did.

This adjustment liquid was used as a paste liquid, and the subsequent steps were carried out in the same manner as in Example 1 to obtain a storage battery separator, and the same tests as in Example 4 were conducted.

As a result, the electrical resistance was 0.00074Ω・100cm”
There were 7 pieces, and the maximum pore diameter was 8.4 μm. Further, the oxidation resistance time was 190 Hr/sheet.

(Effects of the Invention) According to the storage battery separator and the method for manufacturing the same according to the present invention, the following effects can be obtained without deteriorating the functions and characteristics necessary for a separator.

The amount of nonwoven fabric used is reduced by half compared to the case of using a conventional separator (four layers).

Also, the process of sandwiching the paste liquid is not necessary, and instead it can be replaced with paste. Since it is only necessary to apply &, the separator can be manufactured easily without requiring advanced technology. In addition, all processes from the coating process to drying and molding processes can be performed continuously on one line. Therefore,
The separator manufacturing method can be simplified.

Furthermore, since the constituent materials of the separator, especially the glass mat, are bonded over the entire surface, the adhesive force between the constituent materials can be strengthened. Therefore, it is possible to prevent the separation and folding of the 711 when assembled into a pole group.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a manufacturing apparatus and a manufacturing situation for carrying out the method of manufacturing a separator for M batteries according to the present invention. (1) - Rolled nonwoven fabric (2) - Sent out nonwoven fabric (3) - Baseton night tank (4) - Paste liquid (5)
-Glass mat feeding mechanism (6), (7L-roller (8) -Coke (9)
-Glass mat 00) in a falling state -Nonwoven fabric (ll) coated with paste liquid -Nonwoven fabric a1 to which paste Hffl (4) and glass mat (9) are attached -Drying oven 0 - Cutting machine G4) - 1 Battery separator patent applicant Matsubayashi Kogyo Co., Ltd. Representative Patent attorney Akira Kanemaru

Claims (2)

[Claims] (1) A nonwoven fabric, a paste layer containing a filler and a resin,
A separator for a storage battery, characterized in that a glass mat is adhered in this order. (2) a nonwoven fabric, a paste layer containing a filler and a resin,
A method for manufacturing a storage battery separator in which a glass mat is adhered in this order, the paste solution containing a filler and a resin being applied to one side of a nonwoven fabric, and then the glass mat being brought into contact with the applied surface. A method for producing a separator for a storage battery, the method comprising: drying and molding.