KR102724366B1 - Manufacturing method of separator for storage battery - Google Patents

Abstract

The present invention is produced by dissociating glass fiber yarn and synthetic fiber yarn with purified water, applying a hardener to a wetland, drying it in an oven, and compressing it with a press to produce a wetland of a predetermined thickness, thereby achieving the effects of acid resistance, tensile strength, and low electrical resistance.

Description

Manufacturing method of separator for storage battery

The present invention relates to a method for manufacturing a separator for a storage battery, and more specifically, to a method for manufacturing a separator for a storage battery having acid resistance, tensile strength, and low electrical resistance, by dissociating glass fiber yarn and synthetic fiber yarn with purified water, applying a hardener to a wet material, drying the wet material in an oven, and compressing the wet material with a press to produce a predetermined thickness.

In general, batteries are classified into lead-acid batteries, alkaline batteries, and lithium-ion batteries, depending on the materials used in the positive and negative electrodes. Lead-acid batteries are one of the oldest batteries and use lead oxide for the positive electrode and lead for the negative electrode, while alkaline batteries use nickel hydroxide (NiOOH) for the negative electrode. In addition, lithium-ion batteries use lithium oxide for the positive electrode, and the negative electrode is composed of copper, active materials, conductive materials, and binders.

These batteries are further equipped with an electrolyte, which is a medium that only moves ions, and a separator that electrically insulates the positive and negative electrodes and prevents self-discharge. In other words, the four major components of a battery are a positive electrode, a negative electrode, an electrolyte, and a separator.

Meanwhile, the Korean Industrial Standard (KS C 2202) has disclosed regulations on separators for lead-acid batteries. KS C 2202 is a regulation on porous or microporous thin plates inserted to prevent short circuits and maintain gaps between lead-acid battery plates for automobiles, installations, electric vehicles, etc.

Here, the active material is the electrochemical reactant of the electrode, the anode means lead dioxide, and the cathode means sponge-shaped lead. The electrolyte is a medium that conducts ions during the electrochemical reaction within a lead-acid battery, and for lead-acid batteries it means diluted sulfuric acid. The electrical resistance is a value that indicates the degree to which ion conduction is hindered by the separator in diluted sulfuric acid, and is the value per 100 ^cm2 of separator, and free chlorine is defined as chloride ion eluted from the separator in diluted sulfuric acid.

And, the types of separators are classified into microporous rubber separators, reinforced fiber separators, synthetic fiber separators, synthetic resin separators, and absorbent glass mat (AGM, Absorbent Glass Mat Tech) separators, and the separator is used to prevent the electrode plates from being deformed and coming into contact with each other during the chemical reaction between the electrode plates and the electrolyte during charging and discharging, or to prevent internal discharge between the electrode plates.

As a related prior art, Patent Publication No. 10-0858720 (September 9, 2008) discloses a ‘method for manufacturing a separator for a battery.’

The above-mentioned prior art is a method for manufacturing a separator for a storage battery, characterized in that the method comprises: introducing an aqueous emulsion composed of 20 to 30 wt% of methylol urea, 20 to 30 wt% of a water-soluble synthetic resin, and 40 to 60 wt% of water into a beater, mixing 40 to 45 wt% of linter pulp, 20 to 25 wt% of synthetic fiber yarn, and 30 to 40 wt% of glass fiber yarn, so that the mixture has a fiber concentration of 5 to 8 wt%, and dissociating the fibers to produce a stock obtained by pressing and drying the stock.

The above-mentioned conventional technology has the characteristics of having almost no electrical resistance and excellent impact resistance and acid resistance without using asbestos, a manufacturing method that shortens the production process by producing without a separate hardening agent treatment process, and shortening the drying time by using a synthetic resin aqueous solution.

However, the above-mentioned prior art has a problem in that it is a separator made of synthetic fiber material and cannot provide a separator made of glass fiber, which is an AGM separator.

The present invention has been created to solve the problems of the prior art as described above, and an object of the present invention is to provide a method for manufacturing a separator for a storage battery, which is applied to a battery which is less sensitive to temperature changes due to the characteristics of glass fibers and which is formed into a mesh structure so that an electrolyte is impregnated therein and can be charged faster than a general battery, by dissociating glass fibers, which are the main materials of an absorbent glass mat (AGM) separator, and synthetic fibers for reinforcing the tensile strength of the glass fibers, in purified water to create a wetland, removing moisture from the wetland, drying it, and pressing it to a predetermined thickness.

In order to achieve the above-mentioned object, the present invention provides a method for manufacturing a battery separator, comprising the steps of: (A) preparing fiber yarns comprising 6.028 g of first fiber yarns in which 95 wt% of glass fiber yarn and 5 wt% of synthetic fiber yarn are mixed, and second fiber yarns additionally weighing 0.05 wt% based on the first fiber yarn, and 2,000 ml of purified water; (B) introducing the fiber yarn and purified water into a fiber dissociator and dissociating them for 3 minutes; (C) introducing the suspension dissociated in the fiber dissociator into a sheet manufacturing machine having 80 WIRE MESH; (D) introducing an antifoaming agent to remove bubbles generated in the suspension introduced into the sheet manufacturing machine; (E) placing the 80MESH wetland from which the bubbles have been removed into a moisture absorption device and removing 60% of the moisture; (F) a step of spraying a curing agent diluted in purified water at 0.005 weight part per purified water onto the back surface of a wetland from which 60% of moisture has been removed in the above moisture absorption device; (G) a step of drying the wetland on which the curing agent has been sprayed in an oven at a temperature of 110°C for 30 minutes; and (H) a step of pressing the wetland dried for 30 minutes so that it is molded to a thickness of 0.7 t.

The above hardener is characterized in that 0.01 weight part is sprayed relative to the fiber.

The above second fiber yarn is determined between 0.200 g and 0.302 g, and the above synthetic fiber yarn is characterized by being provided with any one of polyethylene yarn, polypropylene yarn, and polyester yarn.

The above curing agent is characterized in that it is provided as an aqueous emulsion composed of 20 to 30 wt% of methylol urea, 20 to 30 wt% of a water-soluble synthetic resin, and 40 to 60 wt% of water.

The above step (H) is characterized by applying pressure of 20 kgf/cm2 when pressurizing the press.

The moisture content of the wetland dried in the above step (G) is characterized as being less than 0.3%.

In this way, the method for manufacturing a separator for a storage battery according to the present invention mixes glass fiber yarn with synthetic fiber yarn and forms it into a mesh structure, so that not only is the electrolyte easily absorbed, but the electrical resistance is very low, and since it is processed into high-density glass fiber yarn, the tensile strength and acid resistance are excellent, so when applied to an automobile battery that is frequently charged and discharged, the battery output is excellent, and the starting power is improved, thereby increasing energy efficiency.

Hereinafter, one embodiment of the present invention will be described in detail.

The method for manufacturing a separator for a battery of the present invention relates to a method for manufacturing an absorbent glass mat (AGM, Absorbent Glass Mat Tech) separator manufactured using glass fiber as a main material.

The method for manufacturing a separator for a battery of the present invention comprises the steps of (A) preparing a fiber yarn comprising 6.028 g of a first fiber yarn mixed with 95 wt% of glass fiber yarn and 5 wt% of synthetic fiber yarn and a second fiber yarn additionally weighing 0.05 wt% of the first fiber yarn, and 2000 ml of purified water; thereby preparing wetland material. Here, the second fiber yarn is weighed at 0.302 g, and the fiber yarn is weighed at 6.330 g.

And, in step (B), the fiber and purified water are put into a fiber dissociator and dissociated for 3 minutes. At this time, it is preferable that the fiber dissociator be equipped with a 3000 rpm pilot machine so that the dissociation state of the fiber can be visually confirmed from the outside.

In addition, in step (C), the suspension dissociated from the fiber dissociator is fed into a sheet manufacturing machine with 80 WIRE MESH laid out.

At this time, bubbles are generated in the suspension of the sheet making machine, and step (D) is performed to remove them. That is, step (D) involves adding an antifoaming agent to remove the bubbles generated in the suspension fed into the sheet making machine.

Here, the defoaming agent may be composed of an olefin solvent with strong alkaline and high temperature resistance and a lipophilic surfactant, or may be composed of a lotion defoaming agent composed of silicone oil and calcium.

Meanwhile, when the foaming agent is injected into the sheet-making machine, the state in which the bubbles are removed from the suspension is called wetland. Then, the 80MESH wetland from which the bubbles are removed is placed on a moisture absorption device to perform step (E) of removing 60% of the moisture.

And, in step (F), a hardener diluted in purified water at 0.005 weight part is sprayed onto the back surface of the wetland from which 60% of the moisture has been removed.

In addition, in step (F), step (G) is performed to dry the wetland to which the hardener has been applied in an oven at a temperature of 110℃ for 30 minutes. Then, step (H) of pressurizing is performed. In step (H), pressurizing is performed so that the dried wetland is formed to a thickness of 0.7 t (0.7 mm), and the error range at this time is allowed to be ±0.05 t (0.05 mm). Here, the dried wetland is a pre-pressurized separator formed to a thickness of 0.7 t or more in an unpressurized state.

Meanwhile, the curing agent is sprayed in an amount of 0.01 weight part relative to the fiber, so that the curing agent is applied to the wetland containing 40% moisture and the outer surface of the wetland is dried in an oven, thereby reinforcing the tensile strength.

And, after step (H), the appearance, acid resistance, tensile strength, thickness, electrical resistance, etc. of the completed separator can be inspected according to the test method of the Korean Industrial Standards.

Meanwhile, the second fiber yarn is determined between 0.200 g and 0.302 g, thereby making it possible to supplement the fiber yarn lost in 80 WIRE MESH. In addition, the synthetic fiber yarn is provided as one of polyethylene yarn, polypropylene yarn, and polyester yarn, and while linter pulp can be used according to customer requirements, it has the disadvantage of taking a longer drying time. Such synthetic fiber yarn acts as an adhesive to fix the glass fiber yarn.

And, the curing agent is composed of an aqueous emulsion composed of 20 to 30 wt% of methylol urea, 20 to 30 wt% of a water-soluble synthetic resin, and 40 to 60 wt% of water. The urea resin such as the methylol urea has a weak impact resistance, but this is reinforced by the water-soluble synthetic resin. And, the curing agent prevents the glass fiber yarn constituting the separator from being deformed during the reaction process of repeating discharge and charge.

In addition, in the above step (H), the press is pressurized at 20 kgf/cm ^2. In the above step (G), the moisture content of the wetland is dried to less than 0.3%.

The operation of the method for manufacturing a separator for a battery according to the present invention having the above-described configuration is as follows.

The battery separator according to the present invention satisfies the hygroscopic glass mat (AGM, Absorbent Glass Mat Tech) separator specified in the following Korean Industrial Standard (KS C 2202:2019). According to the AGM separator specification (Table 1) of the Korean Industrial Standard below:

division KS C 2202 Original invention tensile strength 0.21MPa or more 1.7 Electrical resistance (Ωㆍcm ² ㆍsheet) 0.004 (exceeding 0.30mm) 0.002 Porosity AGM 90% or more AGM 95%

The tensile strength is 0.21 MPa, the electrical resistance is 0.004, and the AGM hygroscopic glass mat is 90%. The present invention, which was measured by the test method specified in KS C 2202:2019, satisfies the above provisions.

The separator according to the present invention is made by introducing a fiber mixed with 95 wt% of glass fiber and 5 wt% of synthetic fiber into a fiber dissociator so that the fiber is dissociated in 2 liters of purified water. Here, the glass fiber improves acid resistance, and the synthetic fiber acts as an adhesive to increase the tensile strength of the glass fiber.

At this time, the synthetic fiber is composed of one of polypropylene yarn, polyethylene yarn, and polyethylene terephthalate yarn.

In addition, the curing agent used in the present invention prevents deformation of the separator gap even when the battery is used for a long time or when frequent charging and discharging are performed, thereby maintaining low electrical resistance and the properties of the glass fiber. The curing agent is an aqueous emulsion obtained by uniformly mixing 20 to 30 wt% of methylol urea, 20 to 30 wt% of a water-soluble synthetic resin, and 40 to 60 wt% of water.

The above methylol urea exhibits physical properties similar to those of urea resin, but is water-soluble, is an initial reactant of urea and formaldehyde, and acts as a curing agent similar to urea resin.

As the above water-soluble synthetic resin, polyvinyl alcohol, water-soluble polyvinyl acetate resin, and water-soluble polybutadiene resin can be used. Polyvinyl alcohol is a water-soluble synthetic resin, and polyvinyl acetate resin and polybutadiene resin are not water-soluble synthetic resins, but they can be easily converted to water solubility by saponifying them with alkali.

The method for manufacturing a separator for a storage battery of the present invention comprises dissociating glass fiber yarn and synthetic fiber yarn in purified water to remove moisture, spraying a hardener on the wet surface from which moisture has been removed, drying in an oven, and pressing to a predetermined thickness, thereby manufacturing a battery having high tensile strength, low resistance, and excellent acid resistance, and thus can be used to manufacture a battery with excellent efficiency applied to electric vehicles that undergo frequent charging and discharging.

The present invention is not limited to the specific preferred embodiments described above, and anyone with ordinary skill in the art to which the present invention pertains may make various modifications without departing from the gist of the present invention claimed in the claims, and such modifications are within the scope of the claims.

Claims (5)

In a method for manufacturing a separator for a battery,
(A) A step for preparing a fiber yarn comprising 6.028 g of a first fiber yarn mixed with 95 wt% of glass fiber yarn and 5 wt% of synthetic fiber yarn and a second fiber yarn additionally weighing 0.05 wt% based on the first fiber yarn, and 2,000 ml of purified water; (B) A step for dissociating the fiber yarn and the purified water into a fiber dissociator for 3 minutes; (C) A step for dissociating the suspension dissociated in the fiber dissociator into a sheet manufacturing machine having 80 WIRE MESH; (D) A step for adding an antifoaming agent to remove bubbles generated in the suspension fed into the sheet manufacturing machine; (E) A step for removing 60% of the moisture from the 80MESH wetland from which the bubbles have been removed by placing it on a moisture absorption device; (F) A step for spraying a hardener diluted in purified water at 0.005 wt% based on purified water onto the back surface of the wetland from which 60% of the moisture has been removed in the moisture absorption device; (G) a step of drying the wetland sprayed with the hardener in an oven at a temperature of 110°C for 30 minutes; and (H) a step of pressing the wetland dried for 30 minutes so that it is molded to a thickness of 0.7 t; wherein the hardener is sprayed in an amount of 0.01 weight part relative to the fiber.
The above second fiber yarn is determined between 0.200 g and 0.302 g, and the above synthetic fiber yarn is provided as one of polyethylene yarn, polypropylene yarn, and polyester yarn.
The above curing agent is provided as an aqueous emulsion composed of 20 to 30 wt% of methylol urea, 20 to 30 wt% of water-soluble synthetic resin, and 40 to 60 wt% of water.
The above step (H) applies pressure of 20 kgf/cm ² when the press is pressed.
A method for manufacturing a battery separator, characterized in that the moisture content of the wetland dried in the above step (G) is less than 0.3%. delete delete delete delete