Zinc-silver battery composite diaphragm paper with organic coating and preparation method thereof

Abstract

The present invention belongs to the technical field of zinc-silver battery diaphragm preparation, specifically a zinc-silver battery composite diaphragm paper with an organic coating, comprising a polyolefin fiber base paper and an organic coating coated on the surface thereof, wherein the organic coating is obtained by coating, acetalization and washing of a coating slurry containing polyvinyl alcohol; the coating slurry containing polyvinyl alcohol is composed of the following raw materials in parts by mass: 70-90 parts by mass of a solvent, 10-30 parts by mass of polyvinyl alcohol, and 1-5 parts by mass of a wetting agent; the preparation method comprises the following steps: S1: preparation of the coating slurry; S2: coating on the surface of the base paper; S3: acetalization reaction; S4: washing process. The present invention coats the surface of the polyolefin fiber base paper with an organic coating, fully utilizing the advantages of the organic material such as high temperature resistance, corrosion resistance and electrolyte wettability, to obtain a composite diaphragm with excellent mechanical and electrical properties, and the method can comprehensively improve the electrical properties and service life of the zinc-silver battery.

Description

Technical Field

[0001] The invention relates to the technical field of zinc-silver battery diaphragm preparation, and in particular to a zinc-silver battery composite diaphragm paper with an organic coating and a preparation method thereof. Background Art

[0002] The development of zinc-silver batteries began in the 19th century. Due to its advantages such as high specific energy, high specific power, stable voltage, high safety in continuous use, good reliability and environmental friendliness, it is widely used in military equipment with special requirements such as missiles, launch vehicles, torpedoes, and recoverable satellites. In the civilian field, zinc-silver batteries are also widely used in news photography, television cameras, portable communications, walkie-talkies, etc. Button-type miniature zinc-silver batteries can be used in electronic watches, hearing aids, computers and pacemakers.

[0003] The zinc-silver single cell battery consists of a plate group, a single cell shell, a single cell cover, a pole column, a gas plug, etc. The plate group includes three parts: a positive plate, a negative plate, and a diaphragm. The performance of the entire battery is determined by the above three materials. The diaphragm has the function of separating the positive and negative electrodes and providing a channel for the diffusion of K+ ions and OH- ions. At the same time, it also needs to prevent the diffusion of silver oxide sol to the negative electrode. Therefore, the performance of the diaphragm seriously affects the electrical performance and safety performance of the zinc-silver battery.

[0004] The diaphragms mainly made of cellulose, modified cellulose, modified polyvinyl alcohol and other materials have good silver resistance, low resistance and high strength, and are currently the most widely used materials for zinc-silver battery diaphragms.

[0005] However, the above-mentioned materials are organic polymer materials, and their inherent properties make them less resistant to high temperatures, alkali corrosion and oxidation. In the battery use environment, the molecular chains will undergo oxidative degradation, the structure will be destroyed and the isolation function will be lost, causing accidents such as battery short circuits. Summary of the invention

[0006] 1. Technical issues to be solved The purpose of the present invention is to solve the problem that organic polymer materials in the prior art have poor high temperature resistance, alkali corrosion resistance and oxidation resistance due to their own properties, and molecular chain oxidation degradation will occur in the battery use environment. A zinc-silver battery composite diaphragm paper with an organic coating and a preparation method thereof are proposed.

[0007] 2. Technical solution In order to achieve the above object, the present invention adopts the following technical solutions: A zinc-silver battery composite diaphragm paper with an organic coating comprises a polyolefin fiber base paper and an organic coating coated on the surface thereof, wherein the organic coating is obtained by subjecting a coating slurry containing polyvinyl alcohol to coating, acetalization reaction and water washing; the coating slurry containing polyvinyl alcohol is composed of the following raw materials in parts by mass: 70-90 parts by mass of a solvent, 10-30 parts by mass of polyvinyl alcohol and 1-5 parts by mass of a wetting agent.

[0008] Preferably, the polyolefin fiber base paper is polyethylene fiber paper, polypropylene fiber paper, or a blend of polyethylene fiber and polypropylene fiber.

[0009] Preferably, the solvent is water, the degree of polymerization of the polyvinyl alcohol is 1000-2000, and the degree of alcoholysis is 98%-99%.

[0010] Preferably, the wetting agent is one or a mixture of any two or more of polyglycosides, fatty acid ester ethoxylates, alkyl and aryl alcohol ethoxylates, alkyl sulfonates and sulfates, alcohol ether sulfates, alkyl phosphates and phosphonates, alkyl sulfosuccinates and sulfated fatty acid esters.

[0011] Preferably, the solid content of the coating slurry is 10wt%-30wt%.

[0012] The present invention also proposes a method for preparing a zinc-silver battery composite diaphragm paper with an organic coating, comprising the following steps: S1: Preparation of coating slurry; S2: coating on the base paper surface; S3: acetalization reaction; S4: water washing process.

[0013] Preferably, the coating slurry is prepared by mixing a solvent, polyvinyl alcohol and a wetting agent, and the slurry is mixed by mechanical stirring.

[0014] Preferably, the process of coating the surface of the base film adopts one or more of the following methods: spray coating, scraping film coating, casting, roller coating, etc., to coat the surface of the polyolefin fiber base paper with an organic coating.

[0015] Preferably, after the surface of the base paper is coated, an acetalization reaction is further performed, the reaction conditions are pH=1.0-7.0, the temperature is about 60-80°C, and the coated base paper is immersed in a 10%-50% formaldehyde aqueous solution for 10-120 minutes.

[0016] 3. Beneficial effects Compared with the prior art, the advantages of the present invention are: (1) In the present invention, an organic coating is coated on the surface of a polyolefin fiber base paper, and the advantages of organic materials such as high temperature resistance, corrosion resistance and electrolyte wettability are fully utilized to obtain a composite diaphragm with excellent mechanical and electrical properties. This method can comprehensively improve the electrical properties and service life of zinc-silver batteries.

[0017] (2) In the present invention, the preparation process of the zinc-silver battery separator has the characteristics of simple production process, low cost, excellent comprehensive performance, etc., and can realize large-scale industrial production. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] Embodiment 1: A zinc-silver battery composite diaphragm paper with an organic coating, comprising a polyolefin fiber base paper and an organic coating coated on the surface thereof, wherein the organic coating is obtained by coating a coating slurry containing polyvinyl alcohol, undergoing acetalization reaction, and washing with water; In this embodiment, the coating slurry containing polyvinyl alcohol is composed of the following raw materials in parts by weight: 70-90 parts by weight of solvent, 10-30 parts by weight of polyvinyl alcohol, and 1-5 parts by weight of wetting agent. The polyolefin fiber base paper is polyethylene fiber paper, polypropylene fiber paper, or a blend of polyethylene fiber and polypropylene fiber. In this embodiment, the solvent is water, the degree of polymerization of polyvinyl alcohol is 1000-2000, the degree of alcoholysis is 98%-99%, the wetting agent is a mixture of one or more of any proportions of polyglycosides, fatty acid ester ethoxylates, alkyl and aromatic alcohol ethoxylates, alkyl sulfonates and sulfates, alcohol ether sulfates, alkyl phosphates and phosphonates, alkyl sulfosuccinates and sulfated fatty acid esters, and the solid content of the coating slurry is 10wt%-30wt%.

[0020] In this embodiment, a method for preparing a zinc-silver battery composite diaphragm paper having an organic coating comprises the following steps: S1: preparing a coating slurry, wherein the coating slurry is prepared by mixing a solvent, polyvinyl alcohol and a wetting agent, wherein the slurry is mixed by mechanical stirring; S2: coating the surface of the base paper, wherein the coating process of the base film surface adopts one or more of the following methods: spray coating, scraping coating, casting, and roller coating, and an organic coating is applied on the surface of the polyolefin fiber base paper; S3: Acetalization reaction, wherein the reaction conditions of the acetalization reaction are pH=1.0-7.0, temperature about 60-80°C, and the coated base paper is immersed in a 10%-50% formaldehyde aqueous solution for 10-120 minutes; S4: water washing process.

[0021] In this embodiment, an organic coating is coated on the surface of the polyolefin fiber base paper, and the advantages of the organic material such as high temperature resistance, corrosion resistance and electrolyte wettability are fully utilized to obtain a composite diaphragm with excellent mechanical and electrical properties. This method can comprehensively improve the electrical performance and service life of the zinc-silver battery.

[0022] In this embodiment, the preparation process of the zinc-silver battery separator has the characteristics of simple production process, low cost, excellent comprehensive performance, etc., and can realize large-scale industrial production.

[0023] The technical indicators of the zinc-silver battery separator prepared by the process of the present invention are shown in the table below.

[0024] Embodiment 2: In this embodiment, 15g of polyvinyl alcohol and 1g of polyglycoside were slowly added to 85mL of water and mechanically stirred to mix evenly to obtain an ideal coating slurry. 2 ) was used as the base paper, and an organic coating was obtained on both surfaces of the base paper by the dip coating method. The base paper was placed in an oven at 80°C and dried for 0.5h. Finally, the coated base paper was immersed in a 37% formaldehyde aqueous solution at pH = 1.5 and a temperature of about 65°C for 20 minutes. After washing with water, an organic coating composite diaphragm was obtained.

[0025] The above composite diaphragm was tested.

[0026] Thickness test results: the film thickness is 108μm.

[0027] High temperature test results: After keeping at 60℃ for 30 minutes, the diaphragm size did not change.

[0028] Liquid absorption test results: The composite membrane was immersed in 30wt% KOH solution for 1h, and the liquid absorption rate was 320% compared with the dry membrane.

[0029] Tensile strength test results: both transverse and longitudinal tensile strengths are greater than 30MPa.

[0030] Embodiment 3: In this embodiment, 20g of polyvinyl alcohol and 2g of alcohol ether sulfate were slowly added to 80mL of water and mechanically stirred to mix evenly to obtain an ideal coating slurry. 2 ) was used as the base paper, and an organic coating was obtained on both surfaces of the base paper by a scraping method. The base paper was placed in an oven at 80°C and dried for 0.5h. Finally, the coated base paper was immersed in a 25% formaldehyde aqueous solution at pH=3.0 and a temperature of about 75°C for 40 minutes. After washing with water, an organic coating composite diaphragm was obtained.

[0031] The above composite diaphragm was tested.

[0032] Thickness test results: the film thickness is 114μm.

[0033] High temperature test results: After keeping at 60℃ for 30 minutes, the diaphragm size did not change.

[0034] Liquid absorption test results: The composite membrane was immersed in 30wt% KOH solution for 1h, and the liquid absorption rate was 371% compared with the dry film.

[0035] Tensile strength test results: both transverse and longitudinal tensile strengths are greater than 30MPa.

[0036] Embodiment 4: In this embodiment, 7g of polyvinyl alcohol and 3g of fatty acid ester ethoxylate were slowly added to 70mL of water and mechanically stirred to mix evenly to obtain an ideal coating slurry. 2 ) was used as the base paper, and an organic coating was obtained on both surfaces of the base paper by spraying, and the base paper was placed in an oven at 80°C for drying for 0.5h. Finally, the coated base paper was immersed in a 30% formaldehyde aqueous solution at pH = 2.4 and a temperature of about 70°C for 60 minutes. After washing with water, an organic coating composite diaphragm was obtained.

[0037] The above composite diaphragm was tested.

[0038] Thickness test results: the film thickness is 95μm.

[0039] High temperature test results: After keeping at 60℃ for 30 minutes, the diaphragm size did not change.

[0040] Liquid absorption test results: The composite membrane was immersed in 30wt% KOH solution for 1h, and the liquid absorption rate was 296% compared with the dry membrane.

[0041] Tensile strength test results: both transverse and longitudinal tensile strengths are greater than 30MPa.

[0042] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A zinc-silver battery composite diaphragm paper with an organic coating, comprising a polyolefin fiber base paper and an organic coating coated on the surface thereof, characterized in that: The organic coating is obtained by coating, acetalization and washing a coating slurry containing polyvinyl alcohol; the coating slurry containing polyvinyl alcohol is composed of the following raw materials in parts by weight: 70-90 parts by weight of solvent, 10-30 parts by weight of polyvinyl alcohol and 1-5 parts by weight of wetting agent.

2. The zinc-silver battery composite diaphragm paper with an organic coating according to claim 1, characterized in that: The polyolefin fiber base paper is polyethylene fiber paper, polypropylene fiber paper, or polyethylene fiber and polypropylene fiber blended paper.

3. The zinc-silver battery composite diaphragm paper with an organic coating according to claim 1, characterized in that: The solvent is water, the polymerization degree of the polyvinyl alcohol is 1000-2000, and the alcoholysis degree is 98%-99%.

4. The zinc-silver battery composite diaphragm paper with an organic coating according to claim 1, characterized in that: The wetting agent is one or a mixture of any two or more of polyglycosides, fatty acid ester ethoxylates, alkyl and aryl alcohol ethoxylates, alkyl sulfonates and sulfates, alcohol ether sulfates, alkyl phosphates and phosphonates, alkyl sulfosuccinates and sulfated fatty acid esters.

5. The zinc-silver battery composite diaphragm paper with an organic coating according to claim 1, characterized in that: The solid content of the coating slurry is 10wt%-30wt%.

6. The method for preparing a zinc-silver battery composite diaphragm paper with an organic coating according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Preparation of coating slurry; S2: coating on the base paper surface; S3: acetalization reaction; S4: water washing process.

7. The method for preparing a zinc-silver battery composite diaphragm paper with an organic coating according to claim 6, characterized in that: The coating slurry is prepared specifically by mixing a solvent, polyvinyl alcohol and a wetting agent, and the slurry is mixed by mechanical stirring.

8. The method for preparing a zinc-silver battery composite diaphragm paper with an organic coating according to claim 6, characterized in that: The process of coating the surface of the base film adopts one or more of the following methods: spraying, scraping, casting, and roller coating, and an organic coating is coated on the surface of the polyolefin fiber base paper.

9. The method for preparing a zinc-silver battery composite diaphragm paper with an organic coating according to claim 6, characterized in that: The acetalization reaction has the following reaction conditions: pH = 1.0-7.0, temperature about 60-80° C., and the coated base paper is immersed in a 10%-50% formaldehyde aqueous solution for 10-120 minutes.

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