A method for producing a polyphenylene sulfide-coated separator

Abstract

The application discloses a preparation method of a polyphenylene sulfide coated diaphragm and relates to the field of battery coated diaphragm preparation. The method comprises the following steps: (1) performing sulfonation treatment on polyphenylene sulfide (PPS) resin raw materials after crushing and impurity removal, and obtaining sulfonated PPS granular materials after cleaning; (2) dispersing the sulfonated PPS granular materials in water, and then adding a dispersant and a binder to mix uniformly, so as to obtain PPS coating slurry; and (3) coating the obtained PPS coating slurry on the surface of a base film, and drying, so as to obtain the polyphenylene sulfide coated diaphragm. The preparation method is simple in process and easy to operate, and a battery polyphenylene sulfide coated diaphragm with excellent performance is successfully prepared. The coated diaphragm can significantly improve the heat resistance of the battery diaphragm, so that the battery diaphragm can still maintain good stability in a high-temperature environment; the chemical corrosion resistance is enhanced, the erosion of chemical substances in the battery is effectively resisted; the mechanical properties are improved, the strength and toughness of the diaphragm are improved, and thus the safety performance and service life of the battery are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery-coated diaphragm preparation, in particular to a preparation method of polyphenylene sulfide-coated diaphragm. BACKGROUND

[0002] Under the situation of increasing energy demand and increasingly stringent environmental protection requirements, new energy industry, especially battery technology, has developed rapidly. The safety performance and cycle life of the battery have become the key indicators to measure the quality of the battery, which is directly related to the user's experience and safety guarantee. Among them, the battery diaphragm as the key component inside the battery plays a crucial role in the safety performance and cycle life of the battery.

[0003] The battery will generate heat during charging and discharging. If the thermal stability of the diaphragm is insufficient, thermal shrinkage or even rupture may occur, leading to positive and negative short circuit and causing thermal runaway of the battery, thereby seriously affecting the safety performance of the battery. Therefore, the thermal stability of the diaphragm is one of the important factors to ensure the safe operation of the battery.

[0004] However, the traditional battery diaphragm has obvious shortcomings in terms of thermal stability. The material properties and structural design of the traditional diaphragm often cannot effectively cope with the temperature changes during the operation of the battery, and are prone to deformation and failure in high temperature environment. In addition, the traditional diaphragm also performs poorly in mechanical properties and chemical stability, and is difficult to withstand the complex chemical environment and mechanical stress inside the battery, which not only limits the charging and discharging performance and cycle life of the battery, but also increases the risk of safety accidents of the battery.

[0005] Therefore, it is of great practical significance and urgent market demand to develop a preparation method that can effectively improve the thermal stability, mechanical properties and chemical stability of the diaphragm to improve the safety performance and cycle life of the battery. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of polyphenylene sulfide-coated diaphragm to improve the safety performance, mechanical properties and chemical stability of the battery diaphragm.

[0007] In order to achieve the above technical purpose, the present application mainly adopts the following technical scheme:

[0008] The present application discloses a preparation method of polyphenylene sulfide-coated diaphragm, comprising the following steps:

[0009] (1) The polyphenylene sulfide PPS resin raw material is crushed, impurity-removed and then sulfonated, and the sulfonated PPS particulate matter is obtained after cleaning;

[0010] (2) The sulfonated PPS particulate matter is dispersed in water, and a dispersing agent and a binder are added to mix uniformly, to obtain PPS coating slurry;

[0011] (3) coating the obtained PPS coating slurry on the surface of the base film, drying, to obtain a polyphenylene sulfide coated separator.

[0012] In the preferred embodiment of the present application, in step (1), the particle size of the crushed polyphenylene sulfide PPS resin raw material is 0.1-5 um.

[0013] In the preferred embodiment of the present application, in step (1), the impurity removal method is: after the crushed PPS particles are washed with distilled water, they are then washed with anhydrous ethanol, and then dried for use.

[0014] In the preferred embodiment of the present application, in step (1), the sulfonation treatment method is: under the protection of an inert atmosphere, the washed and dried PPS particles are sulfonated with 1,2-dichloroethane and chlorosulfonic acid at 50-80℃ for 1-5h.

[0015] In the preferred embodiment of the present application, in step (1), the washing method is: the sulfonated PPS particles are first washed with 1,2-dichloroethane, then washed with acetone after the washing is completed, and dried, to obtain sulfonated PPS particles.

[0016] In the preferred embodiment of the present application, in step (2), the dispersant is an ammonium salt of polycarboxylic acid or a sodium salt of polyacrylic acid, and the addition amount of the dispersant is 0.2-0.8wt% of the weight of the polyphenylene sulfide resin.

[0017] In the preferred embodiment of the present application, in step (2), the binder is one or more of a butadiene-styrene rubber emulsion, a polyacrylate emulsion, and a polyvinylidene fluoride emulsion, and the addition amount of the binder is 3-8wt% of the weight of the polyphenylene sulfide resin.

[0018] In the preferred embodiment of the present application, in step (3), the PPS coating slurry is uniformly coated on the surface of the base film by roll coating or spraying.

[0019] In the preferred embodiment of the present application, in step (3), the base film is a dry base film or a wet base film.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The preparation method is simple in process and easy to operate, and through the steps of crushing, impurity removal, sulfonation treatment and coating of the PPS resin, a battery polyphenylene sulfide coated diaphragm with excellent performance is successfully prepared. The coated film can significantly improve the heat resistance of the battery diaphragm, so that it can still maintain good stability in a high temperature environment; enhance the chemical corrosion resistance, effectively resist the corrosion of the chemical substances inside the battery; improve the mechanical properties, improve the strength and toughness of the diaphragm, thereby greatly improve the safety performance and service life of the battery. DETAILED DESCRIPTION

[0022] To further illustrate the technical means adopted by the present application and the effects achieved, the following will combine specific embodiments to explain a battery polyphenylene sulfide coated diaphragm according to the present application, the specific embodiments, characteristics and effects of the present application will be described in detail as follows. It should be explained in the following examples that the present application is not limited to the following examples, and the disclosed examples and features thereof can be combined with each other without conflict.

[0023] The preparation method of the polyphenylene sulfide coated diaphragm provided by the present application comprises the following steps:

[0024] Step 1: preparation of polyphenylene sulfide coating slurry

[0025] Crushing: the polyphenylene sulfide (PPS) resin is crushed into PPS particulate matter with a particle size of 0.1-5um.

[0026] Impurity removal: the crushed PPS particulate matter is washed with distilled water, then washed with anhydrous ethanol, and then dried for use.

[0027] Sulfonation treatment: under a nitrogen atmosphere, the washed and dried PPS particulate matter is sulfonated with 1,2-dichloroethane and chlorosulfonic acid at 50-80℃ for 1-5h.

[0028] Washing: the sulfonated PPS particulate matter is first washed with 1,2-dichloroethane, then washed with acetone after completion, and dried to obtain the sulfonated PPS particulate matter.

[0029] Preparation of PPS coating slurry: the sulfonated PPS particulate matter is dispersed in water, a dispersing agent and a binder are added, and the mixture is fully mixed and uniformly dispersed to obtain the PPS coating slurry.

[0030] Coating: the PPS coating slurry is uniformly coated on the surface of the dry or wet base film by roll coating or spraying, and the coated film is formed after a certain drying condition.

[0031] The battery polyphenylene sulfide coated diaphragm obtained by the above preparation method can significantly improve the heat resistance, chemical corrosion resistance and mechanical properties of the battery diaphragm, thereby effectively improving the safety performance and service life of the battery.

[0032] The following explanation will be provided through specific implementation details.

[0033] Example 1

[0034] 1. Select an appropriate amount of conventional pure polyphenylene sulfide resin suitable for coating, put it into an air jet mill, adjust the airflow speed to 400m / s, and the grinding time to 10 minutes to grind it into PPS particles with a particle size of 0.1-5um.

[0035] 2. Transfer the pulverized PPS particles to a glass container, add distilled water, stir with a magnetic stirrer for 15 minutes, let stand for 10 minutes, then discard the supernatant. Repeat this process twice. Next, add anhydrous ethanol, stir for 15 minutes, let stand for 10 minutes, then discard the supernatant. Then place the particles in a vacuum drying oven and dry at 80°C for 4 hours for later use.

[0036] 3. In a nitrogen-protected reactor, the cleaned and dried PPS particles are mixed with 1,2-dichloroethane and chlorosulfonic acid. The mass ratio of 1,2-dichloroethane, chlorosulfonic acid, and PPS particles is 10:2:1. The nitrogen inlet device is turned on, and nitrogen is introduced at a flow rate of 5 liters per minute for 30 minutes. Then, the stirring device is started, the speed is set to 300 rpm, and the temperature is gradually increased to 60°C for sulfonation treatment for 3 hours.

[0037] 4. After sulfonation, the product was filtered and transferred to a new container. It was washed three times with 1,2-dichloroethane, stirring for 10 minutes each time, and allowed to stand for 5 minutes before filtering. Then it was washed twice with acetone, stirring for 10 minutes each time, and allowed to stand for 5 minutes before filtering. Finally, the particles were placed in a forced-air drying oven and dried at 80°C for 6 hours to obtain sulfonated PPS particles.

[0038] 5. Disperse the sulfonated PPS particles in deionized water and sonicate for 30 minutes using an ultrasonic disperser. Then add an appropriate amount of polycarboxylate ammonium salt dispersant and styrene-butadiene rubber latex binder, and stir at high speed for 2 hours to ensure thorough mixing and uniform dispersion, thus obtaining the PPS coating film solution.

[0039] 6. Apply the PPS coating solution evenly to the surface of the dry-process base film using a roller coating method. Control the roller coating pressure at 0.2 MPa, the speed at 5 m / min, and the coating thickness at 5 μm. Then, place the coated film in a drying oven and dry it at 120°C for 3 minutes to form the coated film.

[0040] Example 2

[0041] 1. Perform the crushing and impurity removal operations in the same manner as in Example 1.

[0042] 2. Under a nitrogen atmosphere, the cleaned and dried PPS particles were sulfonated with 1,2-dichloroethane and chlorosulfonic acid at 70°C for 4 hours (the cleaned and dried PPS particles were mixed with 1,2-dichloroethane and chlorosulfonic acid, with a mass ratio of 10:2:1). The nitrogen flow rate was 4 liters per minute, the flow time was 25 minutes, and the stirring speed was 250 rpm.

[0043] 3. The cleaning and drying steps are the same as in Example 1.

[0044] 4. When preparing the PPS coating solution, sodium polyacrylate is used as the dispersant and acrylic emulsion is used as the binder. The mixture is ultrasonically dispersed for 25 minutes and then stirred at high speed for 1.5 hours.

[0045] 5. Apply the PPS coating solution to the surface of the wet-process base film using a spraying method, controlling the spraying pressure at 0.3 MPa, the flow rate at 20 ml / min, and the coating thickness at 8 μm. Dry at 100℃ for 5 minutes to obtain the coated film.

[0046] Comparative Example 1

[0047] A 14μm dry-process uniaxially stretched PP diaphragm from Huiqiang New Materials that has not undergone the treatment described in this invention was selected as a comparative example.

[0048] Performance test results:

[0049] The following performance tests were performed on the coated films prepared in Examples 1 and 2, as well as the ordinary diaphragm in the comparative example:

[0050] 1) Heat resistance test: The diaphragms of Comparative Example 1, Example 1 and Example 2 were placed in a high temperature environment (150℃ / 1h) and their shrinkage force was tested.

[0051] 2) Chemical corrosion resistance test: The diaphragms were immersed in strong acid and strong alkali solutions for a certain period of time, and the mass loss of the diaphragms in Comparative Example 1, Example 1 and Example 2 was detected.

[0052] 3) Mechanical property testing: The tensile strength and elongation at break of the diaphragms of Comparative Example 1, Example 1 and Example 2 were determined by tensile testing.

[0053] The test results are shown in Table 1.

[0054] Table 1

[0055]

[0056]

[0057] Based on the above performance test results, it is shown that the polyphenylene sulfide coated film prepared by this invention is significantly superior to traditional ordinary separators in terms of heat resistance, chemical corrosion resistance and mechanical properties, and can effectively improve the safety performance and service life of batteries.

[0058] The above description is merely an embodiment disclosed in this patent. The implementation of this invention is not limited to the above embodiments. It should be noted that any modifications, equivalent transformations, or improvements made without departing from the core scope of this invention are within the protection scope of this invention.

Claims

1. A method for preparing a polyphenylene sulfide coated membrane, characterized in that, Includes the following steps: (1) After crushing and removing impurities, polyphenylene sulfide (PPS) resin raw material is sulfonated and then cleaned to obtain sulfonated PPS particles. (2) Disperse sulfonated PPS particles in water, then add dispersant and binder and mix thoroughly to obtain PPS coating slurry; (3) Coat the obtained PPS coating slurry onto the surface of the base film and dry it to obtain a polyphenylene sulfide coated membrane. In step (1), the sulfonation treatment method is as follows: under the protection of an inert atmosphere, the cleaned and dried PPS particles are sulfonated with 1,2-dichloroethane and chlorosulfonic acid at 50-80℃ for 1-5 hours. In step (2), the dispersant is an ammonium polycarboxylate or sodium polyacrylate, and the amount of the dispersant added is 0.2-0.8 wt% of the weight of the polyphenylene sulfide resin. In step (2), the adhesive is one or more of styrene-butadiene rubber latex, polyacrylate latex, and liquid polyvinylidene fluoride, and the amount of adhesive added is 3-8 wt% of the weight of the polyphenylene sulfide resin.

2. The method for preparing the polyphenylene sulfide coated membrane according to claim 1, characterized in that, In step (1), the particle size of the polyphenylene sulfide (PPS) resin raw material after pulverization is 0.1-5 μm.

3. The method for preparing the polyphenylene sulfide coated membrane according to claim 1, characterized in that, In step (1), the method for removing impurities is as follows: the crushed PPS particles are washed with distilled water, then washed with anhydrous ethanol, and then dried for later use.

4. The method for preparing the polyphenylene sulfide coated separator according to claim 1, characterized in that, In step (1), the cleaning method is as follows: the sulfonated PPS particles are first cleaned with 1,2-dichloroethane, and then cleaned with acetone and dried to obtain sulfonated PPS particles.

5. The method for preparing the polyphenylene sulfide coated separator according to claim 1, characterized in that, In step (3), the PPS coating slurry is uniformly coated on the surface of the base film by roller coating or spraying.

6. The method for preparing the polyphenylene sulfide coated separator according to claim 1, characterized in that, In step (3), the base film is a dry base film or a wet base film.

Images