Preparation method of glass fiber reinforced polycyanophenyl battery diaphragm material
By constructing a stable interfacial bond between glass fiber and polystyrene matrix, the problem of unstable composite material performance was solved, and a battery separator material with high mechanical strength and thermal stability was achieved, meeting the high-temperature application requirements of lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-03-10
AI Technical Summary
It is difficult to achieve uniform composite of glass fiber with other matrix materials, resulting in unstable composite material performance. Furthermore, existing technologies cannot effectively control pore structure and ion conduction performance, thus failing to meet the requirements of different battery systems.
High molecular weight polyphenylene nitrile matrix was synthesized using dehydrated N-methylpyrrolidone and 18-crown-6 phase transfer catalyst. Glass fiber was modified with silane coupling agent, and uniform dispersion was promoted by ultrasonic and mechanical stirring. Hot pressing was then performed to build a stable interfacial bond.
It improves the mechanical strength and thermal stability of glass fiber reinforced polystyrene battery separators, meeting the application requirements of lithium-ion batteries at high temperatures, and features low thermal shrinkage and high tensile strength.
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Figure CN121642431A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of batteries, more particularly, it relates to a preparation method of a glass fiber reinforced polyphenyl nitrile battery separator material. BACKGROUND
[0002] At present, the battery separator material technology field presents a multi-element development trend; from the material type, the traditional polyolefin-based separator, such as polyethylene and polypropylene separator, performs well in chemical stability and certain mechanical properties; the preparation process is relatively mature; however, the traditional polyolefin-based separator has many insurmountable shortcomings, when the battery generates a large amount of heat under high-power charging and discharging or abnormal conditions, the separator is prone to thermal shrinkage and even melt perforation, leading to short circuit of the positive and negative electrodes of the battery, and causing serious safety problems such as thermal runaway; moreover, the pore structure of this kind of separator is difficult to accurately control, and the pore size distribution is not uniform enough, which negatively affects the wettability of the electrolyte and the ion transmission efficiency, and further limits the charging and discharging performance and rate performance of the battery.
[0003] And the existing technology related to glass fiber has tried to use glass fiber for battery separators, for example, glass fiber is made into a glass fiber film as a lithium ion battery separator, which has certain improvement in thermal stability and mechanical strength, and can prevent battery overheating and thermal runaway to some extent, and enhance the shock resistance and impact resistance of the battery; however, these technologies face many problems in the preparation process; on the one hand, the composite process of glass fiber and other matrix materials is complex, and it is difficult to achieve uniform compounding, resulting in unstable performance of the composite material; when compounded with polymers, due to the large difference in surface properties of the two, the interfacial bonding force is weak, and under the stress generated by battery charging and discharging, interfacial debonding phenomenon easily occurs, affecting the overall performance of the material; on the other hand, the existing technology has limited means to control the pore structure and ion conduction performance of the glass fiber-based separator, and cannot match the requirements of different battery systems for the porosity, pore size distribution and ion conductivity of the separator material. SUMMARY
[0004] In order to solve the problem of unstable performance of the composite material caused by the difficulty of uniform compounding of related glass fiber and other matrix materials, the present application provides a preparation method of a glass fiber reinforced polyphenyl nitrile battery separator material.
[0005] The present application provides a preparation method of a glass fiber reinforced polyphenyl nitrile battery separator material, which adopts the following technical scheme:
[0006] A preparation method of a glass fiber reinforced polyphenyl nitrile battery separator material, comprising the following steps:
[0007] S1, synthesis of polybenzocyan polymer: under nitrogen protection, in dehydrated N-methylpyrrolidone, p-bromobenzonitrile, p-hydroxybenzonitrile, anhydrous potassium carbonate and 18-crown-6 were added in turn, heated and stirred, after the reaction was completed, the system was poured into deionized water to precipitate the solid, after filtration, the filtrate was washed with deionized water until it was neutral, then refluxed with ethanol, and finally vacuum dried to obtain polybenzocyan polymer powder;
[0008] S2, preparation of glass fiber: select alkali-free glass fiber with a diameter of 5-15 μm and a length of 0.5-2 mm, dry the glass fiber, and control the water content to be 0.1-1%;
[0009] S3, modification of glass fiber: first, weigh 17-65 g of glass fiber from step S2 and put it into 1-7 wt% silane coupling agent KH-550, then stir the mixture in a 35-40°C water bath, then take out the fiber and wash it with deionized water until it is neutral, and finally dry it at 80-90°C under vacuum;
[0010] S4, preparation of composite material: add 0.1-0.8 g of PVP to 500-750 g of DMF solvent, heat and stir to dissolve, then add 100-200 g of polybenzocyan polymer powder obtained in step S1, then add 17-65 g of modified glass fiber obtained in step S3, stir and disperse, then transfer to an ultrasonic dispersion tank, control the temperature in the tank to be ≤60°C, disperse at an ultrasonic power of 300-500 W and a mechanical stirring speed of 500-1500 r / min for 15-35 minutes, then stand still;
[0011] S5, molding: pour the composite slurry obtained in step S4 into a preheated steel mold, use a scraper to level it, heat and vacuum to cure;
[0012] S6, post-processing: dry the molded blank at 70-110°C and a vacuum degree of -0.08 MPa for 2-6 hours, weigh and calculate the residual solvent content to obtain a glass fiber reinforced polybenzocyan battery separator material.
[0013] By adopting the technical scheme, from the synthesis of polybenzazole polymer, to the interface modification of glass fiber, the uniform preparation of composite slurry, to the final hot-pressing and post-processing, the coordinated control of the parameters of each link can strengthen the interfacial bonding; Specifically, in the polymerization stage, the reaction temperature and time are controlled to ensure that the polybenzazole matrix has a regular molecular chain structure and a suitable molecular weight, providing a basis for interfacial bonding; Then the surface treatment of silane coupling agent is carried out on the glass fiber, which successfully introduces active groups on the surface of the glass fiber, further enhancing the chemical compatibility and wettability of the polymer matrix; In the dispersion stage, the synergistic effect of ultrasonic field and mechanical stirring can promote the dispersion of single fiber in the matrix, avoid agglomeration, and provide a basis for forming a uniform and dense composite material structure; Finally, in the hot-pressing process, by controlling the temperature, pressure and vacuum conditions, not only the polymer melt flows fully and covers the fiber, but also the residual solvent and bubbles are quickly removed, further consolidating the interfacial bonding strength. Through the regulation and synergistic effect of the above links, the stable interfacial bonding between the polybenzazole matrix and the modified glass fiber is formed, and the mechanical strength and high-temperature dimensional stability of the final separator material are improved; Therefore, the prepared glass fiber reinforced polybenzazole battery separator material has low thermal shrinkage rate and high tensile strength, which can meet the requirements of lithium ion battery on the mechanical properties and thermal safety of the separator material.
[0014] Preferably, in step S1, the amount of dehydrated N-methylpyrrolidone is 300-400g, and the mass ratio of p-bromobenzonitrile, p-hydroxybenzonitrile and anhydrous potassium carbonate is 1:1:1.1, and the amount of 18-crown-6 is 2-3g, and the stirring speed is 300r / min.
[0015] By adopting the above technical scheme, the parameters in the synthesis process of polybenzazole are controlled to provide a basis for obtaining a high-performance polymer matrix; Specifically, in terms of raw material ratio, p-bromobenzonitrile and p-hydroxybenzonitrile are used in a 1:1 molar ratio, which makes the two monomers have a uniform sequence distribution in the polymerization chain; And the amount of anhydrous potassium carbonate is slightly increased to 1.1 times the total mass of the raw materials, which is to neutralize the trace amount of acidic by-products generated during the reaction, so that the polymerization reaction can be carried out efficiently in a suitable alkaline catalytic environment; Then add 2-3g of 18-crown-6, which makes the compound can complex potassium ions efficiently, improve the solubility and reactivity of carbonate anions in organic phase, so as to promote the rate and conversion rate of nucleophilic substitution reaction, realize high molecular weight polymerization; The control of the amount of dehydrated solvent is to eliminate the interference of water to the reaction system, avoid the consumption of catalyst or cause the hydrolysis of monomers, and ensure that the polymerization reaction proceeds according to the predetermined path.
[0016] Preferably, in step S1, the parameters of heating and stirring are as follows: heating to 160℃ and stirring for 20 hours; washing with deionized water for 5 times, the amount of ethanol reflux is 500mL, the reflux time is 2 hours, and the last washing liquid is detected by pH test paper to determine whether it is neutral; the parameters of vacuum drying are as follows: vacuum drying at 100℃ for 12 hours.
[0017] By adopting the above technical scheme, since the multiple deionized water washing and ethanol reflux steps are adopted in the post-treatment of the polyphenyl cyanate polymer, the neutrality is ensured by 5 times of washing, and the residual impurities are removed by 500mL of ethanol reflux for 2 hours, and the neutrality of the last washing liquid is detected by pH test paper, so as to ensure the purity of the polymer and avoid the side reactions in subsequent processing; therefore, the polyphenyl cyanate polymer with high purity is obtained, which is beneficial to the formation of uniform phase state in the composite material and improves the electrochemical stability of the separator;
[0018] The reaction temperature is set to 160℃, which can provide molecular activation energy to drive the polycondensation reaction to continue, and can also inhibit the occurrence of side reactions; the reaction time of 20 hours ensures the chain growth of monomers, so as to obtain the expected molecular weight; based on the synergistic regulation of the above multiple parameters, the polyphenyl cyanate polymer powder with high molecular weight and regular structure can be stably prepared; the product as the matrix of the composite separator material provides guarantee for the material to finally realize high mechanical strength and low thermal shrinkage.
[0019] Preferably, before step S1, the N-methyl pyrrolidone is also pretreated: dehydrated by using 4A molecular sieve to obtain dehydrated N-methyl pyrrolidone.
[0020] By adopting the above technical scheme, since the N-methyl pyrrolidone solvent is dehydrated and pretreated before polymerization, water is removed by using 4A molecular sieve to ensure the anhydrous state of the solvent, and to avoid the hydrolysis side reaction or the broadening of the molecular weight distribution caused by water in the high-temperature polymerization reaction; therefore, the dehydrated N-methyl pyrrolidone is obtained, which provides a basis for the synthesis of polyphenyl cyanate polymer and ensures the quality consistency of the polymer.
[0021] Preferably, in step S3, the stirring parameters during water bath are as follows: stirring at a speed of 200r / min for 1.5-3.5 hours; after the fibers are taken out, they are washed with deionized water for 3 times, each time for 10 minutes; and the drying time is controlled to be 2 hours.
[0022] By adopting the above technical scheme, since the modified glass fibers are washed with deionized water for 3 times, each time for 10 minutes, the removal of unreacted silane coupling agent is ensured, and the residual material is avoided to affect the interface bonding between the fibers and the polymer; after washing to neutral, vacuum drying is performed to ensure the surface cleanliness and activity of the modified glass fibers; therefore, the glass fibers with uniform surface modification are obtained.
[0023] Preferably, after step S1, the polycyanide polymer needs to be detected by GPC; after step S3, the modified glass fiber is detected by XPS for its surface nitrogen content.
[0024] By adopting the above technical scheme, the performance detection ensures the consistency and performance repeatability of the material, wherein the GPC detection can improve the polymerization conditions, the XPS detection confirms the grafting rate of the silane coupling agent, and further obtains traceable process parameters, thereby providing a basis for large-scale production.
[0025] Preferably, in step S4, the specific parameters of heating and stirring dissolution are as follows: heating with a 30-70℃ jacket, stirring for 10-15min, until there are no PVP particles in the solution; and the polycyanide polymer powder is added in three times, with an interval of 30 minutes each time; and the specific parameters of standing are as follows: standing for 30 minutes at 30℃ under a vacuum degree of-0.09MPa.
[0026] By adopting the above technical scheme, since 30-70℃ de1 jacket heating and 10-15min stirring process are adopted in the preparation of the composite slurry, it is ensured that PVP as a dispersant can be dissolved in DMF solvent, thereby providing conditions for the uniform dispersion of polycyanide polymer and glass fiber in advance; wherein the phased addition mode of polycyanide polymer further prevents the risk of agglomeration caused by too fast feeding; and the regulation of the heating temperature range can avoid excessive solvent evaporation or material thermal decomposition; therefore, the process can finally obtain a highly uniform slurry basis, which lays a solid foundation for the subsequent efficient ultrasonic-mechanical synergistic dispersion effect.
[0027] Preferably, in step S4, after adding the polycyanide polymer powder, the temperature is raised to 65℃, and stirring is performed at 500r / min for 2 hours, so that the solution is transparent and light yellow, and then the modified glass fiber is added.
[0028] By adopting the above technical scheme, since the temperature is raised to 65℃ after adding the polycyanide polymer powder and stirring at 500r / min for 2 hours, the polymer is dissolved, and the solution is transparent and light yellow, which ensures the stretching and dispersion of the polycyanide molecular chain, avoids the influence of unsolved particles on the film quality, and therefore obtains a transparent polymer solution, thereby providing a stable matrix for the addition of glass fiber and improving the uniformity of the composite material.
[0029] Preferably, in step S4, the material after standing is sampled and observed with a needle tube, and no bubble with a diameter >5μm is allowed.
[0030] By adopting the technical scheme, the slurry without macroscopic defects is obtained, and the compactness and integrity of the separator are ensured.
[0031] Preferably, in step S5, the steel mold is wiped with anhydrous ethanol, sprayed with WD-40 release agent, and preheated before pouring the slurry; the cavity size is 100*20*0.3mm; and the thickness of the scraping is 0.33mm.
[0032] By adopting the technical scheme, the slurry without macroscopic defects is obtained, and the compactness and integrity of the separator are ensured.
[0033] In summary, the present application has the following beneficial effects:
[0034] 1. In the present application, dehydrated N-methylpyrrolidone solvent and 18-crown-6 phase transfer catalyst are used in the polymerization stage to ensure the formation of a polyphenyl cyanide matrix with high molecular weight and regular structure. In the fiber modification stage, the surface activity is enhanced by treating with a silane coupling agent, and in the dispersion stage, ultrasonic and mechanical stirring are used to promote uniform distribution of components, thereby building a stable interfacial bond between the matrix and the fiber, and improving the mechanical strength and thermal stability of the separator material. The material has no significant thermal shrinkage and high tensile strength at high temperature, meeting the requirements of high temperature application of lithium ion batteries.
[0035] 2. In the present application, the silane coupling agent modification process of glass fiber is preferred. Based on the fact that KH-550 can form stable covalent bonds with the hydroxyl groups on the surface of the fiber after hydrolysis, constant temperature stirring ensures uniformity of the reaction, and the surface nitrogen content is maintained within an appropriate range by XPS detection to verify the effective grafting of the coupling agent. Therefore, the interfacial bonding between the modified glass fiber and the polyphenyl cyanide matrix is enhanced, which helps the separator to have high tensile strength and low thermal shrinkage.
[0036] 3. The method of the present application controls the related parameters of mold pretreatment, slurry pouring thickness control, and heat pressing curing, and avoids uneven condensation curing based on preheating. The heat pressing parameters promote polymer chain segment flow and fiber orientation, and the controllable heating and pressure relief rate reduces internal stress. Therefore, the density and tensile strength of the formed blank are high, which ensures the structural integrity and long-term reliability of the separator material in the battery. BRIEF DESCRIPTION OF DRAWINGS
[0037] Figure 1 A flow chart of a preparation method of a glass fiber reinforced polyphthalaldehyde battery separator material according to the present application is shown in the following figure:
[0038] Figure 2 A graph showing the effect of glass fiber content on the performance of a glass fiber reinforced polyphthalaldehyde battery separator material is shown in the following figure:
[0039] Figure 3 A graph showing the thermal shrinkage performance of a glass fiber reinforced polyphthalaldehyde battery separator material at high temperature is shown in the following figure. DETAILED DESCRIPTION
[0040] The present application will be further described in detail below with reference to the accompanying drawings and examples.
[0041] Technical ideas:
[0042] Related technologies use glass fibers for battery separators, for example, glass fibers are made into glass fiber membranes for use as lithium ion battery separators, which have certain improvements in thermal stability and mechanical strength, can prevent battery overheating and thermal runaway to some extent, and enhance the shock resistance and impact resistance of the battery; however, these technologies face many difficulties in the preparation process; on the one hand, the composite process of glass fibers with other matrix materials is complex, it is difficult to achieve uniform compounding, resulting in unstable performance of the composite material; when compounded with polymers, due to the large difference in surface properties between the two, the interfacial bonding force is weak, under the stress generated during battery charging and discharging, interfacial debonding phenomenon easily occurs, affecting the overall performance of the material; on the other hand, the existing technology has limited means to control the pore structure and ion conduction performance of the glass fiber-based separator, and cannot match the requirements of different battery systems for the porosity, pore size distribution and ion conductivity of the separator material.
[0043] The present application discloses a preparation method of a glass fiber reinforced polyphthalaldehyde battery separator material, comprising the following steps: S1, synthesis of polyphthalaldehyde polymer; S2, preparation of glass fiber: selecting alkali-free glass fiber, drying the glass fiber, and controlling its water content to be 0.1-1%; S3, modification of glass fiber; S4, preparation of composite material; S5, molding; S6, post-treatment: drying the molded blank at 70-110℃ under a vacuum degree of -0.08MPa for 2-6 hours, weighing to calculate the residual amount of solvent, and obtaining the glass fiber reinforced polyphthalaldehyde battery separator material.
[0044] This application employs dehydrated N-methylpyrrolidone solvent and 18-crown-6 phase transfer catalyst in the polymerization stage to ensure the formation of a high molecular weight and structurally regular polyphenylene nitrile matrix. In the fiber modification stage, surface activity is enhanced by treatment with silane coupling agent, and ultrasonic and mechanical stirring are used in the dispersion stage to promote uniform distribution of components. This results in a stable interfacial bond between the matrix and the fiber, thereby improving the mechanical strength and thermal stability of the separator material. The material exhibits no significant thermal shrinkage and high tensile strength at high temperatures, meeting the high-temperature application requirements of lithium-ion batteries.
[0045] Example 1
[0046] Glass fiber modification: Ethanol solutions of 1wt% (3g), 5wt% (15g), and 7wt% (22g) were prepared in 500mL beakers. 50g of glass fibers with a diameter of 10μm, a length of 0.5-2mm, and a water content ≤0.5% were added to these solutions. The rotation speed was adjusted to 200r / min, and the holding time was set to 1.5h, 2h, 2.5h, 3h, and 3.5h. The optimal range was determined to be 2-3h. Holding times less than 2h resulted in incomplete reaction, while holding times greater than 3h led to low efficiency. The fibers were then removed and rinsed three times with deionized water, stirring for 10min each time. The first cleaning solution tested neutral using pH test paper. At this point, the fibers were placed in a vacuum drying oven and dried at 85°C for 2 hours. After drying for another 2 hours, they were weighed and no weight increase was observed. The surface nitrogen content was detected using X-ray photoelectron spectroscopy (XPS), and the nitrogen content increased from <0.1 at% before modification to 0.2 at%, indicating insufficient modification. When modified at a concentration of 5 wt%, the weight increased by 0.5-1%, and the nitrogen content increased from <0.1 at% before modification to 1-2 at%, indicating successful grafting of KH-550. At a concentration of 7 wt%, the weight increase exceeded 1.5%, and the prepared composite slurry showed "layered precipitation".
[0047] Example 2
[0048] Polystyrene slurry dispersion: 750g of DMF and 0.5g of PVP (0.5wt%, relative to the composite material) were added to a 1L reactor. The reactor was heated at 50℃ with a jacket and stirred at 500r / min for 15min. No PVP particles were added to the solution. 103g (15wt%), 120g (17wt%), 150g (20wt%), 173g (23wt%), and 194g (25wt%) of polystyrene powder were added in three separate additions with a 30min interval between each addition to avoid clumping. The temperature was then raised to 65℃ and stirred at 500r / min for 2h. Samples were taken to observe the solution state. The results showed that 20-23wt% was the suitable range, and the solution was transparent and pale yellow with no visible particles, indicating that the polystyrene was completely dissolved. When the concentration was <20%, the density after molding was low, and when it was >25%, the slurry viscosity was high and difficult to disperse.
[0049] Example 3
[0050] Glass fiber reinforcement: Take 150g of polystyrene and add 17g (10wt%), 26g (15wt%), 38g (20wt%), 50g (25wt%), and 65g (30wt%) of modified glass fiber respectively. By observing the state of the slurry, it was found that the slurry with 30%wt% glass fiber reinforcement was prone to precipitation. Then, the slurries containing 10wt%, 15wt%, 20wt%, and 25wt% glass fiber reinforcement were transferred to a 10L jacketed temperature-controlled ultrasonic dispersion tank, and the jacket cooling water was turned on to control the temperature inside the tank to ≤60℃. The working parameters of the ultrasonic dispersion tank were adjusted as follows: ultrasonic power 400W, mechanical stirring 1000r / min, synchronous operation for 25min. Then, the ultrasonic and stirring were turned off, and the mixture was allowed to stand at 30℃ under vacuum for 30min. The sample was taken with a syringe and no bubbles with a diameter >5μm were observed. Bubbles will cause the porosity of the material after molding to exceed the standard, which will affect ion transport.
[0051] Example 4
[0052] Select a steel mold with a cavity size of 100×20×0.3mm. Wipe the cavity with anhydrous ethanol, spray with WD-40 release agent, preheat in a 100℃ oven for 30 minutes, slowly pour in the composite slurry, controlling the thickness to 0.33mm, and smooth it with a scraper to avoid overflow. Place the mold in a muffle furnace, heat at a rate of 5℃ / min until it reaches 180℃, pressurize to 8MPa, and simultaneously open the mold vacuum interface, controlling the pumping speed to remove volatile DMF and avoid air bubbles, and maintain pressure for 40 minutes. Then turn off the heating, maintain the pressure until the mold temperature ≤60℃, depressurize at a rate of 0.5MPa / min, open the mold, remove the blank with tweezers, and ensure the surface is flat. The thickness deviation was ±0.02 mm. The blanks were then placed in a vacuum drying oven and dried at 90℃ under vacuum for 4 hours. The residual solvent content was calculated to be ≤0.5 wt%. At this point, the densities of blanks with different glass fiber reinforcement contents were measured. The densities of blanks with 10 wt%, 15 wt%, 20 wt%, and 25 wt% glass fiber reinforcement were 1.09 g / cm³, 1.13 g / cm³, 1.22 g / cm³, and 1.3 g / cm³, respectively. The tensile strengths of the glass fiber reinforcement with different contents, measured by a universal testing machine, were 16–18 MPa, 19–21 MPa, 20–25 MPa, and 25–30 MPa, respectively. The results are recorded as follows: Figure 2 As shown.
[0053] Example 5
[0054] Take a rectangular strip sample measuring 100mm × 20mm × 0.3mm, and use a digital vernier caliper to measure three sets of 50mm gauge lengths (L) along the length direction. 01 L 02 L 03) and three sets of 10mm gauge lengths in the width direction (W) 01 W 02 W 03 The initial thickness (h) of the sample is measured at three locations using a laser diameter gauge, accurate to 0.01 mm and recorded as L0 and W0 respectively. 01 h 02 h 03 The average value is recorded as h0. Next, the measured sample is laid flat on the quartz glass fixture support platform, and the four corners are gently secured with edge clips. After the precision oven is preheated to 150℃±1℃ and stabilized for 10 minutes, the fixture is placed in the oven and kept at a constant temperature for 2 hours. During this period, the temperature deviation must be ≤±2℃; otherwise, the test must be repeated. After the constant temperature period, the fixture is removed wearing high-temperature resistant gloves and cooled for 1 hour in an environment of 23±2℃ and 50±5% relative humidity. If the sample is slightly curled, it is gently pressed flat with a flat plate. The length, width, and thickness gauge length are then remeasured using the initial measurement method, and the average values L1, W1, and h1 are recorded. The remaining two parallel samples are then tested again. Finally, the thermal shrinkage rates in the length (L), width (W), and thickness (h) directions are calculated respectively, and the average value of the three samples is taken. The results are statistically presented as follows: Figure 3 As shown, the thermal shrinkage rate in both length and width directions at 150℃ is ≤0.5%, indicating that the material has "no obvious thermal shrinkage," while the related PE separator has a thermal shrinkage rate of ≥5% at 120℃, meeting the high-temperature stability requirements of battery separator materials.
[0055] Example Conclusion:
[0056] As can be seen from Example 5 and Table 1, the thermal shrinkage rate of the composite material decreases with increasing chopped glass fiber content. This is attributed to the stable interfacial bonding between the glass fiber modified with silane coupling agent KH-550 and the polystyrene matrix, which inhibits molecular chain segment movement at high temperatures, thereby improving dimensional stability. Simultaneously, the ultrasonic-mechanical synergistic dispersion process promotes uniform fiber distribution and synergistically enhances the overall density and interfacial strength of the material, in conjunction with optimized thermoforming parameters. Macroscopically, these influencing factors result in high thermal stability of the composite material at 150°C, with a thermal shrinkage rate meeting the requirements, satisfying the high demands of lithium-ion battery separators for high-temperature applications, and ensuring the structural integrity and long-term reliability of the material.
[0057] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method of making a glass fiber reinforced polycyanide battery separator material, characterized by, Comprising the following steps: S1, synthesis of polybenzocarbon polymer: under nitrogen protection, in dehydrated N-methyl pyrrolidone, p-bromobenzonitrile, p-hydroxybenzonitrile, anhydrous potassium carbonate and 18-crown-6 were added in turn, heated and stirred, after the reaction was completed, the system was poured into deionized water to precipitate the solid, after filtration, the filtrate was washed with deionized water until it was neutral, then refluxed with ethanol, and finally vacuum dried to obtain polybenzocarbon polymer powder; S2, preparation of glass fiber: select alkali-free glass fiber with a diameter of 5-15 μm and a length of 0.5-2 mm, dry the glass fiber, and control the water content to be 0.1-1%; S3, modification of glass fiber: first, weigh 17-65 g of glass fiber from step S2 and put it into 1-7 wt% silane coupling agent KH-550, then stir the mixture in a 35-40°C water bath, then take out the fiber and wash it with deionized water until it is neutral, and finally dry it at 80-90°C under vacuum; S4, preparation of composite material: add 0.1-0.8 g of PVP to 500-750 g of DMF solvent, heat and stir to dissolve, then add 100-200 g of polybenzocarbon polymer powder obtained in step S1, then add 17-65 g of modified glass fiber obtained in step S3, stir and disperse, then transfer to an ultrasonic dispersion tank, control the temperature in the tank to be ≤60°C, disperse under ultrasonic power of 300-500 W and mechanical stirring of 500-1500 r / min for 15-35 minutes, then stand still; S5, molding: pour the composite slurry obtained in step S4 into a preheated steel mold, flatten it with a scraper, heat and vacuum to solidify; S6, post-processing: dry the molded blank at 70-110°C and a vacuum degree of -0.08 MPa for 2-6 hours, weigh and calculate the solvent residue, and obtain the glass fiber reinforced polybenzocarbon battery separator material.
2. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S1, the amount of dehydrated N-methyl pyrrolidone is 300-400 g, and the mass ratio of p-bromobenzonitrile, p-hydroxybenzonitrile and anhydrous potassium carbonate is 1:1:1.1, and the amount of 18-crown-6 is 2-3 g, and the stirring speed of the reaction is 300 r / min.
3. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S1, the parameters of heating and stirring are as follows: heat to 160°C and stir for 20 hours; wash with deionized water for 5 times, the amount of ethanol reflux is 500 mL, the reflux time is 2 hours, and the last cleaning liquid is detected with pH paper to check whether it reaches neutral; the parameters of vacuum drying are as follows: vacuum drying at 100°C for 12 hours.
4. The method of making a glass fiber reinforced polycyanide battery separator material of claim 1, wherein, Before step S1, there is also a pretreatment of N-methyl pyrrolidone: use 4A molecular sieve for dehydration treatment to obtain dehydrated N-methyl pyrrolidone.
5. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S3, the stirring parameters during water bath are as follows: stir at a speed of 200 r / min for 1.5-3.5 hours; after taking out the fiber, wash it with deionized water for 3 times, each time for 10 minutes; and the drying time is controlled to be 2 hours.
6. The method of making a glass fiber reinforced polycyanide battery separator material of claim 1, wherein, After step S1, the polybenzocarbon polymer needs to be detected by GPC; after step S3, the modified glass fiber is detected by XPS for the content of nitrogen element on the surface.
7. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S4, the specific parameters of heating and stirring dissolution are as follows: heating with a 30-70℃ jacket, stirring for 10-15 min until there is no PVP particle in the solution; the polyphenylacetylene polymer powder is added in three times with an interval of 30 min; and the specific parameters of standing are as follows: standing for 30 min at 30℃ under a vacuum degree of-0.09 MPa.
8. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S4, after the polyphenylacetylene polymer powder is added, the temperature is raised to 65℃, and the solution is stirred at 500 r / min for 2 hours until it becomes transparent and light yellow, and then the modified glass fiber is added.
9. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S4, the material after standing is sampled and observed with a needle tube, and no bubble with a diameter of >5 μm is allowed.
10. The method for preparing a glass fiber reinforced polystyrene battery separator material according to claim 1, characterized in that, In step S5, the steel mold is wiped with anhydrous ethanol before pouring the slurry, sprayed with WD-40 release agent, and preheated; the cavity size is 100×20×0.3 mm; and the thickness of scraping is 0.33 mm.