WO2017107150A1 - 用于电池隔膜的涂料、电池隔膜及电池隔膜的制备方法 - Google Patents

用于电池隔膜的涂料、电池隔膜及电池隔膜的制备方法 Download PDF

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WO2017107150A1
WO2017107150A1 PCT/CN2015/098771 CN2015098771W WO2017107150A1 WO 2017107150 A1 WO2017107150 A1 WO 2017107150A1 CN 2015098771 W CN2015098771 W CN 2015098771W WO 2017107150 A1 WO2017107150 A1 WO 2017107150A1
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Prior art keywords
coating
battery separator
water
high temperature
base film
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PCT/CN2015/098771
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English (en)
French (fr)
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苏碧海
曹志锋
瞿威
张辉
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深圳中兴创新材料技术有限公司
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Priority to PCT/CN2015/098771 priority Critical patent/WO2017107150A1/zh
Publication of WO2017107150A1 publication Critical patent/WO2017107150A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery separators, and more particularly to a coating for a battery separator, a battery separator prepared from the coating, and a method of preparing a battery separator from the coating.
  • lithium-ion batteries which are the main energy storage systems, are constantly moving toward high energy density and high safety.
  • the battery separator needs to have the function of closing the channel (ie, shut down), and it is stable, and can effectively separate the positive and negative electrodes of the battery, and will not shrink or even melt due to instability, thereby aggravating the internal short circuit of the battery.
  • Flame retardancy that is, when the battery system reaches a certain temperature, the diaphragm itself has a certain flame retardancy, and will not burn with the other components in the battery system when it is burned and ignited.
  • Electrochemical stability that is, the separator can work stably for a long time in an organic solvent, high potential, high oxidizing environment, and does not cause corrosion, oxidation, swelling, dissolution, deformation, and the like.
  • High physical strength that is, a certain degree of toughness, good puncture resistance and tensile strength, can effectively block the electrode burr and the penetration of lithium dendrites, and prevent internal micro-short circuit.
  • High liquid absorption rate and liquid retention rate that is, a relatively uniform porous structure, and a certain affinity for various components in the electrolyte, ensuring the smoothness of the lithium ion channel of the overall electrolyte system, ionic conductivity Not affected.
  • the current method commonly used in the diaphragm industry is to apply a ceramic temperature-resistant material coating modification to the surface of a polyolefin separator, in which Al 2 O 3 is mainly coated.
  • ceramic coatings have several disadvantages in battery applications that are difficult to overcome. 1) The ceramic particles in the coating are closely packed and bonded by polyacrylate macromolecules; the polyolefin film with ceramic coating has better temperature resistance and stable adhesion when in a separate state; Lithium battery organic electrolyte in an acidic atmosphere, when the battery is used, the ion is shuttled back and forth, and under the high voltage oxidation, the ceramic coating has appeared in the battery cycle when the battery cycle is less than 500 times.
  • reaction formula for the slow reaction of Al 2 O 3 to form water is as follows:
  • Al 2 O 3 particles are extremely small in surface area due to their small size and hydrophilicity.
  • the cost of removing traces of water during film formation is extremely high, and it is difficult to control water to within 1000 ppm.
  • the reaction induced condition of the slow reaction of Al 2 O 3 to form water is only the water content of more than 1 ⁇ 10 -6 ; that is, the reaction of slowly reacting Al 2 O 3 to form water is almost inevitable.
  • the present application discloses a coating for a battery separator, the main components of which include high temperature resistant resin, magnesium carbonate, resin cosolvent and organic solvent; high temperature resistant resin is polyimide, polyether sulfone, polyether ether ketone At least one of a meta-aramid fiber, a para-aramid fiber, a polytetrafluoroethylene and a derivative, a copolymer or a mixture thereof; the resin cosolvent is a strong acid salt of an alkali metal or an alkaline earth metal; the organic solvent is At least one of N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide and tetrahydrofuran; the content of the high temperature resistant resin in the coating is 2 to 10% by weight, carbonic acid
  • the content of magnesium is 20 to 80% of the total weight, the viscosity of the coating is 20 to 200 CPs, and the solid content is 15 to 70%.
  • the high temperature resistant resin is used as the skeleton support of the coating, and has good properties such as temperature resistance, insulation, flame retardancy, oxidation resistance and puncture resistance.
  • the magnesium carbonate in the coating reacts with water to form magnesium hydroxide precipitates and carbon dioxide gas, and the reaction conditions are controlled to uniformly distribute micropores in the coating to further increase the liquid absorption rate of the composite membrane. And fluid retention rate.
  • magnesium hydroxide will pyrolyze at around 396 °C, and a large amount of endothermic heat.
  • the high temperature resistant resin will rapidly undergo carbonization reaction at around 400 °C. Magnesium hydroxide and high temperature resistant resin can better play a flame retardant effect.
  • the high temperature resistant resin used in the present application includes polyimide, polyether sulfone, polyether ether ketone, meta-aramid fiber, para-aramid fiber, polytetrafluoroethylene, and the like. a derivative, copolymer or mixture of polymers, which may be a high temperature resistant resin or two Or a plurality of mixed use, which is not specifically limited herein.
  • the high temperature resistant resin is a meta-aramid fiber having a molecular weight of 200,000 to 1,000,000.
  • polyimide polyether sulfone, polyether ether ketone, meta-aramid fiber, para-aramid fiber, polytetrafluoroethylene, and derivatives of these polymers, copolymerization
  • the substance or the mixture can satisfy the use requirements; however, from the viewpoints of material synthesis cost, workability, environmental friendliness and the like, the present application preferably employs aramid fibers, that is, meta-aramid fibers and para-aramid fibers.
  • meta-aramid fibers Among the two major types of aramid fibers, meta-aramid fiber and para-aramid fiber, the performance of the para-aramid fiber is excellent as that of the meta-aramid fiber, but at the time of processing, the para-aramid fiber must be used.
  • a large amount of protic solvent, 98% concentrated sulfuric acid is widely used in the textile industry.
  • a meta-aramid fiber When it is prepared as a coating on the surface of the base film, especially the polyolefin base film, it will cause a certain degree of carbonization of the polyolefin, which will seriously affect The flexibility, puncture resistance, corrosion resistance and the like of the composite separator; therefore, a more preferred embodiment of the present application employs a meta-aramid fiber as a high temperature resistant resin to prepare a coating. More preferably, meta-aramid fibers having a molecular weight of 200,000 to 1,000,000 are used.
  • the resin cosolvent is CaCl 2 or LiCl, and the preferred resin cosolvent is LiCl.
  • a preferred resin cosolvent is CaCl 2 or LiCl, and more preferably LiCl.
  • the organic solvent is N-methylpyrrolidone or N,N-dimethylacetamide.
  • N-methylpyrrolidone N,N-dimethylacetamide, N,N-dimethylformamide and tetrahydrofuran
  • the recovery difficulty, the toxicity level, and the like are in view of the above, it is preferred to use N-methylpyrrolidone or N,N-dimethylacetamide as the organic solvent of the present application.
  • the coating further comprises a coupling agent, a stabilizer and a binder.
  • the coupling agent is at least one of a fluorine-containing silane coupling agent
  • the stabilizer is at least one of propylene carbonate, phenyl phosphate, tripropylene glycol, ethylene glycol and sodium cellulose
  • the binder is poly At least one of vinylidene fluoride, polyvinylidene fluoride copolymer, silicone rubber, silicone rubber derivative, polyacrylate, polyimide, and epoxy resin. More preferably, the binder is polyvinylidene fluoride or silicone rubber, silicone rubber derivative In terms of heat resistance, cost and environmental protection, the most preferred binder uses homopolyvinylidene fluoride having a molecular weight of more than 600,000.
  • Another aspect of the present application discloses a composite battery separator comprising a base film and a coating applied to at least one surface of the base film, wherein the coating is coated with the coating of the present application.
  • the material and the manufacturing method of the base film are not particularly limited, such as a polyolefin base film, an electrospun membrane such as polyimide, an aromatic amide fiber paper separator, and a polyvinylidene fluoride separator.
  • the silk membrane and the like can be used in the present application; however, from the aspects of the maturity of the process, the cost, the closed cell temperature of the base film, and the like, a polyolefin base film, a single layer polypropylene (abbreviated PP), a single layer polymerization is preferable.
  • Ethylene (abbreviation PE), double-layer PP, double-layer PE, three-layer PP ⁇ PE ⁇ PP, etc.; more preferably single-layer PP or single-layer PE separator; in a more preferred implementation of the present application,
  • a single-layer PP or PE base film with a thickness of 3 to 12 ⁇ m is used.
  • the porosity of the base film is between 35% and 55%, the gas permeability is between 50 and 500 seconds, and the closed cell temperature is between 130 °C and 160 °C. .
  • the composite battery separator of the present application is analyzed by differential scanning calorimetry.
  • the composite battery separator has 1-3 endothermic peaks between 100 and 220 ° C, and has an obvious endothermic peak at 380 to 420 ° C.
  • the composite battery separator of the present application has an absorption peak in a temperature range of 100 to 220 ° C and 380 to 420 ° C, and has a good heat absorption effect, and can guide heat away in time.
  • the composite battery separator can maintain good physical and chemical stability under long-term high temperature.
  • a further aspect of the present application discloses a method for preparing a composite battery separator of the present application, comprising the following steps,
  • step (C) Washing and drying, the product of the step (B) is subjected to a water bath cleaning, and then dried at 40 to 100 ° C to obtain the composite battery separator.
  • the purpose of the step (A) coating is to uniformly apply the coating material to the surface of the base film. Therefore, the conventional coating method capable of coating the coating film on the base film can be used in the present application. Make specific limits.
  • a gravure coating method and a slit extrusion coating method are used. Both methods can be applied to one-side coating or double-sided coating.
  • the coating of the present application is uniformly applied to at least one surface of the selected base film by feeding the gravure roll or the extrusion die accurately and stably by a screw pump.
  • the coating thickness of the present application is preferably 2 to 5 ⁇ m in consideration of the test conditions of actual temperature-resistant flame retardant and the space loss caused by the thickness.
  • step (B) the curing and pore formation of the coating of step (B) in the present application is actually carried out after the step (A) is applied, using water vapor in the air as a precipitation initiator, and the surface of the coating is resistant to high temperatures.
  • the resin has been preliminarily precipitated to form a semi-cured film, and step (B) further applies the coated base film to water and a warm environment to hydrate and warm the coating, and the high temperature resistant resin is further precipitated and solidified.
  • the magnesium carbonate in the coating will form magnesium hydroxide which is more difficult to dissolve with water, and release carbon dioxide to achieve the purpose of pore formation.
  • the coating curing and pore forming of the step (B) are carried out in three ways, which will be described in detail later.
  • the coated separator subjected to the curing treatment of the step (B) may have water, an organic solvent, various auxiliary agents, soluble inorganic salts, etc., and therefore, directly Various residues were washed away by a water bath.
  • the drying process the water adhering to the surface and the gap of the coating is mainly removed, and the principle is that the water is evaporated at a high temperature.
  • the drying method is not particularly limited in the present application; while drying and removing the water, the drying can also be performed.
  • the resin that has just been precipitated acts as a quenching.
  • the preferred drying temperature of the present application is 40 to 100 ° C; and in order to effectively release the stress of the base film and the coating, the present application preferably, during the drying process, The composite battery separator applies a pulling force to make the composite battery diaphragm level in a state of being flat, and the preferred pulling force is 2 to 40N.
  • the specific method for precipitating and curing the high temperature resistant resin is at least one of a high temperature and high humidity box method, a high temperature water spray method, and a mixed solution coagulation bath method;
  • the high temperature and high humidity chamber method includes, The coated base film is placed in a high-temperature closed box, and high-temperature steam is sprayed on the base film, wherein the temperature of the high-temperature steam in the closed box is greater than 100 ° C, and the spraying amount of the high-temperature water vapor is required to be sprayed per square meter.
  • the water absorption of the membrane is more than 0.3mg;
  • the high-temperature water spray method comprises: uniformly spraying the coated base film with hot water of 70-100 ° C, forming a water film on the surface of the coating layer after spraying, spraying
  • the amount of hot water to be poured is calculated according to the thickness of the formed water film: 0.05 to 0.15 ⁇ m;
  • the mixed solution coagulation bath method comprises: immersing the coated base film in a mixture of an organic solvent and water of the high temperature resistant resin used. In the solution, the water content in the mixed solution is more than 50% by weight, and the temperature of the mixed solution is 60 to 150 °C.
  • the basic principle is to create a high temperature environment box with a high water content to a certain level. Therefore, the sealed box used in the present application has a certain volume and The length, a certain degree of airtightness and heat preservation, ensure that the coated diaphragm is in full contact with the high temperature water vapor in the tank and is heated.
  • the coating absorbs an appropriate amount of water vapor and heat, the following reactions occur simultaneously in the coating: (1) precipitation of high temperature resistant resin, (2) reaction of magnesium carbonate with water to form magnesium hydroxide, and release of carbon dioxide; the above two reactions are simultaneously performed , to achieve the purpose of resin precipitation and solidification and pore formation.
  • the precipitated resin has a three-dimensional network structure and has continuity throughout the space; after the magnesium hydroxide particles are captured, the two are tightly bonded together.
  • the coating amount of the diaphragm in order to make the amount of water vapor supplied enough, it is necessary to provide water vapor with a water absorption of more than 0.3 mg per square meter; considering the utilization of H 2 O in the reaction, too little water is insufficient to completely react, excessive water vapor and heat. It also causes a violent reaction to destroy the membrane surface.
  • the amount of water vapor is 0.5 to 1 mg/m 2 per square meter of membrane water absorption, and the high temperature water vapor and the temperature in the tank are 100 to 150. °C.
  • the basic principle of the hot water spray method is to heat the pure water to a certain temperature, and use a precision nozzle to uniformly spray the hot water on the surface of the coating on the surface.
  • a uniform "water film” is formed on the water, and the amount of water and temperature are controlled within a certain range, and the same effect as the first solution can be achieved.
  • the key of this method is to control the uniformity and pressure of the spray.
  • the uneven thickness of the "water film” will make the reaction of the coating differently, the pores of the membrane surface and the thickness distribution are uneven, and the spray is sprayed. If the pressure is too large, the surface of the coating film is directly damaged by the impact of water droplets.
  • the amount of hot water sprayed is calculated according to a water film capable of forming a thickness of 0.05 to 0.15 ⁇ m, and the temperature of the hot water is 70 to 100 ° C. .
  • the main solvent of the high temperature resistant resin is mixed with water in a certain ratio to prepare a mixed solution, wherein the water content needs to be greater than 50% by weight, and the mixed solution is heated to 60 to 150 ° C.
  • the coated base film is introduced into the heated mixed solution, the following reactions occur simultaneously in the coating: (1) precipitation of high temperature resistant resin, (2) reaction of magnesium carbonate with water to form magnesium hydroxide, while releasing carbon dioxide; The above two reactions are carried out simultaneously to achieve the purpose of resin precipitation solidification and pore formation.
  • the precipitated resin has a three-dimensional network structure and has continuity throughout the space; after the magnesium hydroxide particles are captured, the two are tightly bonded together.
  • the water content in the mixed solution must be greater than 50% by weight, which has an extraction effect on the solvent in the coating layer, but in order to control the speed and structure of precipitation of the high temperature resistant resin, it is preferred that the water content in the mixed solution is 50 to 70% by weight. In this range, the resin will gradually precipitate in a loose porous form, leaving sufficient time and space for the reaction of magnesium carbonate.
  • the temperature of the mixed solution is such that the reaction between magnesium carbonate and water is milder. The slow reaction will seriously affect the production efficiency. If the reaction is too intense, the surface structure of the coating will be seriously damaged. According to the physical and chemical properties of the inorganic particles.
  • the reaction speed is controlled to match the precipitation rate of the high temperature resistant resin, and the heat shrinkage of the base film is prevented from being caused by the high temperature. Therefore, the temperature of the optimum mixed solution of the present application is 70 to 100 °C.
  • the coating for battery separator of the present application adds a high temperature resistant resin and magnesium carbonate to the coating.
  • the high temperature resistant resin precipitates to form a cured coating, and the magnesium carbonate reaction releases carbon dioxide.
  • the formation of micropores; the precipitation of the high temperature resistant resin and the formation of the inorganic particles are simultaneously performed, so that the three-dimensional network structure of the resin has spatial continuity and is tightly combined with the inorganic particles; this improves the overall high temperature resistance of the composite battery separator Performance and flame retardancy have a good effect.
  • the composite battery separator prepared by using the coating of the present application not only has excellent high temperature resistance, flame retardancy, but also high liquid absorption rate and liquid retention rate; meanwhile, the composite battery separator of the present application has high ion conductivity and strong electrochemical stability. High physical strength, low thickness expansion ratio, excellent electrochemical stability and physical strength, so that the composite battery separator of the present application can maintain excellent stability even in various circulating environments such as large magnification, high temperature and low temperature; Thereby greatly improving the service life of the battery.
  • FIG. 1 is a flow chart of preparing a composite battery separator in an embodiment of the present application
  • FIG. 2 is a block diagram of the entire process flow including the preparation of the coating material in the embodiment of the present application.
  • the coating of the present application is mainly composed of a high temperature resistant resin and magnesium carbonate, so that the composite battery separator coated with the coating of the present application has temperature resistance, puncture resistance, oxidation resistance and flame retardancy in various use atmospheres. Sex and so on have been effectively improved.
  • the composite battery separator of the present application is placed in a hot box at 150 ° C for testing, and the results show that the TD ⁇ MD shrinkage is less than 3%.
  • the composite battery separator of the present application is composed of inorganic particles as a skeleton, and the high-temperature resin coating of the continuous space three-dimensional network structure is closely combined with the base film, and the entire diaphragm structure is uniform and stable, and the temperature resistance is excellent, and the long-term 150-300 can be used. Continuous operation in a high temperature environment of °C.
  • the inorganic particles in the composite battery separator have good thermal conductivity, can disperse local high temperature in the entire battery body in a very short time, and reduce the risk of local sudden heat and the entire battery failure.
  • the magnesium hydroxide formed by the magnesium carbonate in the coating will pyrolyze at about 396 ° C and absorb a large amount of heat; at the same time, the high temperature resistant resin in the composite battery separator will rapidly undergo carbonization reaction at about 400 ° C, thereby To the flame retardant effect.
  • the space-dimensional three-dimensional network resin layer of the high temperature resistant resin has a very fast liquid absorption speed, and has a higher liquid retention rate while shortening the battery process.
  • the liquid retention rate of the composite battery separator of the present application can be increased by 50% to 150%.
  • the inorganic particles are embedded in the resin coating of the three-dimensional network structure, and the smooth ion channel is constructed, so that the composite battery separator of the present application has much higher than the general modified diaphragm.
  • the ionic conductivity in one implementation of the present application, the composite battery separator having a thickness of 20 ⁇ m has an ionic conductivity of 1.6 ms/m or more; thereby ensuring a small internal resistance of the lithium ion battery. The low consumption and high consistency are of great benefit to the later battery matching application.
  • the high temperature resistant resin material in the coating has excellent properties such as high temperature resistance, acid and alkali resistance, light weight, insulation, anti-aging, long life cycle, etc.; In the lithium-ion battery cycle environment, it can withstand high-density ions and electrons under high voltage and strong electric field, and has strong stability.
  • the prepared composite battery separator was subjected to battery test in various high-voltage systems, and the results showed that the battery cycle performance was good compared to the conventional polyolefin separator or existing
  • the surface-modified coated separator adopts the composite battery separator of the coating of the present application, and the self-expansion rate of the battery during the cycle is extremely low, and the inhibition effect on the battery expansion is very obvious.
  • the coating for the battery separator of this example is composed of a high temperature resistant resin, magnesium carbonate, a resin cosolvent, a coupling agent, a stabilizer, a binder, and an organic solvent.
  • the coating high temperature resistant resin adopts meta-aramid fiber (abbreviated PMIA);
  • the magnesium carbonate adopts magnesium carbonate which is more than 99.99% pure and has a D50 of 0.5 ⁇ m, and the resin auxiliary solvent adopts LiCl; organic solvent N,N-dimethylacetamide is used;
  • the coupling agent is a fluorine-containing silane coupling agent, and the specific example is heptafluorodecyltrimethoxysilane;
  • the binder is a homopolyvinylidene fluoride having a molecular weight of more than 600,000.
  • the stabilizer is propylene carbonate.
  • the base film is a single-layer PP film having a thickness of 12 ⁇ m manufactured by Shenzhen Zhongxing Innovation Material Technology Co., Ltd.
  • the block diagram of the preparation process of the composite battery separator of this example is shown in Fig. 2, including two parts.
  • the preparation of the coating before the preparation of the coating, the meta-aramid fiber is pre-cleaned, specifically, with high-purity acetone.
  • the meta-aramid fiber is washed, then filtered and dried to remove impurities from the fiber as much as possible.
  • the washing solvent of the meta-aramid fiber can use other low-boiling, low-toxic organic solvents in addition to acetone.
  • the basic principle of selection is that it cannot dissolve PMIA, and can dissolve various precursors and halides of PMIA. Impurities, etc.
  • the base film coating Before the base film is coated, as shown in FIG. 2, after the base film is unwound, it is preheated, and then coated, solidified, punctured, washed, dried.
  • the diaphragm was wound up to obtain the composite battery separator of this example.
  • the whole process is designed as a pipeline mode as shown in Fig. 1.
  • the unrolled base film is preheated in advance, so that it is not necessary to prevent preheating after rolling.
  • the coating prepared in this example is loaded into the slit extrusion coating device 2, and the pre-heated base film is unwound through the unwinder 1, after passing through In the case of the slit extrusion coating apparatus 2, it was applied to one surface of the PP film by a slit extrusion coating method, and a gap of 8 ⁇ m was provided between the PP film and the slit extrusion coating device 2.
  • the PP film first enters the high temperature and high humidity box 3, and the high temperature and high humidity box method is used to precipitate and solidify the high temperature resistant resin to form a hole. Specifically, the coated wet film is passed through a relatively closed high temperature.
  • High humidity box 3 wherein the temperature of the high temperature water vapor is greater than 100 ° C, the high temperature water vapor is manufactured by ultrasonic vibration, and the spraying amount is calculated according to the water absorption amount of the film to be sprayed per square meter of 0.3 to 0.8 mg; (C) cleaning and drying will pass The film body of the solidification pore-forming process is transferred to the cleaning tank and the oven section; wherein the cleaning tank 6 adopts the 18-stage pure water cleaning tank, and the tanks in the water tank are connected internally, and the clean water source is continuously supplemented by the countercurrent water inlet method.
  • the water outlet is arranged at the membrane end to guide the mixture away; the residual organic solvent in the tank is less than 0.1%; after the cleaning is completed, the oven 7 adopts a 60 m air-floating hot air oven, and the residual water of the separator is less than 200 ppm. Finally, the winder 8 is used to wind up, and the composite battery separator of this example is obtained.
  • the three methods for precipitating and solidifying the resin of the present application are designed together, that is, a high-temperature high-humidity box method, a high-temperature water spray method, and a mixed solution coagulation bath method, which can be used as needed. select.
  • a spraying device 4 is further disposed in the conveying direction of the base film, and the spraying device 4 is disposed directly above the base film, and can spray high temperature water as required.
  • High-temperature water spray method a water bath 5 is also arranged in the conveying direction of the base film, and the main solvent and water of the high-temperature resistant resin can be introduced into the water bath 5 in proportion, and the water bath is performed at a set temperature to realize mixing.
  • Liquid coagulation bath method It can be understood that the three methods in the pipeline mode shown in FIG.
  • the spraying device 4 can be stopped to remove the solution in the water bath 5;
  • the high-temperature water spray method the high-temperature and high-humidity box 3 stops running, which is only a common one, and also removes the solution in the water bath 5; when the mixed liquid coagulation bath method is selected, the water bath 5 is added The required solution, and the high-temperature high-humidity box 3 and the spraying device 4 are all stopped.
  • the three methods can be randomly selected by three methods, and are not specifically limited herein.
  • the composite battery separator prepared in this example was tested for thickness, porosity, gas permeability, ionic conductivity, oxidation potential, closed cell temperature, film rupture temperature, etc., and the composite battery separator was tested at 105 ° C and The heat shrinkage rate of TD/MD at 150 ° C for 60 min.
  • the above various tests and tests adopt the conventional testing methods in the art, and are not specifically limited herein.
  • the test results are shown in Table 1.
  • the composite battery separator prepared in this example was cut into a width of 44 mm, and a LP053450 liquid soft pack battery was fabricated on a fully automatic battery production line with a design capacity of 1100 mAh and a voltage system of 4.35V.
  • the positive electrode of the battery is made of lithium cobalt oxide cathode material developed by Tianjin No.18, the actual rolling density is 4.15mg/cm 3 ; the negative electrode is made of Dongguan BTR artificial graphite, the actual rolling density is 1.71mg/cm 3 ; the electrolyte is made by Guangzhou Tianci TC-E231 The amount of liquid injection is 2.4g/Ah.
  • the above tests are all based on the conventional testing methods in the art, and are not specifically limited herein. The test results are shown in Table 2.
  • the coating of the present invention and the preparation of the composite battery separator are the same as those of the first embodiment.
  • the base film used for the composite battery separator is a single-layer PP film having a thickness of 12 ⁇ m manufactured by Shenzhen Zhongxing Innovation Material Technology Co., Ltd., except for the coating curing and pore-forming scheme. The rest are the same as in the first embodiment.
  • (A) coating the coating prepared in this example was applied to one surface of the PP film by slit extrusion coating, and a gap of 8 ⁇ m was set.
  • the high-temperature water spray method is used to solidify into a hole.
  • the high-temperature water spray method specifically includes, the coated wet film is passed under the spray port, and coated with hot water of 70 to 100 ° C.
  • the covered film body is uniformly sprayed, and a water film is formed on the surface of the coating layer after spraying, and the amount of hot water sprayed is calculated according to the thickness of the formed water film of 0.05 to 0.15 ⁇ m.
  • the battery separator prepared in this example is subjected to various tests, and is made into a battery for various related tests.
  • the preparation of the battery is the same as that of the first embodiment, and the test items and specific methods are the same as those in the first embodiment, and are not described here.
  • the test results are shown in Tables 1 and 2.
  • the coating of the present invention and the preparation of the composite battery separator are the same as those of the first embodiment.
  • the base film used for the composite battery separator is a single-layer PP film having a thickness of 12 ⁇ m manufactured by Shenzhen Zhongxing Innovation Material Technology Co., Ltd., except for the coating curing and pore-forming scheme. The rest are the same as in the first embodiment.
  • the coating prepared in this example was applied to one surface of the PP film by slit extrusion coating, and a gap of 8 ⁇ m was set.
  • the battery separator prepared in this example is subjected to various tests, and is made into a battery for various related tests.
  • the preparation of the battery is the same as that of the first embodiment, and the test items and specific methods are the same as those in the first embodiment, and are not described here.
  • the test results are shown in Tables 1 and 2.
  • the coating of the present example and the composite battery separator are prepared in the same manner as in the first embodiment except that the base film used for the composite battery separator is a single-layer PE film having a thickness of 12 ⁇ m manufactured by Shenzhen Zhongxing Innovation Material Technology Co., Ltd., and the rest is the same as in the first embodiment. .
  • the battery separator prepared in this example was tested and made into a battery for various related tests.
  • the preparation of the battery was the same as in the first embodiment, and the test items and specific methods were the same as those in the first embodiment, and were not tired here.
  • the test results are shown in Tables 1 and 2.
  • a single-layer PP separator with a thickness of 14 ⁇ m made by Shenzhen Zhongxing innovative Materials Technology Co., Ltd. was directly used for each test, and it was also prepared into a battery for testing.
  • the test items of the PP separator are the same as those in the first embodiment, and the preparation of the battery and the test of the battery are also the same as those in the first embodiment, and are not described here.
  • the test results are shown in Tables 3 and 4.
  • a single-layer PE separator with a thickness of 14 ⁇ m manufactured by Shenzhen Zhongxing innovative Materials Technology Co., Ltd. was directly used for each test, and it was also prepared into a battery for testing.
  • the test items of the PP separator are the same as those in the first embodiment, and the preparation of the battery and the test of the battery are also the same as those in the first embodiment, and are not described here.
  • the test results are shown in Tables 3 and 4.
  • a 16 ⁇ m thick PP/PE/PP three-layer composite separator made by Shenzhen Zhongxing Innovative Materials Technology Co., Ltd. was used for each test, and it was also prepared into a battery for testing.
  • PP/PE/PP In the three-layer composite separator the thickness of each layer is 5/6/5.
  • the tests of the PP/PE/PP three-layer composite separator, the preparation of the battery, and the tests of the battery are the same as those in the first embodiment, and are not described here. The test results are shown in Tables 3 and 4.
  • a single-layer PP film having a thickness of 12 ⁇ m manufactured by Shenzhen Zhongxing innovative Material Technology Co., Ltd. as in the first embodiment was used as a base film, and a ceramic coating was applied on one surface of the base film to obtain a composite separator of the present example.
  • the ceramic coating of this example uses 44% Al 2 O 3 , 2% acrylate binder, 0.8% thickener, 0.5% dispersant, 0.1% defoamer, based on the total weight of the suspension. And a dispersing aid, uniformly dispersed in water to form a stable suspension, uniformly coated on one surface of the PP film by using a micro gravure coating method, and then passed through a multi-stage with a length of 15 m and a temperature between 30 ° C and 60 ° C The oven was dried to form a ceramic coating having a thickness of 2-3 ⁇ m, that is, the composite separator of this example was obtained.
  • the Al 2 O 3 used in this example has a D50 of less than 0.8 ⁇ m, a D90 of less than 1.3 ⁇ m, and a purity of more than 99.99%.
  • the prepared composite separator was subjected to the same tests as in the first embodiment, and was prepared into a battery to test various properties of the battery.
  • the preparation and test items of the battery were the same as those in the first embodiment, and are not described herein.
  • the test results are shown in Tables 3 and 4.
  • a single-layer PE film having a thickness of 12 ⁇ m manufactured by Shenzhen Zhongxing Innovative Material Technology Co., Ltd. as in the fourth embodiment was used as a base film, and a ceramic coating was applied on one surface of the base film to obtain a composite separator of this example.
  • the ceramic coating of this example was the same as that of Comparative Example 4, and the same suspension and coating preparation method were used to form the composite separator of this example.
  • the prepared composite separator was subjected to the same tests as in the first embodiment, and was prepared into a battery to test various properties of the battery.
  • the preparation and test items of the battery were the same as those in the first embodiment, and are not described herein.
  • the test results are shown in Tables 3 and 4.
  • the battery separator prepared in the examples of the present application has a greatly improved film rupture temperature while maintaining the closed cell temperature, thereby improving the high temperature resistance and flame retardancy of the separator; The liquid absorption rate and fluid retention rate are improved to different extents.
  • the battery using the battery separator of the present application has a conventional capacity retention of 500 cycles, and a capacity retention rate of 500 cycles of 60 ° C constant temperature, which is improved compared with the comparative example.
  • the composite battery separator of the present application has high ion conductivity, strong electrochemical stability, high physical strength, low thickness expansion ratio, strong liquid retention ability, excellent electrochemical stability and physical strength, and the present application is made. The composite battery separator can maintain excellent stability even in various cycling environments such as large magnification, high temperature and low temperature; thereby greatly improving the service life of the battery.
  • the present application further tests different high temperature resistant resins, resin solubilizers, organic solvents, stabilizers, and binders.
  • the results show that among them, the meta-aramid fiber with a molecular weight of 200,000 to 1,000,000 is more effective, and other high temperature resistant resins such as polyimide, polyethersulfone, polyetheretherketone, etc., besides the meta-aramid fiber.
  • Para-aramid fibers, polytetrafluoroethylene, and derivatives, copolymers or mixtures of these resins can be used in the present application.
  • Resin co-solvent In addition to LiCl, CaCl 2 can also be used.
  • Organic solvent In addition to N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide or tetrahydrofuran can also be used.
  • a fluorine-containing silane coupling agent can be used as the coupling agent.
  • Stabilizers In addition to propylene carbonate, phenyl phosphate, tripropylene glycol, ethylene glycol or sodium cellulose can also be used.
  • the binder may be a polyvinylidene fluoride copolymer, a silicone rubber, a silicone rubber derivative, a polyacrylate, a polyimide, or an epoxy resin in addition to polyvinylidene fluoride.
  • the results show that the content of the high temperature resistant resin is 2 to 10% of the total weight, the content of magnesium carbonate is 20 to 80% of the total weight, and the viscosity of the coating is 20 ⁇ 200CPs, solid content of 15 ⁇ 70%, can achieve the equivalent effect of the examples in the present application, and prepare a composite with high ionic conductivity, strong electrochemical stability, high physical strength, low thickness expansion rate and strong liquid retention ability. Battery separator.

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Abstract

一种用于电池隔膜的涂料、电池隔膜及电池隔膜的制备方法。电池隔膜涂料主要成份包括耐高温树脂、碳酸镁、树脂助溶剂和有机溶剂，其中耐高温树脂的含量为总重量的2～10％，碳酸镁的含量为总重量的20～80％，涂料的粘度为20～200CPs，固含量为15～70％。采用所述涂料制备的复合电池隔膜具有优秀的耐高温性、阻燃性、抗穿刺和抗拉伸性，吸液率和保液率高、离子电导率高、电化学稳定性强、物理强度高、厚度膨胀率低。强的保液能力和电化学稳定性使所述复合电池隔膜在大倍率、高低温环境中能保持良好的稳定性，从而提高电池的使用寿命。

Description

用于电池隔膜的涂料、电池隔膜及电池隔膜的制备方法 技术领域
本申请涉及电池隔膜领域，特别是涉及一种用于电池隔膜的涂料，由该涂料制备的电池隔膜，以及由该涂料制备电池隔膜的制备方法。
背景技术
随着便携电子设备、电动汽车等的全球普及应用趋势，作为主要储能系统的锂离子电池，不断的向着高能量密度、高安全性方向发展。作为锂离子电池核心材料之一的隔膜，在能够满足正常的电子阻断及锂离子通过的电化学性能之外，业界普遍在整个电池安全性方面给予高度期望。具体来讲就是希望能有以下性能：1)热稳定性，即在电池已经由于某种外部条件导致失效而大量产热的情况下，如正常充放电使用或被置于过热环境等滥用情况下，电池隔膜需要在具备关闭通道的功能(即shut down)的同时，保持稳定，仍能有效分隔电池正、负极，不会因为不稳定造成大范围收缩乃至融化，进而加剧电池内部短路。2)阻燃性，即当电池系统达到某一温度时，隔膜本身有一定的阻燃性，在电池体系中其它组分发生燃烧起火的情况下，不会随同燃烧。3)电化学稳定性，即隔膜能长期在有机溶剂、高电位、高氧化性环境下，稳定工作，不产生腐蚀、氧化、溶胀、溶解、形变等。4)高物理强度，即具有一定的坚韧度，较好的抗穿刺能力及抗拉伸能力，能有效阻挡电极毛刺及锂枝晶的洞穿作用，预防内部微短路。5)高吸液率、保液率，即具有较均匀的多孔结构，且对电解液中的多种成分有一定的亲和性，确保整体电解质体系的锂离子通道的畅通性，离子电导率不受影响。
对于提高电池安全性，当前隔膜行业普遍运用的方法是对聚烯烃隔膜表面进行陶瓷类耐温材料涂覆改性，其中以涂覆Al2O3为主。然而陶瓷涂层在电池应用中有以下几点缺点难以克服。1)涂层中陶瓷颗粒紧密堆积，靠聚丙烯酸酯类大分子粘结；带陶瓷涂层的聚烯烃膜在独立状态时，具有较好的耐温性能和稳定的粘结力；然而长期在锂电池有机电解液偏酸性氛围中，在电池使用时离子来回穿梭撞击下，以及在高电压的氧化作用下，陶瓷涂层在电池循环远远达不到500次时，就已经出现陶瓷涂层和聚烯烃基材之间粘结作用变弱乃至脱离；同时，陶瓷颗粒与颗粒之间也仅仅剩下松散的堆积。此时，已起不到耐温、抗锂枝晶穿刺等作用。2)以Al2O3为代表的陶瓷颗粒在偏酸性的电解液氛围里， 缓慢反应，会生成水，而水会和LiPF6反应进一步生成HF，也就是说，有微量的水存在的情况下，该反应就可能持续进行，进入恶性循环，从而不断的消耗电解质中的活性物质LiPF6，且随着Al3+离子的不断提升，整个电池的自衰不断提高，循环恢复容量不断降低，即容量回复率大大下降；Al2O3缓慢反应生成水的反应公式如下：
Al2O3+6HF→2AlF3+3H2O
LiPF6→LiF+PF5，PF5+H2O→POF3+HF
更为严重的是，3)Al2O3颗粒由于颗粒及其细小，表面积极大，且亲水，制膜过程中除去痕量水分的成本极高，并且很难控制到水分1000ppm以内，但是，Al2O3缓慢反应生成水的反应诱发条件仅是水含量大于1×10-6；也就是说，Al2O3缓慢反应生成水的反应几乎是不可避免的。
发明内容
本申请的目的是提供一种用于电池隔膜的涂料，由其制备的电池隔膜，以及电池隔膜的制备方法。
为了实现上述目的，本申请采用了以下技术方案：
本申请公开了一种用于电池隔膜的涂料，该涂料的主要成份包括耐高温树脂、碳酸镁、树脂助溶剂和有机溶剂；耐高温树脂为聚酰亚胺、聚醚砜、聚醚醚酮、间位芳酰胺纤维、对位芳酰胺纤维、聚四氟乙烯及其衍生物、共聚物或混合物中的至少一种；树脂助溶剂为碱金属或者碱土金属的强酸盐类；有机溶剂为N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺和四氢呋喃中的至少一种；涂料中耐高温树脂的含量为总重量的2～10％，碳酸镁的含量为总重量的20～80％，涂料的粘度为20～200CPs，固含量为15～70％。
需要说明的是，本申请的涂料，在使用时，耐高温树脂作为涂层的骨架支撑，具有较好的耐温、绝缘、阻燃、抗氧化、抗穿刺等性能。在涂层固化的过程中，涂料中的碳酸镁与水反应生成氢氧化镁沉淀以及二氧化碳气体，控制反应条件，可以在涂层中产生均匀分散的微孔，以进一步提高复合隔膜的吸液率和保液率。同时，氢氧化镁在396℃左右会发生热解，大量吸热，耐高温树脂在400℃左右会迅速发生碳化反应，氢氧化镁与耐高温树脂配合能更好的起到阻燃作用。
还需要说明的是，本申请中所采用的耐高温树脂包括聚酰亚胺、聚醚砜、聚醚醚酮、间位芳酰胺纤维、对位芳酰胺纤维、聚四氟乙烯，以及以上这些聚合物的衍生物、共聚物或混合物，可以采用一种耐高温树脂，也可以采用两种 或多种混合使用，在此不做具体限定。
优选的，耐高温树脂为分子量20万至100万的间位芳酰胺纤维。
需要说明的是，在耐高温性能方面，聚酰亚胺、聚醚砜、聚醚醚酮、间位芳酰胺纤维、对位芳酰胺纤维、聚四氟乙烯及这些聚合物的衍生物、共聚物或混合物都能够满足使用需求；但是，从材料合成成本、可加工性和环保性等方面考虑，本申请优选的采用芳酰胺纤维，即间位芳酰胺纤维和对位芳酰胺纤维。间位芳酰胺纤维合对位芳酰胺纤维两大类芳酰胺纤维中，对位芳酰胺纤维的性能虽然和间位芳酰胺纤维同样出色，但是目前在加工时，对位芳酰胺纤维必须要使用大量的质子溶剂，纺织行业内大量使用的是98％的浓硫酸，由其制备成涂料涂覆在基膜特别是聚烯烃基膜的表面时，会造成聚烯烃一定程度的碳化作用，严重影响复合隔膜的柔韧性、抗穿刺性、耐腐蚀性等；因此，本申请更优选的方案中采用间位芳酰胺纤维作为耐高温树脂制备涂料。更优选的采用分子量20万至100万的间位芳酰胺纤维。
优选的，树脂助溶剂为CaCl2或LiCl，优选的树脂助溶剂为LiCl。
需要说明的是，为了为避免其它碱金属、碱土金属离子干扰、影响锂离子电池中的离子传导及体系的酸碱性，因此优选的树脂助溶剂采用CaCl2或LiCl，更优选的采用LiCl。
优选的，有机溶剂为N-甲基吡咯烷酮或N,N-二甲基乙酰胺。
需要说明的是，虽然N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺和四氢呋喃都可以用于本申请，但是，从回收难度、毒性大小等多方面综合考虑，优选采用N-甲基吡咯烷酮或N,N-二甲基乙酰胺作为本申请的有机溶剂。
优选的，涂料还包括偶联剂、稳定剂和粘结剂。
需要说明的是，在没有添加偶联剂、稳定剂和粘结剂的情况下，虽然涂料也可以直接使用，但是，涂料无法长期放置而不沉淀，难以做到工业化生产使用；因此，要制成能长期放置而不发生沉降具有热力学稳定体系的浆料，本申请优选的方案中，在涂料中还添加了偶联剂、稳定剂和粘结剂。可以理解，常规的用于浆料的偶联剂、稳定剂和粘结剂都可以用于本申请；但是，在更优选的方案中，为了达到更好的效果，本申请对偶联剂、稳定剂和粘结剂进行了限定。
优选的，偶联剂为含氟硅烷偶联剂中的至少一种，稳定剂为碳酸丙烯酯、磷酸苯酯、三丙二醇、乙二醇和纤维素钠中的至少一种，粘结剂为聚偏氟乙烯、聚偏氟乙烯共聚物、硅橡胶、硅橡胶衍生物、聚丙烯酸酯类、聚酰亚胺类和环氧树脂类中的至少一种。更优选的，粘结剂为聚偏氟乙烯或硅橡胶、硅橡胶衍 生物，从耐热、成本和环保角度考虑，最优选的粘结剂采用分子量大于60万的均聚聚偏氟乙烯。
本申请的另一面公开了一种复合电池隔膜，包括基膜和涂覆于基膜的至少一个表面的涂层，其中涂层由本申请的涂料涂覆而成。
需要说明的是，本申请对于基膜的材质及制造方法没有特殊的限制，如聚烯烃基膜、聚酰亚胺等的静电纺丝隔膜、芳香族酰胺类纤维纸隔膜、聚偏氟乙烯隔膜、蚕丝隔膜等都可以用于本申请；但是从工艺的成熟度、成本、基膜的闭孔温度等多方面考虑，优选聚烯烃类基膜，单层聚丙烯(缩写PP)、单层聚乙烯(缩写PE)、双层PP、双层PE、三层PP\PE\PP等为主；更优选的采用单层PP或者单层PE隔膜；在本申请的更为优选的实现方式中，采用了厚度在3～12μm的单层PP或者PE基膜，基膜的孔隙率在35％～55％之间，透气值在50～500S之间，闭孔温度在130℃～160℃之间。
进一步的，本申请的复合电池隔膜，采用示差扫描量热法分析，复合电池隔膜在100～220℃间有1-3个吸热峰，并且在380～420℃有明显的吸热峰。
需要说明的是，本申请的复合电池隔膜，由于采用了本申请的涂料制备涂层，因此，在100～220℃间有1-3个吸热峰，并且在380～420℃有明显的吸热峰；这对提高复合电池隔膜的阻燃能力和提高隔膜的整体安全性、稳定性有重要作用。在这两个温度区间有吸热峰，表示复合电池隔膜能够很好的在两个区间内吸收热量；现有的电解液其各组分在150℃～300℃时，会急速汽化，给电池带来急剧的结构破坏，所以本申请的复合电池隔膜在100～220℃和380～420℃温度区间有吸收峰，具有很好的吸热作用，能及时导走热量。此外，在380～420℃有明显的吸热峰，也能够保障复合电池隔膜在长期高温下，仍能保持良好的理化稳定性。
本申请的再一面公开了本申请的复合电池隔膜的制备方法，包括以下步骤，
(A)涂覆，将本申请的涂料涂覆于基膜表面；
(B)涂层的固化和造孔，将涂覆好的基膜置于水和温热环境下，使耐高温树脂析出固化，同时，碳酸镁与水反应生成氢氧化镁沉淀，并释放二氧化碳，形成微孔；
(C)清洗和干燥，对步骤(B)的产物进行水浴清洗，然后在40～100℃下干燥，即获得所述复合电池隔膜。
需要说明的是，步骤(A)涂覆的目的是使涂料均匀施涂于基膜表面，因此，常规的能够将涂料涂覆于基膜的涂覆方式都可以用于本申请，在此不做具体限定。本申请的优选方案中，采用凹版印刷涂布法和狭缝挤出涂布法，这两种方 法都可以实现单面涂布或者双面涂布。通过螺杆泵精确而稳定的给凹版辊或者挤出模头供料，将本申请的涂料均匀的涂在选定的基膜的至少一个表面。通过控制涂布量的来精确控制涂层厚度在1～8μm，从实际耐温阻燃等测试情况与厚度带来的空间损失情况综合考虑，本申请优选的涂层厚度2～5μm。
还需要说明的是，本申请中步骤(B)涂层的固化和造孔，实际上在步骤(A)涂覆完成后，以空气中的水汽作为析出的引发剂，涂层表面的耐高温树脂就已经初步析出形成半固化膜，步骤(B)进一步将涂覆好的基膜置于水和温热环境下，对涂层进行补水和加温，此时耐高温树脂会进一步析出固化，同时，涂层中的碳酸镁会和水生成更难溶的氢氧化镁，并释放出二氧化碳，达到造孔的目的。本申请的优选方案中，分别采用了三种方式实现步骤(B)的涂层固化和造孔，这将在后续详细介绍。
还需要说明的是，对于步骤(C)的清洗和干燥，在经过步骤(B)的固化处理的涂层隔膜，会有水、有机溶剂、多种助剂、可溶性无机盐等，因此，直接通过水浴洗去各种残留。在干燥环节，则主要是将附着在涂层表面及缝隙中的水除去，其原理即是水高温下蒸发，本申请对干燥方法不做特别限制；在干燥除去水的同时，干燥还可以对刚刚析出的树脂起到淬火作用。
还需要说明的是，为了不引起复合电池隔膜受热收缩，本申请优选的干燥温度为40～100℃；而为了有效的释放基膜及涂层的应力，本申请优选的，在干燥过程中对复合电池隔膜施加各向拉力，使复合电池隔膜时刻处于辗平状态，优选的拉力为2～40N。
优选的，步骤(B)中，使耐高温树脂析出固化的具体方法为高温高湿箱法、高温水喷淋法和混合液凝固浴法中的至少一种；高温高湿箱法包括，将涂覆好的基膜置于高温的密闭箱体中，并向基膜喷洒高温水汽，其中密闭箱体中的高温水汽的温度大于100℃，高温水汽的喷洒量按照每平方米需要喷洒的基膜的吸水量大于0.3mg计算；高温水喷淋法包括，采用70～100℃的热水对涂覆好的基膜进行均匀喷淋，喷淋后在涂覆层的表面形成水膜，喷淋的热水量按照所形成的水膜的厚度为0.05～0.15μm计算；混合液凝固浴法包括，将涂覆好的基膜浸泡于所采用的耐高温树脂的有机溶剂和水组成的混合溶液中，混合溶液中水含量大于50wt％，混合溶液的温度为60～150℃。
需要说明的是，对于第一种方案，即高温高湿箱法，其基本原理是营造一个水含量高到一定水平的高温环境箱，因此，本申请所采用的密闭箱体具有一定的容积及长度，有一定的密闭性及保温性，确保涂层隔膜在箱体内与高温水汽的充分接触及受热。当涂层吸收适量的水汽及热量后，涂层中同时发生以下 反应：(1)耐高温树脂析出，(2)碳酸镁与水反应生成氢氧化镁，同时释放二氧化碳；以上两个反应同步进行，达到树脂析出固化和造孔的目的。此时，析出的树脂为立体网状结构，且在整个空间具有连续性；俘获氢氧化镁颗粒之后，两者紧密的结合在一起。根据隔膜涂布量计算，为了使得提供的水汽量足够，需要提供每平米隔膜吸水量大于0.3mg的水汽；考虑反应中H2O利用率，过少的水不足以完全反应，过量的水汽和热量也会引起剧烈反应而破坏膜面，本申请的最优化的方案中，提供水汽的量为每平方米隔膜吸水量为0.5～1mg/m2的水汽，高温水汽和箱体内温度为100～150℃。
对于第二种方案，即高温水喷淋法，热水喷淋法其基本原理是，将纯水加热到一定的温度，使用精密喷头将热水均匀的喷淋在涂层表面，在其表面上形成均匀的“水膜”，水量和温度控制在一定的范围内，同样能达到第一种方案的同等效果。需要特别说明的是，此法的关键是控制喷淋的均匀性及压力，“水膜”厚度不均匀会使得涂层各处反应差异化严重，膜面成孔及厚度分布不均匀，喷淋压力过大则会因水滴撞击直接破坏涂层膜面；本申请优选的方案中，喷淋的热水量按照能够形成0.05～0.15μm厚度的水膜计算，热水的温度为70～100℃。
对于第三种方案，即混合液凝固浴法，将耐高温树脂的主溶剂以一定比例与水混合制成混合溶液，其中水的含量需大于50wt％，并将混合溶液加热到60～150℃的温度，将涂布好的基膜导入加热的混合溶液中，涂层中同时发生以下反应：(1)耐高温树脂析出，(2)碳酸镁与水反应生成氢氧化镁，同时释放二氧化碳；以上两个反应同步进行，达到树脂析出固化和造孔的目的。此时，析出的树脂为立体网状结构，且在整个空间具有连续性；俘获氢氧化镁颗粒之后，两者紧密的结合在一起。其中，混合溶液中水含量必须大于50wt％，这对涂层中的溶剂有萃取作用，但是，为了控制耐高温树脂析出的速度和结构，优选的，混合溶液中含水量在50～70wt％之间；在此范围内，树脂会以疏松多孔状缓慢析出，并为碳酸镁的反应留出足够的时间和空间。另一点需要说明的是，混合溶液的温度是能够使碳酸镁和水反应较温和一个温度，反应过慢会严重影响生产效率，反应过剧烈会严重破坏涂层表面结构，根据无机粒子的物化特性，控制其反应速度与耐高温树脂析出速度相匹配，同时避免高温引起基膜的热收缩，因此，本申请最优的混合溶液的温度为70～100℃。
由于采用以上技术方案，本申请的有益效果在于：
本申请的用于电池隔膜的涂料，在涂料中添加耐高温树脂和碳酸镁，在使用时，耐高温树脂析出形成固化的涂层的同时，碳酸镁反应释放出二氧化碳， 形成微孔；耐高温树脂的析出和无机粒子的生成同时进行，使得树脂的立体网状结构具有空间连续性的同时，与无机粒子紧密的结合在一起；这对提高复合电池隔膜整体的耐高温性能、阻燃性具有很好的效果。采用本申请的涂料制备的复合电池隔膜，不仅具有优秀的耐高温性能、阻燃性而且吸液率、保液率高；同时，本申请的复合电池隔膜离子电导率高、电化学稳定性强、物理强度高、厚度膨胀率低，其优秀的电化学稳定性和物理强度，使得本申请的复合电池隔膜即使在大倍率、高低温等各种循环环境中仍能保持极佳的稳定性；从而大大提高电池的使用寿命。
附图说明
图1是本申请实施例中复合电池隔膜的制备流程图；
图2是本申请实施例中包括涂料的制备在内的整个工艺流程框图。
具体实施方式
本申请的涂料，以耐高温树脂和碳酸镁为主要成分，使得采用本申请的涂料为涂层的复合电池隔膜在各种使用氛围中的耐温性、抗穿刺性、抗氧化性、阻燃性等都得到有效的提高。
具体来说，i)优良的耐高温性能，本申请的一种实现方式中，将本申请的复合电池隔膜置于150℃的热箱进行测试，结果显示，TD\MD收缩均低于3％；本申请的复合电池隔膜以无机粒子为骨架，以连续空间立体网状结构的耐高温树脂涂层与基膜紧密集合，整个隔膜结构均匀稳定，耐温性极佳，能长期在150～300℃的高温环境下持续工作。
ii)阻燃性，复合电池隔膜中的无机粒子具有良好的导热性，能在极短的时间内将局部高温分散到整个电池体，降低了局部骤热而整个电池失效的风险，在涂层中由涂料中的碳酸镁所生成的氢氧化镁，在396℃左右会发生热解，并大量吸热；同时，复合电池隔膜中的耐高温树脂在400℃左右会迅速发生碳化反应，从而起到阻燃作用。
iii)高吸液率、保液率，本申请的涂层中，耐高温树脂的空间立体网状树脂层，吸液速度非常快，在缩短电池制程的同时，具有更高的保液率，相对普通隔膜及一般表面改性隔膜，本申请的复合电池隔膜的保液率能提升50％～150％。
iv)高离子电导率，本申请的涂层中，无机颗粒镶嵌于立体网状结构的树脂涂层中，架构出通畅的离子通道，使得本申请的复合电池隔膜具有远高于一般改性隔膜的离子电导率，本申请的一种实现方式中，厚度达到20μm的复合电池隔膜，其离子电导率均在1.6ms/m以上；从而确保了锂离子电池的内阻小、内 耗极低，同时其一致性极高，对后期电池配组应用带来极大的好处。
v)电化学稳定性，本申请的复合电池隔膜中，其涂层中的耐高温树脂材料具有耐高温、耐酸耐碱、重量轻、绝缘、抗老化、生命周期长等优良性能；因此，在锂离子电池循环环境中，能经受高电压强电场下得高密度离子、电子撞击，稳定性极强。
vi)高物理强度，无机颗粒与耐高温树脂组合，无机颗粒的硬度及耐高温树脂的坚韧度相结合，极大的提升了复合电池隔膜的抗穿刺能力及抗拉伸能力。
vii)长循环寿命，极佳的保液能力及物化稳定性，使得本申请的复合电池隔膜即使在大倍率、高低温等各种循环环境中仍能保持极佳的稳定性，从而大大提高电池的使用寿命。
viii)低厚度膨胀率，本申请的一种实现方式中，对制备的复合电池隔膜在各种高电压体系进行了电池测试，结果显示，电池循环性能良好，相对于普通聚烯烃隔膜或者现有的表面改性涂层隔膜，采用本申请的涂料的复合电池隔膜，其电池循环过程中自身膨胀率极低，对电池膨胀的抑制作用非常明显。
下面通过具体实施例和附图对本申请作进一步详细说明。以下实施例仅对本申请进行进一步说明，不应理解为对本申请的限制。
实施例一
本例的用于电池隔膜的涂料由耐高温树脂、碳酸镁、树脂助溶剂、偶联剂、稳定剂、粘结剂和有机溶剂组成。其中，涂料耐高温树脂采用间位芳酰胺纤维(缩写PMIA)；碳酸镁采用购自于上海牧泓实业的纯度大于99.99％，并且D50为0.5μm的碳酸镁；树脂助溶剂采用LiCl；有机溶剂采用N,N-二甲基乙酰胺；偶联剂采用含氟硅烷偶联剂，本例具体为十七氟癸基三甲氧基硅烷；粘结剂采用分子量大于60万的均聚聚偏氟乙烯；稳定剂采用碳酸丙烯酯。本例的复合电池隔膜，其基膜采用深圳中兴创新材料技术有限公司制的厚度12μm的单层PP薄膜。
本例的复合电池隔膜的制备流程框图如图2所示，包括两大部分，第一，涂料的制备，在制备涂料之前，预先对间位芳酰胺纤维进行清洗，具体的，用高纯度丙酮对间位芳酰胺纤维进行洗涤，然后过滤烘干，尽量除去纤维上的杂质。其中，间位芳酰胺纤维的洗涤溶剂除了采用丙酮以外，还可以采用其它低沸点、低毒害的有机溶剂，选择的基本原则是不能溶解PMIA，而能够溶解合成PMIA的各种前驱体以及卤化物杂质等。制备涂料时，准备好，偶联剂、稳定剂 和粘结剂等助剂，将洗涤并烘干后的PMIA与碳酸镁按质量比1:5溶于N,N-二甲基乙酰胺中，并添加适量LiCl、含氟硅烷偶联剂和均聚聚偏氟乙烯，制备获得粘度为100CPs，固含量约50％的涂覆浆料，即本例的涂料。第二，即基膜涂覆，在基膜进行涂覆之前，如图2所示，在基膜放卷后，预先对其进行预热，然后再进行涂布、固化造孔、清洗、干燥、隔膜收卷，获得本例的复合电池隔膜。整套工艺设计成如图1所示的流水线模式，图1中，放卷的基膜是整卷预先预热的，因此，不需要防卷后再预热。
具体的，如图1所示，(A)涂覆，将本例制备的涂料，装入狭缝挤出涂布装置2中，预先预热的基膜通过放卷机1放卷，在经过狭缝挤出涂布装置2时，通过狭缝挤出涂布法，涂覆在PP薄膜的其中一个表面，PP薄膜与狭缝挤出涂布装置2之间设置间隙8μm。(B)涂覆完成后，PP薄膜先进入高温高湿箱3，采用高温高湿箱法，使耐高温树脂析出固化，成孔，具体的，将涂覆好的湿膜通过相对密闭的高温高湿箱3，其中的高温水汽的温度大于100℃，高温水汽由超声波振荡制造，喷洒量按照每平方米需要喷洒的膜的吸水量0.3～0.8mg计算；(C)清洗和干燥，将经过固化造孔工艺的膜体传输到清洗槽及烘箱段；其中，清洗槽6采用十八级纯水清洗槽，水槽中各级槽体内部联通，采用逆流进水法不断补充清洁水源，在进膜端设置水溢出口将混合液导走；出槽有机溶剂残留低于0.1％；清洗完成后，烘箱7采用60m的气浮式热风烘箱，出箱的隔膜水残留小于200PPm。最后采用收卷机8收卷，即获得本例的复合电池隔膜。
图1所示的流水线模式中，将本申请树脂析出固化的三种方法都设计在一起，即高温高湿箱法、高温水喷淋法和混合液凝固浴法，使用时，可以根据需要随意选择。如图1所示，在高温高湿箱3之后，在基膜的传送方向还设置有一个喷淋装置4，喷淋装置4设置于基膜的正上方，可以按照要求喷淋高温水，实现高温水喷淋法；在基膜的传送方向还设置有一个水浴池5，在水浴池5中可以按比例通入耐高温树脂的主溶剂和水，在设定的温度下进行水浴，实现混合液凝固浴法。可以理解，图1所示的流水线模式中三种方法是可以随意选择使用的；例如，选择高温高湿箱法时，可以停止喷淋装置4，将水浴池5中的溶液抽走；而选择高温水喷淋法时，高温高湿箱3则停止运行，其只是一段普通的箱体，同时也将水浴池5中的溶液抽走；选择混合液凝固浴法时，水浴池5中加入所需的溶液，而高温高湿箱3和喷淋装置4都停止运行即可；当然，在一些特殊生产中，也可以三种方法随意选择两种配合进行，在此不做具体限定。
对本例制备的复合电池隔膜进行厚度、孔隙率、透气性、离子导电率、氧化电位、闭孔温度、破膜温度等检测，并测试了复合电池隔膜分别在105℃和 150℃下60min的热收缩率TD/MD。以上各项检测和测试都采用本领域的常规测试方式，在此不做具体限定。测试结果如表1所示。
同时，将本例制备的复合电池隔膜裁切成44mm宽度，在全自动电池生产线上制成LP053450液态软包电池，设计容量1100mAh，电压体系4.35V。电池正极采用天津十八所研制的钴酸锂正极材料，实际碾压密度4.15mg/cm3；负极采用东莞BTR人造石墨，实际碾压密度1.71mg/cm3；电解液采用广州天赐TC-E231，注液量2.4g/Ah。
测试电池在未注液时1000V绝缘阻抗，以及500V交流漏电电流；测试电池的保液量、0.5C放电容量、满电电阻、满电厚度、60℃满电自衰K值、常规500次循环容量保有率、60℃恒温500次循环容量保有率、60min 150℃热箱中电池最高温度、Φ3mm针刺电池最高温度。以上各项测试都采用本领域的常规测试方式，在此不做具体限定。测试结果如表2所示。
实施例二
本例的涂料以及复合电池隔膜的制备与实施例一相同，复合电池隔膜所采用的基膜为深圳中兴创新材料技术有限公司制的厚度12μm的单层PP薄膜，除涂层固化造孔方案外，其余与实施例一都相同。
具体的，如图1所示，(A)涂覆，将本例制备的涂料，采用狭缝挤出涂布法，涂覆在PP薄膜的其中一个表面，并设置间隙8μm。(B)涂覆完成后，采用高温水喷淋法，固化成孔，高温水喷淋法具体包括，将涂覆好的湿膜通过喷淋口下方，采用70～100℃的热水对涂覆好的膜体进行均匀喷淋，喷淋后在涂覆层的表面形成水膜，喷淋的热水量按照所形成的水膜的厚度为0.05～0.15μm计算。(C)清洗和干燥，同实施例一。
之后对本例制备的电池隔膜进行各项检测，并将其制成电池进行各项相关检测，电池的制备与实施例一相同，测试项目和具体方法与实施例一相同，在此不累述，测试结果如表1和表2所示。
实施例三
本例的涂料以及复合电池隔膜的制备与实施例一相同，复合电池隔膜所采用的基膜为深圳中兴创新材料技术有限公司制的厚度12μm的单层PP薄膜，除涂层固化造孔方案外，其余与实施例一都相同。
具体的，如图1所示，(A)涂覆，将本例制备的涂料，采用狭缝挤出涂布法，涂覆在PP薄膜的其中一个表面，并设置间隙8μm。(B)涂覆完成后，采 用混合液凝固浴法固化成孔，混合液凝固浴法具体包括，将涂覆好的湿膜通过有机溶剂和水组成的混合溶液中，混合溶液中水含量大于50wt％，本例中浴液初始配比为DMAC：H2O＝45:55，而在连续生产中，通过精确计算溶剂引入量，同步调控加水量，始终控制水的含量在50％～60％之间；控制走带速度及凝固浴槽体长度，确保模体凝固浴时间在30～45S之间；控制混合溶液的温度为60～150℃。(C)清洗和干燥，同实施例一。
之后对本例制备的电池隔膜进行各项检测，并将其制成电池进行各项相关检测，电池的制备与实施例一相同，测试项目和具体方法与实施例一相同，在此不累述，测试结果如表1和表2所示。
实施例四
本例的涂料以及复合电池隔膜的制备与实施例一相同，只是复合电池隔膜所采用的基膜为深圳中兴创新材料技术有限公司制的厚度12μm的单层PE薄膜，其余与实施例一都相同。
同样的，对本例制备的电池隔膜进行各项检测，并将其制成电池进行各项相关检测，电池的制备与实施例一相同，测试项目和具体方法与实施例一相同，在此不累述，测试结果如表1和表2所示。
对比例一
本例直接采用深圳中兴创新材料技术有限公司制的厚度14μm的单层PP隔膜进行各项测试，同样也将其制备成电池，进行测试。PP隔膜的测试项目与实施例一相同，电池的制备及电池的测试也与实施例一相同，在此不累述。测试结果如表3和表4所示。
对比例二
本例直接采用深圳中兴创新材料技术有限公司制的厚度14μm的单层PE隔膜进行各项测试，同样也将其制备成电池，进行测试。PP隔膜的测试项目与实施例一相同，电池的制备及电池的测试也与实施例一相同，在此不累述。测试结果如表3和表4所示。
对比例三
本例直接采用深圳中兴创新材料技术有限公司制的厚度16μm的PP/PE/PP三层复合隔膜进行各项测试，同样也将其制备成电池，进行测试。其中，PP/PE/PP 三层复合隔膜中，各层的厚度分别为5/6/5。PP/PE/PP三层复合隔膜的各项测试，电池的制备，以及电池的各项测试与实施例一相同，在此不累述。测试结果如表3和表4所示。
对比例四
本例采用与实施例一相同的深圳中兴创新材料技术有限公司制的厚度12μm的单层PP薄膜作为基膜，在基膜的一个表面进行陶瓷涂层涂覆，获得本例的复合隔膜。
本例的陶瓷涂层，采用悬浮液总重量的44％的Al2O3、2％的丙烯酸酯类粘结剂、0.8％的增稠剂、0.5％的分散剂、0.1％的消泡剂以及分散助剂，于水中均匀分散制成稳定的悬浮液，使用微凹版涂布方式，均匀涂覆于PP薄膜的一个表面，再通过长度为15m温度在30℃～60℃之间的多级烘箱烘干，形成厚度为2-3μm的陶瓷涂层，即获得本例的复合隔膜。其中，本例采用的Al2O3，其D50小于0.8μm、D90小于1.3μm、纯度大于99.99％。
同样，对制备的复合隔膜进行与实施例一相同的各项测试，并将其制备成电池，测试电池的各项性能，电池的制备和测试项与实施例一相同，在此不累述。测试结果如表3和表4所示。
对比例五
本例采用与实施例四相同的深圳中兴创新材料技术有限公司制的厚度12μm的单层PE薄膜作为基膜，在基膜的一个表面进行陶瓷涂层涂覆，获得本例的复合隔膜。
本例的陶瓷涂层与对比例四相同，采用相同的悬浮液和涂层制备方法，形成本例的复合隔膜。
同样，对制备的复合隔膜进行与实施例一相同的各项测试，并将其制备成电池，测试电池的各项性能，电池的制备和测试项与实施例一相同，在此不累述。测试结果如表3和表4所示。
表1  实施例制备隔膜的各项测试结果
Figure PCTCN2015098771-appb-000001
Figure PCTCN2015098771-appb-000002
表2  实施例制备电池的各项测试结果
Figure PCTCN2015098771-appb-000003
Figure PCTCN2015098771-appb-000004
表3  对比例制备隔膜的各项测试结果
Figure PCTCN2015098771-appb-000005
表4  对比例制备电池的各项测试结果
Figure PCTCN2015098771-appb-000006
Figure PCTCN2015098771-appb-000007
从表1至表4的结果可以看出，本申请实施例制备的电池隔膜，在保持闭孔温度不变的情况下，破膜温度大大提高，提高了隔膜的耐高温性能和阻燃性；而吸液率和保液率都有不同程度的提高。此外，采用本申请电池隔膜的电池，其常规500次循环的容量保有，以及60℃恒温500次循环容量保有率，都较对比例有所提高。总的来说，本申请的复合电池隔膜离子电导率高、电化学稳定性强、物理强度高、厚度膨胀率低，保液能力强，其优秀的电化学稳定性和物理强度，使得本申请的复合电池隔膜即使在大倍率、高低温等各种循环环境中仍能保持极佳的稳定性；从而大大提高了电池的使用寿命。
在以上实施例的基础上，本申请进一步对不同的耐高温树脂、树脂助溶剂、有机溶剂、稳定剂和粘结剂等进行了试验。结果显示，其中，分子量20万至100万的间位芳酰胺纤维效果更佳，除了间位芳酰胺纤维以外，其它的耐高温树脂，如聚酰亚胺、聚醚砜、聚醚醚酮、对位芳酰胺纤维、聚四氟乙烯，以及这些树脂的衍生物、共聚物或混合物，都可以用于本申请。树脂助溶剂除了LiCl以外，还可以使用CaCl2。有机溶剂除了N,N-二甲基乙酰胺以外，还可以使用N-甲基吡咯烷酮、N,N-二甲基甲酰胺或四氢呋喃。偶联剂可以使用含氟硅烷偶联剂。稳定剂除了碳酸丙烯酯以外，还可以使用磷酸苯酯、三丙二醇、乙二醇或纤维素钠。粘结剂除聚偏氟乙烯以外，还可以采用聚偏氟乙烯共聚物、硅橡胶、硅橡胶衍生物、聚丙烯酸酯类、聚酰亚胺类和环氧树脂类。此外，根据对耐高温树脂和碳酸镁不同用量的试验，结果显示，耐高温树脂的含量为总重量的2～10％，碳酸镁的含量为总重量的20～80％，涂料的粘度为20～200CPs，固含量为15～70％，都可以达到本申请实施例相当的效果，制备出离子电导率高、电化学稳定性强、物理强度高、厚度膨胀率低，保液能力强的复合电池隔膜。
以上内容是结合具体的实施方式对本申请所作的进一步详细说明，不能认定本申请的具体实施只局限于这些说明。对于本申请所属技术领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干简单推演或替换，都应当视为属于本申请的保护范围。

Claims (10)

  1. 一种用于电池隔膜的涂料，其特征在于：所述涂料的主要成份包括耐高温树脂、碳酸镁、树脂助溶剂和有机溶剂；
    所述耐高温树脂为聚酰亚胺、聚醚砜、聚醚醚酮、间位芳酰胺纤维、对位芳酰胺纤维、聚四氟乙烯及其衍生物、共聚物或混合物中的至少一种；
    所述树脂助溶剂为碱金属或者碱土金属的强酸盐类；
    所述有机溶剂为N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺和四氢呋喃中的至少一种；
    所述涂料中耐高温树脂的含量为总重量的2～10％，碳酸镁的含量为总重量的20～80％，涂料的粘度为20～200CPs，固含量为15～70％。
  2. 根据权利要求1所述的涂料，其特征在于：所述耐高温树脂为分子量20万至100万的间位芳酰胺纤维。
  3. 根据权利要求1所述的涂料，其特征在于：所述树脂助溶剂为CaCl2或LiCl，优选的树脂助溶剂为LiCl。
  4. 根据权利要求1所述的涂料，其特征在于：所述有机溶剂为N-甲基吡咯烷酮或N,N-二甲基乙酰胺。
  5. 根据权利要求1-4任一项所述的涂料，其特征在于：所述涂料还包括偶联剂、稳定剂和粘结剂；
    优选的，所述偶联剂为含氟硅烷偶联剂中的至少一种，所述稳定剂为碳酸丙烯酯、磷酸苯酯、三丙二醇、乙二醇和纤维素钠中的至少一种，所述粘结剂为聚偏氟乙烯、聚偏氟乙烯共聚物、硅橡胶、硅橡胶衍生物、聚丙烯酸酯类、聚酰亚胺类和环氧树脂类中的至少一种。
  6. 一种复合电池隔膜，包括基膜和涂覆于基膜的至少一个表面的涂层，其特征在于：所述涂层由权利要求1-5任一项所述的涂料涂覆而成。
  7. 根据权利要求6所述的复合电池隔膜，其特征在于：采用示差扫描量热法分析，所述复合电池隔膜在100～220℃间有1-3个吸热峰，并且在380～420℃有明显的吸热峰。
  8. 根据权利要求6或7所述的复合电池隔膜的制备方法，其特征在于：包括以下步骤，
    (A)涂覆：将权利要求1-5任一项所述的涂料涂覆于基膜表面；
    (B)涂层的固化和造孔：将涂覆好的基膜置于水和温热环境下，使耐高温树脂析出固化，同时，碳酸镁与水反应生成氢氧化镁沉淀，并释放二氧化碳，形成微孔；
    (C)清洗和干燥：对步骤(B)的产物进行水浴清洗，然后在40～100℃下 干燥，即获得所述复合电池隔膜。
  9. 根据权利要求8所述的制备方法，其特征在于：所述步骤(B)中，使耐高温树脂析出固化的具体方法为高温高湿箱法、高温水喷淋法和混合液凝固浴法中的至少一种；
    所述高温高湿箱法包括，将涂覆好的基膜置于高温的密闭箱体中，并向基膜喷洒高温水汽，其中密闭箱体中的高温水汽的温度大于100℃，高温水汽的喷洒量按照每平方米需要喷洒的基膜的吸水量大于0.3mg计算；
    所述高温水喷淋法包括，采用70～100℃的热水对涂覆好的基膜进行均匀喷淋，喷淋后在涂覆层的表面形成水膜，喷淋的热水量按照所形成的水膜的厚度为0.05～0.15μm计算；
    所述混合液凝固浴法包括，将涂覆好的基膜浸泡于所采用的耐高温树脂的有机溶剂和水组成的混合溶液中，混合溶液中水含量大于50wt％，混合溶液的温度为60～150℃。
  10. 根据权利要求9所述的制备方法，其特征在于：所述混合液凝固浴法中，混合溶液的水含量为50～70wt％，混合溶液的温度为70～100℃；所述高温高湿箱法中，高温水汽的喷洒量为按照每平方米需要喷洒的基膜的吸水量为0.5～1mg计算。
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CN116238174A (zh) * 2023-02-27 2023-06-09 海卓迈博(苏州)新材料有限公司 一种连续化制备碱性电解水复合膜的方法

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