CN114597587A - Aramid fiber coated diaphragm and preparation method thereof - Google Patents

Aramid fiber coated diaphragm and preparation method thereof Download PDF

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Publication number
CN114597587A
CN114597587A CN202210268442.9A CN202210268442A CN114597587A CN 114597587 A CN114597587 A CN 114597587A CN 202210268442 A CN202210268442 A CN 202210268442A CN 114597587 A CN114597587 A CN 114597587A
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temperature
thick film
wind speed
extraction
aramid
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Chinese (zh)
Inventor
周阳
刘杲珺
董浩宇
李论
董秋春
高飞飞
杜敬然
杨冬梅
白耀宗
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Sinoma Lithium Film Co Ltd
China National Building Material Group Co Ltd CNBM
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Sinoma Lithium Film Co Ltd
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Priority to CN202210268442.9A priority Critical patent/CN114597587A/en
Publication of CN114597587A publication Critical patent/CN114597587A/en
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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
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H01M50/406—Moulding; Embossing; Cutting
    • 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/423—Polyamide resins
    • 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
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • 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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/494—Tensile strength
    • 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

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Cell Separators (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for preparing an aramid fiber coating diaphragm by a wet method and the aramid fiber coating diaphragm prepared by the method. The method comprises the following steps: melting and extruding the polyolefin composition, filtering, extruding and plasticizing, and cooling a casting sheet; then carrying out biaxial tension and trimming to obtain a thick film; coating aramid fiber slurry on the thick film; and extracting, drying and transversely stretching the coated thick film. The method provided by the invention can improve the production efficiency of the coating film and reduce the equipment investment.

Description

Aramid fiber coated diaphragm and preparation method thereof
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for preparing an aramid fiber coating diaphragm by a wet method and the aramid fiber coating diaphragm prepared by the method.
Background
With the development of a new energy market, power automobiles pay more attention to safety, endurance mileage and other indexes, and from the viewpoint of safety, a diaphragm needs to have higher puncture strength, low obturator temperature and high rupture temperature, and the endurance mileage needs to improve the energy density of a power battery, so that the diaphragm needs to be thinner and the coating needs to be lighter.
At present, although the conventional performance that lithium ion battery needs can be satisfied to current diaphragm on the market, under higher temperature environment, the base film takes place large tracts of land heat shrink easily, and ceramic coating membrane has higher heat stability, but in case pierced through, broken hole can enlarge rapidly and lead to positive negative pole contact short circuit, appears the incident. In addition, the energy density of the domestic power lithium battery is lower at present, and the endurance mileage of the new energy automobile is limited.
Aramid fiber has the advantages of excellent high-temperature resistance, mechanical property, flame resistance, chemical corrosion resistance, light weight and the like, so that the aramid fiber has wide attention of diaphragm industry people, and a lithium ion battery diaphragm obtained by using the aramid fiber as a coating material has better thermal stability and lower surface density, and can effectively solve the problems of safety and energy density of a power battery.
The existing aramid fiber coating diaphragm needs to prepare a micropore base film firstly, and then aramid fiber slurry is coated on the micropore base film to form a coating layer. The process mainly comprises the following steps: firstly, polyolefin powder, additives and the like are fed, melted and extruded, and then the microporous base membrane is formed through sheet casting, stretching, extraction, stretching, rolling and slitting; before coating aramid slurry, a microporous base membrane needs to be unreeled, pretreated, then coated, extracted, washed, dried, heat-set and the like. The preparation process has the disadvantages of complicated steps, high equipment investment and low production efficiency of coating the diaphragm. In response to these problems, there is a need to develop a new aramid coated membrane preparation process.
Disclosure of Invention
The invention aims to provide a method for preparing an aramid fiber coated membrane by a wet method and the aramid fiber coated membrane prepared by the method. The method provided by the invention can improve the production efficiency of the coating film and reduce the equipment investment.
In a first aspect, the present invention provides a method for preparing an aramid coated membrane by a wet process, comprising:
(1) performing melt extrusion, filtration and extrusion plasticization on the polyolefin composition to obtain a sheet-shaped substrate; wherein the polyolefin composition comprises a polyolefin resin, a pore former, and an antioxidant;
(2) cooling the sheet substrate cast sheet;
(3) performing biaxial tension on the cooled base material, and cutting edges to obtain a thick film;
(4) coating aramid fiber slurry on the thick film;
(5) extracting and drying the coated thick film;
(6) and stretching the dried thick film in the transverse direction.
In a second aspect, the present invention provides an aramid coated membrane prepared by the method of the first aspect of the invention.
Compared with the existing preparation process, the method provided by the invention has the following advantages:
1) effectively improving the coating productivity: directly introducing a coating process on the production procedure of the base film, and forming at one time; the existing process adopts a two-step method, namely, microporous base films are respectively prepared and then coated on the microporous base films by a coating machine. Compared with a two-step method, the method can realize coating on a wider base film, which is more than multiple times of the effective width of a conventional coating machine;
2) the cost of investment equipment is reduced: the method effectively combines the preparation of the base film and the aramid fiber coating process, can reduce related procedures such as base film extraction, base film unreeling and the like, and obviously reduces the cost investment of related equipment.
In addition, compared with the aramid fiber coating film prepared by the existing two-step method, the aramid fiber coating film prepared by the method has higher tensile strength.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
Exemplary embodiments of the present invention will be described in more detail by referring to the accompanying drawings.
FIG. 1 is a schematic view of a coating apparatus according to an embodiment of the present invention.
Fig. 2 is a process flow diagram of a wet process for preparing an aramid coated membrane according to one embodiment of the present invention.
Fig. 3 is a flow chart of a conventional process for producing a base film.
Fig. 4 is a flow chart of a conventional process for preparing an aramid coated membrane by coating slurry on a base film.
Description of the reference numerals
1: a thick film; 2: a first drive guide roller; 3: a second transmission guide roller; 4: a third transmission guide roller; 5: oil removing press rolls; 6: a backing roll; 7: a slot die head; 8: a feed conduit.
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
In a first aspect, the present invention provides a method for preparing an aramid coated membrane by a wet process, comprising:
(1) performing melt extrusion, filtration and extrusion plasticization on the polyolefin composition to obtain a sheet-shaped substrate; wherein the polyolefin composition comprises a polyolefin resin, a pore former, and an antioxidant;
(2) cooling the sheet substrate cast sheet;
(3) performing biaxial tension on the cooled base material, and cutting edges to obtain a thick film;
(4) coating aramid fiber slurry on the thick film;
(5) extracting and drying the coated thick film;
(6) and stretching the dried thick film in the transverse direction.
In the present invention, the polyolefin composition comprises a polyolefin resin, a pore-forming agent and an antioxidant.
The polyolefin resin may be selected from polyethylene, polypropylene. Preferably, the polyolefin resin is ultra-high molecular weight polyethylene (UHMWPE).
The pore former may be selected from liquid or solid hydrocarbons capable of forming a homogeneous mixture with the polyolefin resin above the melting point, and the like, and may be, for example, white oil, paraffin oil, and the like. Preferably, the pore former is a paraffinic oil. The viscosity of the paraffin oil may be 30-70mm2/s。
The antioxidant can improve the thermal stability of the polyolefin resin. The antioxidant can be selected from pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1010), tris (2, 4-di-tert-butylphenyl) phosphite (antioxidant 168), preferably antioxidant 1010.
In one embodiment, the mass ratio of the polyolefin resin to the pore-forming agent is 1: (2-5), and the antioxidant is present in an amount of 0.1-0.5 wt%, based on the total weight of the polyolefin resin and the pore-forming agent.
The method provided by the invention belongs to a process for producing aramid fiber coated membranes by a wet method, and can be implemented on the existing wet-method stretching production line unless otherwise specified (such as an oil removing device), wherein the production line generally comprises: the device comprises a feeding and proportioning unit, an extrusion mixing unit, a cast sheet cooling unit, a biaxial stretching unit, a winding unit and a slitting unit, which are specifically set as well known in the field. The supporting equipment of the wet diaphragm production line can be purchased from Essopu, Toshiba, Steel works, Brukna, Germany, and Union of China.
According to one embodiment, the dosing unit comprises a metering system, a twin-screw extruder provided with a plurality of oil filling openings, a gear pump, a filtering device and a die. The step (1) comprises the following steps: adding polyolefin resin (powder) and an antioxidant into a double-screw extruder, adding a pore-forming agent into the double-screw extruder from an oil filling port arranged on the double-screw extruder, carrying out melt extrusion to a gear pump, and extruding to a filtering device; and extruding the mixture to a die to form the sheet-shaped base material. The melt extrusion can sufficiently mix the components in the polyolefin composition, and can improve the stability of the subsequent extrusion process. Preferably, the melt extrusion conditions include: the temperature is 160 ℃ and 200 ℃, and the rotating speed is 40-70 rpm. The gear pump can reduce the shearing and residence time of materials in the extruder, and the rotating speed of the gear pump can be 70-100 rpm. The filtering device can remove impurities in the melt and improve the uniformity of the melt. According to a preferred embodiment, the conditions of extrusion to the filtering means comprise: the pressure is 3-7MPa, and the temperature is 200-230 ℃. The conditions for extrusion into the die include: the pressure is 2-5MPa, and the temperature is 220-240 ℃.
According to the present invention, in step (2), the melt of the polyolefin composition can be quenched by cooling the cast sheet to cause thermally-induced phase separation of the pore former from the polyolefin while allowing a large portion of the pore former to be locked in the slab. Preferably, the platy substrate is cooled to 8-15 ℃ using a cooling die machine.
According to the invention, step (3) comprises: and (3) feeding the cooled flaky substrate into a biaxial stretching unit, sequentially carrying out preheating, biaxial stretching, sizing and cooling, and then cutting edges through a tractor. The biaxial stretching can make the molecular chain of the polyolefin oriented in longitudinal and transverse directions, and the pore agent is uniformly distributed in the polyolefin. In a preferred embodiment, the stretch ratio in the transverse direction is 5 to 9, and the stretch ratio in the longitudinal direction is 5 to 9 (e.g., 7 in both the transverse direction and the longitudinal direction); the preheating temperature is 100-130 ℃ (such as 122 ℃), and the wind speed is 15-30m/s (such as 25 m/s); the stretching temperature is 100-130 ℃ (such as 119 ℃), and the wind speed is 15-30m/s (such as 28 m/s); the setting temperature is 110-130 ℃ (117 ℃) and the wind speed is 15-30m/s (22 m/s); the cooling temperature is 15-40 deg.C (such as 30 deg.C), and the wind speed is 15-30m/s (such as 25 m/s).
According to the invention, step (4) is preferably carried out in a coating apparatus. The coating apparatus includes: tension cuts off mechanism, deoiling mechanism and coating mechanism. As shown in fig. 1, the tension separation mechanism includes a first transmission guide roller 2 and a second transmission guide roller 3; the coating mechanism comprises a back roll 6, a narrow-slit die head 7 and a feeding pipeline 8; the second transmission guide roller 3 is arranged above the first transmission guide roller 2, and the narrow-slit die head 7 is arranged above the back roller 6. Thick film 1 along first drive deflector roll 2 conveys to on the second drive deflector roll 3, convey through deoiling mechanism and backing roll 6 in proper order, in the data send process, after detaching partial pore-forming agent through deoiling mechanism, charge-in pipeline 8 pours into aramid fiber thick liquids into slot formula die head 7, thereby will aramid fiber thick liquids coating is on thick film 1. According to a preferred embodiment, the oil removing mechanism comprises a third transmission guide roller 4 and an oil removing press roller 5, the third transmission guide roller 4 is positioned below the oil removing press roller 5, and the tops of the second transmission guide roller 3, the third transmission guide roller 4 and the back roller 6 are positioned on the same horizontal line. In this embodiment, thick film 1 conveys to second transmission deflector roll 3 along first transmission deflector roll 2, passes through in proper order third transmission deflector roll 4 and backing roll 6 convey, and in the conveying, deoiling compression roller 5 exerts pressure (for example 1-100N)) in order to remove some pore-forming agent, injects aramid fiber thick liquids into slot die head 7 through charge-in pipeline 8 after, will aramid fiber thick liquids coat on thick film 1 through the die lip of slot die head 7, again through backing roll 6 transmission to extraction washing unit. Deoiling compression roller 5 is equipped with the cylinder, provides the contact extrusion force, and deoiling compression roller 5 gets rid of unnecessary pore-forming agent in thick film 1 (oil film) under the combined action of third transmission deflector roll 4, avoids leading to aramid coating directly to scribble on the pore-forming agent because of the adhesion of pore-forming agent. According to another embodiment, the oil removing mechanism comprises two vacuum adsorption rollers which respectively replace the third transmission guide roller 4 and the oil removing press roller 5 shown in fig. 1 and absorb the pore-forming agent on the film through negative pressure.
In one embodiment, the aramid pulp comprises aramid dope and ceramic powder. Preferably, the aramid raw liquid is a para-aromatic polyamide raw liquid, and the content of the para-aromatic polyamide in the raw liquid is 1-5 wt%. The median particle size (D50) of the ceramic powder is 100-500 nm. The solvent in the aramid dope may be selected from at least one of N-methylpyrrolidone (NMP), dimethyl sulfoxide, N-dimethylformamide, N-Dimethylacetamide (DMAC), tetramethylurea, and acetone, and is preferably selected from N-methylpyrrolidone or N, N-dimethylacetamide.
Preferably, the content of the para-aromatic polyamide is 0.9-5 wt% and the content of the ceramic powder is 1-10 wt% based on the total weight of the aramid pulp.
According to the invention, the extraction of step (5) is carried out in an extraction apparatus. The extractant may be an oily solvent, for example, one or more selected from dichloromethane, chloroform, 1, 1, 1-trichloroethane, hydrofluoroether, hydrofluorocarbons, pentane, hexane, heptane, methanol, ethanol, isopropanol, tripropylene glycol, acetone, methyl ethyl ketone, N-methylpyrrolidone, diethyl ether, tetrahydrofuran, 1, 4-dioxane, N-dimethylformamide, N-dimethylacetamide, toluene and xylene; preferably, dichloromethane or the combination of dichloromethane and the other oily solvents (such as NMP or DMAC) is adopted, compared with the existing aramid fiber coating film which is extracted by water, dichloromethane is more easily heated and volatilized, the drying temperature can be reduced, and the energy consumption can be saved. Methylene dichloride can be used as an extractant of a base film (a film formed by the polyolefin composition), and the base film extractant can be directly used for mixed extraction without introducing other substances.
According to a preferred embodiment, the extraction apparatus comprises 3 to 9 extraction cells (e.g. 5, 7 or 8). The extractant in each extraction tank is dichloromethane.
According to another preferred embodiment, the extraction plant comprises 3 to 9 extraction tanks (e.g. 5, 7 or 8). According to the transmission direction of the thick film, the first two extraction tanks comprise the extractant with concentration gradient, and the extractant in the rest extraction tanks is dichloromethane. The concentration gradient extractant is selected from dichloromethane and NMP. More preferably, the NMP in the first extraction tank is 35-80% by volume and the NMP in the second extraction tank is 40-60% by volume of the NMP in the first extraction tank.
According to an implementation mode, the extraction tank device further comprises a liquid injection pump and an overflow liquid discharge pump, the extraction tank can adopt an overflow liquid adding mode, liquid injection and liquid supplement ports are arranged in the last extraction tank according to the flowing direction of the thick film, an overflow tank is arranged in the first extraction tank, liquid level control is arranged, and the liquid injection pump or the overflow liquid discharge pump is controlled to be started and stopped respectively according to the tank overflow liquid level heights of the last extraction tank and the first extraction tank.
In the step (5), the drying temperature may be 40 to 60 ℃. The coating micropores are formed by extraction and drying.
Optionally, the method of the present invention further comprises: and (5) sending the extraction mixed liquid obtained after extraction in the step (5) to a recovery collection tank for recovery.
According to the invention, step (6) comprises: and (3) feeding the dried thick film into a transverse drawing heat treatment unit, preheating, transversely stretching, shrinking, performing first shaping (transverse spreading), and then performing transverse and longitudinal shrinking and second shaping (micro shrinking). Preferably, in transverse tentering, the transverse stretching magnification is 1.1 to 2 times; the preheating temperature is 110-140 ℃ (such as 127 ℃), and the wind speed is 15-30m/s (such as 25 m/s); the stretching temperature is 110-140 ℃ (such as 125 ℃), and the wind speed is 15-30m/s (such as 28 m/s); the contraction temperature is 110-140 ℃ (such as 128 ℃), and the wind speed is 15-30m/s (such as 28 m/s); the temperature of the first shaping is 110-140 ℃ (such as 135 ℃), and the wind speed is 15-30m/s (such as 22 m/s). In the micro-shrinkage, the shrinkage in the Transverse Direction (TD) is 1-10%, the shrinkage in the Machine Direction (MD) is 1-10%, and the temperature for the second setting is 110-.
According to a more specific embodiment, as shown in fig. 2, the method of the present invention comprises the following steps:
s1: feeding and extruding
Adding polyethylene powder and an antioxidant into a double-screw extruder through a metering system, adding a pore-forming agent into the double-screw extruder from a plurality of oil filling ports on the double-screw extruder through a metering pump according to a set temperature, and performing melt extrusion to a gear pump at the set temperature and the set rotating speed; extruding the mixture to a filtering device under certain pressure and temperature; extruding the mixture into a die to form the flaky base material under certain pressure and temperature.
S2: casting sheet and double-drawing
Cooling the flaky substrate by using a cooling sheet casting machine, feeding the cooled sheet into a bidirectional synchronous drawing unit, and carrying out preheating, drawing, shaping, cooling and other steps to prepare a thick film with required thickness and width under the conditions of set temperature and wind speed.
S3: coating of
The thick film was trimmed by a tractor and fed to the coating apparatus shown in fig. 1. Specifically, thick film 1 carries out "S" type transmission through first transmission deflector roll 2, second transmission deflector roll 3 earlier, cuts off tension, removes the unnecessary pore-forming agent in thick film surface through third transmission deflector roll 4, deoiling compression roller 5, and aramid fiber thick liquids are injected into slot type die head 7 to feed pipe 8, and aramid fiber thick liquids are coated on thick film 1 through the die lip, and then are transmitted to extraction washing unit through backing roll 6.
S4: extraction of
And (3) the coated thick film enters an extraction tank filled with an extracting agent to extract the pore-forming agent in the oil film and the solvent in the slurry, and the extraction tank device adopts a combined type and comprises n (n is an integer selected from 3-9) extraction tanks which are marked as 1# to n # extraction tanks according to the transmission direction of the thick film. An n # → 1# extraction tank adopts an overflow liquid adding mode, liquid injection and liquid supplement ports are arranged in the n # tank, and an extracting agent is supplemented; the overflow launder is set up in the 1# groove, and liquid level control is all established to each extraction tank, controls the liquid charge pump or overflow positive displacement pump respectively to open and stop according to n # groove, 1# groove overflow liquid level height, and wherein the overflow is arranged flowing back to follow-up liquid phase recovery unit (including retrieving collection tank) and is handled. The flow rate of each tank circulating pump is set to be 30-50m3And h, continuously cleaning an oil film in the extraction tank through a W-shaped path, discharging an extraction mixed solution to a recovery collection tank through the No. 1 tank, and drying an extracted thick film.
S5: horizontal pulling
The dried thick film enters a transverse drawing heat treatment unit to be subjected to steps of preheating, stretching, shrinking, shaping and the like, micro transverse amplitude expansion is carried out under the conditions of set temperature and wind speed, and then transverse and longitudinal micro shrinkage and shaping are carried out to obtain a microporous film (thin film);
s6: rolling and slitting
The film is wound in low tension after being trimmed by a tractor and then is cut by a splitting machine.
The scheme shown in figure 2 is carried out on a lithium battery separator production line of isospap, france, unless otherwise specified.
In a second aspect, the present invention provides an aramid coated membrane prepared by the method of the first aspect of the invention. In the method, the aramid fiber is secondarily stretched along with the thick film, so that the orientation of the aramid fiber after stretching is more consistent, and the aramid fiber coating membrane has higher tensile strength.
The present invention will be further described with reference to the following examples, but the scope of the present invention is not limited to these examples.
In the following examples and comparative examples, the polyethylene powder was Ultra High Molecular Weight Polyethylene (UHMWPE) available from selanies under the designation GUR 2122; paraffin oil No. 45, purchased from Zhejiang Zhenjin; the antioxidant is antioxidant 1010, purchased from Basff; the aramid fiber stock solution is purchased from Mitsui Chemicals design institute, Inc. under the trademark T3 (para-aromatic polyamide stock solution, polymer content 3 wt%, solvent NMP); ceramic powder (D50 ═ 400nm) available from suzhou brocade new materials science and technology ltd.
The preparation method of the aramid fiber slurry comprises the following steps: and (2) adding 5 parts by weight of ceramic powder into the aramid fiber stock solution (95 parts by weight) for high-speed dispersion, and filtering the dispersed mixed solution (a 400# filter screen) to obtain the aramid fiber slurry.
Comparative example 1
(1) Production process of base film
The base film is produced with reference to the flow shown in fig. 3.
1) Feeding and extruding
Adding 25 parts by weight of polyethylene powder and 0.3 part by weight of antioxidant into a double-screw extruder through a metering system, simultaneously adding 75 parts by weight of paraffin oil into the double-screw extruder from a plurality of oil filling ports (70 percent of a first oil filling port, 20 percent of a second oil filling port and 10 percent of a third oil filling port) set on the double-screw extruder through a metering pump at a set temperature (110 ℃), and performing melt extrusion to a gear pump at a set temperature and a set rotating speed (180 ℃, 60rpm), wherein the rotating speed of the gear pump is 85 rpm; extruding the mixture into a filtering device under the pressure of 5.5MPa and the temperature of 215 ℃, and extruding the mixture into a die to form a flaky substrate under the pressure of 4MPa and the temperature of 225 ℃.
2) Casting sheet and double-drawing
The sheet substrate was cooled to 12 ℃ using a cooling die machine. The cooled sheet (the thickness is 1300 mu m, the width is 650mm) enters a bidirectional synchronous drawing unit (the bidirectional drawing multiplying power is 7 times), and is sequentially subjected to preheating, bidirectional drawing, shaping and cooling (the preheating is carried out at 122 ℃, the wind speed is 25m/s, the drawing is carried out at 119 ℃, the wind speed is 28m/s, the shaping is carried out at 117 ℃, the wind speed is 22m/s, the cooling is carried out at 30 ℃, the wind speed is 25m/s), and a thick film with the thickness of 30 mu m and the width of 4550mm is prepared.
3) Extraction of
The thick film is through the tractor side cut (thickness 30 mu rn, width 4300mm), later the entering extraction tank that is equipped with the dichloromethane (including 8 extraction tanks altogether of 1# to 8 #), extract out the paraffin oil in the membrane, and 8# to 1# extraction tank adopt the overflow liquid feeding mode, annotate the liquid, the fluid infusion mouth sets up at 8# groove, 1# inslot sets up the overflow launder, all establish liquid level control, according to 8# groove, 1# groove overflow liquid level height controls notes liquid pump or overflow positive displacement pump respectively and stops, wherein the overflow is discharged liquid to follow-up liquid phase recovery unit and is handled. Flow setting of 35m for each tank circulating pump3And h, continuously cleaning the oil membrane in the extraction tank through a W-shaped path, discharging the extraction mixed liquor to a recovery collection tank through a No. 1 tank, and drying the membrane at 45 ℃.
4) Horizontal pulling
The dried film (thickness 12 μm, width 3150mm) enters a transverse drawing heat treatment unit to be subjected to steps of preheating, stretching, shrinking, first sizing and the like, micro transverse width expanding (stretching multiplying power is 1.5 times) is carried out under the conditions of set temperature and set wind speed (preheating is 127 ℃, wind speed is 25m/s, stretching is 125 ℃, wind speed is 28m/s, shrinking is 128 ℃, wind speed is 28m/s, first sizing is 135 ℃, wind speed is 22m/s), and then micro shrinkage (TD direction, shrinkage is 10%, MD direction, shrinkage is 10%) and second sizing (temperature is 130 ℃) are carried out to obtain the film (microporous film).
5) Rolling and slitting
The microporous membrane is cut by a tractor, wound at low tension (winding tension of 8N/m), and then cut into required breadth by a splitting machine for winding (the breadth after cutting is 840 mm).
(2) Aramid fiber coating process
The coating is carried out with reference to the flow shown in fig. 4.
1) Unreeling and coating
Unreeling the cut base film again, feeding the base film into a diaphragm coating unit, and coating aramid fiber slurry on one surface of the base film by using a T-shaped narrow slit type coating mechanism;
2) extracting and drying
The obtained coating film is pre-coagulated in a coagulation bath with concentration gradient (the coagulation bath consists of NMP and water, the volume concentration of the NMP is 40 percent and 20 percent respectively), aramid fibers in the coating are gradually precipitated to form a three-dimensional network structure, and the NMP in the coating is dissolved in the coagulation bath and is slowly replaced. And (3) putting the coating film pre-coagulated by the coagulating bath into the remaining 6 water tanks, fully eluting the residual NMP, and then putting the residual NMP into an oven to be dried at 85 ℃. And (4) carrying out heat treatment on the dried aramid fiber coating membrane at 120 ℃.
3) Rolling and slitting
And collecting the heat-set coating film into a coil and slitting.
The following example illustrates the method of the present invention for wet-preparing an aramid coated separator with reference to fig. 1 and 2.
Example 1
Adding 25 parts by weight of polyethylene powder and 0.3 part by weight of antioxidant into a double-screw extruder through a metering system, simultaneously adding 75 parts by weight of paraffin oil into the double-screw extruder from a plurality of oil filling ports (the first oil filling port is 70 percent, the second oil filling port is 20 percent and the third oil filling port is 10 percent) set on the double-screw extruder through a metering pump at a set temperature (110 ℃), and performing melt extrusion to a gear pump at the set temperature and the set rotating speed (180 ℃, 60rpm), wherein the rotating speed (85rpm) of the gear pump is high; and extruded to a filter unit under a pressure of 5.5MPa and a temperature of 215 ℃ and then extruded to a die under a pressure of 4MPa and a temperature of 225 ℃ to form a sheet-like substrate.
The sheet substrate was cooled to 12 ℃ using a cooling die machine. The cooled sheet (the thickness is 1300 mu m, the width is 650mm) enters a bidirectional synchronous drawing unit (the bidirectional drawing multiplying power is 7 times), and is subjected to the steps of preheating, drawing, shaping, cooling and the like to prepare a thick film with the thickness of 30 mu m and the width of 4550mm under the conditions of set temperature and set wind speed (preheating is 122 ℃, the wind speed is 25m/s, drawing is 119 ℃, the wind speed is 28m/s, shaping is 117 ℃, the wind speed is 22m/s, cooling is 30 ℃, and the wind speed is 25 m/s).
The thick film is trimmed by a tractor (the thickness is 30 mu m, and the width is 4300mm), enters a coating device shown in figure 1, the pressure of an oil removing press roller is controlled to be 25N to remove redundant paraffin oil, and aramid pulp is coated on the thick film (oil film).
The coated thick film enters an extraction tank filled with dichloromethane and NMP to extract paraffin oil in an oil film and NMP in slurry, and the extraction tank device adopts a combined type (comprising 8 extraction tanks from 1# to 8 #). The 8# → 1# extraction tank adopts the overflow liquid feeding mode, annotates liquid, the fluid infusion mouth sets up in 8# groove, mends the dichloromethane, sets up the overflow launder in the 1# groove, all establishes liquid level control, and 1# groove NMP volume concentration sets up at 40%, and 2# groove NMP volume concentration sets up 20%, and all the other grooves are dichloromethane. And respectively controlling the start and stop of a liquid injection pump or an overflow liquid discharge pump according to the overflow liquid level heights of the 8# groove and the 1# groove, wherein the overflow liquid is discharged to a subsequent liquid phase recovery tank for collection and treatment. Flow setting of 35m for each tank circulating pump3And h, continuously cleaning the oil membrane in the extraction tank through a W-shaped path, discharging the extraction mixed liquor to a recovery collection tank through a No. 1 tank, and drying the membrane at 45 ℃.
The dried thick film (thickness is 16 mu m, width is 3200mm) enters a transverse drawing heat treatment unit to be subjected to preheating, transverse drawing, shrinking and first shaping steps, micro transverse expanding (drawing multiplying power is 1.5 times) is carried out at set temperature and wind speed (preheating is 127 ℃, wind speed is 25 m/s; drawing is 125 ℃, wind speed is 28 m/s; shrinking is 128 ℃, wind speed is 28 m/s; first shaping is 135 ℃, wind speed is 22m/s), transverse and longitudinal micro shrinking (TD direction, shrinking 10%, MD direction, shrinking 10%) and second shaping (temperature is 130 ℃) are carried out to obtain the microporous coating film, and finally, the microporous coating film is wound and cut.
Example 2
Adding 25 parts by weight of polyethylene powder and 0.3 part by weight of antioxidant into a double-screw extruder through a metering system, simultaneously adding 75 parts by weight of paraffin oil into the double-screw extruder from a plurality of oil filling ports (the first oil filling port is 70 percent, the second oil filling port is 20 percent and the third oil filling port is 10 percent) arranged on the double-screw extruder through a metering pump at a set temperature (110 ℃), and performing melt extrusion to a gear pump at the set temperature and the set rotating speed (180 ℃, 60rpm) with the rotating speed (85rpm) of the gear pump; and extruded to a filter unit under a pressure of 5.5MPa and a temperature of 215 ℃ and then extruded to a die to form a sheet-like substrate under a pressure of 4MPa and a temperature of 225 ℃.
The sheet substrate was cooled to 12 ℃ using a cooling die machine. The cooled sheet (the thickness is 1300 mu m, the width is 650mm) enters a bidirectional synchronous drawing unit (the bidirectional drawing multiplying power is 7 times), and is subjected to preheating, drawing, shaping, cooling and other steps to prepare a thick film with the thickness of 30 mu m and the width of 4550mm under the conditions of set temperature and wind speed (preheating is 122 ℃, the wind speed is 25m/s, drawing is 119 ℃, the wind speed is 28m/s, shaping is 117 ℃, the wind speed is 22m/s, cooling is 30 ℃, and the wind speed is 25 m/s).
After the thick film is trimmed by a tractor (the thickness is 30 mu m, and the width is 4300mm), the thick film enters a coating device shown in figure 1, the pressure of an oil removing press roller is controlled to be 25N so as to remove redundant paraffin oil, and aramid pulp is coated on the thick film.
The coated thick film enters an extraction tank filled with dichloromethane and NMP to extract paraffin oil in an oil film and NMP in slurry, and the extraction tank device adopts a combined type (comprising 8 extraction tanks from 1# to 8 #). The 8# → 1# extraction tank adopts the overflow liquid feeding mode, annotates liquid, replenishes the liquid mouth and sets up in the 8# groove, mends pure dichloromethane solution, sets up the overflow launder in the 1# groove, all establishes liquid level control, and 1# groove NMP volume concentration sets up at 80%, and 2# groove NMP volume concentration sets up 40%, and all the other grooves are dichloromethane. And respectively controlling the start and stop of a liquid injection pump or an overflow liquid discharge pump according to the overflow liquid level height of the 8# groove and the 1# groove, wherein the overflow liquid is discharged to a subsequent liquid phase recovery tank for recovery. Flow rate of each tank circulating pump is set to 35m3And h, continuously cleaning an oil membrane in the extraction tank through a W-shaped path, discharging an extraction mixed solution to a recovery collection tank through the No. 1 tank, and drying the membrane at 45 ℃.
The dried film (with the thickness of 16 mu m and the width of 3200mm) enters a transverse drawing heat treatment unit to be subjected to preheating, transverse drawing, shrinking, first shaping and other steps, micro transverse expanding (drawing multiplying power is 1.5 times) is carried out under the conditions of set temperature and set wind speed (preheating is 127 ℃, wind speed is 25m/s, drawing is 125 ℃, wind speed is 28m/s, shrinking is 128 ℃, wind speed is 28m/s, first shaping is 135 ℃, wind speed is 22m/s), then micro shrinking (TD direction, shrinking 10%, MD direction, shrinking 10%) and second shaping (temperature is 130 ℃) are carried out to obtain the microporous coating film, and finally, the microporous coating film is wound and cut.
Example 3
Adding 25 parts by weight of polyethylene powder and 0.3 part by weight of antioxidant into a double-screw extruder through a metering system, simultaneously adding 75 parts by weight of paraffin oil into the double-screw extruder from a plurality of oil filling ports (the first oil filling port is 70 percent, the second oil filling port is 20 percent and the third oil filling port is 10 percent) set on the double-screw extruder through a metering pump at a set temperature (110 ℃), and performing melt extrusion to a gear pump at the set temperature and the set rotating speed (180 ℃, 60rpm), wherein the rotating speed (85rpm) of the gear pump is high; and extruded to a filter unit under a pressure of 5.5MPa and a temperature of 215 ℃ and then extruded to a die to form a sheet-like substrate under a pressure of 4MPa and a temperature of 225 ℃.
The sheet substrate was cooled to 12 ℃ using a cooling die machine. The cooled sheet (the thickness is 1300 mu m, the width is 650mm) enters a bidirectional synchronous drawing unit (the bidirectional drawing multiplying power is 7 times), and is subjected to preheating, drawing, shaping, cooling and other steps to prepare a thick film with the thickness of 30 mu m and the width of 4550mm under the conditions of set temperature and set wind speed (preheating is 122 ℃, the wind speed is 25m/s, drawing is 119 ℃, the wind speed is 28m/s, shaping is 117 ℃, the wind speed is 22m/s, cooling is 30 ℃, and the wind speed is 25 m/s).
The thick film is trimmed by a tractor (the thickness is 30 mu m, and the width is 4300mm), enters a coating device shown in figure 1, the pressure of an oil removing press roller is controlled to be 25N to remove redundant paraffin oil, and aramid pulp is coated on the thick film.
The coated thick film enters an extraction tank filled with dichloromethane to extract paraffin oil in the oil film and NMP in the slurry, and the extraction tank adopts a combined device (comprisingTotal 8 extraction tanks 1# to 8 #). 8# → 1# extraction tank adopts the overflow liquid feeding mode, annotates liquid, the fluid infusion mouth sets up at 8# groove, mends pure dichloromethane solution, and the inslot setting overflow launder of 1# all establishes liquid level control, controls infusion pump or overflow positive displacement pump respectively according to 8# groove, 1# groove overflow liquid level and opens and stop, and wherein the overflow is arranged the flowing back to follow-up liquid phase recovery jar and is collected the processing. Flow setting of 35m for each tank circulating pump3And h, continuously cleaning an oil film in the extraction tank through a W-shaped path, discharging an extraction mixed solution to a recovery collection tank through a No. 1 tank, and drying a thick film at 45 ℃.
The dried film (with the thickness of 16 mu m and the width of 3200mm) enters a transverse drawing heat treatment unit to be subjected to the steps of preheating, stretching, shrinking, first shaping and the like, micro transverse expanding (stretching by 1.5 times) is carried out at set temperature and wind speed (preheating at 127 ℃, wind speed of 25m/s, stretching at 125 ℃, wind speed of 28m/s, shrinking at 128 ℃, wind speed of 28m/s, first shaping at 135 ℃, wind speed of 22m/s), then transverse and longitudinal micro shrinking (shrinking by 10 percent in the TD direction and shrinking by 10 percent in the MD direction) and second shaping (at 130 ℃) are carried out to obtain the microporous coating film, and finally, the microporous coating film is wound and cut.
The coating films prepared in the comparative examples and examples were subjected to the following performance tests.
1. Air permeability test method:
under the conditions of temperature and humidity (25 deg.C, 40% humidity) and normal pressure, a pressure of 1.21kPa is applied to a test instrument (Wangsheng type air permeameter), and 100mL of air passes through 6.45cm2The time required for the septum.
3 diaphragms are cut on a diaphragm roll at intervals of 150mm along the longitudinal direction, if the width of the diaphragm is larger than or equal to 100mm, the size of a sample is 100mm multiplied by 100mm, and if the width of the diaphragm is smaller than 100mm, the size of the sample is 100mm (length) multiplied by the width of the diaphragm. And (3) placing the diaphragm in a testing instrument for air permeability testing, and taking the average value of the 3 testing results as the air permeability of the diaphragm.
2. Porosity of the material
The volume of the internal cavities of the membrane is a percentage of the total volume of the membrane. The test is carried out by adopting the method specified by GBT 36363-2018.
3. Thermal shrinkage
The test was carried out according to the method specified in GB/T12027-2004.
4. Tensile strength
The test is carried out according to the requirements of GB/T1040.3-2006, and a sample is prepared by a cutting method, wherein the type of the sample is a type 2 sample. The sample is a strip with the length of 200mm and the width of 25mm, the distance between the clamps is (100 +/-5) mm, and the test speed is (250 +/-10) mm/min.
The test results are shown in table 1.
TABLE 1
Figure BDA0003552557120000151
Figure BDA0003552557120000161
1: 12 means that the thickness of the polyethylene-based film is 12 μm, and 4 means that the thickness of the aramid coating layer is 4 μm.
Comparing the preparation processes of the embodiment and the comparative example, it can be known that the method of the embodiment introduces the coating process before the extraction and water washing after the biaxial stretching, and directly introduces the coating process on the production procedure of the base film, so that the one-step forming of the coating film can be realized, and the method can correspondingly reduce the cost of investment equipment compared with the method of the comparative example, for example, one base film unreeling device, a coating film drying device and a coating film reeling device are omitted. Compared with the production method of the comparative example, the on-line coating process provided by the embodiment enables the conventional performances of the aramid coated film such as heat yield, air permeability and the like to be equivalent to those of the existing coated aramid, the tensile strength of the coated film is higher, and compared with the original aramid diaphragm manufacturing process, the orientation of the aramid fiber after stretching is more consistent due to transverse stretching.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

Claims (10)

1. A method for preparing an aramid coated membrane by a wet method is characterized by comprising the following steps:
(1) performing melt extrusion, filtration and extrusion plasticization on the polyolefin composition to obtain a sheet-shaped substrate; wherein the polyolefin composition comprises a polyolefin resin, a pore former, and an antioxidant;
(2) cooling the cast sheet substrate;
(3) performing biaxial tension on the cooled base material, and cutting edges to obtain a thick film;
(4) coating aramid fiber slurry on the thick film;
(5) extracting and drying the coated thick film;
(6) and stretching the dried thick film in the transverse direction.
2. The method according to claim 1, wherein the polyolefin resin is selected from polyethylene, polypropylene, preferably ultra high molecular weight polyethylene;
the pore-forming agent is paraffin oil;
the antioxidant is selected from tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester and tri (2, 4-di-tert-butylphenyl) phosphite;
preferably, the mass ratio of the polyolefin resin to the pore-forming agent is 1: (2-5), and the antioxidant is contained in an amount of 0.1-0.5 wt% based on the total weight of the polyolefin resin and the pore-forming agent.
3. The method of claim 1, wherein the aramid pulp comprises aramid dope and ceramic powder;
preferably, the aramid raw liquid is para-aromatic polyamide raw liquid, and the content of the para-aromatic polyamide in the raw liquid is 1-5 wt%; the median particle size of the ceramic powder is 100-500 nm;
more preferably, the content of the para-aramid is 0.9-5 wt% and the content of the ceramic powder is 1-10 wt% based on the total weight of the aramid pulp.
4. The method of claim 1, wherein step (1) comprises: adding polyolefin resin and an antioxidant into a double-screw extruder, adding a pore-forming agent into the double-screw extruder from an oil filling port arranged on the double-screw extruder, carrying out melt extrusion to a gear pump, and extruding to a filtering device; extruding to a mould to form a sheet-shaped base material;
preferably, the melt extrusion conditions include: the temperature is 160-; the rotating speed of the gear pump is 70-100 rpm; the conditions for extrusion to the filtration unit include: the pressure is 3-7MPa, and the temperature is 200-; the conditions for extrusion into the die include: the pressure is 2-5MPa, and the temperature is 220-240 ℃.
5. The method of claim 1, wherein step (2) comprises: cooling the flaky substrate to 8-15 ℃ by using a cooling sheet casting machine.
6. The method of claim 1, wherein step (3) comprises: the cooled flaky substrate enters a biaxial stretching unit, and is sequentially preheated, biaxially stretched, shaped, cooled and then trimmed by a tractor;
preferably, the stretching ratio in the transverse direction is 5-9, and the stretching ratio in the longitudinal direction is 5-9; the preheating temperature is 100-130 ℃, and the wind speed is 15-30 m/s; the stretching temperature is 100-130 ℃, and the wind speed is 15-30 m/s; the setting temperature is 110-130 ℃, the cooling temperature is 15-40 ℃ when the wind speed is 15-30m/s, and the wind speed is 15-30 m/s.
7. The method of claim 1, wherein step (4) is performed in a coating apparatus comprising: the device comprises a tension isolating mechanism, an oil removing mechanism and a coating mechanism; the tension isolating mechanism comprises a first transmission guide roller and a second transmission guide roller; the coating mechanism comprises a back roll, a narrow-slit die head and a feeding pipeline;
the second transmission guide roller is arranged above the first transmission guide roller, the narrow-slit die head is arranged above the back roller, the thick film is conveyed to the second transmission guide roller along the first transmission guide roller and is sequentially conveyed by the oil removing mechanism and the back roller, and in the conveying process, after part of pore-forming agent is removed by the oil removing mechanism, aramid pulp is injected into the narrow-slit die head by a feeding pipeline, so that the aramid pulp is coated on the thick film;
preferably, deoiling mechanism includes third transmission deflector roll and deoiling compression roller, third transmission deflector roll is located the below of deoiling compression roller, just the top of second transmission deflector roll, third transmission deflector roll and backing roll is located same water flat line.
8. The method according to claim 1, wherein in step (5), the extraction is carried out in an extraction unit comprising 3 to 9 extraction tanks;
the extracting agent in each extracting tank is dichloromethane; or
According to the transmission direction of the thick film, the first two extraction tanks comprise concentration gradient extraction agents selected from dichloromethane and N-methyl pyrrolidone, the volume concentration of the N-methyl pyrrolidone in the first extraction tank is 35-80%, the volume concentration of the N-methyl pyrrolidone in the second extraction tank is 40-60% of the volume concentration of the N-methyl pyrrolidone in the first extraction tank, and the extraction agent in the rest extraction tanks is dichloromethane.
9. The method of claim 1, wherein step (6) comprises: the dried thick film enters a transverse drawing heat treatment unit, and is subjected to preheating, transverse drawing, contraction and first shaping, and then transverse and longitudinal contraction and second shaping;
preferably, the transverse stretching magnification is 1.1-2 times;
the preheating temperature is 110-140 ℃, and the wind speed is 15-30 m/s; the stretching temperature is 110-140 ℃, and the wind speed is 15-30 m/s; the contraction temperature is 110-140 ℃, and the wind speed is 15-30 m/s; the temperature of the first shaping is 110-140 ℃, and the wind speed is 15-30 m/s;
the transverse shrinkage rate is 0.1-10%, the longitudinal shrinkage rate is 0.1-10%, and the second shaping temperature is 110-.
10. An aramid coated membrane made by the method of any one of claims 1-9.
CN202210268442.9A 2022-03-17 2022-03-17 Aramid fiber coated diaphragm and preparation method thereof Pending CN114597587A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115064838A (en) * 2022-08-16 2022-09-16 中材锂膜(宁乡)有限公司 Heat-resistant needled aramid fiber coated diaphragm, preparation method thereof and battery

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104821382A (en) * 2015-04-13 2015-08-05 铜仁学院 Method for improving surface activity of polyethylene lithium battery diaphragm
CN105393383A (en) * 2013-10-31 2016-03-09 Lg化学株式会社 Method for preparing separation membrane for electrochemical device, and separation membrane for electrochemical device prepared thereby
KR20160051167A (en) * 2014-10-31 2016-05-11 주식회사 엘지화학 Manufacturing method of a porous coated complex separator and separator manufactured by its method
CN105659410A (en) * 2013-11-06 2016-06-08 Lg化学株式会社 Separator for electrochemical device
KR20160129567A (en) * 2015-04-30 2016-11-09 주식회사 엘지화학 A method of manufacturing separator for electrochemical device and separator for electrochemical device manufactured thereby
CN109285981A (en) * 2017-07-20 2019-01-29 上海凯矜新材料科技有限公司 Lithium battery diaphragm and preparation method thereof
CN109560235A (en) * 2018-12-05 2019-04-02 河北金力新能源科技股份有限公司 A kind of new type lithium ion battery aramid fiber diaphragm preparation method

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105393383A (en) * 2013-10-31 2016-03-09 Lg化学株式会社 Method for preparing separation membrane for electrochemical device, and separation membrane for electrochemical device prepared thereby
CN105659410A (en) * 2013-11-06 2016-06-08 Lg化学株式会社 Separator for electrochemical device
KR20160051167A (en) * 2014-10-31 2016-05-11 주식회사 엘지화학 Manufacturing method of a porous coated complex separator and separator manufactured by its method
CN104821382A (en) * 2015-04-13 2015-08-05 铜仁学院 Method for improving surface activity of polyethylene lithium battery diaphragm
KR20160129567A (en) * 2015-04-30 2016-11-09 주식회사 엘지화학 A method of manufacturing separator for electrochemical device and separator for electrochemical device manufactured thereby
CN109285981A (en) * 2017-07-20 2019-01-29 上海凯矜新材料科技有限公司 Lithium battery diaphragm and preparation method thereof
CN109560235A (en) * 2018-12-05 2019-04-02 河北金力新能源科技股份有限公司 A kind of new type lithium ion battery aramid fiber diaphragm preparation method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115064838A (en) * 2022-08-16 2022-09-16 中材锂膜(宁乡)有限公司 Heat-resistant needled aramid fiber coated diaphragm, preparation method thereof and battery
CN115064838B (en) * 2022-08-16 2022-10-25 中材锂膜(宁乡)有限公司 Heat-resistant needled aramid fiber coated diaphragm, preparation method thereof and battery

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