CN111725469B - High-temperature-resistant self-extinguishing lithium battery diaphragm and preparation method and application thereof - Google Patents
High-temperature-resistant self-extinguishing lithium battery diaphragm and preparation method and application thereof Download PDFInfo
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- CN111725469B CN111725469B CN202010587389.XA CN202010587389A CN111725469B CN 111725469 B CN111725469 B CN 111725469B CN 202010587389 A CN202010587389 A CN 202010587389A CN 111725469 B CN111725469 B CN 111725469B
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- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62C—FIRE-FIGHTING
- A62C3/00—Fire prevention, containment or extinguishing specially adapted for particular objects or places
- A62C3/16—Fire prevention, containment or extinguishing specially adapted for particular objects or places in electrical installations, e.g. cableways
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
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- 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
Abstract
The invention relates to a high-temperature-resistant self-extinguishing lithium battery diaphragm and a preparation method and application thereof, wherein the diaphragm is composed of polyolefin and inorganic particles, and comprises 85-99 wt% of polyolefin and 1-15 wt% of inorganic particles, the particle size of the inorganic particles is 0.1-1 mu m, the inorganic particles are processed and formed by an extruder, the polyolefin and a solvent are firstly swelled at the conveying section of the extruder, slurry of the inorganic particles and the solvent is added at the tail end of the conveying section of the extruder, a film is formed by tape casting after plasticizing at a shearing section, and the high-temperature-resistant self-extinguishing lithium battery diaphragm is prepared after bidirectional stretching, extraction and heat setting. Wherein, the inorganic particles are boehmite combinations with different particle sizes or boehmite and two inorganic particles such as silicon dioxide, boron nitride and the like. Compared with the prior art, the invention constructs a heat-resistant and heat-conducting network structure by the inorganic particles with different particle sizes or dimensions to prepare the modified diaphragm, and the prepared diaphragm has the characteristic of self-extinguishing and has better heat resistance.
Description
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a high-temperature-resistant self-extinguishing lithium battery diaphragm and a preparation method and application thereof.
Background
Commercial polyolefin separators such as ultrahigh molecular weight polyethylene (UHMWPE) and polypropylene (PP) have the advantages of high mechanical strength and uniform microporous structure, but the following two defects still exist in power lithium batteries: firstly, the thermal dimensional stability of the diaphragm is poor, and because the diaphragm is mainly formed by stretching holes and the melting point of the material body is lower, when the temperature of the battery is abnormally increased, the diaphragm is easy to shrink, so that the short circuit in the battery with large area is caused, and the safety accident that the battery is on fire or even explodes is caused. Secondly, the electrolyte has poor wetting property to the diaphragm, the retention rate of the electrolyte of the diaphragm is low, and the performance of the battery is seriously influenced.
At present, various large diaphragm manufacturers mainly adopt temperature-resistant ceramic particles (mainly alumina particles) to coat the surface of a polyolefin diaphragm, so that the heat resistance and the electrolyte wettability of the diaphragm are improved, and the diaphragm is more suitable for preparing a high-energy-density power battery and is a development trend of high-end high-performance lithium battery diaphragms. However, the following disadvantages also exist: 1) The inorganic particle coating layer easily blocks micropores of the base film; 2) The acting force between the coating and the base film is not strong enough, so that powder is easy to fall off, and the performance of the battery is influenced; 3) The coating layer enables the thickness of the diaphragm to be obviously increased, the internal resistance of the battery is possibly increased, and the improvement on the energy density of the lithium battery is limited; 4) The coating is widely coated by aluminum trioxide ceramic particles, and the aluminum trioxide ceramic particles have high hardness and great abrasion to mechanical equipment.
Therefore, in view of the above disadvantages of ceramic coating, separator manufacturers have continuously sought more optimal methods for functionally modifying polyolefin separators in recent years. Among them, the document of chinese patent CN 103199210B proposes that inorganic particles, polyolefin and solvent are added into twin screws at the same time, and the membrane with different pore diameters and porosities at the surface part and the central part of the membrane is prepared by melt extrusion, so as to prevent the lithium crystal from penetrating the membrane to cause short circuit in the use of the battery. However, the higher content of added inorganic particles results in a lower stretch ratio of the primary film slab. In addition, the added inorganic particles such as alumina and the like are mainly high in hardness, and the added amount is large, so that the equipment is seriously abraded.
Disclosure of Invention
The invention aims to overcome the defects that the inorganic coating layer in the prior art easily blocks micropores of a base film, inorganic particles are easy to fall off, a diaphragm is easy to rapidly burn or even explode when thermal runaway occurs, the content of the inorganic particles in a matrix is too high, high-rate stretching of the film is not facilitated, the specific gravity of the inorganic particles is high, dispersion is uneven due to low viscosity and easy sedimentation at the initial stage of slurry mixing, and the like, so that the high-temperature-resistant self-extinguishing lithium battery diaphragm and the preparation method and application thereof are provided, firstly, polyolefin and a solvent are swelled at a conveying section of an extruder and enter a shearing section, and then slurry of the inorganic particles and the solvent is added, and the dispersion of the inorganic particles in the matrix is effectively improved; constructing inorganic particles with different particle sizes or dimensions into a heat-resistant and heat-conducting network structure to prepare a modified diaphragm; the addition amount of the inorganic particles is effectively reduced through a synergistic effect; the heat-resistant and heat-conducting network is constructed to improve the heat resistance and self-extinguishing property of the diaphragm, and the high-temperature resistance and safety of the battery are greatly improved.
The purpose of the invention is realized by the following technical scheme:
the high-temperature-resistant self-extinguishing lithium battery diaphragm comprises 85-99 wt% of polyolefin and 1-15 wt% of inorganic particles, wherein the particle size of the inorganic particles is 0.1-1 mu m.
More preferably, the inorganic particles have a particle size of 0.1 to 0.6 μm.
Further preferably, the lithium battery separator includes 85 to 95wt% of polyolefin and 5 to 15wt% of inorganic particles.
Further, the inorganic particles are a combination of boehmites of different particle sizes, including boehmites of two particle size ranges of 0.4 to 0.6 μm and 0.1 to 0.3 μm, which enable uniform dispersion of the boehmite particles in the polyolefin matrix. The mass ratio of the two kinds of boehmite is 1:1 to 1:9, through the regulation and control of the mass ratio, heat-resistant network structures with different compactness degrees can be constructed in the polyolefin matrix.
Further, the inorganic particles are boehmite combined with silica and boron nitride particles, the boehmite is introduced to reduce the abrasion of equipment, and the boehmite accounts for 50-80 wt% of the total weight of the inorganic particles.
Further, the polyolefin is one of ultrahigh molecular weight polyethylene, linear polyethylene, branched polyethylene, high density polyethylene, low density polyethylene or a copolymer thereof.
The preparation method of the high-temperature-resistant self-extinguishing lithium battery diaphragm comprises the following steps:
s1: mixing and emulsifying polyolefin resin and a solvent to obtain uniform slurry, and adding an antioxidant to obtain slurry A;
s2: mixing inorganic particles with a solvent, emulsifying, and ultrasonically dispersing for 3-30 min to obtain slurry B;
s3: adding the slurry A into a double-screw extruder, carrying out pre-swelling and melt mixing through a conveying section of the double-screw extruder, adding the slurry B into the tail end of the conveying section of the double-screw extruder, plasticizing and mixing through a shearing section of the double-screw extruder, and carrying out casting through an oral mold to obtain a primary film;
s4: and carrying out synchronous or asynchronous bidirectional stretching on the primary film in the longitudinal direction and the transverse direction, and then carrying out extraction solvent and drying and heat setting to obtain a lithium battery diaphragm product.
Further, emulsifying the S1 by using an emulsifier at a high speed for 3-10 min.
Further preferably, the time for high speed emulsification is 4 to 6min.
Further preferably, the time for ultrasonic dispersion is 15 to 25min.
Further, the proportion of the polyolefin in the slurry in S1 is 20 to 40wt%.
Further, the solvent is one or more of decalin, paraffin oil, toluene, xylene or trichlorobenzene.
Further, the slurry A is pre-swelled, the temperature of a conveying section of a double-screw extruder in a pre-swelling stage is 90-120 ℃, the temperature of a shearing section of the double-screw extruder is 130-230 ℃, and the rotating speed of a screw is 50-300 r/min.
Further preferably, the temperature of the conveying section of the double-screw extruder is 100-120 ℃, and the temperature of the shearing section of the double-screw extruder is 180-220 ℃.
Further, the draw ratio of the synchronous or asynchronous biaxial stretching in S4 is 7.5X 7.5 to 12.5X 12.5.
More preferably, the stretch ratio is 8 × 8 to 9 × 9.
Further, the thickness of the lithium battery separator product obtained in S4 is 5-20 μm.
In the application of the diaphragm in the lithium battery, the self-extinguishing time T of the diaphragm after being ignited is less than or equal to 5s; the heat yield MD of the diaphragm is less than or equal to 2.1 percent and TD is less than or equal to 2.1 percent under the condition of 105 ℃/1 h.
Compared with the prior art, the invention has the beneficial effects that:
1) The preparation process flow is simple and efficient, modification and film formation are carried out synchronously, and complex post-treatment steps are not needed;
2) Compared with a coating process, the integrated preparation method is beneficial to improving the binding force of the inorganic particles and the matrix and effectively avoiding the occurrence of the powder falling phenomenon.
3) The inorganic material is particularly important for abrasion of equipment during specific production, and the boehmite adopted in the invention has good flame retardant property and lower hardness, and the hardness is less than a threshold value capable of neglecting abrasion, so that the abrasion of the equipment can be reduced to a great extent.
4) Particularly, in the invention, the polyolefin and the solvent are firstly added into the slurry of the inorganic particles and the solvent when the polyolefin and the solvent are swelled in the conveying section of the extruder and enter the shearing section, so that the problem that the slurry is not uniformly dispersed in a screw rod due to the fact that the inorganic particles have high specific gravity and the slurry has low viscosity and is easy to settle in the initial mixing stage of the slurry in the screw rod is avoided, and the dispersion of the inorganic particles in a matrix can be effectively improved.
5) Particularly, the co-introduction of the inorganic particles with different particle sizes in the invention can form a synergistic effect, and compared with the addition of inorganic particles with a single particle size, a lower addition amount can form a heat-resistant and heat-conducting network in a matrix, thereby being beneficial to the dimensional stability and the heat conductivity of the diaphragm at high temperature.
Detailed Description
The present invention is described in detail below with reference to specific examples, but the present invention is not limited thereto in any way.
In order to fully illustrate the characteristics of the lithium ion battery separator in the present example, the following separators prepared in the respective examples and comparative examples were subjected to the relevant tests, the test results of which are shown in table 1, and the test items were as follows:
1. testing of the thickness of the separator: the measurement was carried out at ambient temperature 25 ℃ using a thickness gauge, and the average was taken using a multipoint test.
2. Testing of porosity: cutting the diaphragm into a square of 100mm multiplied by 100mm, calculating the volume, weighing the mass, and calculating by adopting the following formula;
porosity (%) = (volume-mass/separator raw material density)/volume × 100
The raw material density of the diaphragm is an average density calculated according to the ratio of polyolefin to inorganic matter and the respective densities.
Measurement of Gurley air permeability: the air permeameter measures the time required for 100mL of gas to pass through the membrane.
4. Testing puncture strength: a universal tester is adopted, and the curvature radius of the needle head is 0.5mm.
5. Shrinkage test: the diaphragm is cut into 100mm × 100mm square shape and put into an oven at 105 deg.C for 1h. Shrinkage was calculated by measuring the change in length in both MD and TD.
Shrinkage (%) = (original length-length after heat shrinkage)/original length × 100
Example 1
95 parts (in the examples, all parts by weight) of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a twin screw, and 2.5 parts of boehmite with the particle size of 0.1 μm and 2.5 parts of boehmite with the particle size of 0.6 μm and the paraffin oil are subjected to emulsification and ultrasonic treatment, and then fed into the twin screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching 8 x 8 through a synchronous biaxial stretching machine and extraction heat setting.
Example 2
Feeding 95 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) into a double screw, emulsifying and ultrasonically treating 1 part of boehmite with the particle size of 0.1 mu m and 4 parts of boehmite with the particle size of 0.6 mu m and paraffin oil, and then feeding the mixture into the double screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Example 3
Feeding 90 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) into a twin-screw, emulsifying and ultrasonically treating 1 part of boehmite with the particle size of 0.1 mu m and 9 parts of boehmite with the particle size of 0.6 mu m and paraffin oil, and then feeding the mixture into the twin-screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching 8 x 8 through a synchronous biaxial stretching machine and extraction heat setting.
Example 4
85 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a double screw, 5 parts of boehmite with the particle size of 0.2 mu m and 10 parts of boehmite with the particle size of 0.6 mu m and the paraffin oil are subjected to emulsification and ultrasonic treatment, and then the mixture is fed into the double screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Example 5
Feeding 99 parts of ultra-high molecular weight polyethylene and decalin (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) into a double screw, emulsifying and ultrasonically treating 0.5 part of boehmite with the particle size of 0.2 mu m, 0.5 part of boron nitride with the particle size of 0.1 mu m and paraffin oil, and then feeding the mixture into the double screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Example 6
Feeding 85 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) into a twin-screw, emulsifying and ultrasonically treating 10 parts of boehmite with the particle size of 0.2 microns and 5 parts of silica with the particle size of 0.1 microns and paraffin oil, and then feeding the materials into the twin-screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Example 7
85 parts of linear polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a double screw, 10 parts of boehmite with the particle size of 0.2 mu m and 5 parts of silica with the particle size of 0.1 mu m and the paraffin oil are subjected to emulsification and ultrasonic treatment, and then the mixture is fed into the double screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Example 8
85 parts of branched polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a twin-screw, 5 parts of boehmite with the particle size of 0.2 mu m and 10 parts of boehmite with the particle size of 0.6 mu m and the paraffin oil are subjected to emulsification and ultrasonic treatment, and then are fed into the twin-screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching 8 x 8 through a synchronous biaxial stretching machine and extraction heat setting.
Comparative example 1
95 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a double screw, and 5 parts of boehmite with the particle size of 0.1 mu m and the paraffin oil are emulsified, ultrasonically treated, fed into the double screw through the tail end of a conveying section, blended and extruded. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Comparative example 2
95 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a double screw, and 5 parts of boehmite with the particle size of 0.6 mu m and the paraffin oil are emulsified and ultrasonically mixed and fed into the double screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching 8 x 8 through a synchronous biaxial stretching machine and extraction heat setting.
Comparative example 3
85 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a double screw, and 15 parts of boehmite with the particle size of 0.2 mu m and the paraffin oil are subjected to emulsification and ultrasonic treatment and then fed into the double screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Comparative example 4
85 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a twin-screw, and 15 parts of boehmite with the particle size of 0.6 mu m and the paraffin oil are subjected to emulsification and ultrasonic treatment and then are fed into the twin-screw through the tail end of a conveying section for blending and extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the modified diaphragm is obtained by stretching by 8 x 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Comparative example 5
100 parts of ultra-high molecular weight polyethylene and paraffin oil (the solid content of the ultra-high molecular weight polyethylene is 25 wt.%) are fed into a twin-screw to be subjected to blending extrusion. The temperature of the conveying section is 100 ℃, the temperature of the shearing section is 210 ℃, the membrane is obtained by stretching 8 multiplied by 8 through a synchronous biaxial stretching machine and extracting and heat setting.
Comparative example 6
2wt.% of PVA was dissolved in deionized water and dispersed with stirring for 2h to form a homogeneous slurry. 0.6 μm boehmite particles were added to an aqueous solution of PVA and stirred for 2h to form a slurry (20% boehmite solids). Both sides of the base film prepared in comparative example 5 were coated with a gravure coater to a thickness of 3 μm on one side.
Comparative example 7
The boehmite in the above example 1 was replaced with silica of equal mass, and the separator was prepared according to the same process, and after a certain period of operation, a significant wear mark was generated on the surface of the roll of the apparatus. With boehmite, however, no significant signs of wear were evident over the same period of time.
Table 1 performance test data of lithium battery separators in examples and comparative examples
Comparing example 1 and comparative example 5, it can be seen that the thermal shrinkage of the separator blended with boehmite is significantly reduced.
Comparing examples 1 and 2 with comparative examples 1 and 2, it can be seen that synergistic effect can be achieved by adding boehmite with different particle sizes and blending with ultra-high molecular weight polyethylene, and the heat resistance of the diaphragm is better than that of the boehmite with single particle size.
The flame combustion conditions of the base film and the boehmite blending membranes with different particle sizes are summarized in the table, and different from a pure UHMWPE membrane, the UHMWPE/boehmite membrane has a self-extinguishing phenomenon after being ignited, which shows that the prepared UHMWPE/boehmite membrane has a self-extinguishing effect.
Comparing comparative example 6 and example 4, it can be seen that the air permeability of the separator prepared by adding boehmite with different particle sizes and ultra-high molecular weight polyethylene and blending is obviously improved compared with the coated separator, which is helpful for the rapid transmission of lithium ions in the separator.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (8)
1. A preparation method of a high-temperature-resistant self-extinguishing lithium battery diaphragm is characterized by comprising the following steps:
s1: mixing polyolefin resin and a solvent, emulsifying to obtain uniform slurry, and adding an antioxidant to obtain slurry A;
s2: mixing inorganic particles with a solvent, emulsifying, and ultrasonically dispersing to obtain slurry B;
s3: adding the slurry A into a double-screw extruder, carrying out pre-swelling and melt mixing through a conveying section of the double-screw extruder, adding the slurry B into the tail end of the conveying section of the double-screw extruder, and carrying out plasticizing mixing through a shearing section of the double-screw extruder and then carrying out casting through an oral die to obtain a primary film;
s4: carrying out synchronous or asynchronous bidirectional stretching on the primary film in the longitudinal direction and the transverse direction, and then obtaining a lithium battery diaphragm product after extraction solvent and drying and heat setting;
the obtained lithium battery diaphragm comprises 85-99wt% of polyolefin and 1-15wt% of inorganic particles, and the particle size of the inorganic particles is 0.1-1 mu m;
the inorganic particles are a combination of boehmites with different particle sizes, wherein the boehmites comprise two particle size ranges of 0.4 to 0.6 μm and 0.1 to 0.3 μm, and the mass ratio of the two boehmites is 1:1 to 1:9.
2. the preparation method of the high-temperature-resistant self-extinguishing lithium battery diaphragm as claimed in claim 1, wherein the proportion of the polyolefin in the slurry in S1 is 20 to 40 wt%;
the solvent is one or a mixture of more of decalin, paraffin oil, toluene, xylene or trichlorobenzene.
3. The preparation method of the high-temperature-resistant self-extinguishing lithium battery diaphragm as claimed in claim 1, wherein the conveying section temperature of the double-screw extruder is 90-120 ℃ o C, the temperature of the shearing section of the double-screw extruder is 130 to 230 o And C, the rotating speed of the screw is 50 to 300r/min.
4. The preparation method of the high-temperature-resistant self-extinguishing lithium battery diaphragm as claimed in claim 1, wherein the stretching ratio of synchronous or asynchronous biaxial stretching in S4 is 7.5 x 7.5 to 12.5 x 12.5.
5. The preparation method of the high-temperature-resistant self-extinguishing lithium battery diaphragm as claimed in claim 1, wherein the thickness of the lithium battery diaphragm product obtained in S4 is 5-20 μm.
6. The high-temperature-resistant self-extinguishing lithium battery separator prepared by the preparation method of the high-temperature-resistant self-extinguishing lithium battery separator as claimed in any one of claims 1 to 5, wherein the adopted inorganic particles are a combination of boehmite, silica and boron nitride particles, and boehmite accounts for 50-80wt% of the total weight of the inorganic particles.
7. A high temperature resistant self-extinguishing lithium battery separator as recited in claim 6, wherein the polyolefin used is one of ultra-high molecular weight polyethylene, linear polyethylene, branched polyethylene, high density polyethylene, low density polyethylene or their copolymers.
8. The use of a high temperature resistant self-extinguishing lithium battery separator as defined in claim 6 in a lithium battery, wherein the self-extinguishing time T after ignition of the separator is less than or equal to 5s; the diaphragm is at 105 o Under the condition of C/1h, the heat yield MD of the diaphragm is less than or equal to 2.1 percent, and the TD is less than or equal to 2.1 percent.
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| JP2018076476A (en) * | 2016-11-10 | 2018-05-17 | 有限会社ケー・イー・イー | High temperature low heat shrinkable polyolefin multilayer microporous film and method for producing the same |
| JP6346986B1 (en) * | 2016-12-20 | 2018-06-20 | 旭化成株式会社 | Electric storage device separator and laminate, wound body and secondary battery using the same |
| CN110621731A (en) * | 2017-05-26 | 2019-12-27 | 旭化成株式会社 | Polyolefin microporous membrane, separator for electricity storage device, and electricity storage device |
| CN108963164A (en) * | 2018-06-28 | 2018-12-07 | 深圳市旭然电子有限公司 | Inorganic ceramic coating functions lithium ion battery isolation film, preparation method and its lithium ion battery |
| CN111244369A (en) * | 2018-11-28 | 2020-06-05 | 旭化成株式会社 | Polyolefin microporous membrane |
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