CN114725612A - High-toughness lithium ion battery blending diaphragm and preparation method thereof - Google Patents
High-toughness lithium ion battery blending diaphragm and preparation method thereof Download PDFInfo
- Publication number
- CN114725612A CN114725612A CN202210426404.1A CN202210426404A CN114725612A CN 114725612 A CN114725612 A CN 114725612A CN 202210426404 A CN202210426404 A CN 202210426404A CN 114725612 A CN114725612 A CN 114725612A
- Authority
- CN
- China
- Prior art keywords
- lithium ion
- ion battery
- toughness
- polyethylene
- diaphragm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 47
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 47
- 238000002156 mixing Methods 0.000 title claims abstract description 31
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 46
- -1 polyethylene form Polymers 0.000 claims abstract description 45
- 239000012528 membrane Substances 0.000 claims abstract description 39
- 229920000642 polymer Polymers 0.000 claims abstract description 38
- 239000004014 plasticizer Substances 0.000 claims abstract description 23
- 238000009998 heat setting Methods 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 15
- 239000011343 solid material Substances 0.000 claims abstract description 14
- 230000008569 process Effects 0.000 claims abstract description 9
- 238000000605 extraction Methods 0.000 claims abstract description 4
- 238000001125 extrusion Methods 0.000 claims abstract description 4
- 238000004804 winding Methods 0.000 claims abstract description 3
- 239000004698 Polyethylene Substances 0.000 claims description 44
- 229920000573 polyethylene Polymers 0.000 claims description 44
- 239000003921 oil Substances 0.000 claims description 41
- 235000019198 oils Nutrition 0.000 claims description 41
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 33
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims description 33
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 24
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 22
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 21
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 18
- 229920001577 copolymer Polymers 0.000 claims description 16
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 15
- QGJOPFRUJISHPQ-UHFFFAOYSA-N Carbon disulfide Chemical compound S=C=S QGJOPFRUJISHPQ-UHFFFAOYSA-N 0.000 claims description 15
- 238000005266 casting Methods 0.000 claims description 14
- 230000001360 synchronised effect Effects 0.000 claims description 12
- 238000009423 ventilation Methods 0.000 claims description 12
- 239000003795 chemical substances by application Substances 0.000 claims description 11
- 239000002480 mineral oil Substances 0.000 claims description 11
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 10
- 229920001911 maleic anhydride grafted polypropylene Polymers 0.000 claims description 10
- 235000010446 mineral oil Nutrition 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 10
- 239000008096 xylene Substances 0.000 claims description 8
- 229920001912 maleic anhydride grafted polyethylene Polymers 0.000 claims description 7
- 239000003549 soybean oil Substances 0.000 claims description 7
- 235000012424 soybean oil Nutrition 0.000 claims description 7
- 229920000468 styrene butadiene styrene block copolymer Polymers 0.000 claims description 7
- 239000008240 homogeneous mixture Substances 0.000 claims description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 abstract description 8
- 229910052744 lithium Inorganic materials 0.000 abstract description 8
- 210000001787 dendrite Anatomy 0.000 abstract description 6
- 238000005096 rolling process Methods 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 7
- 238000005303 weighing Methods 0.000 description 7
- 229960001701 chloroform Drugs 0.000 description 6
- 230000009471 action Effects 0.000 description 2
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- 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
-
- 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
-
- 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
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Abstract
The invention provides a high-toughness lithium ion battery blending diaphragm and a preparation method thereof, wherein the diaphragm is made of a solid material with micropores, and the preparation method at least comprises the following steps: pretreating the toughening polymer; mixing the solid materials in a high-speed mixer; the mixed material and the plasticizer are processed through an extrusion process, and then the high-toughness lithium ion battery blending diaphragm is obtained through a stretching process, an extraction process, a heat setting process and a winding process. The toughening polymer is introduced into a membrane system by a blending method, and the toughening polymer and polyethylene form a homogeneous system by the promotion of pretreatment, a compatibilizer, strong mechanical force and a plasticizer. The diaphragm obtained by the invention has high puncture resistance, is less likely to be punctured by lithium dendrites in the lithium ion battery, and greatly improves the safety of the lithium ion battery.
Description
Technical Field
The invention relates to the technical field of lithium batteries, in particular to a high-toughness lithium ion battery blending diaphragm and a preparation method thereof.
Background
With the rapid development of new energy industry, the demand of people for high-performance energy storage equipment is increasing dramatically. The lithium ion battery has the advantages of small volume, high energy density, long cycle life, no memory effect, high average output voltage, small self-discharge and the like, and becomes the secondary battery which is most widely applied at present.
The main components of the lithium ion battery comprise a positive electrode, a negative electrode, electrolyte and a diaphragm, wherein the diaphragm has the functions of separating the positive electrode from the negative electrode so as to prevent the battery from short circuit, providing a lithium ion transmission channel and storing the electrolyte. However, in the use process of the lithium ion battery, lithium dendrite is generated inevitably due to non-uniform current, non-uniform electrode surface and the like, and if the generated lithium dendrite punctures the diaphragm, the battery is short-circuited, the battery temperature is rapidly increased, and safety accidents such as fire, explosion and the like are easily caused. Therefore, it is important to develop a high-toughness lithium ion battery separator for improving the puncture strength of the separator to improve the battery safety.
In view of the above, there is a need for an improved lithium battery separator in the prior art to solve the above problems.
Disclosure of Invention
The invention aims to provide a high-toughness lithium ion battery blending diaphragm, which solves the problem of low puncture strength of the diaphragm and avoids the occurrence of battery short circuit caused by the penetration of lithium dendrite on the diaphragm.
In order to achieve the purpose, the invention provides a high-toughness lithium ion battery blending membrane which is composed of a solid material with micropores, wherein the solid material is a homogeneous mixture of polyethylene, a toughening polymer and a compatibilizer.
In some embodiments, the solid material has a composition ratio of: polyethylene: 74% -95%, toughening polymer: 4% -25%, compatibilizer: 0.4 to 2.5 percent.
In some embodiments, the polyethylene has a number average molecular weight between 80 and 190 ten thousand g/mol.
In some embodiments, the toughening polymer is one or both of an ethylene-vinyl acetate copolymer and an ethylene-octene copolymer, and the VA content of the ethylene-vinyl acetate copolymer is between 8 wt% and 28 wt%.
In some embodiments, the compatibilizer is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and styrene-butadiene-styrene triblock copolymer.
The invention also discloses a preparation method of the high-toughness lithium ion battery blending diaphragm, and the lithium ion battery blending diaphragm with excellent performance is prepared by biaxial tension.
In order to achieve the purpose, the invention provides a preparation method of a high-toughness lithium ion battery blended diaphragm, which comprises the following steps:
the method comprises the following steps: extruding the toughening polymer and the plasticizer by an extruder and then granulating to obtain a toughening polymer pretreatment material;
step two: placing polyethylene, a toughening polymer pretreatment material and a compatibilizer in a high-speed mixer, and uniformly mixing to obtain a mixed material;
step three: adding the mixed material prepared in the step two into an extruder, injecting white oil into the extruder, extruding and casting the mixture to a chill roll through a T-shaped die head to obtain a cast sheet;
step four: performing biaxial stretching on the cast sheet prepared in the step three by using a synchronous biaxial stretcher to obtain an oil-containing film;
step five: extracting the oil-containing membrane prepared in the step four by using an extracting agent to prepare a wet membrane;
step six: and D, standing the wet film prepared in the fifth step at a ventilation position at room temperature, fixing the wet film by using a clamping die, then carrying out heat setting, and finally carrying out a winding process to prepare the high-toughness lithium ion battery blending diaphragm.
In some embodiments, in the first step, the extrusion temperature is between 100 ℃ and 140 ℃, and the screw rotation speed of the extruder is between 130rpm and 150 rpm;
in the second step, the fly cutter rotating speed of the high-speed mixer is between 550r/min and 830r/min, the charging barrel rotating speed of the high-speed mixer is between 9r/min and 12r/min, and the stirring time of the high-speed mixer is between 30min and 45 min;
in the third step, the temperature of the chill roll is between 10 ℃ and 25 ℃;
in the fourth step, the biaxial stretching temperature is 115-125 ℃, and the biaxial stretching magnification is 6-8 times;
in the fifth step, the extraction time is between 2min and 4 min;
in the sixth step, the heat setting temperature is between 90 ℃ and 130 ℃, and the heat setting time is between 0.5min and 2 min.
In some embodiments, in the step one, the component mass ratio of the toughening polymer pretreatment material is 50 wt% to 65 wt% of the toughening polymer, and 35 wt% to 50 wt% of the plasticizer, wherein the plasticizer is one or more of white oil, mineral oil, soybean oil, toluene and xylene.
In some embodiments, in the third step, the cast sheet comprises 18 wt% to 30 wt% of solid material and 70 wt% to 82 wt% of plasticizer, and the thickness of the cast sheet is between 700 μm and 1000 μm.
In some embodiments, in step five, the extractant is one or more of dichloromethane, chloroform, benzene, carbon disulfide and ethanol.
Compared with the prior art, the invention has the beneficial effects that: the toughening polymer is introduced into the membrane system, and a homogeneous system is difficult to form between the polar toughening polymer and the nonpolar polyethylene. The acting force between the nonpolar chain segment of the compatibilizer and the polyethylene is strong, the acting force between the polar chain segment of the compatibilizer and the toughening polymer is strong, and the interaction between the toughening polymer and the polyethylene is promoted due to the existence of the compatibilizer. In addition, under the action of the plasticizer, the mechanical force action of the high-speed stirrer and the double-screw extruder provides favorable conditions for realizing good compatibility between the toughening polymer and the polyethylene, entangles molecular chains of the toughening polymer and the polyethylene, and improves the toughness of the modified diaphragm, thereby obtaining higher puncture resistance and improving the elongation at break. The prepared diaphragm has the puncture resistance strength of more than or equal to 500g and the elongation at break of more than or equal to 95 percent, and is not easy to be punctured by lithium dendrite generated in the using process of the lithium ion battery, so that the safety of the lithium ion battery is improved.
Drawings
FIG. 1 is a process flow diagram of the preparation method of the high-toughness lithium ion battery blended membrane.
Detailed Description
The present invention is described in detail with reference to the embodiments shown in the drawings, but it should be understood that these embodiments are not intended to limit the present invention, and those skilled in the art should understand that functional, methodological, or structural equivalents or substitutions made by these embodiments are within the scope of the present invention.
Example 1
The high-toughness lithium ion battery blending membrane is composed of a solid material with micropores, wherein the solid material is a homogeneous mixture of polyethylene, a toughening polymer and a compatibilizer. The solid material comprises the following components in percentage by weight: polyethylene: 74% -95%, toughening polymer: 4% -25%, compatibilizer: 0.4 to 2.5 percent.
Wherein the number average molecular weight of the polyethylene is between 80 and 190 ten thousand g/mol. The toughening polymer is one or two of an ethylene-vinyl acetate copolymer and an ethylene-octene copolymer, and the VA content of the ethylene-vinyl acetate copolymer is 8-28 wt%. The compatibilizer is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene and styrene-butadiene-styrene triblock copolymer.
A preparation method of a high-toughness lithium ion battery blended diaphragm comprises the following steps:
the method comprises the following steps: extruding the toughening polymer and the plasticizer by an extruder and then granulating to obtain a toughening polymer pretreatment material, wherein the extrusion temperature is between 100 and 140 ℃, and the screw rotating speed of the extruder is between 130 and 150 rpm;
step two: placing polyethylene, a toughening polymer pretreatment material and a compatibilizer into a high-speed mixer, and uniformly mixing to obtain a mixed material, wherein the rotating speed of a fly cutter of the high-speed mixer is 550-830 r/min, the rotating speed of a charging barrel of the high-speed mixer is 9-12 r/min, and the stirring time of the high-speed mixer is 30-45 min;
step three: adding the mixture prepared in the step two into an extruder, injecting white oil into the extruder, extruding and casting the mixture to a chilling roller through a T-shaped die head to obtain a cast sheet, wherein the temperature of the chilling roller is between 10 and 25 ℃;
step four: carrying out biaxial stretching on the cast sheet prepared in the step three by using a synchronous biaxial stretching machine to obtain an oil-containing film, wherein the biaxial stretching temperature is 115-125 ℃, and the biaxial stretching magnification is 6-8 times;
step five: extracting the oil-containing membrane prepared in the step four by using an extracting agent to prepare a wet membrane, wherein the extraction time is between 2min and 4 min;
step six: and (4) standing the wet film prepared in the fifth step at a ventilation position at room temperature, fixing the wet film by using a clamping mould, then carrying out heat setting, wherein the heat setting temperature is between 90 and 130 ℃, the heat setting time is between 0.5 and 2min, and finally carrying out a rolling process to prepare the high-toughness lithium ion battery blending diaphragm.
In the preparation process, the mass ratio of the components of the toughening polymer pretreatment material in the step one is 50-65 wt% of the toughening polymer, 35-50 wt% of the plasticizer is one or more of white oil, mineral oil, soybean oil, toluene and xylene; in the third step, the components of the casting sheet are 18 wt% -30 wt% of solid material and 70 wt% -82 wt% of plasticizer, and the thickness of the casting sheet is between 700 mu m and 1000 mu m; in the fifth step, the extracting agent is one or more of dichloromethane, trichloromethane, benzene, carbon disulfide and ethanol.
In the embodiment, polyethylene with the number average molecular weight of 150 ten thousand g/mol, ethylene-vinyl acetate copolymer with the VA content of 9 wt% are selected, maleic anhydride grafted polyethylene is selected as a compatibilizer, white oil is selected as a plasticizer, and dichloromethane is selected as an extracting agent;
respectively weighing 50% of ethylene-vinyl acetate copolymer and 50% of white oil according to the mass percentage, extruding the mixture at the temperature of 105 ℃ and the rotation speed of a screw of 150rpm, and granulating the mixture by a granulator to obtain an ethylene-vinyl acetate copolymer pretreatment material;
respectively taking 20.90% of polyethylene, 2.18% of ethylene-vinyl acetate copolymer pretreatment material, 0.02% of maleic anhydride grafted polyethylene and 76.90% of white oil according to mass percentage, uniformly mixing the polyethylene, the ethylene-vinyl acetate copolymer pretreatment material and the compatibilizer in a high-speed mixer, wherein the rotating speed of a fly cutter of the high-speed mixer is 750r/min, the rotating speed of a charging barrel is 9r/min, and the stirring time is 35min, extruding the obtained mixed material and the white oil through a double-screw extruder, extruding and casting the mixture to a chill roll through a T-shaped die, wherein the temperature of the chill roll is 18 ℃, and obtaining a cast sheet, and the thickness of the cast sheet is 750 mu m;
carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretching machine, wherein the stretching temperature is 125 ℃, and the stretching magnification is 6 times to obtain an oil-containing film; extracting the oil-containing membrane by using dichloromethane for 2min to obtain a wet membrane; and standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping mould, performing heat setting at 130 ℃ for 1min, and rolling to obtain the high-toughness lithium ion battery blending diaphragm.
Example 2
In the embodiment, polyethylene with the number average molecular weight of 170 ten thousand g/mol is selected, ethylene-octene copolymer is selected as toughening polymer, maleic anhydride grafted polypropylene is selected as compatibilizer, mineral oil is selected as plasticizer, and trichloromethane is selected as extractant;
weighing 60% of ethylene-octene copolymer and 40% of mineral oil according to the mass percentage, extruding the ethylene-octene copolymer-mineral oil sample strip at the extruder temperature of 130 ℃ and the screw rotation speed of 130rpm, and granulating by a granulator to obtain an ethylene-octene copolymer pretreatment material;
respectively taking 18.24% of polyethylene, 2.02% of ethylene-octene copolymer pretreatment material, 0.01% of maleic anhydride grafted polypropylene and 79.73% of mineral oil according to mass percent, uniformly mixing the polyethylene, the ethylene-octene copolymer pretreatment material and a compatibilizer in a high-speed mixer, wherein the fly cutter rotating speed of the high-speed mixer is 800r/min, the charging barrel rotating speed is 10r/min and the stirring time is 30min, extruding the obtained mixed material and the mineral oil through a double-screw extruder, extruding and casting the mixture to a chill roll through a T-shaped die head, and the chill roll temperature is 20 ℃ to obtain a cast piece, wherein the cast piece thickness is 800 mu m;
carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 122 ℃, and the stretching magnification is 7 times, so as to obtain an oil-containing film; extracting the oil-containing membrane by trichloromethane for 3min to obtain a wet membrane; and standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping mould, performing heat setting at 120 ℃ for 1min, and rolling to obtain the high-toughness lithium ion battery blending diaphragm.
Example 3
In the embodiment, polyethylene with the number average molecular weight of 120 ten thousand g/mol, ethylene-vinyl acetate copolymer with the VA content of 18 wt% are selected, styrene-butadiene-styrene triblock copolymer is selected as a compatibilizer, xylene is selected as a plasticizer, and ethanol is selected as an extracting agent;
respectively weighing 55% of ethylene-vinyl acetate copolymer and 45% of xylene according to mass percentage, extruding the ethylene-vinyl acetate copolymer-xylene sample strips at the temperature of 115 ℃ and the screw rotating speed of 140rpm, and granulating by a granulator to obtain an ethylene-vinyl acetate copolymer pretreatment material;
respectively taking 20.35% of polyethylene, 6.52% of ethylene-vinyl acetate copolymer pretreatment material, 0.03% of styrene-butadiene-styrene triblock copolymer and 73.10% of dimethylbenzene according to mass percent, uniformly mixing the polyethylene, the ethylene-vinyl acetate copolymer pretreatment material and a compatibilizer in a high-speed mixer, wherein the rotating speed of a fly cutter of the high-speed mixer is 650r/min, the rotating speed of a charging barrel is 10r/min, the stirring time is 40min, extruding the obtained mixed material and the dimethylbenzene through a double-screw extruder, extruding and casting the mixed material and the dimethylbenzene to a chill roll through a T-shaped die head, and the temperature of the chill roll is 15 ℃ to obtain a cast sheet, wherein the thickness of the cast sheet is 800 mu m;
carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 120 ℃, and the stretching magnification is 8 times, so as to obtain an oil-containing film; extracting the oil-containing membrane with ethanol for 3.5min to obtain wet membrane; and standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping mould, performing heat setting at 110 ℃ for 1.5min, and rolling to obtain the high-toughness lithium ion battery blend diaphragm.
Example 4
In the embodiment, polyethylene with the number average molecular weight of 100 ten thousand g/mol is selected, an ethylene-octene copolymer is selected as a toughening polymer, a styrene-butadiene-styrene triblock copolymer is selected as a compatibilizer, toluene is selected as a plasticizer, and carbon disulfide is selected as an extractant;
weighing 65% of ethylene-octene copolymer and 35% of toluene according to mass percent, extruding the ethylene-octene copolymer-toluene sample strip at 135 ℃ and 130rpm of screw rotation speed, and granulating by a granulator to obtain ethylene-octene copolymer pretreatment material;
respectively taking 20.80% of polyethylene, 7.96% of ethylene-octene copolymer pretreatment material, 0.04% of styrene-butadiene-styrene triblock copolymer and 71.20% of toluene by mass percent, uniformly mixing the polyethylene, the ethylene-octene copolymer pretreatment material and a compatibilizer in a high-speed mixer, wherein the fly cutter speed of the high-speed mixer is 600r/min, the charging barrel speed is 12r/min, the stirring time is 40min, extruding the obtained mixed material and the toluene through a double-screw extruder, extruding and casting the mixture to a chill roll through a T-shaped die, wherein the temperature of the chill roll is 13 ℃, and obtaining a cast sheet, and the thickness of the cast sheet is 900 micrometers;
carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 118 ℃, and the stretching magnification is 8 times, so as to obtain an oil-containing film; extracting the oil-containing membrane by using carbon disulfide for 4min to obtain a wet membrane; and standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping mould, performing heat setting at 90 ℃ for 2min, and rolling to obtain the high-toughness lithium ion battery blending diaphragm.
Example 5
In the embodiment, polyethylene with the number average molecular weight of 80 ten thousand g/mol, ethylene-vinyl acetate copolymer with the VA content of 24 wt% are selected, maleic anhydride grafted polypropylene is selected as a compatibilizer, soybean oil is selected as a plasticizer, and dichloromethane is selected as an extracting agent;
respectively weighing 50% of ethylene-vinyl acetate copolymer and 50% of soybean oil according to the mass percentage, extruding the mixture at the temperature of 110 ℃ and the rotating speed of a screw of 140rpm, and granulating the mixture by a granulator to obtain an ethylene-vinyl acetate copolymer pretreatment material;
respectively taking 21.56% of polyethylene, 12.83% of ethylene-vinyl acetate copolymer pretreatment material, 0.05% of maleic anhydride grafted polypropylene and 65.56% of soybean oil according to mass percentage, uniformly mixing the polyethylene, the ethylene-vinyl acetate copolymer pretreatment material and a compatibilizer in a high-speed mixer, wherein the rotating speed of a fly cutter of the high-speed mixer is 780r/min, the rotating speed of a charging barrel is 12r/min and the stirring time is 35min, extruding the obtained mixed material and the soybean oil through a double-screw extruder, extruding and casting the mixture to a chill roll through a T-shaped die, wherein the temperature of the chill roll is 18 ℃, and obtaining a cast piece, and the thickness of the cast piece is 850 mu m;
carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 118 ℃, and the stretching magnification is 7 times, so as to obtain an oil-containing film; extracting the oil-containing membrane by using dichloromethane for 3min to obtain a wet membrane; and (3) standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping die, performing heat setting at 90 ℃ for 1.5min, and rolling to obtain the high-toughness lithium ion battery blending diaphragm.
Example 6
In the embodiment, polyethylene with the number average molecular weight of 180 ten thousand g/mol, ethylene-vinyl acetate copolymer with the VA content of 28 wt% are selected, maleic anhydride grafted polyethylene is selected as a compatibilizer, white oil is selected as a plasticizer, and benzene is selected as an extracting agent;
respectively weighing 55% of ethylene-vinyl acetate copolymer and 45% of white oil according to the mass percentage, extruding the mixture at 115 ℃ and 150rpm of screw rotation speed, and granulating the mixture by a granulator to obtain an ethylene-vinyl acetate copolymer pretreatment material;
respectively taking 22.50% of polyethylene, 13.57% of ethylene-vinyl acetate copolymer pretreatment material, 0.07% of maleic anhydride grafted polyethylene and 63.86% of white oil according to mass percentage, uniformly mixing the polyethylene, the ethylene-vinyl acetate copolymer pretreatment material and the compatibilizer in a high-speed mixer, wherein the rotating speed of a fly cutter of the high-speed mixer is 820r/min, the rotating speed of a charging barrel is 12r/min, the stirring time is 30min, extruding the obtained mixed material and the white oil through a double-screw extruder, extruding and casting the mixture to a chill roll through a T-shaped die, and the temperature of the chill roll is 20 ℃ to obtain cast pieces, wherein the thickness of the cast pieces is 950 mu m;
carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 120 ℃, and the stretching magnification is 7 times, so as to obtain an oil-containing film; extracting the oil-containing membrane with benzene for 3.5min to obtain wet membrane; and (3) standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping die, performing heat setting at 100 ℃ for 1min, and rolling to obtain the high-toughness lithium ion battery blending diaphragm.
Comparative example 1
Selecting polyethylene with the number average molecular weight of 150 ten thousand g/mol, selecting white oil as a plasticizer, and selecting dichloromethane as an extracting agent; extruding polyethylene and white oil by a double-screw extruder, wherein the polyethylene accounts for 23% of the total mass, the white oil accounts for 77% of the total mass, extruding and casting to a chill roll through a T-shaped die head, and the temperature of the chill roll is 18 ℃ to obtain a cast piece, and the thickness of the cast piece is 750 mu m; carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 125 ℃, and the stretching magnification is 6 times to obtain an oil-containing film; extracting the oil-containing membrane by using dichloromethane for 2min to obtain a wet membrane; and standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping mould, performing heat setting at 130 ℃ for 1min, and rolling to obtain the lithium ion battery diaphragm.
Comparative example 2
Selecting polyethylene with the number average molecular weight of 170 ten thousand g/mol, selecting ethylene-octene copolymer as toughening polymer, selecting maleic anhydride grafted polypropylene as compatibilizer, selecting mineral oil as plasticizer and selecting trichloromethane as extractant; extruding polyethylene, ethylene-octene copolymer, maleic anhydride grafted polypropylene and mineral oil by an extruder, wherein the polyethylene accounts for 18.24% of the total mass, the ethylene-octene copolymer pretreatment material accounts for 2.02%, the maleic anhydride grafted polypropylene accounts for 0.01%, and the mineral oil accounts for 79.73% of the total mass, extruding and casting to a chill roll through a T-shaped die head, wherein the temperature of the chill roll is 20 ℃, and obtaining a cast piece, and the thickness of the cast piece is 800 mu m; carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 122 ℃, and the stretching magnification is 7 times, so as to obtain an oil-containing film; extracting the oil-containing membrane with chloroform for 3min to obtain wet membrane; and (3) standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping die, performing heat setting at 120 ℃ for 1min, and rolling to obtain the high-toughness lithium ion battery blending diaphragm.
Comparative example 3
Selecting polyethylene with the number average molecular weight of 120 ten thousand g/mol, selecting ethylene-vinyl acetate copolymer with the VA content of 18 wt%, selecting dimethylbenzene as a plasticizer and selecting ethanol as an extracting agent; respectively weighing 55% of ethylene-vinyl acetate copolymer and 45% of xylene according to mass percentage, extruding the ethylene-vinyl acetate copolymer-xylene sample strips at the temperature of 115 ℃ and the screw rotating speed of 140rpm, and granulating by a granulator to obtain an ethylene-vinyl acetate copolymer pretreatment material; respectively taking 20.35% of polyethylene, 6.55% of ethylene-vinyl acetate copolymer pretreatment material and 73.10% of dimethylbenzene according to mass percent, uniformly mixing the polyethylene and the ethylene-vinyl acetate copolymer pretreatment material in a high-speed mixer, wherein the rotating speed of a fly cutter of the high-speed mixer is 650r/min, the rotating speed of a charging barrel is 10r/min, and the stirring time is 40min, extruding the obtained mixed material and the dimethylbenzene through a double-screw extruder, extruding and casting the mixed material to a chill roll through a T-shaped die head, and the temperature of the chill roll is 15 ℃ to obtain a cast piece, wherein the thickness of the cast piece is 800 mu m; carrying out biaxial stretching on the cast sheet by a synchronous biaxial stretcher, wherein the stretching temperature is 120 ℃, and the stretching magnification is 8 times, so as to obtain an oil-containing film; extracting the oil-containing membrane with ethanol for 3.5min to obtain wet membrane; and standing the wet film at a ventilation position at room temperature, fixing the wet film by using a clamping mould, performing heat setting at 110 ℃ for 1.5min, and rolling to obtain the high-toughness lithium ion battery blend diaphragm.
Table 1 comparison of the properties of the separators prepared in the examples
| Item | Puncture resistance Strength (g) | Tensile Strength (MPa) | Elongation at Break (%) |
| Example 1 | 552.49 | 210.55 | 96.13 |
| Example 2 | 662.71 | 230.38 | 99.37 |
| Example 3 | 567.44 | 216.71 | 95.74 |
| Example 4 | 688.32 | 222.57 | 98.28 |
| Example 5 | 636.24 | 223.76 | 95.27 |
| Example 6 | 711.93 | 242.57 | 100.89 |
| Comparative example 1 | 384.55 | 169.12 | 66.73 |
| Comparative example 2 | 424.15 | 197.22 | 72.91 |
| Comparative example 3 | 454.154 | 213.76 | 70.28 |
As can be seen from Table 1, the puncture strength, the tensile strength and the elongation at break of the diaphragm prepared by the method are improved compared with those of the diaphragm prepared by the comparative example, and the toughness of the diaphragm can be improved by adding the toughening polymer in the diaphragm system, pretreating the toughening polymer and adding the compatibilizer, so that the high-toughness lithium ion battery blended diaphragm is obtained, and the high puncture strength is obtained.
When the diaphragm prepared by the invention is applied to the lithium ion battery, the risk that the diaphragm is pierced by lithium dendrites can be reduced, and the safety of the lithium ion battery is improved.
The above-listed detailed description is merely a detailed description of possible embodiments of the present invention, and it is not intended to limit the scope of the invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention are intended to be included within the scope of the present invention.
Furthermore, it should be understood that although the present specification describes embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and it is to be understood that all embodiments may be combined as appropriate by one of ordinary skill in the art to form other embodiments as will be apparent to those of skill in the art from the description herein.
Claims (10)
1. The high-toughness lithium ion battery blended membrane is characterized by being composed of a solid material with micropores, wherein the solid material is a homogeneous mixture of polyethylene, a toughening polymer and a compatibilizer.
2. The high-toughness lithium ion battery blend membrane according to claim 1, wherein the solid material comprises the following components in percentage by weight: polyethylene: 74% -95%, toughening polymer: 4% -25%, compatibilizer: 0.4 to 2.5 percent.
3. The high-toughness lithium ion battery blend membrane according to claim 2, wherein the number average molecular weight of the polyethylene is between 80 and 190 ten thousand g/mol.
4. The high-toughness lithium ion battery blend membrane as claimed in claim 2, wherein the toughening polymer is one or two of ethylene-vinyl acetate copolymer and ethylene-octene copolymer, and the VA content of the ethylene-vinyl acetate copolymer is between 8 wt% and 28 wt%.
5. The high-toughness lithium ion battery blend membrane according to claim 2, wherein the compatibilizer is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene and a styrene-butadiene-styrene triblock copolymer.
6. A preparation method of the high-toughness lithium ion battery blended membrane according to any one of claims 1 to 5, characterized by comprising the following steps:
the method comprises the following steps: extruding the toughening polymer and the plasticizer by an extruder and then granulating to obtain a toughening polymer pretreatment material;
step two: placing polyethylene, a toughening polymer pretreatment material and a compatibilizer in a high-speed mixer, and uniformly mixing to obtain a mixed material;
step three: adding the mixed material prepared in the step two into an extruder, injecting white oil into the extruder, extruding and casting the mixture to a chill roll through a T-shaped die head to obtain a cast sheet;
step four: performing biaxial stretching on the cast sheet prepared in the step three by using a synchronous biaxial stretcher to obtain an oil-containing film;
step five: extracting the oil-containing membrane prepared in the step four by using an extracting agent to prepare a wet membrane;
step six: and D, standing the wet film prepared in the fifth step at a ventilation position at room temperature, fixing the wet film by using a clamping die, then carrying out heat setting, and finally carrying out a winding process to prepare the high-toughness lithium ion battery blending diaphragm.
7. The preparation method of the high-toughness lithium ion battery blend membrane according to claim 6,
in the first step, the extrusion temperature is between 100 ℃ and 140 ℃, and the screw rotating speed of an extruder is between 130rpm and 150 rpm;
in the second step, the fly cutter rotating speed of the high-speed mixer is between 550r/min and 830r/min, the charging barrel rotating speed of the high-speed mixer is between 9r/min and 12r/min, and the stirring time of the high-speed mixer is between 30min and 45 min;
in the third step, the temperature of the chill roll is between 10 ℃ and 25 ℃;
in the fourth step, the biaxial stretching temperature is 115-125 ℃, and the biaxial stretching magnification is 6-8 times;
in the fifth step, the extraction time is between 2min and 4 min;
in the sixth step, the heat setting temperature is between 90 ℃ and 130 ℃, and the heat setting time is between 0.5min and 2 min.
8. The preparation method of the high-toughness lithium ion battery blended membrane according to claim 7, wherein in the first step, the mass ratio of the components of the toughening polymer pretreatment material is 50 wt% -65 wt% of the toughening polymer, 35 wt% -50 wt% of the plasticizer, and the plasticizer is one or more of white oil, mineral oil, soybean oil, toluene and xylene.
9. The preparation method of the high-toughness lithium ion battery blended membrane according to claim 7, wherein in the third step, the cast sheet comprises 18-30 wt% of solid material and 70-82 wt% of plasticizer, and the thickness of the cast sheet is 700-1000 μm.
10. The method for preparing the high-toughness lithium ion battery blend membrane according to claim 7, wherein in the fifth step, the extracting agent is one or more of dichloromethane, chloroform, benzene, carbon disulfide and ethanol.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210426404.1A CN114725612B (en) | 2022-04-22 | 2022-04-22 | High-toughness lithium ion battery blending diaphragm and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210426404.1A CN114725612B (en) | 2022-04-22 | 2022-04-22 | High-toughness lithium ion battery blending diaphragm and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114725612A true CN114725612A (en) | 2022-07-08 |
| CN114725612B CN114725612B (en) | 2023-11-21 |
Family
ID=82245811
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210426404.1A Active CN114725612B (en) | 2022-04-22 | 2022-04-22 | High-toughness lithium ion battery blending diaphragm and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114725612B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117559081A (en) * | 2024-01-08 | 2024-02-13 | 中材锂膜(内蒙古)有限公司 | Ultrathin polyolefin lithium battery diaphragm, preparation method thereof and lithium ion battery |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101356206A (en) * | 2005-03-17 | 2009-01-28 | 陶氏环球技术公司 | Thermoplastic vulcanizate comprising interpolymers of ethylene/alpha-olefins |
| JP2009091461A (en) * | 2007-10-09 | 2009-04-30 | Asahi Kasei Chemicals Corp | Microporous polyolefin film |
| CN102751459A (en) * | 2011-04-22 | 2012-10-24 | 北京东皋膜技术有限公司 | Nano microporous diaphragm made of post-crosslinked rubber and polyolefin composite, and manufacturing method thereof |
| CN107057334A (en) * | 2017-05-12 | 2017-08-18 | 四川恒领皓睿塑胶科技有限公司 | Toughness reinforcing strengthens the preparation method of polymer composites |
| CN111200094A (en) * | 2020-01-14 | 2020-05-26 | 江苏厚生新能源科技有限公司 | High-strength high-elongation lithium battery diaphragm and preparation method thereof |
| CN112405935A (en) * | 2020-11-19 | 2021-02-26 | 厦门长塑实业有限公司 | Matte black polyamide film for lithium ion battery, black master batch of matte black polyamide film and preparation method of black master batch |
-
2022
- 2022-04-22 CN CN202210426404.1A patent/CN114725612B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101356206A (en) * | 2005-03-17 | 2009-01-28 | 陶氏环球技术公司 | Thermoplastic vulcanizate comprising interpolymers of ethylene/alpha-olefins |
| JP2009091461A (en) * | 2007-10-09 | 2009-04-30 | Asahi Kasei Chemicals Corp | Microporous polyolefin film |
| CN102751459A (en) * | 2011-04-22 | 2012-10-24 | 北京东皋膜技术有限公司 | Nano microporous diaphragm made of post-crosslinked rubber and polyolefin composite, and manufacturing method thereof |
| CN107057334A (en) * | 2017-05-12 | 2017-08-18 | 四川恒领皓睿塑胶科技有限公司 | Toughness reinforcing strengthens the preparation method of polymer composites |
| CN111200094A (en) * | 2020-01-14 | 2020-05-26 | 江苏厚生新能源科技有限公司 | High-strength high-elongation lithium battery diaphragm and preparation method thereof |
| CN112405935A (en) * | 2020-11-19 | 2021-02-26 | 厦门长塑实业有限公司 | Matte black polyamide film for lithium ion battery, black master batch of matte black polyamide film and preparation method of black master batch |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117559081A (en) * | 2024-01-08 | 2024-02-13 | 中材锂膜(内蒙古)有限公司 | Ultrathin polyolefin lithium battery diaphragm, preparation method thereof and lithium ion battery |
| CN117559081B (en) * | 2024-01-08 | 2024-04-05 | 中材锂膜(内蒙古)有限公司 | Ultrathin polyolefin lithium battery diaphragm, preparation method thereof and lithium ion battery |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114725612B (en) | 2023-11-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105576172B (en) | cross-linked polyolefin diaphragm and preparation method thereof | |
| CN102931371B (en) | Battery diaphragm preparation method | |
| CN102320133A (en) | A kind of polyolefin battery separation film and preparation method thereof | |
| CN112467304B (en) | Organic fiber reinforced polyethylene lithium battery diaphragm and preparation method thereof | |
| CN103618055A (en) | Preparation method for polyolefin diaphragm of lithium ion battery | |
| CN114725612A (en) | High-toughness lithium ion battery blending diaphragm and preparation method thereof | |
| CN111086181A (en) | Preparation method of lithium battery diaphragm | |
| CN102627796A (en) | Polyethylene composition for manufacturing lithium battery diaphragm | |
| WO2024001488A1 (en) | Ultrahigh strength separators and preparation methods thereof | |
| KR101042931B1 (en) | Method for producing polyolefine microporous membrane | |
| CN111180645B (en) | Polyolefin porous membrane and preparation method thereof | |
| CN113921990A (en) | High-heat-resistance and high-breakdown-resistance lithium battery microporous diaphragm and preparation method thereof | |
| CN115458867A (en) | Polyolefin diaphragm and preparation method and application thereof | |
| CN101914259A (en) | Material special for preparing lithium ion battery diaphragm and preparation method thereof | |
| CN110931688A (en) | Highly extended polyolefin separator and applications | |
| CN116417751A (en) | High-strength lithium ion battery diaphragm and preparation method thereof | |
| CN112670668B (en) | Ultra-high molecular weight polyethylene lithium battery diaphragm and preparation method thereof | |
| WO2022052469A1 (en) | Polyolefin micro-porous membrane and preparation method therefor | |
| CN110945681A (en) | Lithium battery diaphragm and preparation method thereof | |
| CN116259924B (en) | Low-closed-pore-temperature diaphragm and preparation method thereof | |
| CN114566757B (en) | Lithium ion battery diaphragm with high strength and high liquid absorption rate and preparation method thereof | |
| CN106459467A (en) | Microporous polyolefin membrane | |
| CN112490582A (en) | High-mechanical-strength high-toughness diaphragm and preparation method thereof | |
| CN110931692A (en) | Polyolefin diaphragm and preparation method and application thereof | |
| CN104868082A (en) | Electrostatic spinning composite membrane for lithium ion battery and production technology of composite membrane |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |