CN112670665A - High-performance lithium battery diaphragm and preparation method thereof - Google Patents
High-performance lithium battery diaphragm and preparation method thereof Download PDFInfo
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- CN112670665A CN112670665A CN202011537072.1A CN202011537072A CN112670665A CN 112670665 A CN112670665 A CN 112670665A CN 202011537072 A CN202011537072 A CN 202011537072A CN 112670665 A CN112670665 A CN 112670665A
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 43
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 43
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- 239000012528 membrane Substances 0.000 claims abstract description 45
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims abstract description 36
- 229920013636 polyphenyl ether polymer Polymers 0.000 claims abstract description 36
- 238000005266 casting Methods 0.000 claims abstract description 28
- 238000003756 stirring Methods 0.000 claims abstract description 27
- 229920002725 thermoplastic elastomer Polymers 0.000 claims abstract description 27
- 239000000203 mixture Substances 0.000 claims abstract description 23
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 21
- 229920000642 polymer Polymers 0.000 claims abstract description 21
- 238000001035 drying Methods 0.000 claims abstract description 19
- 238000007493 shaping process Methods 0.000 claims abstract description 19
- 239000007788 liquid Substances 0.000 claims abstract description 13
- 239000002245 particle Substances 0.000 claims abstract description 13
- 238000001816 cooling Methods 0.000 claims abstract description 11
- 238000005096 rolling process Methods 0.000 claims abstract description 10
- 238000005406 washing Methods 0.000 claims abstract description 10
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 claims description 25
- 229920001610 polycaprolactone Polymers 0.000 claims description 25
- 239000004632 polycaprolactone Substances 0.000 claims description 25
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 20
- 238000002156 mixing Methods 0.000 claims description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 8
- 239000000155 melt Substances 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 239000004698 Polyethylene Substances 0.000 claims description 2
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical class C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 claims description 2
- 229920001577 copolymer Polymers 0.000 claims description 2
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 2
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims description 2
- -1 polyethylene Polymers 0.000 claims description 2
- 229920000573 polyethylene Polymers 0.000 claims description 2
- 239000000843 powder Substances 0.000 claims description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 2
- 229920000468 styrene butadiene styrene block copolymer Polymers 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 abstract description 4
- 238000009998 heat setting Methods 0.000 abstract description 2
- 229920000098 polyolefin Polymers 0.000 abstract description 2
- 238000012545 processing Methods 0.000 abstract description 2
- 229920001955 polyphenylene ether Polymers 0.000 abstract 1
- 238000001125 extrusion Methods 0.000 description 7
- 239000002994 raw material Substances 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000004721 Polyphenylene oxide Substances 0.000 description 5
- 229920006380 polyphenylene oxide Polymers 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229910001416 lithium ion Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 239000003063 flame retardant Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- SCYULBFZEHDVBN-UHFFFAOYSA-N 1,1-Dichloroethane Chemical compound CC(Cl)Cl SCYULBFZEHDVBN-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000004699 Ultra-high molecular weight polyethylene Substances 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000002145 thermally induced phase separation Methods 0.000 description 1
- 229920000785 ultra high molecular weight polyethylene Polymers 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- 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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- Cell Separators (AREA)
Abstract
The invention discloses a high-performance lithium battery diaphragm and a preparation method thereof. The diaphragm comprises the following components in percentage by weight: 30-59 wt.% polyphenylene ether; 1-10 wt.% of thermoplastic elastomer; 40-60 wt% of high polymer pore-forming agent. The preparation method comprises the following steps: (1) respectively crushing polyphenyl ether, thermoplastic elastomer and high polymer pore-forming agent particles, and drying in vacuum; (2) stirring and dispersing polyphenyl ether, a thermoplastic elastomer and a high polymer pore-forming agent to obtain a mixture; (3) putting the mixture into an extruder, and casting the mixture to a cooling roller for shaping through a die orifice to prepare a casting membrane; (4) longitudinally stretching the obtained cast membrane, transversely stretching, washing with dichloromethane, heat setting and rolling to obtain the high-performance lithium battery diaphragm; compared with the traditional polyolefin diaphragm, the high-performance lithium battery diaphragm prepared by the invention has the characteristics of high flame retardance, high strength, high heat resistance and high liquid absorption, and can be applied to the field of forming and processing of high-end lithium battery diaphragms.
Description
Technical Field
The invention relates to the technical field of new energy batteries, in particular to a high-performance lithium battery diaphragm and a preparation method thereof.
Background
The explosion of the lithium ion battery market is growing, the production and development of upstream and downstream materials are strongly pulled, and higher requirements are put forward on the performance of each material component. The diaphragm is one of the most critical inner layer assemblies in the structure of the lithium battery, and mainly has the functions of separating the positive and negative pole pieces to prevent the short circuit of the battery, ensuring the normal passing of lithium ions during charging and discharging and ensuring the normal work of the battery. The performance of the diaphragm directly affects the capacity, rate, service life and safety performance of the battery. Due to different preparation processes, the consistency of the diaphragm is likely to be greatly different, and some diaphragms have the phenomena of closed holes and blind holes, so that the capacity of the lithium battery is directly reduced, and the charge-discharge cycle life is prolonged. In addition, the flame retardance, the high-temperature stability and the mechanical strength of the diaphragm play an important role in improving the safety performance of the lithium ion battery.
In order to meet the current market requirements, the invention develops a high-performance lithium battery diaphragm, polyphenylene oxide and a thermoplastic elastomer are used as the substrate material of the diaphragm, a high polymer soluble in dichloroethane is used as a pore-forming agent, and the high-temperature-resistant, high-flame-retardant, high-strength and high-liquid-absorption-rate diaphragm is successfully developed.
Disclosure of Invention
The invention aims to provide a high-performance lithium battery diaphragm and a preparation method thereof, so as to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: the battery diaphragm comprises the following components in percentage by weight: 30-59 wt% of polyphenyl ether, 1-10 wt% of thermoplastic elastomer and 40-60 wt% of polymer pore-forming agent.
Furthermore, the melt flow rate of the polyphenyl ether is 0.1-2g/min, the heat distortion temperature is more than 160 ℃, and the melting point is more than 240 ℃.
Furthermore, the thermoplastic elastomer is one or more of a polyethylene butylene copolymer, a styrene-butadiene-styrene block copolymer, a hydrogenated styrene-butadiene block copolymer, an ethylene-vinyl acetate copolymer and an ethylene-vinyl alcohol copolymer, and the melt flow rate is 0.1-1.5 g/min.
Further, the high polymer pore-forming agent is polycaprolactone, the melt flow rate is 0.01-1.5g/min, and the melting point is higher than 40 ℃.
A preparation method of a high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, thermoplastic elastomer and high polymer pore-forming agent particles in a liquid nitrogen crusher, and drying for later use after crushing is finished;
(2) mixing and stirring the polyphenyl ether obtained in the step (1), the thermoplastic elastomer and the high polymer pore-forming agent to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, casting through a die orifice, and shaping through a cooling roller to prepare a casting membrane;
(4) and (4) longitudinally stretching the cast membrane prepared in the step (3), transversely stretching, washing with dichloromethane, shaping at high temperature, and rolling to prepare the high-performance lithium battery diaphragm.
Further, a preparation method of the high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, thermoplastic elastomer and high polymer pore-forming agent particles in a liquid nitrogen crusher, and drying for 1-10h at the temperature of 30-150 ℃ and the vacuum degree of less than or equal to-50 KPa for later use after crushing;
(2) mixing and stirring the polyphenyl ether, the thermoplastic elastomer and the high polymer pore-forming agent obtained in the step (1) for 0.5-2h, wherein the stirring speed is 50-200rpm, and the stirring temperature is 15-30 ℃, so as to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, casting by a die orifice, and shaping at the temperature of a cooling roller of 20-40 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the casting film prepared in the step (3) at the temperature of 150-.
Further, the particle size of the powder of the polyphenyl ether, the thermoplastic elastomer and the high polymer pore-forming agent in the step (1) is 1-50 um.
Further, the temperature of the extruder in the step (3) is 150-.
Further, the longitudinal stretching magnification of the casting film obtained in the step (4) is 2-8 times, and the transverse stretching magnification is 2-12 times.
The invention aims to provide a preparation method of a high-performance lithium battery diaphragm, the lithium battery diaphragm can be applied to the field of high-end power batteries, high-temperature-resistant, high-flame-retardant and high-strength polyphenyl ether is selected as a main matrix material of the diaphragm, a thermoplastic elastomer is added to endow the diaphragm with good elasticity, a high polymer soluble in dichloromethane is used as a pore-forming agent, and the high polymer pore-forming agent is dispersed in a diaphragm base material to form a special dispersed phase structure through an extrusion blending technology. Preparing a casting film by adopting a casting technology, improving the mechanical strength by longitudinal and transverse high-rate stretching, washing by dichloromethane to form a microporous structure, further improving the performance by heat setting, and finally rolling to obtain the high-performance lithium battery diaphragm.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention adopts the high polymer pore-forming agent to be dissolved in dichloromethane for pore formation, the micropores have the advantages of good connectivity, no blind holes and uniform pore size distribution, and the defect that the microporous diaphragm prepared by the traditional thermally induced phase separation method is easy to form a closed cellular pore structure is overcome.
(2) Compared with the traditional method using oily micromolecules, the method has the advantages of low volatilization and easy recovery, can effectively improve the production environment of the diaphragm, and reduces the production cost.
(3) When the high-performance lithium battery diaphragm is prepared, polyphenyl ether is used as a main matrix material of the diaphragm, and the thermoplastic elastomer is added to endow the diaphragm with good elasticity. Compared with the traditional polyolefin diaphragm, the high-performance high-temperature-resistant high-strength high-flame-retardance high-heat-resistance high-strength high-liquid-absorption-rate high-safety lithium battery diaphragm has the advantages of being high in flame retardance, high in heat resistance, high in strength and high in liquid absorption rate, greatly improving the service performance and safety performance of the lithium battery, being simple in preparation method and being capable of being applied to the field of forming and processing.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Preparing raw materials: 50g of polyphenyl ether, 5g of ethylene-vinyl alcohol copolymer serving as a thermoplastic elastomer and 45g of polycaprolactone.
The preparation method of the high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, ethylene-vinyl alcohol copolymer and polycaprolactone in a liquid nitrogen crusher until the particle size is 30 mu m, and crushing; drying polyphenylene oxide at 150 deg.C and vacuum degree of-50 KPa for 10h, drying ethylene-vinyl alcohol copolymer at 100 deg.C and vacuum degree of-50 KPa for 10h, and drying polycaprolactone at 40 deg.C and vacuum degree of-50 KPa for 10 h;
(2) mixing and stirring the polyphenyl ether, the ethylene-vinyl alcohol copolymer and the polycaprolactone obtained in the step (1) for 1h at the stirring speed of 150rpm and the stirring temperature of 30 ℃ to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, wherein the temperature of the extruder is 265 ℃, the rotating speed is 100rpm, and the extrusion amount is 400 kg/h; casting through a die orifice, and shaping at the temperature of a cooling roller of 30 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the cast membrane prepared in the step (3) at the temperature of 230 ℃, wherein the longitudinal stretching magnification is 6 times, transversely stretching the cast membrane at the temperature of 230 ℃, wherein the transverse stretching magnification is 6 times, washing the cast membrane by using dichloromethane after stretching, shaping the cast membrane at the temperature of 250 ℃, and rolling the cast membrane to prepare the high-performance lithium battery diaphragm.
Example 2
Preparing raw materials: 45g of polyphenyl ether, 5g of ethylene-vinyl alcohol copolymer serving as a thermoplastic elastomer and 50g of polycaprolactone.
The preparation method of the high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, ethylene-vinyl alcohol copolymer and polycaprolactone in a liquid nitrogen crusher until the particle size is 30 mu m, and crushing; drying polyphenylene oxide at 150 deg.C and vacuum degree of-50 KPa for 10h, drying ethylene-vinyl alcohol copolymer at 100 deg.C and vacuum degree of-50 KPa for 10h, and drying polycaprolactone at 40 deg.C and vacuum degree of-50 KPa for 10 h;
(2) mixing and stirring the polyphenyl ether, the ethylene-vinyl alcohol copolymer and the polycaprolactone obtained in the step (1) for 1h at the stirring speed of 150rpm and the stirring temperature of 30 ℃ to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, wherein the temperature of the extruder is 265 ℃, the rotating speed is 100rpm, and the extrusion amount is 400 kg/h; casting through a die orifice, and shaping at the temperature of a cooling roller of 30 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the cast membrane prepared in the step (3) at the temperature of 230 ℃, wherein the longitudinal stretching magnification is 6 times, transversely stretching the cast membrane at the temperature of 230 ℃, wherein the transverse stretching magnification is 6 times, washing the cast membrane by using dichloromethane after stretching, shaping the cast membrane at the temperature of 250 ℃, and rolling the cast membrane to prepare the high-performance lithium battery diaphragm.
Example 3
Preparing raw materials: 35g of polyphenyl ether, 5g of ethylene-vinyl alcohol copolymer serving as a thermoplastic elastomer and 60g of polycaprolactone.
The preparation method of the high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, ethylene-vinyl alcohol copolymer and polycaprolactone in a liquid nitrogen crusher until the particle size is 30 mu m, and crushing; drying polyphenylene oxide at 150 deg.C and vacuum degree of-50 KPa for 10h, drying ethylene-vinyl alcohol copolymer at 100 deg.C and vacuum degree of-50 KPa for 10h, and drying polycaprolactone at 40 deg.C and vacuum degree of-50 KPa for 10 h;
(2) mixing and stirring the polyphenyl ether, the ethylene-vinyl alcohol copolymer and the polycaprolactone obtained in the step (1) for 1h at the stirring speed of 150rpm and the stirring temperature of 30 ℃ to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, wherein the temperature of the extruder is 265 ℃, the rotating speed is 100rpm, and the extrusion amount is 400 kg/h; casting through a die orifice, and shaping at the temperature of a cooling roller of 30 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the cast membrane prepared in the step (3) at the temperature of 230 ℃, wherein the longitudinal stretching magnification is 6 times, transversely stretching the cast membrane at the temperature of 230 ℃, wherein the transverse stretching magnification is 6 times, washing the cast membrane by using dichloromethane after stretching, shaping the cast membrane at the temperature of 250 ℃, and rolling the cast membrane to prepare the high-performance lithium battery diaphragm.
Example 4
Preparing raw materials: 40g of polyphenyl ether, 10g of ethylene-vinyl alcohol copolymer serving as a thermoplastic elastomer and 50g of polycaprolactone.
The preparation method of the high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, ethylene-vinyl alcohol copolymer and polycaprolactone in a liquid nitrogen crusher until the particle size is 40 mu m, and drying for 7 hours at the temperature of 90 ℃ and the vacuum degree of-100 KPa for later use after crushing;
(2) mixing and stirring the polyphenyl ether, the ethylene-vinyl alcohol copolymer and the polycaprolactone obtained in the step (1) for 0.5 to 2 hours at the stirring speed of 180rpm and the stirring temperature of 30 ℃ to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, wherein the temperature of the extruder is 230 ℃, the rotating speed is 90rpm, and the extrusion amount is 300 kg/h; casting through a die orifice, and shaping at the temperature of a cooling roller of 20 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the cast membrane prepared in the step (3) at the temperature of 150 ℃, wherein the longitudinal stretching magnification is 6 times, transversely stretching the cast membrane at the temperature of 150 ℃, wherein the transverse stretching magnification is 6 times, washing the cast membrane by using dichloromethane after stretching, shaping the cast membrane at the temperature of 200 ℃, and rolling the cast membrane to prepare the high-performance lithium battery diaphragm.
Example 5
Preparing raw materials: 45g of polyphenyl ether, 5g of ethylene-vinyl alcohol copolymer serving as a thermoplastic elastomer and 50g of polycaprolactone.
(1) Respectively crushing polyphenyl ether, ethylene-vinyl alcohol copolymer and polycaprolactone in a liquid nitrogen crusher until the particle size is 40 mu m, and drying for 7 hours at the temperature of 90 ℃ and the vacuum degree of-100 KPa for later use after crushing;
(2) mixing and stirring the polyphenyl ether, the ethylene-vinyl alcohol copolymer and the polycaprolactone obtained in the step (1) for 0.5 to 2 hours at the stirring speed of 180rpm and the stirring temperature of 30 ℃ to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, wherein the temperature of the extruder is 230 ℃, the rotating speed is 90rpm, and the extrusion amount is 300 kg/h; casting through a die orifice, and shaping at the temperature of a cooling roller of 20 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the cast membrane prepared in the step (3) at the temperature of 150 ℃, wherein the longitudinal stretching magnification is 2 times, transversely stretching the cast membrane at the temperature of 150 ℃, wherein the transverse stretching magnification is 2 times, washing the cast membrane by using dichloromethane after stretching, shaping the cast membrane at the temperature of 200 ℃, and rolling the cast membrane to prepare the high-performance lithium battery diaphragm.
Example 6
Preparing raw materials: 45g of polyphenyl ether, 5g of ethylene-vinyl alcohol copolymer serving as a thermoplastic elastomer and 50g of polycaprolactone.
The preparation method of the high-performance lithium battery diaphragm comprises the following steps;
(1) respectively crushing polyphenyl ether, ethylene-vinyl alcohol copolymer and polycaprolactone in a liquid nitrogen crusher until the particle size is 30 mu m, and crushing; drying polyphenylene oxide at 150 deg.C and vacuum degree of-50 KPa for 10h, drying ethylene-vinyl alcohol copolymer at 100 deg.C and vacuum degree of-50 KPa for 10h, and drying polycaprolactone at 40 deg.C and vacuum degree of-50 KPa for 10 h;
(2) mixing and stirring the polyphenyl ether, the ethylene-vinyl alcohol copolymer and the polycaprolactone obtained in the step (1) for 1h at the stirring speed of 150rpm and the stirring temperature of 30 ℃ to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, wherein the temperature of the extruder is 265 ℃, the rotating speed is 100rpm, and the extrusion amount is 400 kg/h; casting through a die orifice, and shaping at the temperature of a cooling roller of 30 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the cast membrane prepared in the step (3) at the temperature of 230 ℃, wherein the longitudinal stretching magnification is 8 times, transversely stretching the cast membrane at the temperature of 230 ℃, wherein the transverse stretching magnification is 8 times, washing the cast membrane by using dichloromethane after stretching, shaping the cast membrane at the temperature of 250 ℃, and rolling the cast membrane to prepare the high-performance lithium battery diaphragm.
Comparative example 1
Comparative example 1 is an ultra high molecular weight polyethylene alumina ceramic coated membrane produced by a company using a wet and coating process.
Test examples
The diaphragms prepared in the above examples 1 to 6 and comparative example 1 were tested for tensile strength and elongation at break by a universal mechanical tester; testing the porosity and the liquid absorption rate by adopting a weighing method; testing the thermal shrinkage rate by using a vacuum oven dryer, wherein the testing temperature is 120 ℃, and the testing time is 30 min; the limit oxygen index is tested by using a limit combustion tester, and the test result is shown in table 1;
TABLE 1
It can be seen from table 1 that the high-performance lithium battery separators prepared in examples 1 to 6 have significant performance advantages in strength, toughness, flame retardancy, heat resistance, and absorption rate, compared to comparative example 1. Compared with the examples 1-3, under the condition of the same preparation method, the content of the polycaprolactone is increased, and the porosity of the diaphragm is obviously improved. In example 2, the elongation at break of the separator was significantly increased by increasing the amount of the ethylene-vinyl alcohol copolymer compared to example 4. In example 5, the tensile strength of the separator was reduced by reducing the draw ratio, compared with example 2, in the case of the same amount of the component.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A high performance lithium battery separator, characterized in that; the battery diaphragm comprises the following components in percentage by weight; 30-59 wt% of polyphenyl ether, 1-10 wt% of thermoplastic elastomer and 40-60 wt% of polymer pore-forming agent.
2. The high performance lithium battery separator according to claim 1, wherein; the melt flow rate of the polyphenyl ether is 0.1-2g/min, the heat distortion temperature is more than 160 ℃, and the melting point is more than 240 ℃.
3. The high performance lithium battery separator according to claim 1, wherein; the thermoplastic elastomer is one or more of a polyethylene butylene copolymer, a styrene-butadiene-styrene block copolymer, a hydrogenated styrene-butadiene block copolymer, an ethylene-vinyl acetate copolymer and an ethylene-vinyl alcohol copolymer.
4. The high-performance lithium battery separator according to claim 3, wherein; the thermoplastic elastomer has a melt flow rate of 0.1 to 1.5 g/min.
5. The high performance lithium battery separator according to claim 1, wherein; the high polymer pore-forming agent is polycaprolactone, the melt flow rate is 0.01-1.5g/min, and the melting point is higher than 40 ℃.
6. A preparation method of a high-performance lithium battery diaphragm is characterized by comprising the following steps of; comprises the following steps;
(1) respectively crushing polyphenyl ether, thermoplastic elastomer and high polymer pore-forming agent particles in a liquid nitrogen crusher, and drying for later use after crushing is finished;
(2) mixing and stirring the polyphenyl ether obtained in the step (1), the thermoplastic elastomer and the high polymer pore-forming agent to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, casting through a die orifice, and shaping through a cooling roller to prepare a casting membrane;
(4) and (4) longitudinally stretching the cast membrane prepared in the step (3), transversely stretching, washing with dichloromethane, shaping at high temperature, and rolling to prepare the high-performance lithium battery diaphragm.
7. The method for preparing a high-performance lithium battery separator according to claim 6, wherein; comprises the following steps;
(1) respectively crushing polyphenyl ether, thermoplastic elastomer and high polymer pore-forming agent particles in a liquid nitrogen crusher, and drying for 1-10h at the temperature of 30-150 ℃ and the vacuum degree of less than or equal to-50 KPa for later use after crushing;
(2) mixing and stirring the polyphenyl ether, the thermoplastic elastomer and the high polymer pore-forming agent obtained in the step (1) for 0.5-2h, wherein the stirring speed is 50-200rpm, and the stirring temperature is 15-30 ℃, so as to obtain a mixture;
(3) putting the mixture prepared in the step (2) into an extruder, casting by a die orifice, and shaping at the temperature of a cooling roller of 20-40 ℃ to prepare a casting membrane;
(4) and (3) longitudinally stretching the casting film prepared in the step (3) at the temperature of 150-.
8. The method for preparing a high-performance lithium battery separator according to claim 7, wherein; in the step (1), the particle size of the powder of the polyphenyl ether, the thermoplastic elastomer and the high polymer pore-forming agent is 1-50 um.
9. The method for preparing a high-performance lithium battery separator according to claim 7, wherein; the temperature of the extruder in the step (3) is 150-.
10. The method for preparing a high-performance lithium battery separator according to claim 7, wherein; and (4) the longitudinal stretching magnification of the casting film obtained in the step (4) is 2-8 times, and the transverse stretching magnification is 2-12 times.
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| CN202011537072.1A CN112670665A (en) | 2020-12-23 | 2020-12-23 | High-performance lithium battery diaphragm and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114050307A (en) * | 2021-11-17 | 2022-02-15 | 深圳市汉清达科技有限公司 | High-performance lithium battery |
| CN114566757A (en) * | 2021-12-31 | 2022-05-31 | 宁波长阳科技股份有限公司 | High-strength high-liquid-absorption-rate lithium ion battery diaphragm and preparation method thereof |
-
2020
- 2020-12-23 CN CN202011537072.1A patent/CN112670665A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114050307A (en) * | 2021-11-17 | 2022-02-15 | 深圳市汉清达科技有限公司 | High-performance lithium battery |
| CN114050307B (en) * | 2021-11-17 | 2024-04-12 | 深圳市汉清达科技有限公司 | High-performance lithium battery |
| CN114566757A (en) * | 2021-12-31 | 2022-05-31 | 宁波长阳科技股份有限公司 | High-strength high-liquid-absorption-rate lithium ion battery diaphragm and preparation method thereof |
| CN114566757B (en) * | 2021-12-31 | 2023-08-04 | 宁波长阳科技股份有限公司 | Lithium ion battery diaphragm with high strength and high liquid absorption rate and preparation method thereof |
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