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Compound lithium battery diaphragm prepared by spraying electrospun fibers to polyolefin microporous membrane and preparation method thereof

A technology of polyolefin microporous membrane and polyolefin diaphragm, which is applied in the directions of electrospinning, fiber processing, battery pack parts, etc., can solve the problems of increasing the safety of the diaphragm, the mechanical strength needs to be improved, and the relative sliding is easy to occur. The effect of improving charge-discharge cycle stability, improving electrochemical stability window, and improving high-temperature thermal stability

Inactive Publication Date: 2017-10-20
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this invention, the upper diaphragm and the lower diaphragm are laminated on both sides of the ceramic slurry layer, which greatly increases the safety of the diaphragm and greatly reduces the short circuit phenomenon during the manufacturing process and use of the lithium battery. However, the existence of the intermediate ceramic slurry may cause The bonding force between the upper and lower diaphragm layers is limited, and relative sliding is easy to occur
[0007] Patent CN201410542516.9 proposes a ceramic-coated separator for lithium batteries and its preparation method, which is mainly to uniformly coat the water-based ceramic coating slurry composed of alumina, adhesive, etc. on the surface of the substrate separator to make a ceramic Composite diaphragm, the ceramic coating diaphragm prepared by this method has improved thermal safety and strong wettability to electrolyte, which can improve the cycle life of the battery when applied to lithium batteries, but the bonding force between the ceramic phase and the organic phase is weak, and it is easy to There is a phenomenon of ceramic shedding (powder falling)
[0008] Patent CN201410806915.1 proposes a preparation method of a lithium battery separator. Two layers of polyethylene film are laminated on the upper and lower sides of the non-woven fabric base layer. The prepared lithium battery separator has high porosity, low thickness, high liquid absorption, The characteristics of low resistance make the lithium battery have the advantages of high capacity and long service life, but the polyethylene diaphragm on the outer layer of the composite film makes the overall thermal stability of the diaphragm poor, which cannot improve the safety performance of the lithium battery diaphragm.
[0009] Patent CN201610038212.8 proposes a new high-performance electrospun polyarylether sulfone ketone lithium battery diaphragm preparation method. During the electrospinning process, a high-speed rotating roller is used as a receiving device to obtain polyarylether with highly oriented fibers Sulfone ketone nanofiber membrane, the diaphragm prepared by this method has high porosity, can withstand high temperature of 220 ° C, and has good wettability to electrolyte, but the oriented fiber diaphragm only has high mechanical strength in one direction, and the mechanical strength in the other direction is high. Intensity needs to be improved

Method used

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  • Compound lithium battery diaphragm prepared by spraying electrospun fibers to polyolefin microporous membrane and preparation method thereof
  • Compound lithium battery diaphragm prepared by spraying electrospun fibers to polyolefin microporous membrane and preparation method thereof
  • Compound lithium battery diaphragm prepared by spraying electrospun fibers to polyolefin microporous membrane and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Take a certain amount of N,N dimethylacetamide (DMAc) solvent and dissolve a certain amount of PPESK powder in a round bottom flask to prepare a 25% mass fraction of PPESK polymer solution; place the PPESK solution in a magnetic stirrer The spinning solution was prepared by magnetic stirring at a constant temperature of 60°C for 8 hours, and then stored in a brown glass bottle for later use. Use a disposable syringe to take 5ml of poly(aryl ether sulfone ketone) spinning solution, use a stainless steel needle with a diameter of 0.6 mm as the spinning needle, fix the syringe on the spinning machine support, and stick the polypropylene PP diaphragm flat on the receiving plate , Adjust the position of the spinning needle so that the needle is in the center of the PP septum. Set the internal temperature of the electrospinning machine to 25℃, humidity to 25%, adjust the distance between the flat-mouth stainless steel needle and the receiving plate to 20cm, adjust the voltage ...

Embodiment 2

[0032] Take a certain amount of tetrahydrofuran and N,N dimethylformamide (DMF) mixed solvent with a volume ratio of 6:4, and dissolve a certain amount of PPESK powder in a round bottom flask to prepare a 20% mass fraction of PPESK polymer solution , Put the solution in a magnetic stirrer at 60°C and magnetically stir for 12 hours to obtain a spinning solution, and then store it in a brown glass bottle for later use. Stick the polypropylene PP diaphragm flatly on the receiving plate, and adjust the position of the spinning needle so that the needle is at the center of the PP diaphragm. Set the internal temperature of the electrospinning machine to 30℃, humidity to 20%, adjust the distance between the flat-mouth stainless steel needle and the receiving plate to 25cm, adjust the voltage to 25kV, and set the injection speed of the polyarylethersulfone ketone solution to 0.12mm / min, the spinning time is 1.5h. After the spinning is finished, remove the diaphragm from the receiving ...

Embodiment 3

[0035] Take a certain amount of tetrahydrofuran and N,N dimethylacetamide (DMAc) mixed solvent with a volume ratio of 4:6, dissolve a certain amount of PPESK powder in a round bottom flask to prepare a 15% mass fraction of PPESK polymer solution ; Place the solution in a magnetic stirrer at 60°C and magnetically stir for 12 hours to prepare a spinning solution, which is then stored in a brown glass bottle for later use. Stick the polyethylene PE diaphragm flatly on the receiving plate, and adjust the position of the spinning needle so that the needle is at the center of the PE diaphragm. Set the internal temperature of the electrospinning machine to 35℃, humidity to 20%, adjust the distance between the flat-mouth stainless steel needle and the receiving plate to 10cm, adjust the voltage to 15kV, and set the injection speed of the polyarylethersulfone ketone solution to 0.08mm / min, spinning time 2.5h, after spinning is finished, remove the diaphragm from the receiving plate, an...

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Abstract

The invention relates to a compound lithium battery diaphragm prepared by spraying electrospun fibers to a polyolefin microporous membrane and a preparation method thereof. The compound lithium battery diaphragm is a three-layered compound membrane by spraying electrospun fibers to the surface of the polyolefin microporous membrane. The intermediate layer of the three-layered compound membrane is formed by a polyolefin microporous diaphragm, the outer layer is formed by a polyaryl ether sulfone ketone nano fiber membrane which is high-temperature-resistant and good in wettability of electrolyte, the compound membrane has relatively high mechanical strength due to the polyolefin diaphragm of the intermediate layer, and the thermal stability and the wettability of electrolyte of the polyolefin diaphragm are effectively improved as a result of the polyaryl ether sulfone ketone nano fibers of the outer layer. Electrochemical testing verifies that the compound diaphragm shows relatively great ionic conductivity and relatively small interface resistance. In addition, the compound diaphragm assembled battery test result shows a stable cycle performance and a good high-rate discharge performance. Therefore, the polyolefin / polyaryl ether sulfone ketone three-layered compound membrane is expected to be a novel high performance lithium battery diaphragm.

Description

Technical field [0001] The invention relates to a novel lithium ion battery diaphragm and a preparation method thereof. Specifically, the invention relates to a method for preparing a composite lithium battery diaphragm by spraying a polyolefin microporous film with electrostatic spinning fibers, and belongs to the technical field of lithium battery diaphragms. Background technique [0002] With the depletion of fossil fuels such as coal and oil, energy issues have attracted more and more attention. Due to the advantages of high energy density and high power density, lithium batteries have been widely used in portable electronic products such as mobile phones and notebooks. In recent years, with the promotion of electric vehicles and hybrid vehicles, the demand for lithium power batteries has become more extensive. The safety performance and charge and discharge performance of the battery put forward higher requirements. [0003] Separator is an important component in lithium batt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14D01D5/00D04H1/4326D04H1/728
CPCD01D5/003D01D5/0084D04H1/4326D04H1/728H01M50/403H01M50/411H01M50/44H01M50/449Y02E60/10
Inventor 阮诗伦龚文正王新宇李征谷俊峰宋贝贝
Owner DALIAN UNIV OF TECH
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