Composite separator and preparation method thereof

A composite diaphragm, inorganic composite technology, applied in the application of lithium batteries, lithium battery composite diaphragm and its preparation, the field of composite diaphragm materials, can solve the problems that cannot be well adapted to the battery production process, to improve the migration and diffusion ability, Wide range of application fields and improved compatibility

Active Publication Date: 2019-05-28
CHANGSHA ADVANCED MATERIALS IND RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, although the heat resistance of the separator prepared by this method is good, its mechanical strength, such as tensile strength and needle punch strength, is far behind that of the polyolefin separator, which cannot well meet the requirements of the battery production process.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The preparation method of lithium battery composite diaphragm is as follows:

[0031] Step a. Dissolve the polyimide with N,N-dimethylacetamide and tetrahydrofuran at 45-50°C under stirring conditions to prepare a polyimide solution with a mass concentration of 17%, and then add lithium hydroxide , continue to stir to form a uniform and stable spinning solution; vacuum defoaming for later use.

[0032] Step b. Inject the spinning solution obtained in a into the nozzle of the electrospinning machine, use corona-treated 9 μm thick polyethylene microporous membrane (PE) as the base material, at a temperature of 30-40 ° C and a humidity of less than 50 Electrospinning was carried out in an environment with %RH and an electric field strength of 100 kv / m to obtain the primary product of the composite separator.

[0033] Step c. Carry out roll-setting treatment at 120° C. on the initial product of the composite diaphragm obtained in b, and then dry at 105° C. to obtain a comp...

Embodiment 2

[0036] The preparation method of lithium battery composite diaphragm is as follows:

[0037]Step a. Dissolve polyarylsulfone with dimethyl sulfoxide under stirring conditions at 20-25°C to prepare a polyarylsulfone solution with a mass concentration of 15%, then add lithium hexafluorophosphate, and continue stirring to form a uniform and stable spinning solution ; Reserve after vacuum defoaming.

[0038] Step b. Inject the spinning solution obtained in a into the nozzle of an electrospinning machine, and use a corona-treated 16 μm thick polypropylene microporous membrane (PP) as the substrate, at a temperature of 30-40 ° C and a humidity of less than 50 Electrospinning was carried out in an environment with %RH and an electric field strength of 150 kv / m to obtain the primary product of the composite separator.

[0039] Step c. The primary product of the composite diaphragm obtained in b is subjected to roll-setting treatment at 130°C, and then dried at 120°C.

[0040] Step d...

Embodiment 3

[0044] The preparation method of lithium battery composite diaphragm is as follows:

[0045] Step a. Dissolve polyaryl ether sulfone ketone with N-methylpyrrolidone and tetrahydrofuran under stirring conditions at 55° C. to prepare a polyaryl ether sulfone ketone solution with a mass concentration of 20%, and then add bis(trifluoromethyl sulfone Acyl) imide lithium, continue to stir to form a uniform and stable spinning solution; set aside after vacuum defoaming.

[0046] Step b. Inject the spinning solution obtained in a into the nozzle of an electrospinning machine, and use a corona-treated 16 μm thick polyolefin three-layer composite microporous membrane (PP / PE / PP) as the base material, at a temperature of 30- Electrospinning is carried out in an environment of 40° C., humidity lower than 50% RH, and electric field strength of 120 kv / m to obtain the primary product of the composite diaphragm.

[0047] Step c. Carry out roll-setting treatment at 140° C. on the primary produ...

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Abstract

The invention relates to a composite separator and a preparation method thereof. The lithium battery composite separator is formed by compounding a polyolefin microporous membrane and one or two high-temperature-resistant non-woven fabric layers, wherein the thickness of the composite separator is 6-40[mu]m, the surface density is 5-35g/m<2>, the porosity is 35-50%, the liquid absorption rate is greater than 150%, the thermal shrinkage rate at 130 DEG C is less than 0.5%, and the ionic conductivity is (1.0-5.0)*10<-3>S/cm. The composite separator disclosed by the invention has the advantages that the is fast; the lithium battery composite diaphragm has the characteristics of fast electrolyte infiltration, high liquid absorption rate, low thermal shrinkage rate, good mechanical property andthe like, the compatibility of the separator and an electrolyte is improved, the safety and the service life of a lithium battery are improved, and the prepared composite separator also adapts to thetechnological requirements of mechanical assembly of a battery production line and has a relatively wide application field.

Description

technical field [0001] The invention belongs to the field of diaphragms, and relates to a composite diaphragm material, in particular to a lithium battery composite diaphragm with high ion conductivity and high temperature resistance, a preparation method thereof, and an application thereof in lithium batteries. technical background [0002] With the advancement of science and technology and the development of society, high-efficiency energy storage equipment has gradually become an indispensable part of people's work and life. As one of the high-efficiency energy storage materials, lithium batteries have the advantages of high energy density, high power density, long cycle life, no memory performance, fast charging and discharging, etc., and have been widely used in portable devices such as mobile phones and notebook computers. With the rise and promotion of electric vehicles and hybrid vehicles in recent years, the demand for lithium batteries has become more extensive and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/052H01M50/403H01M50/417H01M50/44H01M50/449H01M50/491H01M50/497
CPCY02E60/10
Inventor 王芳黄活阳李衍李真真罗熙雯
Owner CHANGSHA ADVANCED MATERIALS IND RES INST CO LTD
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