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Composite porous diaphragm, and preparation method and application thereof

A technology of porous diaphragm and porous membrane, which is applied in the direction of electrical components, circuits, battery pack components, etc., can solve the problems of unable to meet the needs of power batteries and limit high-temperature performance, and achieve easy-to-implement processes and equipment, good universality, low cost effect

Inactive Publication Date: 2015-04-29
INST OF CHEM CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the currently produced separator is a single-layer structure, which limits the high-temperature performance and cannot meet the needs of power batteries.

Method used

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  • Composite porous diaphragm, and preparation method and application thereof
  • Composite porous diaphragm, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Dissolve 0.5g of polyethersulfone in 25ml of dichloromethane as a solvent, fully stir at 25°C for 10 minutes to obtain a transparent solution, then add 0.5ml of auxiliary ethanol under stirring conditions, and continue stirring for 5 minutes to obtain a dip coating solution. At an ambient temperature of 25°C and a humidity of 40-60%, dip-coat PE separator for 10s (thickness 20μm, porosity 55%, pore size 2-500nm), the dip-coated membrane is translucent, and the surface solvent quickly Volatilize, dry, and then solidify at 80°C for 5 minutes to obtain a composite porous membrane. The composite membrane has a thickness of 22 μm, a porosity of 55%, and a pore diameter of 2 nm-2 μm. Its morphology can be observed with a scanning electron microscope, see figure 1 .

Embodiment 2

[0028]Dissolve 0.5g of polyethersulfone in a mixed solvent of 15ml of dichloromethane and 10ml of toluene, fully stir at 25°C for 10min to obtain a transparent solution, then add 0.5ml of auxiliary ethanol under stirring conditions, and continue stirring for 5min to obtain Dip solution. In the same example as above, a composite porous diaphragm is obtained by dip coating (the thickness of the PE film is 20 μm, the porosity is 55%, and the pore diameter is 2-500 nm) and heat treatment. The composite membrane has a thickness of 22 μm, a porosity of 55%, and a pore diameter of 2 nm-2 μm.

Embodiment 3

[0030] Dissolve 0.5g of polyethersulfone in 25ml of dichloromethane as a solvent, fully stir at 25°C for 10 minutes to obtain a transparent solution, then add 1.0ml of auxiliary agent isopropanol under stirring conditions, and continue stirring for 5 minutes to obtain a dip coating solution. At a temperature of 25°C and a humidity of 40-60%, dip-coat the PE separator for 10s (the thickness of the PE film is 20μm, the porosity is 55%, and the pore size is 2-500nm), after the surface is dried, it is treated at 80°C for 5min, and then The second dip coating, the second heat treatment, the third dip coating, and the third heat treatment were carried out under the same conditions, and finally a composite porous diaphragm was obtained. The composite membrane has a thickness of 22 μm, a porosity of 55%, and a pore diameter of 2 nm-4 μm.

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Abstract

The invention discloses a composite porous diaphragm, and a preparation method and application thereof. The method comprises a step of compounding a layer of a heat-resisting porous material on the surface of a polyethylene diaphragm like polyethylene and polyvinylidene fluoride and a step of carrying out curing and pore forming in the process of compounding so as to obtain the composite porous diaphragm. The composite porous diaphragm brought forward in the invention employs multilayer materials with different thermal properties, so unique performance in the process of heating is presented, i.e., the composite porous diaphragm is converted from a porous membrane to a compact membrane with a basically unchangeable size when the composite porous diaphragm is heated to a certain temperature (a pore closing temperature), and changes comprise that an intermediate polyethylene layer undergoes pore closing and a heat-resisting composite layer maintains its original shape, thereby maintaining dimensional integrity of the composite porous diaphragm. The unique performance is directed at the demand for high security of power cells; and according to verification results of small-scale and medium-scale testing, the preparation method is applicable to large-scale production and is a special technology for a diaphragm of a power cell.

Description

technical field [0001] The invention relates to a composite porous diaphragm, a preparation method and application thereof. Background technique [0002] The dwindling oil resources have seriously restricted the development of the automobile industry. In the existing research on alternative energy sources for vehicle power, pure battery power is an important development direction. Driven by domestic and foreign electric vehicle-related industrial policies, a new round of lithium-ion power battery investment and development boom is taking shape internationally. [0003] The battery separator material is one of the key inner components of the battery. Its function is to separate the positive and negative electrodes of the battery but allow ions to pass through quickly; when the battery is overheated, it blocks the current conduction in the battery through the closed-pore function to realize the safety protection of the battery. In addition, the chemical stability and electro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M2/18C08J9/36C08J9/38C08L23/06
CPCY02E60/10
Inventor 杨振忠李焦丽张成亮梁福鑫王朝阳
Owner INST OF CHEM CHINESE ACAD OF SCI