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A kind of high heat-resistant lithium-ion battery diaphragm and preparation method thereof

A lithium-ion battery, high heat-resistant technology, applied in the direction of secondary batteries, battery pack components, circuits, etc., can solve the problems of small pore size of heat-resistant coating, low air permeability of diaphragm, poor heat resistance, etc., to achieve power consumption Low energy, simple and easy preparation method, and the effect of ensuring permeability

Active Publication Date: 2016-08-24
乐凯胶片股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to increase the fusing temperature of the lithium-ion battery diaphragm, improve the puncture resistance of the diaphragm, improve the durability of the diaphragm material under high voltage conditions, and enhance its service life, the current common practice is to modify it. One is to add a heat-resistant layer on the polyolefin porous membrane. The heat-resistant layer usually uses inorganic ceramic particles and polymer heat-resistant fibers. The preparation method usually includes the following steps: preparing coating liquid, coating, solidifying, washing and setting, Drying, in which the micropores of the film are formed in one step during the solidification process, but there are the following problems: the pore size of the heat-resistant coating is small and uniform, and the porosity is low; the air permeability of the diaphragm is low, and the heat resistance is poor

Method used

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  • A kind of high heat-resistant lithium-ion battery diaphragm and preparation method thereof
  • A kind of high heat-resistant lithium-ion battery diaphragm and preparation method thereof
  • A kind of high heat-resistant lithium-ion battery diaphragm and preparation method thereof

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preparation example Construction

[0025] The preparation method of the high heat-resistant lithium-ion battery diaphragm of the present invention adopts the "two-step pore-making" technology, that is, the microporous film coated with the heat-resistant coating is coated at room temperature and air-dried for 30-120 seconds for prefabrication Pores, if the drying time is too short, the pore-forming agent will not be fully volatilized, and the effect of pre-forming pores will not be achieved; if the drying time is too long, the coating will appear in a gel state. After pre-forming holes, a new phase of heat-resistant fiber coagulation is formed on the edge of the part where the pore-forming agent exists, and the local surface tension rises to form tiny holes. Diffusion-dissolution pore formation in a one-step coagulation bath is easier to perform.

[0026] The coagulation bath in the coagulation step of the present invention contains organic solvent N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidon...

Embodiment 1

[0040] (1) Preparation of coating solution: Add 1g of polym-phenylene isophthalamide to a container containing 98g of N,N-dimethylacetamide solvent, and stir slowly with a stirrer until the fibers are completely dissolved . Add 0.25g of n-pentane and 0.75g of ethyl acetate into the above solution evenly, stir evenly, and keep stirring for 60min to obtain a uniform coating solution;

[0041] (2) Coating: Heat the above-mentioned coating solution to 30°C. During the stirring process, the mouth of the container should be sealed to reduce the volatilization of the solvent. The polyethylene microporous base film is immersed in the above coating solution, and the base film is pulled out of the coating solution at a coating speed of 1 cm / s;

[0042] (3) Prefabricated holes: air dry for 120s in the air;

[0043] (4) Coagulation: then immerse it in a coagulation bath composed of 20% ethanol, 20% ethylene glycol, and 3% N,N-dimethylacetamide, and stay for 15 seconds.

[0044] (5) Was...

Embodiment 2

[0048] (1) Preparation of coating solution: Add 3g of polym-phenylene isophthalamide into a container containing 94g of N,N-dimethylacetamide solvent, and stir slowly with a stirrer until the fibers are completely dissolved . Add 0.75g of petroleum ether and 2.25g of ethyl acetate into the above solution evenly, stir evenly, and keep stirring for 60min to obtain a uniform coating solution;

[0049] (2) Coating: Then heat the coating solution to 50°C. During the heating and stirring process, the mouth of the container should be sealed to reduce the volatilization of the solvent. After that, the polyethylene with a porosity of 50% should be coated by dip coating. The microporous base film is immersed in the above coating solution, and the base film is pulled out of the coating solution at a coating speed of 10mm / s;

[0050] (3) Prefabricated holes: air dry for 110s in the air;

[0051] (4) Coagulation: immerse it in a coagulation bath composed of 7% N,N-dimethylacetamide, 10% ...

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PUM

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Abstract

A high heat-resistant lithium-ion battery separator, comprising a polyolefin porous membrane and at least one layer of heat-resistant coating coated on the polyolefin porous membrane, the coating surface density of the heat-resistant coating is 2.0-3.0g / m2, the average pore diameter of the coating is 6-10 μm; the fusing temperature of the lithium-ion battery separator is ≥210°C, the porosity is 40-70%, and the air permeability is ≤500s / 100cc·in2·1.22KPa. The membrane of the invention has uniform pore diameter, sufficiently high porosity and high fusing temperature, which are enough to ensure the safety of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a high-heat-resistant lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] Rechargeable lithium-ion batteries have the advantages of high working voltage, high energy density, long cycle life, no memory effect, no pollution, and fast charging and discharging. They are widely used in daily electronics, electrical appliances and digital products, and have a broad market space. and good development prospects. With the increasing demand for battery quality, the technical problem of how to ensure the safety of lithium batteries follows. [0003] Polyolefin separator is one of the key components of rechargeable lithium-ion batteries and the key to ensuring the safety of lithium-ion batteries. The quality of the separator has a great impact on the capacity, service life and safety of the battery. In order to increase the fusing te...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16H01M50/449
CPCH01M10/0525H01M50/403H01M50/449Y02E60/10
Inventor 江晓利高甲刘国鑫彭朝利
Owner 乐凯胶片股份有限公司