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Preparation method of para-aramid nanometer fiber composite lithium ion battery separator

A para-aramid fiber and nanofiber technology is applied in the field of preparation of para-aramid nanofiber composite lithium ion battery separator, which can solve the problem of poor separator adhesion, increased surface energy of coating slurry, poor battery performance, etc. problems, to achieve the effect of improving high temperature resistance, saving solvent and energy, low viscosity and surface energy

Active Publication Date: 2017-12-08
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method has the following problems: PPTA fibers or resins are difficult to dissolve, and the adhesion to the polyolefin separator is poor, and additional binders need to be added
On the one hand, there are other impurities in the composite membrane, and on the other hand, the porosity is reduced, both of which will cause a decline in battery performance.
The 2nd, in the Japanese patent that the patent No. is unexamined 2010-254731, proposed the technology that the polymerization solution of p-aramid fibers is coated as a slurry, but still there are following three problems in its technical scheme: (1 ) A large amount of solubilizing salt (the solubilizing salt is more than 6% of the solvent quality) has been added in the aramid polymer solution, which causes the surface energy of the coating slurry to increase, and it is difficult to spread evenly on the surface of the base film with low surface energy. As a result, the uniformity and bonding fastness of the prepared composite diaphragm are not good; (2) In order to dissolve a large amount of solubilizing salt, the solvent needs to be heated to 100°C to dissolve the solubilizing salt and then cooled to 20°C for polymerization, resulting in The energy consumption increases and the operation process is cumbersome; (3) The solidification and precipitation process of this technical solution is completed in pure water, and the rapid desolventization process makes the aramid fiber coating dense and cannot form a through-hole structure, resulting in a decrease in the lithium ion passing efficiency, and the battery poor performance

Method used

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  • Preparation method of para-aramid nanometer fiber composite lithium ion battery separator
  • Preparation method of para-aramid nanometer fiber composite lithium ion battery separator

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preparation example Construction

[0022] The preparation method of the p-aramid fiber nanofiber composite lithium-ion battery diaphragm that the present invention proposes comprises the following steps:

[0023] (1) Preparation of para-aramid polymerization slurry:

[0024] Under the protection of nitrogen, add 1.5 to 3 parts of solubilizing salt and 0.5 to 2.5 parts of p-phenylenediamine to 100 parts by weight of N-methyl-2-pyrrolidone with a water content of less than 100 ppm, stir in an ice-water bath until completely dissolved, Then add terephthaloyl dichloride, keep stirring to carry out polymerization, wherein the molar ratio of terephthaloyl dichloride to p-phenylenediamine is: 1.000-1.010, polymerize for 10-30 minutes, stop stirring, and obtain para-aramid polymerization pulp material, wherein the solubilizing salt is calcium chloride or lithium chloride;

[0025] (2) Coating:

[0026] Coating the para-aramid polymerization slurry on the surface of the base film by a coating method to prepare a coati...

Embodiment 1

[0034] Measure 1 LN-methyl-2-pyrrolidone, add 20.00g of calcium chloride and 17.30g of p-phenylenediamine in a nitrogen protection and ice-water bath, stir at a speed of 500rpm until completely dissolved, then reduce the stirring speed to Raise to 800rpm and add 32.71g of terephthaloyl chloride to it, stop stirring after 12 minutes of reaction; spread a polypropylene porous film with a thickness of 25 μm on an automatic coating machine, adjust the height of the scraper to 150 μm, at a speed of 3m / min Coating; immerse the coated diaphragm in a coagulation bath containing N-methyl-2-pyrrolidone: water = 9:1 (v:v) to solidify, take it out after 30 seconds, wash it with water for 20 seconds, and set it at 100°C and drying for 15 minutes to obtain a lithium-ion battery separator composed of para-aramid fiber nanofibers. The thickness of the lithium-ion battery separator composed of para-aramid nanofibers is 30 μm, and the thickness of the para-aramid nanofiber layer is 5 μm.

[00...

Embodiment 2

[0037]Measure 1 LN-methyl-2-pyrrolidone, add 15.00g of calcium chloride and 5.00g of p-phenylenediamine in a nitrogen protection and ice-water bath, stir at a speed of 500rpm until completely dissolved, then reduce the stirring speed to Increase to 800rpm and add 9.45g terephthaloyl chloride to it, stop stirring after 30 minutes of reaction; spread a polyethylene porous film with a thickness of 20 μm on the automatic coating machine, adjust the height of the scraper to 50 μm, at a speed of 3m / min Coating; immerse the coated diaphragm in a coagulation bath containing N-methyl-2-pyrrolidone: water = 19:1 (v:v) to solidify, take it out after 10 seconds, wash it with water for 8 seconds, and set it at 100°C and dry for 1 min to obtain a lithium-ion battery separator composed of para-aramid fiber nanofibers. The thickness of the lithium-ion battery separator composed of para-aramid nanofibers is 20.5 μm, and the thickness of the para-aramid nanofiber layer is 0.5 μm.

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Abstract

The invention relates to a preparation method of a para-aramid nanometer fiber composite lithium ion battery separator, and belongs to the technical field of a high polymer material. The preparation method comprises the steps of preparing para-aramid polymer paste, coating the para-aramid polymer paste on a surface of a base membrane by a coating method, and solidifying the coating film in coagulation bath comprising N-methly-2-pyrrolidone and water to obtain the para-aramid nanometer fiber composite lithium ion battery separator; and washing and drying the para-aramid nanometer fiber composite lithium ion battery separator to obtain a finished product of the para-aramid nanometer fiber composite lithium ion battery separator. Compared with the prior art, the preparation method has the advantages that a solvent and an energy source are saved, energy consumption is also reduced, and unfavorable influence of impurity on battery performance is prevented; and moreover, the preparation process is simple, and the high-temperature resistant performance of the separator is improved, the prepared separator has favorable ion conductivity and can obtain relatively good performance when used as the lithium ion battery separator.

Description

technical field [0001] The invention relates to a method for preparing a para-aramid nanofiber composite lithium-ion battery diaphragm, and belongs to the technical field of polymer materials. Background technique [0002] In recent years, the lithium-ion battery industry has developed rapidly. As a mature and common form of energy in mobile devices, compared with other types of batteries, it has the characteristics of high energy density, high working voltage, no memory effect and long cycle life. A lithium-ion battery generally includes a positive electrode, a negative electrode, a separator, and an electrolyte. The separator serves to make the positive and negative electrodes in a state of electronic insulation but conduction of lithium ions. With the rise of electric vehicles, the emergence of high-power power batteries poses a huge challenge to the safety of lithium-ion batteries. At present, the common lithium-ion battery separator is made of polyolefin, usually a sa...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16C08G69/28C08G69/32H01M50/403H01M50/411H01M50/449H01M50/489
CPCC08G69/28C08G69/32H01M50/411H01M50/44H01M50/403H01M50/449Y02E60/10
Inventor 庹新林何濂远
Owner TSINGHUA UNIV
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