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Lithium ion battery diaphragm and preparation method thereof

A lithium-ion battery and diaphragm technology, which is applied in secondary batteries, battery pack components, secondary battery repair/maintenance, etc., can solve the problems of easy melting, explosion and short circuit of the diaphragm, and achieve the purpose of preventing danger and improving safety performance Effect

Active Publication Date: 2018-05-29
JIANGXI TONRY NEW ENERGY TECH DEV CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a lithium-ion battery separator and a preparation method thereof, which are used to solve the problem that the separator in the lithium-ion battery in the prior art is easy to melt at a relatively high temperature and short circuit occurs. even the problem of exploding

Method used

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  • Lithium ion battery diaphragm and preparation method thereof

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preparation example Construction

[0049] The present invention also provides a method for preparing a lithium-ion battery diaphragm, which can prepare the above-mentioned diaphragm, and the preparation method at least includes the following steps:

[0050] First, prepare a polyolefin substrate layer with micropores;

[0051] Then, a sealant is formed on at least one side surface of the polyolefin base material layer, and the melting point of the sealer is lower than the melting point of the polyolefin base material layer, so as to ensure that when the temperature of the lithium-ion battery rises, the The sealing material is melted before the polyolefin substrate layer and sealed into the micropores of the polyolefin substrate layer, so as to block the electric path of the lithium-ion battery.

[0052] The polyolefin substrate layer with micropores can be prepared by conventional methods in the art.

[0053] As an example, the polyolefin substrate layer may be prepared using a thermally induced phase separatio...

Embodiment 1

[0072] 1. Select the ND12 series PE microporous base membrane produced by the thermally induced phase separation (TIPS) method and asynchronous double-drawing process of Shanghai Enjie Company. The mass ratio of the two polyolefins is 30 / 50, the density is 0.954, and the thickness is 12 μm , the porosity is 40%, and the air permeability is 200sec / 100ml;

[0073] 2. Coating the PE microporous base film with an MCD type coating machine (purchased from Fuji Machinery Industry Co., Ltd.), that is, the ratio of polyethylene oxide to polyethylene of the sealing material is 3:7, and the melting point is 85 ° C. The diameter is 350nm, and the distance from the micropore is 95nm. The composition slurry is coated on the PE microporous membrane, the coating rate of the sealing material is 80%, and finally baked in an oven to prepare a high-safety lithium-ion battery separator.

Embodiment 2

[0075] 1. Select the ND12 series PE microporous base membrane produced by the thermally induced phase separation (TIPS) method and asynchronous double-drawing process of Shanghai Enjie Company. The mass ratio of the two polyolefins is 40 / 50, the density is 0.958, and the thickness is 12 μm. The porosity is 40%, and the air permeability is 200sec / 100ml;

[0076] 2. Coating the PE microporous base film with an MCD type coating machine (purchased from Fuji Machinery Industry Co., Ltd.), that is, the ratio of polyethylene oxide and polyethylene of the sealing material is 4:6, and the melting point is 90 ° C. The diameter is 400nm, and the distance from the micropore is 98nm. The composition slurry is coated on the PE microporous membrane, the coating rate of the sealer is 90%, and finally baked in an oven to obtain a high-safety lithium-ion battery separator.

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Abstract

The invention provides a lithium ion battery diaphragm and a preparation method thereof. The lithium ion battery diaphragm at least comprises a polyolefin substrate layer and a pore sealing substance,wherein the polyolefin substrate layer comprises micro pores; the pore sealing substance is formed on the surface of at least one side of the polyolefin substrate layer; and the melting point of thepore sealing substance is lower than that of the polyolefin substrate layer. According to the lithium ion battery diaphragm provided by the invention, if the temperature of a battery is relatively high, before the polyolefin substrate layer is possibly molten, the pore sealing substance on the polyolefin substrate layer can be automatically molten firstly, the micro pores in the polyolefin substrate layer can be just blocked by the molten pore sealing substance, then the battery is prevented from electrification , danger can be avoided, and the security performance of the diaphragm is greatlyimproved.

Description

technical field [0001] The invention relates to the field of new energy lithium-ion battery diaphragms, in particular to a lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] At present, with the widespread application of power vehicles in daily life, due to the emergence of a large number of series-parallel battery packs, the safety performance of lithium-ion batteries has attracted much attention. In lithium-ion batteries, the separator used as a material to separate the positive and negative electrodes has higher and higher requirements for the safety of the battery, especially the short-circuit resistance of the separator and the contact performance between the positive and negative electrodes. The separator used in lithium-ion batteries is generally a polyolefin-based microporous membrane, because the melting point of this polyolefin-based microporous membrane is lower than 150°C, and there are a large number of micropores on th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/42H01M50/403H01M50/417
CPCH01M10/4235H01M50/403H01M50/411Y02E60/10
Inventor 程跃许东红邓洪贵岳齐
Owner JIANGXI TONRY NEW ENERGY TECH DEV CO LTD