Composite stacked and coated lithium ion battery diaphragm and preparation method thereof

A technology for ion batteries and lithium composites, which is applied in battery components, separators/films/diaphragms/spacers, circuits, etc., and can solve the problem that pure polyolefin separators cannot meet the needs of lithium-ion batteries and their safety. The problem of obtaining microporous materials with uniform pore size and low lithium ion conductivity can achieve the effect of high excellent rate, uniform pore size and wide range of material selection

Active Publication Date: 2015-03-04
HORIZON SPECIALTY MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, the vast majority of lithium-ion battery separators are polyolefins, usually polypropylene or polyethylene or a combination of the two. Due to the large difference in polarity between polyolefins and battery fluid, the wettability of the battery fluid to the separator is low. The low conductivity of lithium ions seriously affects the performance of the battery
With the development of new energy technology, especially the development of power lithium-ion batteries, higher requirements have been put forward for the pore size and distribution of the separator, the wettability of the electrolyte, and high temperature resistance. Pure polyolefin separators can no longer meet the requirements. Lithium-ion battery use and safety requirements
The existing production methods of lithium-ion battery separators include wet and dry processes. Due to the limitation of process conditions, it is difficult to produce microporous materials with uniform pore size, and at the same time, the selection of materials is also subject to great restrictions.
Due to the need to stretch the film, the produced diaphragm has a large shrinkage, which is also unfavorable to the final usability, and the excellent rate of the produced product is low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] A lithium-ion battery separator is prepared by single-layer coating, with a total thickness of 15 μm and a porosity of 55%, comprising the following steps:

[0034] a. Coating preparation:

[0035] The slurry components include: 2 parts of sodium chloride (NaCl), 13 parts of polyvinylpyrrolidone (PVP), 55 parts of xylene, 10 parts of liquid paraffin, 10 parts of thermoplastic elastomer (SEBS), 10 parts of homopolypropylene (i -PP). The SEBS is a linear styrene-butadiene triblock copolymer hydrogenated with polybutadiene block, wherein the content of styrene is 30wt%, and the solution viscosity is 500mPa·s. The melting point Tm of the i-PP is 168° C., the melt index MI is 10 g / min, and the added soluble porogen accounts for 4 times the total mass of other mixtures.

[0036] Slurry preparation method: After grinding NaCl, PVP, xylene, and liquid paraffin for 30 minutes, heat to 120°C, put in SEBS and i-PP, stir and dissolve to obtain a coating slurry.

[0037] b. Coati...

Embodiment 2

[0042] A lithium-ion battery separator is prepared by single-layer coating, with a total thickness of 16 μm and a porosity of 43%, including the following steps:

[0043] a. Coating preparation:

[0044] The components of slurry A-1 include: 1 part of silane coupling agent (KH570), 20 parts of ethyl acetate, 9 parts of nano silicon dioxide (nano-SiO 2 ), 25 parts of propoxylated trimethylolpropane (TMP3POTA), 10 parts of polyethylene glycol 1000 (PEG-1000), 5 parts of polyethylene glycol 200 (PEG-200), 30 parts of pure acrylate resin (DR-A845 ).

[0045] The preparation method of slurry A-1: ​​put KH570 into ethyl acetate, stir for 50min and then put in nano-SiO 2 , after stirring for 30 minutes, put in TMP3POTA, PEG-1000 and PEG-200, after stirring for 30 minutes, put in DR-A845, and stir for 30 minutes to get slurry A-1.

[0046] The composition of slurry A-2 includes: 40 parts of polyethylene wax and 60 parts of xylene. The polyethylene wax has an average particle size ...

Embodiment 3

[0056] A lithium-ion battery diaphragm was prepared by a two-layer overcoating method, with a total thickness of 25 μm, the thickness of the first layer was 20 μm, the thickness of the second layer was 5 μm, and the porosity was 43%, including the following steps:

[0057] a. Coating preparation:

[0058] The components of slurry B-1 include: 0.5 parts of silane coupling agent (KH570), 49.5 parts of ethyl acetate, and 50 parts of porous alumina. The average particle diameter of the porous alumina is 18 μm, and the average pore diameter is 8 nm.

[0059] The preparation method of slurry B-1: put KH570 into ethyl acetate, stir for 5 minutes, then add porous alumina, and stir for 30 minutes to obtain slurry B-1.

[0060] The ingredients of slurry B-2 include: 5 parts of 1-hydroxy-cyclohexyl-phenyl ketone (PI184), 40 parts of 4-tert-butylcyclohexyl acrylate (TBCHA), 15 parts of ethoxylated trimethylolpropane triacrylate (TMP3EOTA) and 40 parts aliphatic urethane acrylate (DR-U21...

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Abstract

The invention relates to a composite stacked and coated lithium ion battery diaphragm and a preparation method thereof. The diaphragm is a porous diaphragm which is prepared by mixing one or many kinds of coating sizing agents and is provided with a layer or multiple layers of structures; the porous diaphragm comprises the following components in parts by weight: 30-100 parts of a polymeric material, 0-70 parts of inorganic powder bodies and a surface treating agent thereof, and 0-50 parts of a compatibilizer; the polymeric material at least selects and uses two kinds of polymeric materials, one kind of the polymeric materials is a thermoplastic material of which the melting point or the viscous flow temperature is 100-150 DEG C, and the other kind of the polymeric materials is a thermoplastic material or a thermosetting material of which the melting point or the viscous flow temperature is higher than or equivalent to that of the thermoplastic material of which the melting point or the viscous flow temperature is 100-150 DEG C. The composite stacked and coated lithium ion battery diaphragm provided by the invention is uniform in bore diameter, good in wettability, favorable in heat resistance and good in hot melting and closing function, and the preparation method for the composite stacked and coated lithium ion battery diaphragm is simple in technology, wide in the material selecting range, and controllable in the micropore forming condition.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a laminated composite lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] The green and pollution-free secondary battery lithium-ion battery is in line with the development direction of energy and environmental protection in various countries today, and its usage in all walks of life is increasing rapidly. As an important part of lithium-ion batteries, the separator plays the role of separating the positive and negative electrodes of the battery cell, and its performance directly affects the overall performance of the battery. [0003] The lithium-ion battery separator is used to isolate the positive and negative electrodes in the battery, allowing free ions to pass between them, preventing the two electrodes from contacting and short-circuiting, and protecting the battery. Therefore, in addition to requiring a certain poro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14H01M50/403H01M50/446H01M50/489H01M50/491
CPCH01M50/40H01M50/46H01M50/449Y02E60/10
Inventor 冯润财郑少华
Owner HORIZON SPECIALTY MATERIAL
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