Abab-type multilayer lithium-ion battery separator with thermal shutdown function and preparation method thereof

A lithium-ion battery, thermal shutdown technology, applied to battery components, separators/films/diaphragms/spacers, circuits, etc., can solve the residual stress of porous films, poor thermal dimensional stability, and reduce the diaphragm Thermal shrinkage and other issues, to achieve effective thermal shutdown function, improve thermal stability, uniform thickness

Active Publication Date: 2020-02-14
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The process route of the manufacturing process is relatively complicated, the investment in equipment is large, and the production efficiency is low (Deimede V, Elmasides C. Separators forlithium-ion batteries: A Review on the Production Processes and Recent Developments. Energy Technology, 2015, 3(5): 453-468)
In addition, the disadvantage of the current commercial multilayer separator is that the porous film prepared after multiple stretches has residual stress, which makes it easy to shrink greatly when encountering high temperature, resulting in poor thermal dimension. stability
In order to improve the poor thermal stability of the current commercial multilayer polyolefin separators, researchers are committed to reducing the thermal shrinkage of the separators through various modification methods
For example, the organic polymer / inorganic oxide with excellent thermal stability is coated on the surface of the diaphragm, but this process is complicated and difficult to produce in batches, which greatly increases the cost of the diaphragm

Method used

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  • Abab-type multilayer lithium-ion battery separator with thermal shutdown function and preparation method thereof
  • Abab-type multilayer lithium-ion battery separator with thermal shutdown function and preparation method thereof
  • Abab-type multilayer lithium-ion battery separator with thermal shutdown function and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Example 1: Using solid paraffin as diluent and n-hexane as extractant, microlayer co-extrusion technology and thermal phase separation method were used to prepare a polypropylene / polyethylene multilayer porous diaphragm with uniform layer thickness.

[0052] Specific steps are as follows:

[0053] (1) Preparation of polypropylene / polyethylene masterbatch

[0054] Before micro-layer co-extrusion, solid paraffin is pre-dispersed in polypropylene resin and polyethylene resin, and the above components are pre-mixed, and put into a twin-screw extruder to prepare a masterbatch of polypropylene resin and polyethylene resin ;

[0055] Its raw material composition is counted as in parts by mass:

[0056] 45 parts of polypropylene resin,

[0057] 45 parts of polyethylene resin,

[0058] 110 parts of solid paraffin,

[0059] 180 parts of n-hexane;

[0060] (2) Preparation of polypropylene resin / polyethylene resin multilayer porous separator

[0061] Two-component micro-laye...

Embodiment 2

[0072] Example 2: Polypropylene / polyethylene multilayer porous diaphragms with different layer thicknesses were prepared by using solid paraffin as diluent and petroleum ether as extractant by microlayer coextrusion technology and thermal phase separation method.

[0073] Specific steps are as follows:

[0074] (1) Preparation of polypropylene resin / polyethylene resin masterbatch

[0075] Before the micro-layer co-extrusion, the diluent is pre-dispersed in the polypropylene resin and polyethylene resin, and the above components are pre-mixed, and put into the twin-screw extruder to prepare the masterbatch of polypropylene resin and polyethylene resin ;

[0076] Its raw material composition is counted as in parts by mass:

[0077] 45 parts of polypropylene resin,

[0078] 70 parts of polyethylene resin,

[0079] 150 parts of solid paraffin

[0080] 190 parts of petroleum ether;

[0081] (2) Preparation of polypropylene resin / polyethylene resin multilayer porous separator ...

Embodiment 3

[0083] Example 3: Using liquid paraffin as diluent and chloroform as extractant, microlayer co-extrusion technology and heat-induced phase separation method were used to prepare ethylene-propylene copolymer / polyethylene oxide multilayer porous diaphragm.

[0084] Specific steps are as follows:

[0085] (1) Preparation of ethylene-propylene copolymer / polyethylene oxide masterbatch

[0086] Before micro-layer co-extrusion, the diluent is pre-dispersed in polyethylene oxide and ethylene-propylene copolymer, and the above components are pre-mixed, and then put into a twin-screw extruder to prepare polyethylene oxide and ethylene-propylene copolymer material masterbatch;

[0087] Its raw material composition is counted as in parts by mass:

[0088] 80 parts of ethylene-propylene copolymer,

[0089] 80 parts of polyethylene oxide,

[0090] 80 parts of liquid paraffin,

[0091] 130 parts of chloroform;

[0092] (2) Preparation of ethylene-propylene copolymer / polyethylene oxide ...

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Abstract

The invention belongs to the technical field of polymer materials, in particular to an ABAB type multilayer lithium-ion battery diaphragm with thermal shutdown function and a preparation method thereof. The present invention selects a polymer with a higher melting point as the A layer, selects a polymer with a lower melting point as the B layer, and combines the microlayer co-extrusion technology with the thermally induced phase separation technology to prepare an ABAB alternating multilayer lithium-ion battery diaphragm. The present invention utilizes the low melting point of the polymer B layer to obtain a lower diaphragm closed cell temperature to prevent the temperature from further increasing under high temperature conditions, and utilizes the high melting point of the polymer A layer to obtain a higher film deformation temperature to avoid the positive The short circuit caused by the contact of the negative electrode makes the diaphragm have a wider safety window and more effective thermal shutdown function; the diaphragm prepared by the present invention has uniform thickness, rich submicron porous structure, uniform and controllable pore structure, and thermal stability Excellent, with an effective thermal shutdown function, and has application prospects in the fields of lithium-ion battery separators and other fields.

Description

technical field [0001] The invention belongs to the technical field of polymer materials, and in particular relates to a lithium-ion battery diaphragm and a preparation method thereof. Background technique [0002] Lithium-ion batteries (LIB) are widely used in MP3, mobile phones, notebook computers and other fields due to their high working voltage, high energy density and long cycle life (Arora P, Zhang Z. Battery separators. Chemical Reviews, 2004, 104(10 ): 4419-4462). However, due to the existence of flammable electrolytes and oxidants in lithium-ion batteries, there are hidden dangers of fire and explosion during battery use. In order to promote the application of lithium-ion batteries in high energy density fields, it is necessary to further improve their safety and stability. Using a battery separator with thermal shutdown is an effective way to prevent catastrophic thermal failure during Li-ion battery life. From the consideration of safety performance, the diaphr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M50/403H01M50/457H01M50/489
CPCH01M50/409H01M50/403Y02E60/10
Inventor 浦鸿汀李亚捷
Owner TONGJI UNIV
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