High-temperature-resistant flame-retardant battery diaphragm, and preparation method and application thereof

A technology for battery separators and lithium battery separators, applied in secondary batteries, battery pack components, circuits, etc., can solve problems such as battery short circuit, ceramic particles are easy to fall, and the stability of lithium battery separators is reduced, achieving excellent heat resistance and mechanical properties, good electrolyte wettability, excellent heat insulation and flame retardant performance

Active Publication Date: 2021-02-23
CHINA UNIV OF GEOSCIENCES (BEIJING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the temperature exceeds 160°C, the diaphragm structure will be damaged and the battery will be short-circuited.
In practical applications, the temperature of the battery can be as high as 200°C in a short period of time, far exceeding the melting point of polyethylene and polypropylene separators, making the separators invalid and easily leading to fires and combustion incidents in electric vehicles
[0003] The traditional ceramic lithium battery diaphragm is coated with a coating containing ceramic particles on one or both sides of the diaphragm substrate to improve the safety of the diaphragm, but the coating process is complicated and the controllability is poor. Ceramic particles The coating is very easy to cause uneven or uneven coating, which will lead to a decrease in the stability of the lithium battery separator at high temperatures
Since lithium batteries are widely used in mobile phones, computers, electric vehicles and other fields, the voltage and capacity of lithium batteries continue to increase, and there are higher requirements for the high-temperature stability of lithium battery separators, while traditional ceramic lithium battery separators work at high temperatures. , the coated ceramic particles are easy to fall off, resulting in a short circuit between the positive and negative electrodes of the lithium battery, resulting in serious safety accidents

Method used

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  • High-temperature-resistant flame-retardant battery diaphragm, and preparation method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0034] This embodiment provides a high-temperature-resistant flame-retardant battery separator, and the preparation method includes the following steps:

[0035] (1) Preparation of nanocellulose suspension: add carboxymethylcellulose to ionic liquid (1 ethyl-3-methylimidazolium acetate) to dissolve, and hydrolyze at 160°C for 12 hours to obtain nanocellulose fibers Suspension, wherein the nanocellulose fibers have a diameter of 2 nm and an aspect ratio of 100.

[0036] (2) Preparation of basalt fiber slurry: add basalt fiber with a diameter of 3 μm and a length of 20 μm into the solvent (N-methylpyrrolidone), and then add silane coupling agent KH550, wherein the amount of silane coupling agent is basalt 0.5 wt% of fiber, stirred for 2 hours to form a slurry.

[0037] (3) Spinning: the nanocellulose fiber suspension in (1) is mixed with the basalt slurry in (2) to obtain a mixed solution, and the volume fractions of the nanocellulose fiber suspension and the basalt slurry are ...

Embodiment 2

[0041] This embodiment provides a high-temperature-resistant flame-retardant battery separator, and the preparation method includes the following steps:

[0042] (1) Preparation of nanocellulose suspension: add cellulose nitrate to ionic liquid (1 ethyl-3-methylimidazolium acetate) to dissolve, and perform hydrolysis at 120°C for 12 hours to obtain nanocellulose fiber suspension liquid, wherein the nanocellulose fibers have a diameter of 50 nm and an aspect ratio of 60.

[0043] (2) Preparation of basalt fiber slurry: add basalt fiber with a diameter of 15 μm and a length of 70 μm into the solvent (N-methylpyrrolidone), and then add silane coupling agent KH560, wherein the amount of silane coupling agent is basalt 0.5 wt% of fiber, stirred for 4 hours to form a slurry.

[0044] (3) Spinning: the nanocellulose fiber suspension in (1) is mixed with the basalt slurry in (2) to obtain a mixed solution, and the volume fractions of the nanocellulose fiber suspension and the basalt ...

Embodiment 3

[0048] This embodiment provides a high-temperature-resistant flame-retardant battery separator, and the preparation method includes the following steps:

[0049] (1) Preparation of nanocellulose suspension: add natural fibers extracted from cotton to ionic liquid (1 ethyl-3-methylimidazolium acetate) to dissolve, and hydrolyze at 80°C for 12 hours to obtain nanofibers Suspension of cellulose fibers with a diameter of 500 nm and an aspect ratio of 15.

[0050] (2) Preparation of basalt fiber slurry: add basalt fiber with a diameter of 25 μm and a length of 100 μm into the solvent (N-methylpyrrolidone), and then add silane coupling agent KH560, wherein the amount of silane coupling agent is basalt 0.5 wt% of fiber, stirred for 4 hours to form a slurry.

[0051] (3) spinning: the nanocellulose fiber suspension in (1) is mixed with the basalt slurry in (2) to obtain a mixed solution, and the volume fractions of the nanocellulose fiber suspension and the basalt slurry are 50% and ...

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Abstract

The invention provides a high-temperature-resistant flame-retardant battery diaphragm, and a preparation method and an application thereof. The high-temperature-resistant flame-retardant battery diaphragm comprises nano cellulose fibers and basalt fibers, wherein the mass fraction of the nano cellulose fibers is 99%-60%, and the mass fraction of the basalt fibers is 1%-40%. The diaphragm preparedby optimally combining the nano cellulose fibers and the basalt fibers gives play to the advantages of the nano cellulose fibers and the basalt fibers, has high porosity, good electrolyte wettabilityand excellent heat resistance and mechanical properties, and can improve the rate capability, prolong the service life and improve the safety of the battery.

Description

technical field [0001] The invention relates to the technical field of battery separator materials, and more particularly, to a high-temperature-resistant and flame-retardant battery separator, a preparation method and application thereof. Background technique [0002] The battery diaphragm is a layer of diaphragm material between the positive and negative electrodes of the battery. As a key material for lithium batteries, the diaphragm plays the role of isolating electrons, preventing direct contact between the positive and negative electrodes, and allowing lithium ions in the electrolyte to pass freely. At the same time, The separator also plays a vital role in ensuring the safe operation of the battery. Currently, commercial lithium battery separators on the market are mainly microporous polyolefin separators based on polyethylene (PE) and polypropylene (PP). This type of separator relies on low cost, good mechanical properties, excellent Due to the advantages of chemica...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/44H01M50/446H01M50/431H01M50/411H01M50/403H01M10/0525H01M10/054D01D5/00D04H1/4382D04H1/728
CPCH01M10/0525H01M10/054D04H1/4382D04H1/728D01D5/003D01D5/0092D01D5/0061Y02E60/10
Inventor 张以河李益王琦王珂
Owner CHINA UNIV OF GEOSCIENCES (BEIJING)
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