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Composite lithium ion battery diaphragm and preparation method thereof

A lithium-ion battery and composite technology, applied in the direction of secondary batteries, battery components, separators/films/diaphragms/spacers, etc., can solve the problems of low strength and production efficiency, easy short circuit, and easy wiping of the fiber layer In order to reduce the short-circuit rate of the battery, meet the high capacity and improve the performance

Inactive Publication Date: 2015-07-08
LONGYAN ZIJIN INNOVATION RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a composite lithium-ion battery diaphragm and its preparation method to solve the problems of low strength and production efficiency of pure electrospun fiber membranes, easy short circuit of existing non-woven polymer coated diaphragms, and problems of existing non-woven fabrics. The problem that the fiber layer is easily scratched and damaged in the cloth / electrospinning technology

Method used

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  • Composite lithium ion battery diaphragm and preparation method thereof
  • Composite lithium ion battery diaphragm and preparation method thereof
  • Composite lithium ion battery diaphragm and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 1) Preparation of electrospinning solution: dissolve polyimide in DMAc (N,N-dimethylacetamide), the polyimide mass volume ratio concentration concentration is 5wt%, measure the polyimide solution The viscosity is 100mPa.S.

[0035] 2) Electrospinning: The prepared polyimide solution electrospinning solution is passed through a nanofiber spinning machine to carry out single-sided continuous electrospinning on a PET non-woven fabric substrate to obtain a PI / PET nanofiber composite film. The electrospinning conditions are as follows: temperature 10°C, positive voltage 20kV, negative voltage 530kV, spinning speed 1g per minute per meter width;

[0036] The composite membrane obtained after the spinning is completed is subjected to post-treatment: first, it is formed by hot pressing with a roller at 80° C., and then dried in an oven at 120° C. for 1 minute.

[0037] Electron micrographs of the surface of unmodified non-woven fabric samples are as follows: figure 1 As shown...

Embodiment 2

[0042] 1) Preparation of electrospinning solution: Preparation of electrospinning solution: dissolve polyimide in DMAc (N,N-dimethylacetamide), the mass volume ratio concentration of polyimide is 30wt%, and measure the The viscosity of the polyimide solution is 3000mPa.S.

[0043] 2) Electrospinning: The prepared polyimide solution electrospinning solution is carried out double-sided continuous electrospinning on the PET non-woven fabric substrate through a nanofiber spinning machine to obtain a PI / PET nanofiber composite film, The electrospinning conditions are: temperature 40°C, positive voltage 50kV, negative voltage 30kV, spinning speed 10g per minute per meter width;

[0044] The composite membrane obtained after the spinning is completed is subjected to post-treatment: first, it is formed by hot pressing with a roller at 200° C., and then dried in an oven at 120° C. for 5 minutes.

[0045] 3) Preparation of polymer porous coating by phase transfer method: PVDF-HFP (Arke...

Embodiment 3

[0047] 1) Preparation of electrospinning solution: Preparation of electrospinning solution: dissolve polyacrylonitrile (PAN) in NMP, the mass volume ratio concentration of polyacrylonitrile is 10wt%, and the viscosity of the polyimide solution is measured to be 1000mPa. S.

[0048] 2) Electrospinning: The prepared polyacrylonitrile solution electrospinning solution is passed through a nanofiber spinning machine to carry out single-sided continuous electrospinning on a PP non-woven fabric substrate to obtain a PAN / PP nanofiber composite film. The conditions of electrospinning described above are: temperature 30°C, positive voltage 20kV, negative voltage negative 30kV, spinning speed 5g per minute per meter width;

[0049] The composite membrane obtained after the spinning is completed is subjected to post-processing: first, it is formed by hot pressing with a roller at 100° C., and then dried in an oven at 120° C. for 4 minutes.

[0050] 3) Preparation of polymer porous coatin...

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Abstract

The invention discloses a composite lithium ion battery diaphragm comprising a nonwoven fabric substrate layer, an electrostatic spinning layer and a polymer porous coating, and the structure compound mode is as follows: polymer porous coating / electrostatic spinning layer / nonwoven fabric substrate layer / electrostatic spinning layer / polymer porous coating; nonwoven fabric substrate layer / electrostatic spinning layer / polymer porous coating; or polymer porous coating / nonwoven fabric substrate layer / electrostatic spinning layer / polymer porous coating. The composite lithium ion battery diaphragm uses nonwoven fabric as a substrate to ensure the diaphragm high porosity and heat resistance, electrostatic spinning layers are arranged on the upper and lower surfaces of the nonwoven fabric substrate, the nonwoven fabric pore diameter can be reduced, the pore diameter is uniform, and the problem of short circuit caused by local macropore of the nonwoven fabric diaphragm can be solved, and by the arrangement of the polymer porous coating, the absorption and electrolyte maintaining capacity of the diaphragm can be improved, battery positive and negative electrodes can be bonded, battery mechanical properties can be improved, and the battery safety can be ensured. The prepared composite lithium ion battery diaphragm can satisfy the security requirements of large current charging discharging and running in harsh environments of a high-capacity high-power power battery.

Description

technical field [0001] The invention relates to the technical field of battery separators, in particular to a composite lithium-ion battery separator and a preparation method thereof. Background technique [0002] Lithium-ion power batteries are the key core components of new energy vehicles. The performance requirements of high-capacity and high-power lithium-ion power batteries under dynamic conditions such as high power output and fast charging and discharging pose a major challenge to the safety of lithium batteries. It puts forward higher requirements for the strength, thermal dimensional stability, thermochemical and electrochemical stability of the separator. The poor electrolyte absorption and retention ability of the polyolefin separator obtained by the traditional stretching process affects the battery capacity, and the porosity is not high (about 40%), which affects the rate discharge performance and cycle life of the battery. In addition, the heat resistance does...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M50/403H01M50/44H01M50/449
CPCH01M10/0525H01M50/403H01M50/409H01M50/411H01M50/44Y02E60/10
Inventor 刘向文李文锋
Owner LONGYAN ZIJIN INNOVATION RES INST
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