Lithium battery diaphragm preparation method based on mixed solvent multi-stage volatilization mechanism

A lithium battery separator and mixed solvent technology, applied in battery pack parts, circuits, electrical components, etc., can solve problems such as poor mechanical strength and rate performance

Active Publication Date: 2018-06-08
SHENZHEN LI S TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The phase inversion method is a common method for preparing polymer separators for lithium batteries. Its advantages are simple process, low cost, and easy operation. The obtained film has high liquid absorption rate, good electri...

Method used

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  • Lithium battery diaphragm preparation method based on mixed solvent multi-stage volatilization mechanism
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  • Lithium battery diaphragm preparation method based on mixed solvent multi-stage volatilization mechanism

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Embodiment 1

[0026] see figure 1 , the invention provides a method for preparing a lithium battery separator based on a mixed solvent multistage volatilization mechanism, comprising the following steps:

[0027] S1: Weigh a certain quality of PVDF-HFP, add a certain quality of acetone, the mass ratio of PVDF-HFP to acetone is: 0.1, and heat and stir in a water bath at 45°C-55°C to form a uniform first colloidal solution. Viscosity: 1500cp.

[0028] S2: Weigh a certain quality of PVDF-HFP and add it to a certain quality of acetone. The mass ratio of PVDF-HFP to acetone is 0.6. Stir at room temperature to form a uniform suspension, then add it to the first colloidal solution and stir at room temperature to obtain Uniform second colloidal solution, viscosity: 2000cp. The mass ratio of PVDF-HFP added in step S1 to PVDF-HFP added in this step is 3.0.

[0029] S3: Add a certain amount of NMP into the second colloidal solution, the mass ratio of NMP to the second colloidal solution is 0.2, and...

Embodiment 2

[0032] see figure 1 , the invention provides a method for preparing a lithium battery separator based on a mixed solvent multistage volatilization mechanism, comprising the following steps:

[0033] S1: Weigh a certain quality of PVDF-HFP, add a certain quality of acetone, the mass ratio of PVDF-HFP to acetone is: 0.12, and heat and stir in a water bath at 45-55°C to form a uniform first colloidal solution. The viscosity is: 2000cp.

[0034] S2: Weigh a certain mass of PVDF-HFP and add it to a certain mass of acetone, the mass ratio is: 0.4, stir at room temperature to form a uniform suspension, then add it to the first colloidal solution and stir at room temperature to obtain a uniform second colloidal solution Solution, viscosity: 3000cp. The mass ratio of PVDF-HFP added in step S1 to PVDF-HFP added in this step is 3.5.

[0035] S3: Add a certain amount of NMP into the second colloidal solution, the mass ratio of NMP to the solution is 0.4, and continue stirring to obtain...

Embodiment 3

[0038] see figure 1 , the invention provides a method for preparing a lithium battery separator based on a mixed solvent multistage volatilization mechanism, comprising the following steps:

[0039] S1: Weigh a certain amount of PVDF-HFP, add it into a certain amount of acetone, the mass ratio of PVDF-HFP to acetone is 0.14, and heat and stir in a water bath at 45-55°C to form a uniform first colloidal solution, the viscosity For: 2200cp;

[0040] S2: Weigh a certain quality of PVDF-HFP and add it to a certain quality of acetone. The mass ratio of PVDF-HFP to acetone is 0.3. Stir at room temperature to form a uniform suspension, and then add it to the first colloidal solution and stir at room temperature to obtain Uniform second colloidal solution, viscosity: 3000cp. The mass ratio of PVDF-HFP added in step S1 to PVDF-HFP added in this step is 3.8.

[0041] S3: Add a certain amount of DMF into the second colloidal solution, the mass ratio of DMF to the second colloidal solu...

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Abstract

The invention discloses a lithium battery diaphragm preparation method based on a mixed solvent multi-stage volatilization mechanism. The preparation method comprises the steps of performing heating dissolution on a certain mass of PVDF-HFP in a certain mass of first solvent, performing normal temperature dissolution on a certain mass of PVDF-HFP in a certain mass of first solvent, enabling the above two parts to be mixed uniformly and then adding a certain mass of second solvent, performing uniform mixing and than coating a base material, and carrying out drying to obtain the lithium batterydiaphragm. According to the preparation method, the PVDF-HFP is added into the first solvent in two times to form a cross-linked network structure with link; then the second solvent is added to dissolve a part of the link, and the dissolved partial link forms the cross-linked network structure to wind around the linkage; after drying, the first solvent is volatilized to form main lithium ion transmission holes; and the second solvent is volatilized to form holes in the cross-linked network structure around the link, so that the surrounding strength of the link of the lithium battery thin filmis reinforced, and the strength of the lithium battery diaphragm is further reinforced.

Description

technical field [0001] The invention relates to the technical field of lithium battery separators, in particular to a method for preparing lithium battery separators based on a mixed solvent multistage volatilization mechanism. Background technique [0002] In recent years, with the continuous development of new energy sources, the demand for lithium batteries is also increasing. Improving the overall safety and electrochemical performance of batteries is the focus of the current development of lithium batteries. The separator is an important part of the lithium battery, which affects the interface structure and internal impedance, and plays a vital role in the thermal stability, cycle performance, rate performance and safety of the battery. [0003] The phase inversion method is a common method for preparing polymer separators for lithium batteries. Its advantages are simple process, low cost, and easy operation. The obtained film has high liquid absorption rate, good elect...

Claims

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Application Information

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IPC IPC(8): H01M2/14H01M2/16C09D127/14C09D7/20H01M50/403H01M50/426H01M50/446H01M50/489
CPCC09D127/14C08L2205/025H01M50/403H01M50/411C08L27/14Y02E60/10
Inventor 何伟东杨铜陵陈太宝
Owner SHENZHEN LI S TECH CO LTD
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