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Preparation method of porous PVDF film for battery separator

A battery diaphragm and scraping film technology, applied in secondary batteries, battery pack components, circuits, etc., to achieve good thermal stability, stable performance, and improved electrochemical performance

Active Publication Date: 2018-10-23
HENAN INST OF ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] As human beings have higher and higher requirements for product quality, a single PVDF diaphragm can no longer meet people's needs

Method used

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  • Preparation method of porous PVDF film for battery separator
  • Preparation method of porous PVDF film for battery separator
  • Preparation method of porous PVDF film for battery separator

Examples

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Effect test

Embodiment 1

[0033] A method for preparing a porous PVDF membrane for a battery diaphragm, the preparation steps are as follows:

[0034] (1) Put the PVDF powder in a drying oven at 60 °C for 1 h at a constant temperature; in order to improve the film-forming performance of PVDF, the polymer modifier polyacrylonitrile (PAN) was mixed with PVDF, and the mass ratio of PVDF:PAN was 5:1 , using DMAC as a solvent to prepare a film-scraping liquid with a solution concentration of 20%; in order to obtain a porous film with a higher porosity, a certain amount of porogen polyvinyl alcohol is added to the solution, and its content is the total of PVDF and PAN. 2% of the mass, while adding PVDF and PAN with a mass content of 0.4% nano-titanium dioxide to improve the electrochemical performance of the separator;

[0035] (2) Put all the raw materials in (2) into an Erlenmeyer flask, stir in a constant temperature water bath at 60 °C for 8 h, and let stand at room temperature for 12 h for defoaming.

...

Embodiment 2

[0039] A method for preparing a porous PVDF membrane for a battery diaphragm, the preparation steps are as follows:

[0040] (1) The PVDF powder was baked in a 60 °C drying oven at a constant temperature for 1 h; in order to improve the film-forming performance of PVDF, the polymer modifier polyurethane was mixed with PVDF, where the mass ratio of PVDF and polyurethane was 4:1, and DMF was used as the Solvent, add 3% poor solvent dehydrated alcohol of DMF volume content at the same time, make the scraping film liquid that the solution concentration is 20%; In order to make the porous film with higher porosity, add a certain amount of porogen in the solution Polyvinylpyrrolidone K-30, whose content is 4% of the total mass of PVDF and PAN, while adding PVDF and polyurethane with a mass content of 0.4% nano-zirconia to improve the electrochemical performance of the separator;

[0041] (2) Put all the raw materials in (2) into an Erlenmeyer flask, stir in a constant temperature wa...

Embodiment 3

[0044] A method for preparing a porous PVDF membrane for a battery diaphragm, the preparation steps are as follows:

[0045](1) Put the PVDF powder in a drying oven at 60 °C for 1 h at constant temperature; in order to improve the film-forming performance of PVDF, the polymer modifier polyacrylonitrile was mixed with PVDF, where the mass ratio of PVDF:PAN was 2:1, and the volume Ratio is 3:1 DMF and DMAC make good solvent, add the poor solvent dehydrated alcohol of 3% of good solvent volume content simultaneously, make mass concentration be the scraping liquid of 20%; For making the higher porous of porosity Membrane, add a certain amount of porogen chitosan in the solution, its content is 5% of the total mass of PVDF and PAN, at the same time add PVDF and nano zirconium dioxide with a mass content of polyacrylonitrile 1% to improve the electrochemical performance of the separator performance;

[0046] (2) Put all the raw materials in (2) into an Erlenmeyer flask, stir in a c...

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Abstract

The invention discloses a preparation method of a porous PVDF film for a battery separator. In order to improve the film forming performance of a PVDF coating solution, a polymer modifier is selectedto mix with PVDF and is dissolved in a mixed solvent obtained by compounding a PVDF good solvent with different PVDF good solvents, or the mixed solvent system added with a small amount of poor solvents for full dissolving to obtain a homogeneous solution. In order to ensure the ionic penetration of the porous PVDF film, the porous PVDF film is made into a porous structure. A certain amount of pore-forming agent is added into the homogeneous solution, after full dissolving t, inorganic nanoparticles for a battery are added to improve electrochemical performances of the porous PVDF film on thebasis of improvement of mechanical properties. The PVDF coating solution prepared by the steps is used for scraping to form a film, the film is respectively pre-evaporated in air, solidified in a coagulation bath, eluted and dried to obtain the porous PVDF film for the battery separator.

Description

technical field [0001] The invention relates to the field of battery diaphragm preparation, in particular to a method for preparing a porous PVDF membrane for a battery diaphragm. Background technique [0002] Cameras, computers, and mobile phones have spread all over the world. Electric vehicles, new energy vehicles, and solar energy have become symbols of the development of the new era. Efficient and safe lithium-ion batteries have a huge impact on environmental protection. A lithium-ion battery separator with excellent performance is one of the keys to manufacture efficient and safe lithium-ion batteries. [0003] Lithium-ion battery separators that have been commercialized today include polyethylene and polypropylene. However, this type of diaphragm has low liquid absorption, low porosity, poor surface energy, and poor affinity for electrolytes. Aiming at the shortcomings of commercial battery separators, many experts and scholars have undergone continuous research and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/446Y02E60/10
Inventor 王利娜石素宇娄辉清刘仕鹏凡辰
Owner HENAN INST OF ENG
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