Polymer slurry, composite diaphragm and preparation method thereof

A composite diaphragm and polymer technology, applied in the direction of structural parts, electrical components, battery pack parts, etc., can solve the problems of poor uniformity of the diaphragm, poor coating process, poor air permeability, etc., to save drying procedures, simplify the preparation process, and improve the effect of cell consistency

Active Publication Date: 2019-10-22
DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the defect of poor air permeability of the full-coverage coated PVDF, there are currently two ways to improve the coated PVDF diaphragm: the first is surface gravure coating, which takes advantage of the relatively poor dispersion of PVDF particles in water. It prepares PVDF aggregates like a ball and a ball, and does not allow it to form a continuous full coverage. The second is point spraying, making PVDF into a larger island, and bonding the positive and negative plates and the separator through Stick together with mechanical riveting, such as CN106784535A
However, both of the above two preparation methods have the disadvantages of poor control of the coating process, poor uniformity of the diaphragm, and relatively high cost.
[0006] On the other hand, a single ceramic coated diaphragm and a single PVDF coated diaphragm cannot combine the advantages of high temperature resistance and viscosity. The traditional method is to first coat the ceramic coating, dry it, and then apply it on the basis of the ceramic coating. Coating PVDF coating on the top requires multiple coatings and drying, the process is complicated and the cost is high, such as CN109461867A, and the application is PVDF full-coverage coating, which has poor air permeability

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  • Polymer slurry, composite diaphragm and preparation method thereof
  • Polymer slurry, composite diaphragm and preparation method thereof
  • Polymer slurry, composite diaphragm and preparation method thereof

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preparation example Construction

[0064] According to some embodiments of the present invention, the preparation method of the ceramic slurry includes the following steps: firstly add a dispersant and a wetting agent to deionized water, and stir in a zigzag stirring disperser at a speed of 300~600 r / min 0.5 h to obtain a solution; the Al 2 o 3 Add the particles into the solution, first stir at 3000-4000 r / min for 3 h to obtain a ceramic dispersion; adjust the speed to 1500-2000 r / min, add binder and thickener, stir for 1 h, Finally, reduce the rotation speed to 100-200r / min to defoam, and filter to obtain ceramic slurry.

[0065] In the preparation process of the above-mentioned ceramic slurry, a dispersant and a wetting agent are firstly added for pre-dispersion; adding Al 2 o 3 After stirring at a high speed to generate a strong shear force, the aggregated large particles can be quickly dispersed into smaller particles to enhance the dispersion effect; after the ceramic particles are dispersed, the binder...

Embodiment approach

[0081] The invention also provides a preparation method of the polymer slurry. According to some embodiments of the present invention, the preparation method of the polymer slurry includes the following steps: firstly adding the polymer, the dispersant and the binder into the deionized water for stirring and mixing, shaking and dispersing to obtain the polymer pre-solution; Add a thickener to the polymer pre-solution, stir to dissolve, continue to add wetting agent A and wetting agent B, stir to disperse, and filter to obtain a polymer slurry.

[0082] (3) Composite diaphragm

[0083] Another aspect of the present invention also provides a composite diaphragm, comprising a base film, a ceramic coating and a polymer dot coating respectively coated on both sides of the base film, such as figure 1 and figure 2 shown. The ceramic coating can endow the separator with good heat resistance, and the polymer dot coating can improve the bonding performance between the separator and ...

Embodiment 1

[0114] (1) Preparation of ceramic slurry: first add 0.2 parts of dispersant polyethylene glycol and 0.2 parts of wetting agent octadecyltrimethylammonium chloride to 100 parts of deionized water, and stir in a zigzag disperser at 500 r / min speed stirring for 0.5 h to obtain the solution; 25 parts of Al 2 o 3 The particles were added to the solution, and stirred at 4000 r / min for 3 h to obtain a ceramic dispersion; the speed was adjusted to 1500 r / min, and 0.5 parts of binder PVP (polyvinylpyrrolidone, brand K60) and 0.6 Thickener CMC (sodium carboxymethylcellulose), stirred for 1 h, and finally reduced the speed to 150 r / min to defoam, filtered to obtain ceramic slurry.

[0115] (2) Preparation of PVDF slurry: Mix 22 parts of PVDF powder with 100 parts of deionized water, 0.3 parts of BYK LP-C 22136 dispersant, 2 parts of PVP (polyvinylpyrrolidone, brand K60) binder, and use a high-speed oscillator Shake and disperse for 30 minutes to make a PVDF pre-dispersion, then add 0....

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Abstract

The invention relates to the technical field of lithium-ion battery diaphragm preparation, and discloses a polymer slurry, a composite diaphragm and a preparation method thereof. The polymeric slurry includes 10-30 parts by weight of a polymer, 0.05-1.0 parts by weight of a thickener, 5.1-26.5 parts by weight of a wetting agent, 1.0-5.0 parts by weight of a binder, 0.1-1.0 parts by weight of dispersant and 80-120 parts by weight of water. The composite diaphragm provided by the invention includes a base film, a ceramic coating and a polymer dot coating respectively coated on both sides of the base film, wherein the polymer dot coating is obtained by coating the above polymer slurry through high-pressure jet flow. The composite diaphragm has good thermal stability, strong cohesive force and good air permeability, and when it is applied to a lithium-ion battery, it is beneficial to improve the performance of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery diaphragm preparation, and more specifically, to a polymer slurry suitable for high-pressure jet coating, a composite diaphragm prepared from the slurry, and a lithium-ion battery containing the composite diaphragm. Background technique [0002] Lithium-ion batteries have the advantages of high specific energy, long cycle life, no memory effect, safety, reliability, and fast charging and discharging, and have become a research hotspot in new power supply technologies in recent years. The composition of a lithium-ion battery includes a positive electrode, a negative electrode, a separator and an electrolyte. As a barrier between the positive and negative electrodes, the separator plays a vital role in the performance of the lithium-ion battery, and its performance directly affects the capacity and cycle of the battery, especially It is an important factor affecting the safety performanc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/446
CPCH01M10/0525H01M50/431H01M50/403H01M50/449H01M50/411Y02E60/10
Inventor 李义涛邹智杰何鑫云晧张凌飞程宗盛肖文武吴慧娟
Owner DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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