Battery diaphragm, preparation method thereof and battery

A battery separator and separator technology, applied in battery pack parts, separators/films/diaphragms/spacers, circuits, etc., can solve problems such as diving at the end of the battery cycle, blocking holes in the battery diaphragm, and increasing the internal resistance of the battery. Achieve the effect of improving rate discharge and cycle life, low battery internal resistance, and low coverage

Pending Publication Date: 2022-06-24
SINOMA LITHIUM BATTERY SEPARATOR CO LTD
View PDF8 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existing PVDF-coated separators are usually multi-layer coatings, which generally have shortcomings such as high coating coverage, too strong adhesion, or large swelling of the coating in the electrolyte, which will cause battery damage. Increased internal resistance, plugging of the battery diaphragm, diving at the end of the battery cycle, etc.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Battery diaphragm, preparation method thereof and battery
  • Battery diaphragm, preparation method thereof and battery
  • Battery diaphragm, preparation method thereof and battery

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0080] A second aspect of the embodiments of the present application provides a method for preparing a battery separator, comprising:

[0081] S02. Mix PVDF resin, thickener, binder, water and dispersant evenly to obtain PVDF slurry;

[0082] S04, spray the PVDF slurry on the surface of at least one side of the diaphragm substrate by means of rotary spraying to obtain a PVDF coating comprising ring-like coating points, and the distribution density of the ring-like coating points is 30 pieces / cm 2 ~800 / cm 2 ;

[0083] S06, drying the separator substrate and the PVDF coating sprayed thereon to obtain a battery separator.

[0084] In some embodiments, step S02 in the above preparation method may further include:

[0085] S022. Mix the first PVDF resin, the second PVDF resin and the thickener and knead them evenly to obtain a first mixture. The swelling degree of the first PVDF resin in the ethylene carbonate solvent is 0% to 30%, and the second PVDF The swelling degree of the...

Embodiment 1

[0101] Weigh 8kg of the first PVDF resin, 2kg of the second PVDF resin, 0.1kg of sodium carboxymethyl cellulose and ultrapure water and mix, stir and knead for 20min to form a uniform creamy shape, then add acrylic acid-polyurethane dispersant under stirring and ultrapure water to adjust the solid content of the slurry to form a homogeneous solution; finally, add a polyacrylic acid amine binder to the homogeneous solution, stir and mix evenly to obtain PVDF slurry.

[0102] The PVDF slurry obtained above was coated on one side of the polyethylene diaphragm base material using a high-speed rotary spraying machine, the coating speed was 50 m / min, the rotational speed of the rotating nozzle was 10000 rpm / min, and the battery diaphragm was obtained after drying. Among them, the thickness of the polyethylene diaphragm substrate is 12 μm, the thickness of the single-layer PVDF coating is 2 μm, and the coating area of ​​the PVDF coating accounts for 24.5% of the surface area of ​​the ...

Embodiment 2

[0104] Weigh 10kg of the first PVDF resin and mix with hydroxyethyl cellulose, stir for 30min to form a homogeneous creamy mixture, then add ultrapure water under stirring to adjust the solid content of the slurry and form a homogeneous solution; Add polyacrylic acid amine binder, stir and mix evenly to obtain PVDF slurry.

[0105] The PVDF slurry obtained above was simultaneously coated on both sides of the diaphragm substrate by a high-speed rotary sprayer. The diaphragm substrate was a 9 μm ceramic coating film composed of a 7 μm polyethylene diaphragm and a 2 μm ceramic coating. It is 30m / min, the rotating speed of the rotating nozzle is 8000rpm / min, and the battery separator is obtained after drying. The thickness of the single-layer PVDF coating is 1 μm, and the coating area of ​​the PVDF coating accounts for 18.6% of the surface area of ​​the ceramic coating membrane.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
thicknessaaaaaaaaaa
thicknessaaaaaaaaaa
diameteraaaaaaaaaa
Login to view more

Abstract

The invention discloses a battery diaphragm and a preparation method thereof and a battery, the battery diaphragm comprises a diaphragm base material and a PVDF coating coated on at least one side surface of the diaphragm base material, and the PVDF coating comprises ring-like coating points with the distribution density of 30/cm < 2 >-800/cm < 2 >. Compared with an existing multi-layer coating diaphragm, the battery diaphragm provided by the invention has the advantages that the coverage rate of the PVDF coating is relatively low, the air permeability of the battery diaphragm is good, good bonding force between the battery diaphragm and a battery pole piece can be ensured, and meanwhile, the performance of rate discharge, cycle life and the like of a battery can be improved.

Description

technical field [0001] The present application relates to the technical field of batteries, and in particular, to a battery separator, a preparation method thereof, and a battery. Background technique [0002] At present, PVDF-coated modified battery separators have been widely used in lithium-ion batteries. Since the PVDF coating layer in the battery separator has good adhesive properties, it can play the role of bonding the positive and negative electrodes and the separator during the battery preparation process, which can shorten the ion channel, improve the hardness of the battery, and thus improve the battery safety. [0003] Existing PVDF-coated diaphragms include oil-based PVDF-coated diaphragms, water-based PVDF roll-coated diaphragms, and the like. However, the existing PVDF-coated separators are usually multi-layer coating layers, which generally have shortcomings such as high coating coverage, excessive adhesion, or large swelling degree of the coating in the el...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/40H01M50/403H01M50/449
CPCH01M50/40H01M50/403H01M50/449
Inventor 孙婧秦文娟高飞飞王连广甘珊珊刘淑真汤晓刘杲珺白耀宗
Owner SINOMA LITHIUM BATTERY SEPARATOR CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap