Composite diaphragm, preparation method thereof and lithium ion battery

A composite diaphragm and base film technology, applied in secondary batteries, battery pack parts, separators/films/diaphragms/spacers, etc. The effect of reducing the thermal closed cell temperature and improving the safety performance

Pending Publication Date: 2022-05-13
EVE ENERGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the temperature rises further, the material of the diaphragm cannot prevent the rupture of the diaphragm, thus affecting the safety performance of the diaphragm

Method used

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

Examples

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Effect test

Embodiment 1

[0072] This embodiment provides a composite diaphragm ( figure 1 ), the composite separator includes a laminated solid electrolyte layer 1, a base film 2 (Celgard 2400) and a polymer microsphere layer 3; the thickness of the solid electrolyte layer is 3 μm, and the thickness of the polymer microsphere layer is 3 μm, and the thickness of the base film is 9 μm.

[0073] In terms of mass percentage, the solid electrolyte layer is composed of 30wt% Al 2 o 3 Composed of 70wt% PVDF (HSV900), surface density is 12g / m 2 The polymer microsphere layer is polyethylene microspheres with a median particle size of 1 μm and an average degree of polymerization of 5000.

[0074] Described preparation method comprises the steps:

[0075] (1) Al 2 o 3 Add N,N-dimethylformamide for ultrasonic dispersion for 15 minutes to form a suspension, add PVDF to the suspension and planetary stir for 30 minutes at a speed of 1200r / min to obtain a solid electrolyte glue, the solid electrolyte glue The ...

Embodiment 2

[0079] This embodiment provides a composite diaphragm ( figure 1 ), the composite separator includes a stacked solid electrolyte layer 1, a base film 2 (Celgard 2400) and a polymer microsphere layer 3; the thickness of the solid electrolyte layer is 2 μm, and the thickness of the polymer microsphere layer is 2 μm, and the thickness of the base film is 8 μm.

[0080] In terms of mass percentage, the solid electrolyte layer is made of 20wt% ferroelectric ceramic material (BaTiO 3 ) and 80wt% PVDF-HFP (Solvay 21510), with an areal density of 11g / m 2 The polymer microsphere layer is polyethylene microspheres, the median particle size is 200nm, and the average degree of polymerization is 2000.

[0081] Described preparation method comprises the steps:

[0082] (1) BaTiO 3 Add N-methylpyrrolidone for ultrasonic dispersion for 5 minutes to form a suspension, add PVDF-HFP to the suspension and planetary stir for 20 minutes at a speed of 1000r / min to obtain a solid electrolyte glue...

Embodiment 3

[0086] This embodiment provides a composite diaphragm ( figure 1 ), the composite separator includes a laminated solid electrolyte layer 1, a base film 2 (Celgard 2400) and a polymer microsphere layer 3; the thickness of the solid electrolyte layer is 5 μm, and the thickness of the polymer microsphere layer is 5 μm, and the thickness of the base film is 10 μm.

[0087] In terms of mass percentage, the solid electrolyte layer is composed of 40wt% super acidic oxide (acidic ZrO 2 ) and 60wt% PVC (S-700), with a surface density of 15g / m 2 The polymer microsphere layer is polyethylene microspheres with a particle size of 2 μm and a degree of polymerization of 10,000.

[0088] Described preparation method comprises the steps:

[0089] (1) the acidic ZrO 2 Add dimethyl sulfoxide for ultrasonic dispersion for 30 minutes to form a suspension, add PVC to the suspension and planetary stir for 40 minutes, the speed is 1500r / min, to obtain a solid electrolyte glue, the viscosity of th...

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Abstract

The invention provides a composite diaphragm, a preparation method thereof and a lithium ion battery. The composite diaphragm comprises a solid electrolyte layer, a base membrane and a polymer microsphere layer which are stacked, the solid electrolyte layer comprises an inorganic filler and a polymer; the polymer comprises any one or a combination of at least two of PVDF (Polyvinylidene Fluoride), PVDF-HFP (Polyvinyl Fluoride-Hexafluoropropylene) or PVC (Polyvinyl Chloride); the polymer microsphere layer comprises polyethylene microspheres. By compounding the two functional material coatings, the thermal hole closing temperature of the composite diaphragm is reduced, meanwhile, the thermal diaphragm breaking temperature is increased, and the safety performance of the lithium ion battery is improved on the premise that the good electrochemical performance of the composite diaphragm is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of manufacturing lithium ion batteries, and relates to a composite diaphragm, in particular to a composite diaphragm, a preparation method thereof and a lithium ion battery. Background technique [0002] Lithium-ion batteries are composed of positive electrode materials, negative electrode materials, separators, electrolytes, and battery casings. In the lithium-ion battery structure, the diaphragm is one of the key inner components. The performance of the diaphragm determines the interface structure and internal resistance of the battery, and directly affects the capacity, cycle performance and safety performance of the battery. A separator with excellent performance plays an important role in improving the overall performance of the battery. [0003] As lithium-ion batteries are used more and more widely, their safety performance and environmental protection requirements are also increasing. At present, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M50/40H01M50/403H01M50/457H01M10/0525
CPCH01M50/40H01M50/403H01M10/0525H01M50/457
Inventor 陈规伟董洁冀亚娟
Owner EVE ENERGY CO LTD
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