Unlock instant, AI-driven research and patent intelligence for your innovation.

Composite diaphragm for lithium battery and preparation method thereof

A composite diaphragm and lithium battery technology, which is applied to battery pack parts, chemical instruments and methods, circuits, etc., can solve the problems of difficult control of pore size, large environmental pollution, large amount of solvents, etc., and achieve good mechanical properties and good connectivity , high puncture strength effect

Active Publication Date: 2020-06-19
新纶新能源材料(常州)有限公司
View PDF6 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the wet production of microporous membranes, the pore size and porosity are easier to control, and the tortuosity of the pores is relatively high, but a large amount of solvent is required, the process is complicated, and the environmental pollution is large; the process of dry production is simple, and the tortuosity of the pores is relatively high. Low, not only single-layer diaphragms can be produced, but also multi-layer composite diaphragms can be produced to improve production efficiency, but the pore size is difficult to control

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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] This embodiment provides a composite separator for a lithium battery, which has a three-layer structure, the surface layers on both sides are high-strength polypropylene microporous membranes, and the core layer is a low-melting point self-shutoff polyethylene microporous membrane;

[0037] The raw material of the high-strength polypropylene microporous membrane is polypropylene resin with a molecular weight of 300,000-1,000,000, a molecular weight distribution index Mw / Mn of 4-8, an isotacticity>96%, and a melt flow rate of 1.3-3.3;

[0038] The raw material of the low-melting point self-shutoff polyethylene microporous membrane is high-density polyethylene, the molecular weight is 100,000-300,000, the molecular weight distribution index Mw / Mn is 4-8, and the melt flow rate is 0.2-0.8.

[0039] This embodiment also provides the preparation method of the above-mentioned composite diaphragm for lithium battery, comprising the following steps:

[0040] The polypropylene r...

Embodiment 2

[0050] This embodiment provides a composite separator for a lithium battery, which has a three-layer structure, the surface layers on both sides are high-strength polypropylene microporous membranes, and the core layer is a low-melting point self-shutoff polyethylene microporous membrane;

[0051] The raw material of the high-strength polypropylene microporous membrane is polypropylene resin with a molecular weight of 300,000-1,000,000, a molecular weight distribution index Mw / Mn of 4-8, an isotacticity>96%, and a melt flow rate of 1.3-3.3;

[0052] The raw material of the low-melting point self-shutoff polyethylene microporous membrane is high-density polyethylene, the molecular weight is 100,000-300,000, the molecular weight distribution index Mw / Mn is 4-8, and the melt flow rate is 0.2-0.8.

[0053] This embodiment also provides the preparation method of the above-mentioned composite diaphragm for lithium battery, comprising the following steps:

[0054] The polypropylene r...

Embodiment 3

[0064] This embodiment provides a composite separator for a lithium battery, which has a three-layer structure, the surface layers on both sides are high-strength polypropylene microporous membranes, and the core layer is a low-melting point self-shutoff polyethylene microporous membrane;

[0065] The raw material of the high-strength polypropylene microporous membrane is polypropylene resin with a molecular weight of 300,000-1,000,000, a molecular weight distribution index Mw / Mn of 4-8, an isotacticity>96%, and a melt flow rate of 1.3-3.3;

[0066] The raw material of the low-melting point self-shutoff polyethylene microporous membrane is high-density polyethylene, the molecular weight is 100,000-300,000, the molecular weight distribution index Mw / Mn is 4-8, and the melt flow rate is 0.2-0.8.

[0067] This embodiment also provides the preparation method of the above-mentioned composite diaphragm for lithium battery, comprising the following steps:

[0068] The polypropylene r...

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
molecular weight distributionaaaaaaaaaa
thicknessaaaaaaaaaa
sizeaaaaaaaaaa
Login to View More

Abstract

The invention provides a composite separator for a lithium battery, which has a three-layer structure, the surface layers on both sides are high-strength polypropylene microporous membranes, and the core layer is a low-melting point self-shutoff polyethylene microporous membrane; the high-strength polypropylene The raw material of microporous membrane is polypropylene resin, its molecular weight is 300000-1000000, molecular weight distribution index Mw / Mn is 4-8, isotacticity> 96%, melt flow rate is 1.3-3.3; low melting point self-shutdown polymer The raw material of the ethylene microporous membrane is high-density polyethylene, its molecular weight is 100000-300000, the molecular weight distribution index Mw / Mn is 4-8, and the melt flow rate is 0.2-0.8. The composite diaphragm for lithium batteries of the present invention has a lower closed cell temperature and a higher membrane rupture temperature, a wider self-shutoff safety window, good mechanical properties, and high puncture resistance. Good safety performance, suitable pore size, uniform distribution, good penetration, low internal resistance of the battery, which is conducive to improving the working efficiency of the battery.

Description

technical field [0001] The invention relates to a composite separator for lithium batteries and a preparation method thereof, belonging to the technical field of lithium batteries. Background technique [0002] Lithium-ion battery separator is an important component in lithium-ion batteries. It is a thin film material with nano-scale pores, which plays a role in blocking the positive and negative electrodes in the battery and preventing the internal short circuit of the battery; at the same time, it must allow ions The current passes quickly to ensure the rapid transmission of lithium ions between the positive and negative electrodes during battery charging and discharging. The microporous structure, physical properties, chemical properties, and thermal properties of the separator determine the interface structure and internal resistance of the battery, which directly affect the capacity, cycle performance, and safety performance of the battery. A separator with excellent pe...

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 Patents(China)
IPC IPC(8): H01M2/16H01M2/14B32B27/08B32B27/32B32B3/24B29C48/08B29C48/21B29C48/49B29C48/92B29C55/04B29C69/02B29C71/02B29L7/00B29L9/00H01M50/403H01M50/411H01M50/457H01M50/491
CPCB29C48/0018B29C48/18B29C48/49B29C48/92B29C55/04B29C71/02B32B3/266B32B27/08B32B27/32B29L2007/00B29L2009/00B32B2457/10B32B2307/558B29C2948/92704B29C2948/92904H01M50/403H01M50/411H01M50/449Y02E60/10
Inventor 杨茜
Owner 新纶新能源材料(常州)有限公司