Polyolefin microporous membrane with improved adhesion performance and production method and application thereof

A polyolefin microporous film and bonding performance technology, which is applied in chemical instruments and methods, structural parts, separators/films/diaphragms/spacers, etc., can solve the problem that the preparation process of wet lithium battery separators is not environmentally friendly and production Due to the difficulty of controlling the preparation process and the defects of the single-layer lithium battery separator, it can improve the wettability and liquid absorption performance, good adhesion and good safety.

Inactive Publication Date: 2019-07-16
SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 1. The single-layer lithium battery diaphragm is prone to a small number of defects, and the production and preparation process is difficult to control;
[0006] 2. The thinner the lithium battery diaphragm, the lower the strength, and it needs to increase the strength to ensure safety;
[0007] 3. The preparation process of the wet lithium battery separator is not environmentally friendly and the cost is high;
[0008] 4. In the initial stage of battery short-circuit heating, if the lithium battery diaphragm can be disconnected in time, and further stop or prevent the short circuit, the safety of lithium batteries can be greatly improved, but it is difficult to do so with existing lithium battery diaphragms.
With the demand for thinner battery separators, the above properties are becoming more and more difficult to reconcile

Method used

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  • Polyolefin microporous membrane with improved adhesion performance and production method and application thereof
  • Polyolefin microporous membrane with improved adhesion performance and production method and application thereof
  • Polyolefin microporous membrane with improved adhesion performance and production method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] The polyolefin microporous membrane preparation device of this example, wherein, the part that is used to prepare the middle layer of the multi-layer structure of micro-nano lamination, such as figure 1 As shown, it includes two extruders 1, co-extrusion module 5, micro-nano layer multiplier 2, extrusion die 3 and cooling traction module 4; wherein, two extruders 1 are used to extrude and prepare the middle layer respectively Two different specifications of polypropylene raw materials; the co-extrusion module 5 is set at the output port of the two extruders, and is used to merge and extrude the polyolefin materials extruded by the two extruders, and then transport them to the micro-nano layer The multiplier 2; the micro-nano layer multiplier 2 is a split-layer container as a whole, which is used to divide the molten polyolefin material extruded by the co-extrusion module 5 into several strands, and then each strand forms a layer, and finally forms several layers Laminat...

Embodiment 2

[0064]This example adopts the same device and method of Example 1 to prepare a polyolefin microporous membrane with improved bonding performance. The difference is that the base film of this example has an isotacticity of 98% and a melt index of 1.3g / 10min polypropylene, the lower surface layer is made of polypropylene which is the same as the upper surface layer, the isotacticity of the first polypropylene in the middle layer is 97%, the melt index is 0.8g / 10min, the isotacticity of the second polypropylene is 98%, The melt index was 1.3 g / 10 min. The middle layer is a cross-stacked 16-layer composite structure formed by 8-layer first polypropylene layer and 8-layer second polypropylene layer through micro-nano lamination technology. The preparation of the 16-layer stacked middle layer specifically uses three series-connected micro Nanolayer multiplier. The total thickness of the base film of this example is 16 microns, the thickness of the upper surface layer is 3 microns,...

Embodiment 3

[0067] This example adopts the same device and method as in Example 1 to prepare a polyolefin microporous membrane with improved bonding performance. The difference is that the base film of this example has an isotacticity of 97% and a melt index of 1.5g / It is made of 10min polypropylene, the lower surface layer is made of polypropylene which is the same as the upper surface layer, the isotacticity of the first polypropylene in the middle layer is 98.5%, the melt index is 0.6g / 10min, the isotacticity of the second polypropylene is 97%, The melt index was 1.5 g / 10 min. The middle layer is a cross-stacked 32-layer composite structure formed by micro-nano lamination technology with 16 layers of the first polypropylene layer and 16 layers of the second polypropylene layer. Four series-connected micro Nanolayer multiplier. The total thickness of the base film of this example is 16 microns, the thickness of the upper surface layer is 2 microns, the thickness of the lower surface l...

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Abstract

The invention discloses polyolefin microporous membrane with improved adhesion performance and a production method and application thereof. The polyolefin microporous membrane comprises base membraneand polyvinylidene fluoride coatings which cover two surfaces of the base membrane; the base membrane is composed of an upper surface layer, a middle layer and a lower surface layer, the middle layeris of a multi-layer structure, which is formed through a micro-nano laminating technology, of polypropylene or a multi-layer structure, which is formed through the micro-nano laminating technology, ofa polypropylene layer and a polyethylene layer; and both the upper surface layer and the lower surface layer are polypropylene layers. According to the polyolefin microporous membrane, the multi-layer structure of the base membrane has better safety, and by means of the middle layer formed through the micro-nano laminating technology, not only is the mechanical performance of a diaphragm be improved, but also the diaphragm can be made to be thinner, so that the requirements of a thin high-safety diaphragm are met. By means of the polyvinylidene fluoride coatings, cohesiveness among the polyolefin microporous membrane and an anode and a cathode of a battery is better, the produced battery has better integration, and the wettability and the liquid absorption property of a diaphragm electrolyte can be improved; and the polyolefin microporous membrane with the improved adhesion performance benefits improvement of the cycle performance of the battery.

Description

technical field [0001] The present application relates to the field of lithium-ion battery separators, in particular to a polyolefin microporous membrane with improved bonding performance and its preparation method and application. Background technique [0002] Lithium battery separator is one of the most important materials in lithium batteries. It is a difficult point in the production process to prepare a safe, environmentally friendly, and low-cost microporous membrane. Lithium battery separators need to be balanced in terms of safety, functionality, and cost. This is the development direction and research focus of lithium battery separators in the future. [0003] At present, there are two methods of manufacturing lithium battery separators: wet method and dry method. In order to improve the performance of the lithium battery separator, a functional coating is applied on the surface of the separator for modification to meet specific needs. Lithium battery separators p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B27/06B32B27/32B32B33/00H01M2/14H01M2/16H01M2/18H01M50/403H01M50/417H01M50/457
CPCB32B27/08B32B27/32B32B33/00B32B2307/54B32B2307/5825B32B2307/584B32B2307/726B32B2255/10B32B2255/26H01M50/403H01M50/463H01M50/411Y02E60/10
Inventor 王哲姚坤樊孝红
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD
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