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Multi-layer low-temperature blocking lithium battery separator and preparation method thereof

A lithium battery separator, low temperature technology, applied in the direction of lithium battery, battery pack parts, non-aqueous electrolyte battery, etc., can solve the difficulty of lithium battery separator safety, functionality, cost balance of separator, and preparation process of wet lithium battery separator It is not environmentally friendly enough, and it is difficult to meet the problems of safety, environmental protection, and low cost at the same time, so as to achieve the effects of environmental protection and safety in the preparation process, improved mechanical properties, and high functionality

Inactive Publication Date: 2019-05-21
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.
[0009] In general, the existing lithium battery separator preparation methods, whether wet process or dry process, have certain defects and deficiencies, and it is difficult to meet the production requirements of safe, environmentally friendly and low-cost preparation at the same time; the prepared lithium It is also difficult for battery separators to strike a balance in terms of safety, functionality, and cost of the separator

Method used

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  • Multi-layer low-temperature blocking lithium battery separator and preparation method thereof
  • Multi-layer low-temperature blocking lithium battery separator and preparation method thereof
  • Multi-layer low-temperature blocking lithium battery separator and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] 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 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 to multiply The device 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 a plurality of layers sta...

Embodiment 2

[0064] In this example, the same device and method as in Example 1 were used to prepare a multilayer low-temperature barrier lithium battery separator. The isotacticity of the first polypropylene in the middle layer is 97%, and the melt index is 0.8g / 10min. The second polypropylene had an isotacticity of 99% and a melt index of 2 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 thickness of the multilayer polypropylene microporous layer of this example is 16 microns, the thickness of the upper surface layer is 2 microns, the thickness of the lower surface layer is 2 microns, and the thickness of the middle layer is 12 microns, and the thickness of the two polypropylene layers in the middle layer is equal...

Embodiment 3

[0067] In this example, the same device and method as in Example 1 were used to prepare a multilayer low-temperature barrier lithium battery separator. Made of polypropylene with a regularity of 98% and a melt index of 1.5g / 10min, the lower surface layer is made of polypropylene which is the same as the upper surface layer; the first polypropylene in the middle layer has an isotacticity of 99% and a melt index of 0.5g / 10min , the isotacticity of the second polypropylene was 98%, and 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 thickness of the multilayer polypropylene microporous layer of this example is 16 microns, the thickness of the upper surface layer is 2 microns, the thickness of the lower surface layer is 2 microns, the thick...

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Abstract

The invention discloses a multi-layer low-temperature blocking lithium battery separator and a preparation method thereof. The multi-layer low-temperature blocking lithium battery separator comprisesmultiple polypropylene micropore layers and a coating layer, wherein the multiple polypropylene micropore layers are formed by a micronano lamination technology, and the coating layer is coated on atleast one surface and is formed by coating of aqueous dispersion emulsion of a polymer of which a melting point is lower than 140 DEG C. By the multi-layer low-temperature blocking lithium battery separator, on one hand, the multiple-layer polypropylene micropore structure has better safety by the micronano lamination technology; on the other hand, the tensile strength and the puncturing strengthof the separator are improved, meanwhile, the battery separator can be thinner, and the demands of the mechanical property and the safety of the thin and high-safety battery separator can be satisfied; and moreover, by the additional coating layer, hole closing under a relatively low temperature can be achieved, and the battery safety is improved. The multi-layer low-temperature blocking lithium battery separator has the advantages of high strength, a few defects, good safety and low cost, and the balance of the lithium battery separator on high safety, high function and low cost can be met.

Description

technical field [0001] The present application relates to the field of lithium battery separators, in particular to a multilayer low-temperature barrier lithium battery separator and a preparation method thereof. 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 prepared by wet meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M2/14H01M10/052H01M50/403H01M50/411H01M50/449H01M50/489
CPCY02E60/10
Inventor 王哲张胜刚刘琳张辉
Owner SHENZHEN ZHONGXING NEW MATERIAL TECH CO LTD