Composite porous membrane and preparation method thereof

A porous and porous film technology, applied in the direction of electrical components, circuits, battery pack components, etc., can solve the problems of electrochemical performance impact, diaphragm volume change, and low diaphragm utilization, and achieve low surface tension and glass transition temperature Low, the effect of avoiding curling phenomenon

Active Publication Date: 2016-09-07
DONGGUAN AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since such polyolefin-based separators have a melting point of 200°C or lower, they have a drawback that such separators shrink or melt when the temperature of the battery increases due to internal and / or external factors, resulting in a change in the volume of the separator
However, inorganic particles have another inherent water-absorbing property, and the moisture is difficult to dry and remove, which will undoubtedly greatly affect the electrochemical performance of lithium-ion batteries that are particularly sensitive to moisture; on the other hand, relatively polymeric Ethylene (PE) wet-process diaphragms and polypropylene (PP) dry-process diaphragms are more difficult to coat. Many researchers use corona to increase the polarity of polypropylene, resulting in complicated processes and poor diaphragm utilization. Low level defects

Method used

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  • Composite porous membrane and preparation method thereof
  • Composite porous membrane and preparation method thereof
  • Composite porous membrane and preparation method thereof

Examples

Experimental program
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Embodiment 1

[0030] Embodiment 1: This embodiment provides a composite porous diaphragm, including an organic layer and an inorganic coating disposed on the surface of the organic layer, wherein the organic layer is a polyethylene porous film with a thickness of 12 μm (porosity 45%). In terms of weight percentage, the inorganic coating includes 0.66% water-soluble polymer thickener sodium carboxymethyl cellulose, 0.22% water-based dispersant sorbitan monolaurate, and 11% styrene-butadiene rubber emulsion (The glass transition temperature of dry glue is lower than 50°C, and the melting point is higher than 250°C) and 88.12% inorganic alumina powder (median particle size is 1.5um, specific surface is 4m2 / g), the solubility parameter of styrene-butadiene rubber emulsion is 17.6 (J / cm 3 ) 1 / 2 , The surface tension is 44 dynes / cm. The thickness of the inorganic coating is 3 µm, coated on both sides, so the thickness of the entire composite porous separator is 18 µm.

[0031] Using a scanning...

Embodiment 2

[0032] Embodiment 2: This embodiment provides a composite porous diaphragm, including an organic layer and an inorganic coating disposed on the surface of the organic layer, wherein the organic layer is a polypropylene porous film with a thickness of 16 μm (50% porosity). In percent by weight, the inorganic coating wherein includes 1% water-soluble polymer thickener carboxyethyl cellulose, 1% water-based dispersant polyoxyethylene dioleate, 2% pure acrylic latex emulsion (the The glass transition temperature of dry glue is lower than 50°C, and the melting point is higher than 250°C) and 96% of inorganic silica powder (median particle size is 0.5um, specific surface is 4m 2 / g), the solubility parameter of pure acrylic latex emulsion is 16.6 (J / cm 3 ) 1 / 2 , surface tension 40 dynes / cm. The thickness of the inorganic coating is 2 µm, and it is coated on both sides, so the thickness of the entire composite porous separator is 20 µm.

Embodiment 3

[0033] Embodiment 3: This embodiment provides a composite porous membrane, including an organic layer and an inorganic coating disposed on the surface of the organic layer, wherein the organic layer is a polypropylene / polyethylene / polypropylene composite porous film with a thickness of 20 μm (porosity 43%). In percent by weight, the inorganic coating wherein includes 0.5% water-soluble polymer thickener polyacrylamide, 0.5% water-based dispersant tetraethylene glycol monostearate, 20% styrene-acrylic latex emulsion (its The glass transition temperature of dry glue is lower than 50°C, and the melting point is higher than 250°C) and 79% of inorganic zirconia powder (median particle size is 0.3um, specific surface is 8m 2 / g), the solubility parameter of styrene-acrylic latex emulsion is 17.8(J / cm 3 ) 1 / 2 , The surface tension is 42 dynes / cm. The thickness of the inorganic coating is 4 µm, and it is coated on one side, thus, the thickness of the entire composite porous separat...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a composite porous diaphragm which comprises an organic layer and an inorganic coating arranged on the surface of the organic layer, wherein the organic layer is a polyolefin porous diaphragm layer; the inorganic coating comprises the following components in percentage by weight: 0.2-2% of water-soluble high molecular thickener, 0.2-5% of waterborne dispersing agent, 1-30% of waterborne latex and 63-98.6% of inorganic particles; and the waterborne latex is a high-molecular polymer of which the solubility parameter is less than or equal to 18(J / cm<3>)1 / 2 and the surface tension is less than or equal to 44 dynes / cm. Compared with the prior art, the composite porous diaphragm provided by the invention has good heat-resistant shrinkage performance; and meanwhile, with better puncture strength, the inorganic coating of the diaphragm effectively reduces the short-circuit risk in a battery, and improves the safety performance of the battery. Moreover, the invention also discloses a preparation method of the diaphragm.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a composite porous separator and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used as power sources for various mobile devices since their commercialization due to their high energy density, high operating voltage, no memory effect, and long cycle life. However, with the large-scale application of lithium-ion batteries, battery safety issues have become increasingly prominent. [0003] At present, the separators used in lithium-ion batteries and lithium-ion polymer batteries are generally polyolefin-based separators. Since such polyolefin-based separators have a melting point of 200°C or lower, they have a drawback that such separators shrink or melt when the temperature of the battery increases due to internal and / or external factors, resulting in a change in the volume of the separator . The shrinkage or mel...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M2/16
CPCY02E60/10
Inventor 邓耀明赖旭伦柳娜陈杰庞佩佩
Owner DONGGUAN AMPEREX TECH
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