Battery diaphragm and preparation method thereof

A technology for battery separators and porous membranes, applied in the field of battery separators and their preparation, can solve the problems of weak interlayer bonding, lower ion transmission rate, and easy detachment of laminated membranes, and achieve long service life and good closed cell protection Function, the effect of strong adhesion

Active Publication Date: 2012-06-27
合肥长阳新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that the bonding force between the layers is not strong, and the laminated

Method used

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  • Battery diaphragm and preparation method thereof
  • Battery diaphragm and preparation method thereof
  • Battery diaphragm and preparation method thereof

Examples

Experimental program
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Effect test

preparation example Construction

[0053] The preparation method of the battery diaphragm provided by the invention comprises the following steps:

[0054] (1) Add binary organic acid anhydride and organic diamine to a solvent whose mass is 4-9 times the total mass of binary organic acid anhydride and organic diamine at a molar ratio of 0.7-1.4:1, and simultaneously add a mass of binary organic A pore-forming substance that is 0.02-0.2 times the total mass of acid anhydride and organic diamine is stirred at 30-60°C for 4-20 hours to obtain a viscous mixture with an intrinsic viscosity [η] = 100-200 ml / g ;

[0055] (2) At 30-65°C, coat the mixture obtained in step (1) on a stainless steel plate with a thickness of 200-400 microns, and then dry at 30-130°C for 5-10 minutes to remove Solvent, obtain polyamic acid film;

[0056] (3) adopting the mode of gradient temperature rise, the polyamic acid film obtained in step (2) is heated in nitrogen to carry out imidization, obtains the polyimide film of 20-40 microns...

Embodiment 1

[0062] (1) Biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether are added to the total mass of biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether at a molar ratio of 1.1:1. In the N-2-methylpyrrolidone of 4 times of quality, add the calcium hydroxide (average particle size is 1.5 microns) that quality is biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether total quality 0.02 times simultaneously, Stirring at 35°C for 6 hours gave a viscous mixture with an intrinsic viscosity [η]=150 ml / g;

[0063](2) Coating the mixture obtained in step (1) on a stainless steel plate at 30°C, the thickness of the coating layer is 350 microns, and then drying at 120°C for 5 minutes to remove the solvent to obtain a polyamic acid film;

[0064] (3) The polyamic acid film obtained in step (2) is heated in nitrogen to carry out imidization by means of gradient temperature rise to obtain a polyimide non-porous film of 38 microns. The heating method is: ke...

Embodiment 2

[0068] The battery separator is prepared as described in Example 1, wherein the quality of calcium hydroxide (with a particle size of 1.5 microns) in step (1) is the total mass of biphenyltetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether 0.04 times, the intrinsic viscosity of the viscous mixture of gained is [η]=160 milliliters / gram; Adjust the coating layer thickness of polyamic acid membrane, the thickness of the polyimide nonporous membrane of gained is 30 microns, finally obtained The thickness of the battery separator is 36 microns.

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Abstract

The invention relates to the technical field of lithium-ion batteries, in particular to a battery diaphragm and a preparation method thereof. In order to overcome the defects of weak adhesive force and low penetration rate among all the composite layers of the battery diaphragm in the prior art, the invention provides the battery diaphragm. The battery diaphragm comprises a polyimide porous-film layer and a polyolefin porous-film layer, wherein the polyolefin porous-film layer is bonded on the polyimide porous-film layer; and a through hole is arranged on the battery diaphragm, the aperture of the through hole is 60 to 250 nanometers, and the porosity is 30 to 60 percent. The thickness of the battery diaphragm is 30 to 50 microns, and the thickness of the polyimide porous-film layer is 20 to 40 microns. Compared with the prior art, the battery diaphragm provided by the invention has strong bonding forces and high penetration rates among layers. The invention also provides the preparation method of the battery diaphragm, and the method comprises a coating working procedure, has a simple process and is easy to operate. The battery diaphragm provided by the invention can be widely applied to the lithium-ion batteries.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a battery diaphragm and a preparation method thereof. Background technique [0002] With the development of information technology, our demand for mobile power is also growing rapidly. At the same time, compared with traditional batteries, the direction of demand has also changed: high energy, small size, light weight, and high safety performance have become mobile batteries. The new direction of power development. Lithium-ion batteries have become the first choice for many portable electronic devices and electric vehicles due to their high energy density, long cycle life, safety and pollution-free, and fast charging and discharging performance. [0003] The components of an ion battery include: electrodes, electrolytes, polymer diaphragms (battery diaphragms), etc. The diaphragm between the two electrodes plays a very important role. It not only separates the two ...

Claims

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Application Information

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IPC IPC(8): H01M4/16H01M4/18H01M10/0525
CPCY02E60/122Y02E60/126Y02E60/10
Inventor 不公告发明人
Owner 合肥长阳新能源科技有限公司
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