Lithium ion battery diaphragm for overcharge protection and preparation method thereof

A lithium-ion battery, overcharge protection technology, applied in secondary batteries, battery pack components, circuits, etc., to achieve the effects of good effect, easy mass production, and simple and controllable preparation method

Inactive Publication Date: 2014-11-19
INST OF CHEM MATERIAL CHINA ACADEMY OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traditional lithium-ion battery non-woven separators need to add electrolyte additives and solvents to effectively solve the

Method used

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  • Lithium ion battery diaphragm for overcharge protection and preparation method thereof
  • Lithium ion battery diaphragm for overcharge protection and preparation method thereof
  • Lithium ion battery diaphragm for overcharge protection and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0078] Example 1:

[0079] Fluorencarbazole copolymer and triphenylamine-fluorene copolymer, polyvinylidene fluoride-copolymer-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO) and tin oxide are mixed in a mass ratio of 1:0.5:0.1 , The mass ratio of fluorencarbazole copolymer and triphenylamine-fluorene copolymer is 9:1, and the mass ratio of PVDF-HFP and PEO is 5:1; then it is dissolved in chloroform and N,N-dimethylformamide (DMF), stir uniformly at a speed of 1300 rpm, and then heat to a temperature of 80°C and continue to stir until it is completely dissolved to obtain a mixture; the obtained mixture is electrostatically charged at a voltage of 25 kV and a receiving distance of 20 cm. After spinning, the product was collected by a flat current collector after 2 hours, then separated, formed into holes, and dried in a vacuum oven at 80°C for 12 hours to obtain a lithium ion battery separator with a thickness of 50 μm.

[0080] Structure diagram such as figure 2 Shown.

...

Example Embodiment

[0084] Example 2:

[0085] Mix fluorenebenzene copolymer, triphenylamine-fluorene copolymer, polyvinylidene fluoride-copolymer-hexafluoropropylene (PVDF-HFP), polyacrylonitrile (PAN), and salicylic acid in a mass ratio of 1:8:0.5 , Wherein the mass ratio of fluorenebenzene copolymer and triphenylamine-fluorene copolymer is 1:5, the mass ratio of PVDF-HFP and PAN is 7:3; then it is dissolved in tetrachloromethane, N,N-dimethylethyl In amide (DMAc) and N,N-dimethylformamide (DMF), stir uniformly at a speed of 500 rpm, and then heat to a temperature of 60 ℃ and continue to stir until completely dissolved to obtain a mixture; Under the conditions of voltage of 5kV and receiving distance of 7cm, electrospinning, after 2 hours, collect the product with a flat current collector, then remove 85% by mass of the inactive components inside the product, and then separate, form holes, It was dried in a vacuum oven at 60°C for 14 hours to obtain a lithium ion battery separator with a thicknes...

Example Embodiment

[0088] Example 3

[0089] Fluorencarbazole copolymer and fluorenebenzene copolymer, polyvinylidene fluoride-copolymer-hexafluoropropylene (PVDF-HFP), glycerin are weighed according to the mass ratio of 1:15:10, of which the fluorencarbazole copolymer and The mass ratio of the fluorenebenzene copolymer is 8:2; then the active polymer and the inactive polymer are separately dissolved in N,N-dimethylformamide (DMF), stirred evenly at a speed of 1300 rpm, and then heated Continue to stir until the temperature is 80℃ to completely dissolve to obtain two mixtures; place the obtained two mixtures in a concentric structure of the electrospinning needle tip, under the conditions of a voltage of 15kV and a receiving distance of 20cm, electrospinning for 1 hour Then, the product was collected by a solution-rotating current collector, and then separated, formed into holes, and dried in a vacuum oven at 90°C for 11 hours to obtain a lithium ion battery separator with a thickness of 50 μm.

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Abstract

The invention discloses a lithium ion battery diaphragm for overcharge protection and a preparation method thereof. After electrically active polyfluorene polymers, inactive polymers and pore-forming agents are mixed, an electrostatic spinning method is used to prepare and obtain a lithium ion battery diaphragm of different structures. Since the electrical conductivity of the diaphragm changes with voltage, the diaphragm is capable of reversibly changing between insulation and conductivity; the overcharge protection safety of a battery is improved; the interface impedance and reaction impedance of a composite diaphragm are reduced; when large current overcharge occurs to the anode materials of the battery, the diaphragm maintains excellent structural stability and electrochemical performance. The invention has the advantages of simple preparation process, low cost and good effect, and is conducive to industrial production.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery separator for overcharge protection and a preparation method thereof. Background technique [0002] Lithium-ion batteries are now widely used in various portable electronic devices, and are considered as ideal supporting batteries for electric vehicles. At present, one of the main obstacles hindering the development of large-capacity and high-power lithium-ion batteries is that the safety of batteries needs to be further improved. Studies have shown that overcharging is the most dangerous factor leading to unsafe behavior of lithium-ion batteries. [0003] When the battery is in an overcharged state, the lithium ions in the positive electrode material will be excessively deintercalated, and the positive electrode with excessively deintercalated lithium has an unstable structure, strong oxidation, and high reactivity and instability in the electrolyte. T...

Claims

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Application Information

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IPC IPC(8): H01M2/16
CPCH01M10/0525H01M50/403H01M50/411H01M50/44Y02E60/10
Inventor 王斌程建丽
Owner INST OF CHEM MATERIAL CHINA ACADEMY OF ENG PHYSICS
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