Composite negative plate for lithium ion battery as well as preparation method of composite negative plate and lithium ion battery

A technology for lithium-ion batteries and negative plates, applied in electrode manufacturing, battery electrodes, electrode rolling/calendering, etc., can solve problems such as battery deformation, battery short circuit, etc., achieve long service life, improve cycle service life, and be easy to prepare Effect

Active Publication Date: 2014-03-26
TONGDING INTERCONNECTION INFORMATION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In view of this, the first aspect of the embodiment of the present invention provides a composite negative electrode sheet for lithium-ion batteries, which is used to solve the internal short circuit of the battery and the deformation of the battery cell that are easily caused by the winding arrangement of the separator and the positive and negative electrode sheets in the prior art. problems, and can improve the safety performance and cycle life of lithium-ion batteries

Method used

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  • Composite negative plate for lithium ion battery as well as preparation method of composite negative plate and lithium ion battery

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preparation example Construction

[0048] In a second aspect, embodiments of the present invention provide a method for preparing a composite negative electrode sheet for a lithium-ion battery, such as figure 1 As shown, it includes the following steps: spray the polyamic acid solution on the surface of the negative electrode sheet by electrospinning, then carry out mechanical rolling, and finally convert the polyamic acid sprayed on the surface of the negative electrode sheet into polyamide by thermal imidization treatment. imine, and form a polyimide nanofiber film on the surface of the negative electrode sheet to obtain a composite negative electrode sheet for lithium ion batteries.

[0049] In the second aspect of the embodiment of the present invention, the polyamic acid solution is prepared as follows: add a binary organic acid anhydride and an organic diamine into an organic solvent, stir, and undergo condensation reaction to obtain a polyamic acid solution.

[0050] The binary organic acid anhydrides ar...

Embodiment 1

[0077] A preparation method for a composite negative electrode sheet for a lithium ion battery, comprising the steps of:

[0078] (1) Synthesis of polyamic acid solution

[0079] Add 45 grams of pyromellitic dianhydride (PMDA) and 42 grams of diaminodiphenyl ether (ODA) to the mixing tank, add 500 milliliters of N, N-dimethylformamide (DMF), and then The mixture was stirred and reacted for 2 hours, and a condensation reaction occurred to obtain a uniform polyamic acid solution.

[0080] (2) Negative sheet preparation

[0081] The mixture of 200 grams of negative electrode active material artificial graphite, 3 grams of binder styrene-butadiene rubber (SBR) and 3 grams of carboxymethyl cellulose (CMC) is added to 200 grams of water, then stirred in a vacuum mixer to form a uniform slurry . The slurry was evenly coated on both sides of a 9-micron copper foil, and the surface density of the coating was controlled to be 17.8 mg / cm2, then dried at 100° C., and rolled to obtain a...

Embodiment 2

[0090] A preparation method for a composite negative electrode sheet for a lithium ion battery, comprising the steps of:

[0091] (1) Synthesis of polyamic acid solution

[0092] Add 45 grams of isopropyl diphthalic anhydride and 42 grams of diphenylsulfone diamine into the mixing tank, add 500 milliliters of N, N-dimethylacetamide (DMAc), then stir and react at 10°C for 8 hours, and condensation occurs The reaction obtains a uniform polyamic acid solution.

[0093] (2) Negative sheet preparation

[0094] The mixture of 200 grams of negative electrode active material artificial graphite, 3 grams of binder styrene-butadiene rubber (SBR) and 3 grams of carboxymethyl cellulose (CMC) is added to 200 grams of water, then stirred in a vacuum mixer to form a uniform slurry . The slurry was evenly coated on both sides of a 9-micron copper foil, and the surface density of the coating was controlled to be 17.8 mg / cm2, then dried at 100° C., and rolled to obtain a negative electrode s...

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Abstract

The invention provides a composite negative plate for a lithium ion battery as well as a preparation method of the composite negative plate and a lithium ion battery. The preparation method of the composite negative plate for the lithium ion battery comprises the following steps of spraying polyamide acid solution onto the surface of the negative plate in an electrostatic spinning manner, then mechanically rolling the negative plate, finally converting polyamide acid on the surface of the negative plate into polyimide through the heat imidization treatment, and forming a polyimide nanometer fiber membrane on the surface of the negative plate to obtain the composite negative plate for the lithium ion battery. By adopting the preparation method, the process of firstly independently preparing a positive plate, the negative plate and a diaphgram and then winding the diaphragm and the positive and negative plates in the prior art can be simplified, and the internal short circuit and cell deformation problems caused by the winding of the diaphragm and the positive and negative plates in the prior art can be solved. The lithium ion battery prepared by adopting the composite negative plate for the lithium ion battery is excellent in safety performance and long in service life and can be used as a high-capacity and power battery.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a composite negative electrode sheet for lithium-ion batteries, a preparation method thereof, and a lithium-ion battery. Background technique [0002] Lithium-ion batteries have been widely used in mobile phones, notebook computers and other fields due to their advantages such as light weight, small size, high working voltage, high energy density, high output power, high charging efficiency and no memory effect. [0003] Lithium-ion batteries usually consist of a positive electrode sheet, a negative electrode sheet, a separator, an electrolyte, and a casing. Among them, the separator is mainly a commercially available polyethylene (PE) film or polypropylene (PP) film with a thickness of 20-40 μm and a porosity of about 40%. , to block the positive and negative pole pieces to prevent the internal short circuit of the battery, but to allow the ion flow to pass through quickly,...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M4/139H01M2/14H01M50/40H01M50/403H01M50/414H01M50/491
CPCH01M4/13H01M10/0525H01M4/139H01M2/16Y02E60/122H01M4/0435H01M50/44H01M50/46H01M50/491H01M50/414H01M4/133H01M4/1393H01M4/661Y02E60/10
Inventor 叶海林张光辉
Owner TONGDING INTERCONNECTION INFORMATION CO LTD
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