Method for preparing lithium-ion secondary battery pole piece

A secondary battery, lithium ion technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of complex manufacturing process, high manufacturing cost, no thick pole pieces, etc., achieve high energy density, simple and easy preparation process The effect of line and rate performance improvement

Active Publication Date: 2012-09-26
NINGDE AMPEREX TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Thereby overcoming the disadvantages that the thick pole piece prepared by the method in the prior art does not have a continuous gradient distribution of porosity, the manufacturing process is complex and the manufacturing cost is high

Method used

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  • Method for preparing lithium-ion secondary battery pole piece
  • Method for preparing lithium-ion secondary battery pole piece
  • Method for preparing lithium-ion secondary battery pole piece

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment 1: see figure 1 As shown, the pole piece prepared by the method of the present invention includes a current collector 10 and a diaphragm 20 arranged on the current collector 10, and the thickness of the diaphragm 20 is greater than or equal to 160 μm (preferably 160 to 3000 μm); From the surface of the current collector 10 to the direction away from the surface of the current collector 10, the porosity of the diaphragm 20 gradually increases.

[0023] Wherein, the pole piece includes a positive pole piece and a negative pole piece.

[0024] The production of the positive electrode sheet: the positive electrode active material lithium cobalt oxide (LiCoO 2), conductive agent carbon black, polymer binder polyvinylidene fluoride (PVDF) and dispersing solvent N-methylpyrrolidone (NMP) are uniformly mixed in a weight ratio of 96:2:2:80 to obtain a slurry, and then transfer Coating method The slurry is evenly coated on the aluminum foil current collector with a t...

Embodiment 2

[0027] Embodiment 2: different from embodiment 1, the polymer binder in the making process of positive electrode plate is polyimide (PI), and dispersion solvent is dimethyl sulfoxide (DMSO), and non-solvent spraying quality is 5 wt% of the mass of the positive electrode active material, and the thickness of the positive electrode membrane is 250 μm. Lithium cobalt oxide (LiCoO 2 ), the mass ratio of conductive agent carbon black and polyimide (PI) is 94:3:3 in sequence.

[0028] The thickness of the negative electrode membrane is 250 μm.

[0029] The rest are the same as in Embodiment 1, and will not be repeated here.

Embodiment 3

[0030] Embodiment 3: Different from Example 1, the polymer binder in the production process of the positive electrode sheet is polyamide (PA), the dispersion solvent is dimethylformamide (DMF), and the non-solvent spraying quality is positive electrode activity 10 wt% of the mass of the substance, the thickness of the positive electrode membrane is 300 μm. Lithium cobalt oxide (LiCoO 2 ), the mass ratio of conductive agent carbon black and polyamide (PA) is 92:4:4 in sequence.

[0031] The thickness of the negative electrode membrane is 300 μm.

[0032] The rest are the same as in Embodiment 1, and will not be repeated here.

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Abstract

The invention belongs to the technical field of lithium-ion secondary batteries and in particular relates to a method for preparing a lithium-ion secondary battery pole piece. Poriness of a film piece is gradually increased from the direction close to the surface of a current collector to the direction far away from the surface of the current collector. The method comprises the following steps of: coating a sizing agent containing an active substance, a conductive agent, a polymer binding agent and a disperse solvent on the current collector to obtain a film piece containing the disperse solvent; and spraying nonsolvent to the surface of the film piece containing the current collector by adopting an ultrasonic spray method and drying and rolling the film piece to obtain the pole piece. Compared with the prior art, the thick pole piece prepared by the method has continuous gradient distribution poriness so that a battery assembled by the thick pole piece prepared by the method has higher energy density and good electrochemical performance. The capacity play is normal, the rate performance is obviously improved, the analysis lithium condition is obviously improved, and the cycling stability is also improved obviously.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion secondary batteries, and in particular relates to a preparation method of pole pieces of lithium-ion secondary batteries. Background technique [0002] Lithium-ion secondary batteries have become one of the most widely used secondary batteries due to their advantages of high voltage, high energy density and long cycle life. However, with the miniaturization of portable electronic devices and the continuous development of long standby time, as well as the use of high-power and high-energy devices such as electric bicycles and electric vehicles, the energy density of lithium-ion secondary batteries as energy storage power sources has been proposed more and more. Come higher demands. [0003] In actual design, reducing the mass percentage of inactive materials by increasing the mass percentage of active materials or increasing the thickness of pole pieces is one of the effective ways to increase...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/139
CPCY02E60/122Y02E60/10
Inventor 郎野李伟
Owner NINGDE AMPEREX TECH
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