Thick electrode with good electrochemical performance and its preparation method

An electrochemical and electrode technology, applied in the field of thick electrodes and their preparation, can solve the problems of reducing the electrochemical performance of the outer layer of the pole piece, unable to retain the electrolyte, etc., to solve the problem of concentration polarization, good electrochemical performance, improve The effect of energy density

Active Publication Date: 2012-01-18
DONGGUAN AMPEREX TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the charge-discharge cycle of the battery, the transmission of lithium ions in the electrode pole piece is from the outside (away from the current collector) to the inside (close to the current collector). The structural design of non-uniform porosity with reduced fluid direction, after a period of charging and discharging cycles, the outer layer of the electrode with small porosity cannot retain sufficient electrolyte for the transmission of lithium ions, so it will reduce the outer layer of the electrode. Continuous performance of layer electrochemical performance

Method used

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  • Thick electrode with good electrochemical performance and its preparation method
  • Thick electrode with good electrochemical performance and its preparation method
  • Thick electrode with good electrochemical performance and its preparation method

Examples

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Embodiment 1

[0046] The production of the positive electrode sheet: the positive electrode active material lithium cobaltate (LiCoO 2 ), the conductive agent carbon black, the binder polyvinylidene fluoride (PVDF) and the solvent N-methylpyrrolidone (NMP) are uniformly mixed in a weight ratio of 92:3:5:80 to obtain the inner layer slurry to be coated ;The inner layer slurry is evenly coated on the aluminum foil current collector with a thickness of 14 microns, and then dried at 110°C, and the inner layer diaphragm with a coating thickness of about 150 microns is obtained after the first cold pressing treatment.

[0047] The positive electrode active material lithium cobaltate (LiCoO) coated with 0.6% aluminum oxide 2 ), carbon nanotubes, polyvinylidene fluoride (PVDF) and solvent N-methylpyrrolidone (NMP) in a weight ratio of 94:1.5:4.5:80 to uniformly mix the outer layer slurry to coat the baked The dried inner membrane is then dried at 110° C., and the outer membrane with a coating thic...

Embodiment 2

[0051] The production of the positive electrode sheet: the positive electrode active material lithium cobaltate (LiCoO 2 ), the conductive agent carbon black, the binder polyvinylidene fluoride (PVDF) and the solvent N-methylpyrrolidone (NMP) are uniformly mixed in a weight ratio of 92:3:5:80 to obtain the inner layer slurry to be coated ; The inner layer slurry is evenly coated on the aluminum foil current collector with a thickness of 14 microns, the thickness of the coating is about 150 microns, and then dried at 110° C. to obtain the inner membrane.

[0052] The positive electrode active material lithium cobaltate (LiCoO) coated with 0.6% aluminum oxide 2 ), carbon nanotubes, benzoic acid, polyvinylidene fluoride (PVDF) and solvent N-methylpyrrolidone (NMP) in a weight ratio of 92: 1.5: 1.5: 5: 80 to uniformly mix the outer layer slurry Coating on the baked inner membrane, the thickness of the coating is about 150 microns, and then drying at 110°C to obtain the outer memb...

Embodiment 3

[0056] The production of the positive electrode sheet: the positive electrode active material lithium cobaltate (LiCoO 2 ), the conductive agent carbon black, the binder polyvinylidene fluoride (PVDF) and the solvent N-methylpyrrolidone (NMP) are uniformly mixed in a weight ratio of 90:3:7:80 to obtain the inner layer slurry to be coated ; The inner layer slurry is evenly coated on an aluminum foil current collector with a thickness of 14 microns, the coating thickness is about 250 microns, and then dried at 110° C. to obtain an inner membrane.

[0057] The positive electrode active material lithium cobaltate (LiCoO) coated with 0.6% aluminum oxide 2 ), carbon nanotubes, benzoic acid, polyvinylidene fluoride (PVDF) and solvent N-methylpyrrolidone (NMP) in a weight ratio of 90:1.5:1.5:7:80 to uniformly mix the outer layer slurry Coating on the dried inner membrane, the thickness of the coating is about 300 microns, and then drying at 110°C to obtain the outer membrane, thus ma...

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Abstract

The invention discloses a thick electrode with a good electrochemical performance. The electrode comprises a current collector and an electrode membrane containing active substances and conductive substances. With a thickness greater than 300 micrometers, the electrode membrane includes an internal membrane layer close to the current collector and an external membrane layer far from the current collector. The conductivity of the electrode membrane decreases from the internal membrane layer to the external membrane layer, while the porosity of the electrode membrane increases from the internal membrane layer to the external membrane layer. The internal membrane layer has great conductivity which can make electrons at the current collector entering or separating from the internal membrane layer rapidly. With great porosity, the external membrane layer can adsorb a lot of electrolyte, thus solving the problem of poor electrolyte wettability of thick electrodes. In addition, the invention also discloses a preparation method of a thick electrode with a good electrochemical performance.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, more specifically, the invention relates to a thick electrode with good electrochemical performance and a preparation method thereof. Background technique [0002] At present, with the continuous advancement of science and technology, the application field of lithium-ion batteries has also expanded rapidly, and has expanded from the initial portable mobile devices such as mobile phones and cameras to large electric devices with high power and high energy requirements such as electric bicycles and electric vehicles. Therefore, the requirements for the design and manufacturing process of lithium-ion batteries are getting higher and higher. [0003] Large-scale equipment such as electric bicycles and electric vehicles require lithium-ion batteries to have high energy density. From a design point of view, the ideal way to increase the energy density is to increase the content of active materials...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/139
CPCY02E60/122Y02E60/10
Inventor 赵丰刚陈治汪颖许瑞郎野王娜
Owner DONGGUAN AMPEREX TECH
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