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A pole piece with ultra-low resistance, its preparation method and lithium ion battery containing the pole piece

A technology for lithium-ion batteries and pole pieces, which is applied in the direction of electrode carriers/collectors, battery electrodes, secondary batteries, etc., can solve the problems of battery performance degradation, adhesive force degradation, peeling, etc., and achieve high performance stability and low The effect of internal resistance

Active Publication Date: 2021-03-02
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many kinds of organic binders, such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC), and their specific properties are also different, but their common characteristics are poor electrical properties. Conductor, the addition of this poorly conductive binder will significantly increase the resistance of the pole piece, so the amount of binder used in the pole piece is strictly limited
In addition, the adhesive force of these organic binders will decrease due to long-term use or temperature rise, which will gradually loosen or even peel off the electrode layer, resulting in a decrease in battery performance.

Method used

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  • A pole piece with ultra-low resistance, its preparation method and lithium ion battery containing the pole piece

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Mix and disperse epoxy resin, carbon black, and lithium iron phosphate in N-methylpyrrolidone at a weight ratio of 2:3:95 to make a positive electrode slurry, and coat the electrode layer on both sides of the aluminum foil by a coating machine. The dry thickness on one side is 100 μm. The coated pole piece was compacted on a roller press, and then heat-treated at 400° C. for 20 h under an argon atmosphere to obtain a positive pole piece. The square resistance of the pole piece was tested by the four-probe method.

Embodiment 2

[0028] Mix and disperse phenolic resin, carbon black, and lithium iron phosphate in N-methylpyrrolidone at a weight ratio of 10:2:88 to make a positive electrode slurry, and coat the electrode layer on both sides of the aluminum foil by a coating machine, and the electrode layer is single The surface dry thickness is 100 μm. The coated pole piece was compacted on a roller press, and then heat-treated at 500° C. for 10 h under a nitrogen atmosphere to obtain a positive pole piece. The square resistance of the pole piece was tested by the four-probe method.

Embodiment 3

[0030] Mix and disperse pitch particles, carbon nanotubes and lithium iron phosphate in N-methylpyrrolidone at a weight ratio of 80:10:10 to make positive electrode slurry, and coat the electrode layer on both sides of the aluminum foil by a coating machine. The dry thickness on one side is 100 μm. The coated pole piece was heat-treated at 500° C. for 10 h in a vacuum atmosphere to obtain a positive pole piece. The square resistance of the pole piece was tested by the four-probe method.

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Abstract

The invention provides a lithium-ion battery pole piece with ultra-low resistance, a preparation method thereof, and a lithium-ion battery containing the pole piece. The battery pole piece with ultra-low resistance of the present invention uses pyrolytic carbon as the binding phase instead of conventional organic binders to connect active material particles, conductive agents and current collectors into an integrated pole piece, thereby obtaining ultra-low resistance. The preparation method is to mix the organic matter with the active material particles and the conductive agent, coat it on the current collector, and then conduct heat treatment at a temperature above 400°C in an oxygen-isolated atmosphere. The battery pole piece of the invention has reasonable structure design, simple and easy-to-control preparation process, excellent product performance, and is convenient for large-scale preparation of ultra-low resistance lithium-ion batteries.

Description

technical field [0001] The invention relates to a lithium-ion battery pole piece with ultra-low resistance, a preparation method thereof, and a lithium-ion battery containing the pole piece, belonging to the field of new energy and energy storage devices. Background technique [0002] The pole piece of the existing lithium-ion battery is composed of: the electrode active material with the ability to store lithium and the conductive agent that improves the conductivity are bonded to the current collector (usually copper foil or aluminum foil) through an organic binder. The binding agent plays the role of connecting the active material particles and the conductive agent particles to form an electrode layer, and connecting the electrode layer to the current collector. There are many kinds of organic binders, such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC), and their specific properties are also different, but their...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/66H01M4/58H01M4/1397H01M10/0525
CPCH01M4/1397H01M4/5825H01M4/667H01M10/0525Y02E60/10
Inventor 李荐黄祖琼王利华周宏明
Owner CENT SOUTH UNIV